EPA-600/2 75 003
MARCH 1975
Environmental Protection Technology Series
Federal Aircraft Noise Research,
Development, and Demonstration
Programs: FY 73 - FY 75
Office of Research and Development
U.S. Environmental Protection Agency
Washington, DC 20460
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RESEARCH REPORTING SERIES
Research reports of the Office of Research and Development,
Environmental Protection Agency, have been grouped into five
series. These five broad categories were established to
facilitate further development and application of environmental
technology. Elimination of traditional grouping wan consciously
planned to foster technology transfer and a maximum interface
in related fields. The five series are:
1. Environmental Health Effects Research
2. Environmental Protection Technology
3. Ecological Research
4. Environmental Monitoring
5. Socioeconomic Environmental Studies
This report has been assigned to tho ENVIRONMENTAL PROTECTION
TECHNOLOGY series. This series describes research performed
to develop and demonstrate instrumentation, equipment and
methodology to repair oc prevent environmental degradation
from point and non-point sources of pollution. This work
provides the new or improved technology required for the
control and treatment of pollution sources to meet environmental
quality standards.
This report has been reviewed by the Office of Research and
Development. Approval docs not signify that the contents
necessarily reflect the views and policies of the Environmental
Protection Agency, nor does mention of trade names or commercial
products constitute endorsement or recommendation for use.
Document is available to the public through the National Technical
Information Service, Springfield, Virginia 22151.
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Report 600/2-75-003
March 1975
FEDERAL AIRCRAFT NOISE
RESEARCH, DEVELOPMENT AND DEMONSTRATION
PROGRAMS: FY73 - FY75
Prepared by
The Interagency Aircraft Noise Research Panel
Task No. 21AXV
Program Element No. 1GB090
Project Office:
Noise Technology Staff
Office of Research & Development
U.S. Environmental Protection Agency
Washington, D.C. 20460
Prepared for
U.S. Environmental Protection Agency
Office of Research and Development
Washington, D.C. 20460
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ABSTRACT
The Interagency Aircraft Noise Research Panel was established by
the Environmental Protection Agency to aid EPA in fulfilling its re-
sponsibility for coordinating the Federal noise research activities.
This report is the first prepared by the Panel and provides an inven-
tory of current and planned Federal aircraft noise RD&D programs. The
Federal agencies which sponsor aircraft noise RD&D are the National
Aeronautic and Space Administration, the Department of Transportation,
the Department of Defense, the National Science Foundation, and the
EPA. The report is organized by technical areas with each agency's
programs presented under the appropriate technical area. Emphasis is
on fiscal years 1974 and 1975, but summary information on fiscal years
1973 and 1976 is also included. The Appendix contains detailed pro-
grammatic information as furnished by the Federal agencies on their
aircraft related RD&D activities.
iii
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TABLE OF CONTENTS
Page
1. INTRODUCTION 1
2. SUMMARY 3
3. SUBSONIC CONVENTIONAL TAKEOFF AND LANDING AIRCRAFT NOISE
PROGRAMS 9
4. BASIC RESEARCH AND TECHNOLOGY 13
5. POWERED LIFT AIRCRAFT NOISE TECHNOLOGY 19
6. ROTORCRAFT/VTOL NOISE TECHNOLOGY 23
7. SUPERSONIC CRUISE AIRCRAFT NOISE TECHNOLOGY 27
8. AIR TRANSPORTATION SYSTEMS STUDIES 31
9. GENERAL AVIATION NOISE RELATED TECHNOLOGY 35
10. REFERENCES 37
11. GLOSSARY OF ACRONYMS AND TERMS 39
12. APPENDIX - COMPENDIUM OF AIRCRAFT NOISE RELATED FEDERAL
PROGRAM PLANNING AND PROJECT DESCRIPTIONS 41
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LIST OF TABLES
2.1 Summary of Funding by Technical Area, Agency, and
Fiscal Year 4
2.2 Funding Summary for Subsonic CTOL Aircraft Noise Programs 5
2.3 Funding Summary for Basic Research and Technology Programs 5
2.4 Funding Summary for Powered Lift Aircraft Noise Technology 6
2.5 Funding Summary for Rotorcraft/VTOL Noise Technology 6
2.6 Funding Summary for Supersonic Cruise Aircraft Noise
Technology 7
3.1 NASA Noise Relevant Subsonic CTOL Aircraft Programs Noise
Relevant Program Costs 11
3.2 DOT/FAA Aircraft Noise AbatementSource Noise Reduction
Program Schedule (July 1, 1974) 12
4.1 NASA Noise Relevant Basic Research and Technology Noise
Relevant Program Costs 14
4.2 DOT/ONA Jet Noise Research Program 15
4.3 DOD Aircraft Noise Research Programs 18
5.1 NASA Noise Relevant Powered Lift Aircraft Technology
Programs Noise Relevant Program Costs 21
5.2 DOT/FAA Program Schedule Relevant to Powered Lift Air-
craft Noise Technology .22
6.1 NASA Noise Relevant Rotorcraft/VTOL Technology Programs
Noise Relevant Program Costs 25
7.1 NASA Noise Relevant Supersonic Cruise Aircraft Technology
Studies Noise Relevant Program Costs 28
7.2 DOT/FAA Source Sonic Boom Reduction, Operational Sonic
Boom Reduction Program Schedule (July 1, 1974) 30
vii
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LIST OF TABLES (continued)
8.1 NASA Noise Relevant Air Transportation Systems Studies
Noise Relevant Program Costs 33
8.2 EPA Aircraft Noise Systems Studies 34
9.1 NASA Noise Relevant General Aviation Aircraft Technology
Studies Noise Relevant Program Costs 36
viii
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1. INTRODUCTION
Section 4(C)(1) of the Noise Control Act of 1972 requires that
the Administrator of the Environmental Protection Agency coordinate
research programs of all Federal agencies. To aid the Administrator
in fulfilling this requirement, each agency must furnish to the Admin-
istrator such information as may be necessary to determine the nature,
scope, and results of the noise research programs of the agency. A
further requirement under Section 4(C)(3) is that the Administrator
publish a report from time to time to describe the status and progress
of Federal noise research programs and assess the contributions of
these programs to the Federal Government's overall efforts to control
noise.
To fulfill these provisions relating to aircraft noise research,
the EPA Office of Research and Development has organized an interagency
Aircraft Noise Research Panel. The responsibilities of the Panel in-
clude collecting programmatic information to develop an inventory of
Federal aircraft noise research and providing the expertise to make
an assessment of the adequacy of current programs to meet public health
and welfare goals relative to noise as specified by the Environmental
Protection Agency.
This is an interim report prepared under the cognizance of the
Aircraft Noise Research Panel as a first step in carrying out a plan
of action to assess aircraft noise related research, development and
demonstration (RD&D). The purpose of this report is to provide an
inventory of current and planned Federal aircraft noise RD&D programs,
and it represents the initial data base upon which the assessment will -
be made.
The report is organized by technical areas with each agency's
programs presented under the appropriate technical areas. Sections
1 through 9 provide an overview of objectives and funding for the
programs with emphasis on fiscal years (FY) 1974 and 1975. Summary
information on past funding for FY 1973 and planned obligations for
FY 1976 are also included. The Appendix contains detailed program-
matic information as furnished by the Federal agencies on their air-
craft noise related RD&D activities.
In the future, the Aircraft Noise Research Panel will carry out
the assessment phase of its responsibilities. To accomplish this
objective the Panel will:
1. Review the public health and welfare goals and objectives
relating to noise as developed by the Environmental Protec-
tion Agency;
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2. Establish appropriate Working Groups for specific technology
areas calling on the expertise available in Federal agencies
engaged in aircraft KD&D;
3. Identify specific requirements and need for detailed review
of Federal programs and analyze industry independent research
and development programs;
4. Coordinate Working Group activity and integrate findings of
the Working Groups relative to the adequacy of ongoing pro-
grams ;
5. Prepare a summary report that specifies the extent to which
current programs can meet the EPA public health and welfare
goals and objectives relative to noise and make recommenda-
tions on what should be done where the assessment indicates
that the schedule for meeting EPA goals and objectives can-
not be accomplished with current programs and plans.
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2. SUMMARY
The overall Federal activity in aircraft noise related research,
development and demonstration is summarized in Table 2.1, Table 2.1
shows the technical areas under investigation, the Federal agencies
with a significant program in each technical area and noise relevant
funding data for fiscal years 1973 through 1976. Funding data for
FY 1975 and FY 1976 are based on planned obligations.
It is noted from Table 2.1, that a significant amount of total
funding in FY 73 and FY 74 is associated with studies to reduce noise
of the current commercial fleet and is shown under subsonic conven-
tional takeoff and landing (CTOL) aircraft. Several study categories
related to noise of existing commercial aircraft are presented in
Table 2.2. The programs included in Table 2.2 involve operational
procedures for reduced noise exposure, technology development, and
demonstration to support decision making on the question of retrofit
of the existing commercial fleet and demonstration of advanced tech-
nology for nacelle design for application on modern wide-body trans-
ports. The status of some of the NASA and DOT/FAA activities iden-
tified in Table 2.2 were reviewed before the United States House of
Representatives Subcommittee on Aeronautics and Space Technology
in July 1974. The testimonies presented by NASA and DOT/FAA are in-
cluded in the Appendix of this report.
The ongoing programs to provide the research and technology base
necessary to design more quiet future generation, aircraft are summa-
rized in Table 2.3, page 5. Major areas of investigation are propul- .
sion system noise, materials, and nonpropulsive noise (airframe aero-
dynamic noise). A parallel decrease of propulsion system noise and
airframe noise is required to reduce approach noise of future aircraft
below FAR-36 minus 10 dB (see References 1 and 2, Section 10, for
detailed technical treatment of this point).
Programs to develop acceptably quiet commercial powered lift air-
craft to reduce congestion around major cities are summarized in Table
2.4. The technical objectives of these programs are given in Section
4, and detailed program planning is included in the Appendix. A
technical treatment of progress and prospects for powered lift aircraft
is provided in Reference 1, Section 10.
Table 2.5 summarizes program activity and funding for rotorcraft
and vertical takeoff and landing (VTOL) aircraft. These programs,
conducted by NASA, have civil and military applications. Noise rele-
vant technology development for application to supersonic cruise air-
craft is given in Table 2,6. These programs are basic and deal with
propulsion, aerodynamics and sonic boom.
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Table 2.1 SUMMARY OF FUNDING BY TECHNICAL AREA,
AGENCY, AND FISCAL YEAR
Funding in Thousands of Dollars
Technical Area
Basic Research and
Technology
Powered Lift Aircraft
Noise Technology
Rotorcraft/VTOL
Noise Technology
Air Transportation
Systems Studies
Supersonic Cruise Air-
craft Noise Technology
Subsonic Conventional
Takeoff and Landing
Aircraft Noise Programs
General Aviation Noise
Technology
Agency
NASA
DOT
DOD
Total
NASA
DO:
Total
NASA
DOD
Total
NASA
EPA
Total
NASA
DOT
Total
NASA
DOT
Total
NASA
FY 73
10,765(1)
2,830
1.784
15,379
4,406(1)
241
4,647
- (2)
267
267
255
- (4)
255
2,070(1-3)
316
2,386
27,704(1>6>
8,176
35,880
80(1)
FY 74
14,149
785
1,752
16,686
2,082
-
2,082
1,774
534
2,303
428
404
832
2,086
299
2,385
25,204
1,899
27,103
355
FY 75
13,840
1,282
793
15,915
2,977
-
2,977
2,284
675
2,959
248
248
1,490
100
1,590
6,017
900
6,917
448
FY 76
14,269
1,760
1,112
17,141
2,952
-
2,952
2,294
275
2,569
227
227
1,730
-
. 1,730
2,703
-
2,703
996
GRAND TOTAL
58.894
51.751
31.054
28.318
1. The NASA funding data included in this table for FY 73 are based on information
supplied to EPA by NASA in December, 1973. The content of the breakouts by research
area is not exactly the same as those for other fiscal years listed.
2. FY 73 funding included in Powered Lift Aircraft Noise Technology.
3. Some program activity inc. uded here thiit is listed under Basic Research and Tech-
nology for other fiscal years.
4. EPA FY 74 total includes some funds committed in FY 73.
5. See Section 11 for an explanation of acronyms, abbreviations, and definition of
noise relevant program costs.
6. For FY 73, $1090K of the funds listed were for subsonic engine and nacelle tech-
nology-Quiet Engine I.
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Table 2.2. FUNDING SUMMARY FOR SUBSONIC CTOL AIRCRAFT. NOISE PROGRAMS
Area
Noise Reduction Flight
Procedures Experiments
Terminal Configured Vehicle
Agency
NASA
NASA
Funding^ Distribution, Thousands
FY 74
3,600
271
FY 75
1,380
1,563
of Dollars
FY 76
_
1,613
Operating Systems Experiments
REFAN Program
Advanced Acoustic Composite
Nacelle Program
Source Noise Reduction
NASA
NASA
DOT/FAA
20,803
530
1,899
2,514
560
900
-
1,090
-
Table 2.3. FUNDING
Area
Propulsion Noise Reduction
GRAND TOTAL
27,103
SUMMARY FOR BASIC RESEARCH
Agency
NASA
DOT/ONA*
DOD
Total
Propulsion System Integration NASA
Nonpropulsive Noise
Human Response**
Materials and Sound Propa-
gation
DOD
Total
NASA
DOT/ONA
DOD
Total
GRAND TOTAL
6,917
2,703
AND TECHNOLOGY PROGRAMS
Funding^ Distribution, Thousands
FY 74
13,348
750
563
14,661
801
272
1,073
(1,154)
35
917
952
16,686
FY 75
12,194
1,232
271
13,697
1,646
75
1,721
(1,200)
50
447
497
15,915
of Dollars
FY 76
12,490
1,710
400
14,600
1,779
125
1^904
(1,458)
50
587
637
17,141
*DOT/FAA funding included in Table 2.2
**NASA allocations for Human Response studies are shown here for informational purposes only.
These resources are accounted for in the Federal noise effects research fiscal data .(Reference 3)
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Table 2.4. FUNDING SUMMARY FOR POWERED LIFT AIRCRAFT NOISE TECHNOLOGY
CTi
Area
Advanced Powered Lift Aircraft
Augmentor Wing Flight Experiment
Quiet Clean Short Haul
Experimental Engine (QCSEE)
Quiet Propulsive Lift Research
Aircraft
STOL Operating Systems
Experiments
GRAND
Agency
NASA
NASA
NASA
NASA
NASA
TOTAL
Funding Distribution,
Thousands
FY 74 FY 75
310 1
160
167
1,310
135
2,082 2
Table 2.5. FUNDING SUMMARY FOR ROTORCRAFT/VTOL NOISE
Area
Advanced Rotorcraft
Aerodynamic Technology
Advanced VTOL Aircraft Aero-
dynamic Technology
Tilt Rotox Research Aircraft
Program
Rotor Systems Research Aircraft
Rotor Systems for RSRA
VTOL Operating Systems
Experiments
Agency
NASA
DOD
Total
NASA
NASA
NASA
DOD
Total
NASA
NASA
Funding Distribution^
,480
-
840
-
657
,977
of Dollars
FY 76
1,470
-
825
.-
657
2,952
TECHNOLOGY
Thousands
FY 74 FY 75
920 1
34
954 1
(Total) 80
(Total) 274
500
500
1,000
(Total)
(Total)
,045
-
,045
150
_
675
675
465
624
of Dollars
FY 76
1,040
-
1,040
160
_
275
275
470
624
GRAND TOTAL
2,308
2,959
2,569
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Table 2.6. FUNDING SUMMARY FOR SUPERSONIC CRUISE AIRCRAFT NOISE TECHNOLOGY
Area
Propulsion Technology
Aerodynamic Performance
Source and Operational Sonic
Boom Reduction
Agency
NASA
NASA
DOT/FAA
Funding Distribution
FY 74
1,422
664
299
, Thousands
FY 75
1,233
257
100
of Dollars
FY 76
1,360
370
-
GRAND TOTAL 2,385 1,590 1,730
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A more detailed treatment of the Federal noise relevant RD&D sum-
marized in Tables 2.1 to 2,6 is given in subsequent sections of this
report. Program planning and several status reviews (July 1973) on the
potential of reducing noise of the current commercial fleet are includ-
ed in the Appendix.
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3. SUBSONIC CONVENTIONAL TAKEOFF AND
LANDING AIRCRAFT NOISE PROGRAMS
Noise relevant programs relating to subsonic conventional take-
off and landing aircraft technology are listed in this section. These
programs have application to the existing commercial fleet and the
newer wide-body aircraft designs.
National Aeronautics and Space Administration
The status of NASA programs noted here was reviewed in testimony
before the United States House of Representatives Subcommittee on
Aeronautics and Space Technology in July 1974. The brief technical
descriptions of programs that follow can be understood in proper con-
text by referring directly to that testimony which is included in
the Appendix.
Noise reduction flight procedures experiments. To reduce
90 EPNdB approach noise footprint by at least 60% through
scheduled airlines' demonstrations of avionic systems for
noise abatement flight procedures.
Terminal configured vehicles operating systems experiments.
To identify and provide proven technology and operating
techniques for advanced CTOL and RTOL aircraft for reducing
approach and landing accidents, reducing weather minima,
increasing air traffic controller productivity and airport
and airway capacity, saving fuel by more efficient terminal
area operations, and reducing noise by operational proce-
dures during the 1976-2000 time period.
REFAN Program. To provide the technology to obtain a 75
percent reduction in the noise footprint area of JT8D-
Powered Aircraft (727, 737, and DC-9) which account for
over 60 percent of domestic fleet operations.
Advanced acoustic composite nacelle flight program. To
demonstrate on a modern wide-body transport in airline
operation the application of advanced interwoven acoustic
absorbent and composite structural materials to an engine
which will:
Reduce the noise footprint area of future production
wide-body transport aircraft by 30 percent with no
increase in aircraft weight or fuel consumption or
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alternately reduce aircraft weight and fuel consumption
with no increase in noise.
Together with advanced technology engines, reduce the 90 EPNdB
noise footprint area of advanced technology transport aircraft
to 5.2 square kilometers (2 square miles) with no increase in
aircraft weight or fuel consumption resulting from the na-
celle or alternately reduce aircraft weight and fuel consump-
tion together with some noise reduction.
Table 3.1 is a summary of noise relevant funding for the subsonic
conventional takeoff and landing aircraft noise program. Listed in
the table are a descriptive title of the program and gross RD&D and
manpower costs for FY's 1974 through 1976. The Appendix contains more
detailed program descriptions on all programs.
Department of Transportation-Federal Aviation Administration
DOT/FAA has several subsonic conventional takeoff and landing
aircraft noise programs under the overall program of source noise re-
duction. The objective of this program is to develop a noise source
prediction capability for all categories of aircraft. Projects under
the source noise prediction and reduction program and their objectives
are:
Core engine noise control. To provide theoretical and exper-
imental data to assist the designers in developing future
aircraft capable of conforming to lower noise levels than are
now required by FAR Part 36. This program would more prop-
erly be listed in Section 4 but is presented here since it
cannot be easily separated from the schedule and cost data
of other programs presented in this section.
Prediction of aircraft configuration effects. To study the
feasibility of use of aircraft configuration and engine place-
ment to reduce noise propagation to the ground plus develop-
ment of prediction procedures for configurations of practical
interest.
General aviation aircraft. To survey and define the noise
characteristics of all general aviation aircraft plus develop-
ment of suitable noise prediction capabilities.
Retrofit feasibility. To provide test data to assist in de-
termining whether certain classes of turbofan propelled air-
planes in the current fleet can be modified for meaningful
noise reduction in a feasible manner. The results of this
10
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Table 3.1. HAS; NOISE RELEVANT SUBSONIC CTOt AIRCRAFT PROGRAKS
NOISE RELEVANT PROGRAM COSTS
(Thousands of Dollars)
Descriptive Title
Noise Reduction Flight
Procedure Experiments
Terminal Configured Vehi-
cle System Experiments
REFAN Program
Advanced Acoustic Com-
posite Nacelle Program
TOTALS
FY 1.974
Cross Manpower Cross
RAD Costs Total RAD
3140
214
460
57
FY 1975
Manpower
Costs Total
FY 1976
Gross
R&D
Manpower
Coats Total
3600 1050
271 1430
130
113
1380
1563
1500
113
1613
19545
500
23399
1258
30
1S05
20803
530
25204
1000
500
4000
1514
60
2017
2514
560
6017
1000
2500
90
203
1090
2703
programmatic activity were reviewed before the United States
House of Representatives Subcommittee on Aeronautics and Space
Technology July 1974. That testimony is included in the Ap-
pendix.
Table 3.2 gives the schedule and funding for source noise reduc-
tion programs. The Appendix contains additional information on the
direction and status of these projects.
11
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Table 3.2. DOT/FAA AIRCRAFT NOISE ABATEMENT--SOURCE NOISE REDUCTION
Program Schedule (July 1, 1974)
Program Element/Subprogram CY
202-551
Source Noise Reduction
CTOL Aircraft
Source Noise Prediction
and Reduction
Core Engine Noise Control
Prediction of Aircraft
Configuration Effects
General Aviation Aircraft
Retrofit Feasibility
Commercial Jet Aircraft
Executive Jet Aircraft
FY| 73* L 74 * | 75 * 76 * 77
1972 1973 1974 1975 1976 1977
Continuing Effort
Award Gas Generator Award Report
w Report,, w ^
1 1
Award leport
1 1
Award
r |
727 '07 DC-9
1
Award
1 V 1
*Funding allocations (1001 noise relevant) are: FY 73-$8,176,000; FY 74-$l,899,000;
FY 75-$900,000; FY 76-No Data.
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4. BASIC RESEARCH AND TECHNOLOGY
Strict guidelines have not been employed in listing various agency
programs under the category of Basic Research and Technology. In general,
the results of programs presented in this section have a broader range
of application and are more fundamentally oriented than programs listed
in other sections.
National Aeronautics and Space Administration
Descriptive titles and specific objectives for each noise relevant
study being conducted by NASA are:
Propulsion noise reduction. To provide data and a
technology base for reducing aircraft propulsion
noise with minimum weight, performance, and economic
penalties.
Nonpropulsive noise. To understand and minimize, by
aerodynamic means, the undesirable effects of airframe
noise.
Human Response. To define and quantify those properties
of aircraft noise exposure that are responsible for
causing negative individual and community response to
air transportation systems.
Funding data for programs included with each study category are
shown in Table 4.1. The Appendix contains objective documentation for
the programs listed in Table 4.1.
Department of Transportation-Office of Noise Abatement
Studies relevant to aircraft noise reduction are sponsored by the
Office of Noise Abatement within the Office for Systems Development and
Technology and by the Federal Aviation Administration within DOT. While
some FAA studies may be appropriately considered here, a consistent
treatment of cost data requires their listing elsewhere. For this reason,
only the 'DOT/ONA programs are considered under Basic Research and
Technology.
DOT/ONA sponsors one program in aircraft noise reduction. This
program is directed toward understanding, modeling, and suppressing jet
noise. The studies included in the program are conducted under contract
and through interagency agreement. The title, contracting organization,
and funding data for each project are shown in Table 4.2. Detailed
descriptions of each project are included in the Appendix.
13
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Table 4.1 NASA NOISE RELEVANT BASIC RESEARCH AND TECHNOLOGY
NOISE RELEVANT PROGRAM COSTS
(Thousands of Dollars)
FY 1974
FY 1975
FY 1976
Gross Manpower Gross Manpower Gross Manpower
Descriptive Title R&D Costs Total R&D Costs Total R&D Costs Total
Propulsion Noise
Reduction
Basic Noise Research 2108
Noise Technology
and Prediction 3073
Nonpropulsive Noise
Airframe Aerodynamic
Noise 408
1886 3994
6281 9354
1300
4450
2161
4283
3461 1500 2200
8733 4330 4460
3700
8790
393 801
900
746
1646 1000 779
1779
Human Response
Acceptance of Aircraft
Operations
(796) (358) (1154) (842) (358) (1200) (1100) (358) (1458)
5589 8560 14,149 6650 7190 13,840 6830 7439 14,269
GRAND TOTALS
Vrhe fiscal data for NASA's Human Response studies are accounted for in
the Federal noise effects research resource allocations and shown here
for informational purposes only. (Reference 3)
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Table 4.2 DOT/ONA JET NOISE RESEARCH PROGRAM
Oi
Project Title
Modeling Jet Noise
Noise Reduction from
Supersonic Jet Flow
with Co-Axial Jets
Jet Combustion Noise
Effects of Nonlinearity
on Jet Noise Propulsion
On the Origin of Combus-
tion Generated Noise
High Velocity Jet Noise
Source Location and
Reduction Program
Interagency Symposium;
Transportation Noise
Acoustic Material Research
Suppression of Multiple
Pure Tones
GRAND TOTALS
Contracting Contract Program
Organization Number Manager
Planned Obligations
(Thousands of.Dollars)
FY73 FY74 FY75 FY76
use
DOT-OS-0000-2 G.Banerian 75 75 50 50
Syracuse DOT-OS-20094 G.Banerian 75 75 75 75
Cal. Tech. DOT-OS-20197 G.Banerian 147 50 50 50
UT DOT-OS-4117 G.Banerian 0 20 0 0
NCSU DOT-OS-40056 G.Banerian 0 25 30 30
GE DOT-OS-30034 G.Banerian 2500 500 1000 1500
G.Banerian 0555
MIT DOT-OS-30011 G. Banerian 33 35 50 50
VPI DOT-OS-50047 G. Banerian 0 0 22 0
2830 785 1282 1760
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Department of Defense
DOD has projects in several research categories. General areas of
research are summarized below:
Propulsion Noise Reduction
e Jet Exhaust noise programs. To develop the technology
base necessary to significantly reduce aircraft
propulsion system noise with minimum associated perfor-
mance and weight penalties.
Rotating machinery noise programs. To define the
fundamental physical mechanisms by which combustion
affects the general sound field surrounding an engine,
to aid in providing design guidelines and techniques
for modifying the combustion process for minimum
noise levels, developing effective combustor noise
suppression devices, and establishing criteria for
engine design, development and control.
Duct acoustics and suppression programs. To develop
computer routines to predict the effect of duct
linings on noise propagation and to optimize a given
duct configuration for maximum noise reduction.
Propeller noise programs. To formulate and computer
program a comprehensive unified aerodynamic acoustic
source theory and to reduce propeller noise through
utilizing unique propeller designs based on noise
source theory analysis.
Structural Response Programs
Objectives of projects in this area are:
To investigate the effects of high intensity sound
on aircraft structures.
To study the effects of high lift device noise on
aircraft structures and the community environment.
To dampen noise in helicopters.
Sound Propagation Programs
Objectives of projects in this area are:
To analyze the generation and propagation of multiple turbojet
exhaust noise sources.
16
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To analyze the aerodynamic generation of noise,
propagation, and detectability of unpowered
aircraft.
Airflow Surface Interaction Programs
Objectives of the projects in this area are:
To investigate the reduction of noise by liquid
vaporization.
To investigate the dynamics of vortices and
shock waves in nonuniform media.
To investigate the areas of boundary layer flows.
Table 4.3 is a compilation of the DOD funding distribution on
Basic Research and Technology Programs. The Appendix contains a
brief description of each project.
17
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Table 4.3 DOD AIRCRAFT NOISE RESEARCH PROGRAMS1
Funding Level, Thousands of Dollars
Descriptive Title'
Propulsion Noise Reduction
Jet Exhausts
Rotating Machinery
Duct Acoustics and
Suppression
Propeller Noise
Structural Response Programs
Sound Propagation Programs
Airflow Surface Interaction
Agency
Air Force
Air Force
Army,
Navy
Air Force
Army
Air Force
Air Force
Air Force
Navy
Air Force
FY 73
447
297
10
26
178
580
246
-
FY 74
204
288
45
26
335
582
272
-
FY 753
122
75
65
9
302
145
75
FY 76
250
85
65
-
340
247
125
GRAND TOTALS
1,784
1,752
793
1,112
programs are 100% noise relevant.
2See Appendix for detailed project listing and description of projects
3Data on FY 75 and FY 76 are incomplete.
-------
5. POWERED LIFT AIRCRAFT NOISE TECHNOLOGY
Noise technology activities associated with power-generated lift
aircraft technology programs are considered in this section. Coverage
is restricted to STOL/RTOL aircraft for short-haul applications to meet
civil and military transport needs.
National Aeronautics and Space Administration
The major study categories related to powered lift aircraft with
noise relevancy being conducted by NASA are as follows;
Advanced powered lift aircraft aerodynamic technology.
To develop the aerodynamics and systems technology
needed to attain the integrated aerodynamic perfor-
mance, noise, stability, control, and handling
qualities characteristics required for viable powered
lift in civil and military aircraft designs.
C-8 augmentor wing flight experiment. To validate in
flight the augmentor wing powered lift concept devel-
oped in laboratory programs as a practical means for
providing STOL capability. To assess in flight the
handling qualities of this type of aircraft. To
provide a versatile representative powered lift air-
craft for assessment of navigation and control systems
requirements for safe terminal area operation.
Quiet, clean, short-haul experimental engine (QCSEE).
To design, build, and test experimental engines to
consolidate and demonstrate the technology needed
for very quiet, clean, and efficient propulsion
system for economically viable and environmentally
acceptable powered lift short-haul aircraft.
Quiet propulsive lift technology (Advanced medium
STOL (AMST) prototype aircraft). To obtain, through
participation in the Air Force AMST prototype programs,
propulsive lift flight research data on a straight-
wing externally blown flap configuration at lift
coefficients up to about 3.5.
STOL operating systems experiments. To establish a
technology base upon which operational STOL short-
haul systems can be based with confidence in the
1978-2000 time period. To demonstrate operating
systems technology, operating procedures, and guidance,
navigation, and control concepts for high-density
terminal area operation.
19
-------
Funding data for these programs are given in Table 5.1. Specific
technology goals, milestones, and technical and management approach are
given in the Appendix for each NASA study category presented in Table 5.1.
Department of Transportation-Federal Aviation Administration
The FAA participates with NASA in program activity related to powered
lift aircraft technology as noted previously in Table 5.1. Additionally,
the FAA conducts a program on V/STOL aircraft. A descriptive title and
broad statement of objectives for this program follows:
V/STOL aircraft - noise source reduction. To identify,
evaluate, and control component noise sources inherent
in V/STOL systems including studies of jet propulsion
and rotary systems and noise prediction techniques.
Table 5.2 gives the FAA identification number for the V/STOL aircraft
noise program, the major subprogram titles, the program schedule, and funding
data as of July 1, 1974. For FY 1974 and FY 1975 contract funding is included
with other programs and is therefore listed elsewhere in this report. A more
detailed description of this program is given in the Appendix.
20
-------
Table 5.1 NASA NOISE RELEVANT POWERED LIFT AIRCRAFT TECHNOLOGY
NOISE RELEVANT PROGRAM COSTS
(Thousands of Dollars)
FY 1974 FY 1975 FY 1976
Gross Manpower Gross Manpower Gross Manpower
Descriptive Title R&D Costs Total R&D Costs Total R&D Costs Total
Advanced Powered Lift 140 170 310 900 580 1480 900 570 1470
Aircraft Aerodynamic
Technology
C-8 Augmentor Wing 100 60 160 - -
Flight Experiment
Quiet, Clean Short- 137 30 167 800 40 840 800 25 825
Haul Experimental
Engine (QCSEE)
Quiet Propulsive Lift 1100 210 1310 - -
Technology
STOL Operating Systems 107 28 135 600 57 657 600 57 657
Experiments
TOTALS 1584 498 2082 2300 677 2977 2300 652 2952
-------
Table 5.2. DOT/FAA PROGRAM SCHEDULE RELEVANT TO POWERED
LIFT AIRCRAFT NOISE TECHNOLOGY
ho
Program Element/Subprogram Program Element
Number
V/STOL Aircraft
202-590
Source Noise Prediction and Reduction
Jet Propulsors
Rotary Propulsors
TY I 73 * | 74"
75
76
CY| 1972 | 1975 [ 1974 | 1975 1976
Continuing Effort
Award Report
Award Report
*Funding for FY 1973: $241,000 - 1007. noise relevant.
-------
6. ROTORCRAFT/VTOL NOISE TECHNOLOGY
This section considers noise relevant studies associated with
technology programs for aircraft with rotor induced lift and advanced
VTOL lift concepts. It deals primarily with VTOL aircraft for civil
and military applications.
National Aeronautics and Space Administration
The noise relevant rotorcraft technology programs and statements
of objectives are as follows:
Advanced rotorcraft aerodynamic technology. To determine and
improve the performance, dynamic loads, noise, control, sta-
bility, vibration, and handling qualities characteristics of
helicopter rotors and rotorcraft configurations in order to
permit the development of rotorcraft having substantially greater
mission and cost effectiveness than current (1973) operational
vehicles in military and civil usage.
Advanced VTQL aircraft aerodynamic technology. To provide the
technology required to enable the development of viable mili-
tary and civil aircraft having effective VTOL capability to-
gether with speed, range, operating cost, and mission/operational
capabilities, approaching those of 1973 operational medium range
military and civil CTOL aircraft. This requires the development
of a thorough knowledge and understanding of the aerodynamic
performance, noise, control, stability characteristics, and
piloting qualities peculiar to VTOL system concepts.
Tilt rotor research aircraft. To demonstrate advanced rotor-
craft technology for military and civil VTOL vehicles having
twice the cruise speed of the helicopter while retaining its
efficient hover capability.
Rotor systems research aircraft. To provide a unique flight
test capability in 1976 for advanced rotor research on a wide
variety of promising new rotor concepts. To expedite improved
rotorcraft research through the use of a specially designed
flight test vehicle.
Rotor systems for rotor systems research aircraft (RSRA). To
select, acquire, and evaluate on the Rotor Systems Research
Aircraft (RSRA), under joint development by the Army and NASA,
three practical advanced rotor systems concepts. To demonstrate
through tests of these concepts in the real flight environment
23
-------
the integrated performance, dynamics, and acoustics technology
improvements achievable.
VTOL operating systems experiments. To establish a technology
base leading to improved operational capability, improved VTOL
operating efficiency, and decreased environmental impact. To
support military technology requirements for assuring VTOL
operational capability with a wide variety of landing sites
and under reduced visibility conditions.
Table 6,1 provides a funding summary of the Rotorcraft/VTOL air-
craft technology studies with noise relevance being conducted by NASA.
Specific technology goals, milestones, and technical approach are in-
cluded in the Appendix for each of the studies listed in Table 6.1.
Department of Defense
DOD Rotorcraft/VTOL noise technology programs and their objec-
tives are:
Tip vortex effects on rotary-wing aerodynamics. To signifi-
cantly reduce undesirable rotor blade noise signatures and
alleviate the blade-tip vortex interaction problem.
Glare and noise reduction of helicopter rotor blades. To
develop various materials and compositions capable of reducing
the glint, glare, and noise from helicopter rotor blades with-
out impairing lift or increasing weight or drag.
Unsteady aerodynamics of blade-vortex interaction. To study
the unsteady aerodynamic mechanisms responsible for helicopter
noise.
Investigation of noise generation on a hovering rotor. To
define the noise field generated by a rotor,
Analytical studies of helicopter rotor broadband noise genera-
tion. To establish a closed form solution for predicting the
broadband noise intensity radiated by helicopter rotors.
Studies in low speed flight. To investigate problems asso-
ciated with low speed flight of helicopters.
Systems studies of helicopter noise requirements. To establish
a new methodology for systems analysis which includes noise
criteria and to develop a new wind tunnel facility for making
24
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Table 6.1 NASA NOISE RELEVANT ROTORCRAFT/VTOL TECHNOLOGY PROGRAMS
NOISE RELEVANT PROGRAM COSTS
(Thousands of Dollars)
FY 1974
FY 1975
FY 1976
to
Gross Manpower
Descriptive Title R&D Costs
Advanced Rotorcraft
Aerodynamics Technology
Helicopter Aerodynamics
Tilt Rotor Aerodynamics
Civil Helicopter Tech.
Rotor Systems Technology
Rotor Acoustics and
Aeroelasticity
Advanced VTOL Aircraft
Aerodynamic Technology
Tilt Rotor Research
Aircraft Program
Rotor Systems Research
Aircraft
Rotor Systems for RSRA
VTOL Operation Systems
Experiments
265 180
20 10
220 50
140 35
-
50 30
250 24
500
_ _
.
Total
445
30
270
175
-
80
274
500
«.
_
Gross
R&D
205
70
280
-
195
100
..
^
400
400
Manpower
Costs
95
40
55
-
105
50
_
65
224
Total
300
110
335
-
300
150
.
465
624
Gross
R&D
200
70
280
-
200
100
^
400
400
Manpower
Costs
100
40
50
-
100
60
mt
70
224
Total
300
110
330
-
300
160
^
470
624
TOTALS
1445
329
1774
1650
634 2284 1650
644 2294
-------
useful noise measurements on V/STOL aircraft types.
Tilt rotor research aircraft. To supplement funding of pro-
gram conducted by NASA in cooperation with the Air Force.
Rotor systems research aircraft. To supplement funding of
program being conducted by NASA in cooperation with the Air
Force.
Funding levels for DOD Rotorcraft Noise Technology Programs are:
$267,000 for FY 1973, $534,000 for FY 1974, $675,000 for FY 1975, and
$275,000 in FY 1976. The Appendix contains brief descriptions of DOD
programs listed here.
26
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7. SUPERSONIC CRUISE AIRCRAFT NOISE TECHNOLOGY
Programs with noise relevancy that are directed toward providing
a technology base for future generation aircraft with supersonic cruise
capability are presented in this section. It is noted that many of the
programs listed under Section 4, Basic Research and Technology, have
direct application to supersonic cruise aircraft.
National Aeronautics and Space Administration
NASA has two programs dedicated to supersonic cruise aircraft
(SCAR) technology with noise relevancy:
SCAR propulsion technology. To establish an expanded super-
sonic propulsion technology base in parallel with the expansion
of other supersonic disciplinary technologies which will permit
the reduction of noise in takeoff and landing to levels less
than the Douglas DC-10 and Lockheed 1011; reduce fuel consump-
tion rates which can make supersonic cruise aircraft signifi-
cantly more efficient; and nitric oxide emissions at high alti-
tudes that are greatly reduced from levels possible with today's
technology.
SCAR aerodynamic performance technology. To establish an ex-
panded supersonic aerodynamics technology base in parallel
with the expansion of other supersonic disciplinary technolo-
gies which will permit improvements in L/D, reductions in sonic
boom, and the translation of technical advances into integrated
aircraft systems.
Table 7.1 is a funding summary for the supersonic cruise aircraft
noise technology programs. Each program and noise related project is
listed. More detailed program descriptions are given in the Appendix.
Department of Transportation-Federal Aviation Administration
The FAA is conducting two programs relative to supersonic cruise
aircraft noise technology. They are:
Source sonic boom reduction. This is an effort to develop a
definition of the air and ground system requirements for suc-
cessful threshold mach number operation.
27
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Table 7.1 NASA NOISE RELEVANT SUPERSONIC CRUISE AIRCRAFT TECHNOLOGY STUDIES
NOISE RELEVANT PROGRAM COSTS
(Thousands of Dollars)
FY 1974
FY 1975
Ni
00
Gross Manpower Gross Manpower
Descriptive Titles R&D Costs Total R&D Costs Total
Propulsion Technology
Propulsion Noise 618
Reduction Technology
Experimental Engine 410
Cycle Studies
Low Noise Engine 46
Unique Components
Aerodynamic Performance
Technology
Integration Studies 137
Theory
Sonic Boom 137
TOTALS 1348
330 948 843 390 1233
18 428 -
46
90 227 -
30 30 -
270 407 167 90 257
738 2086 1010 480 1490
FY 1976
Gross Manpower
R&D Costs Total
90 370
-------
Operational sonic boom reduction. This effort is to provide
prototype, digital, lightweight, inexpensive sonic boom recor-
ders and to obtain real time atmospheric data for use in long-
range threshold mach number operational feasibility studies.
Table 7.2 shows the program schedule for the source sonic boom
reduction and operational sonic boom reduction programs. The schedule
has been updated to indicate milestones and targets as of July 1, 1974.
29
-------
Table 7.2. DOT/FAA SOURCE SONIC BOOM REDUCTION, OPERATIONAL SONIC BOOM
REDUCTION PROGRAM SCHEDULE (JULY 1, 1974)
u>
o
Program Element/Subprogram !CY
202-554
Source Sonic Boom Reduction
Supersonic boomless flight
research
Ft. Worth F-lll/F-8 opera-
tional research boomless
flight; other operational
programs.
Operational Sonic Boom
Reduction
Sonic boom signature proto-
type digital recording sys-
tem. Operation, maintenance
and data collection during
operational programs
FT
T3 *
1972
1973
75 *
T5~*~
1974
1975
1976
Phase I Phase II Phase III
RFP
t
Final
ard Report
Phase IV
Trans. System
Flight RFP Award
WWW
Phase I Phase II Phase III
Award Report Report Report
1977
Final
Report
Field 2 Prototypes
Award Delivery Test recorders
Final
Report
*Funding allocations (lOOt noise relevant) are: FY 73 - $316,000; FY 74 - $299,000;
FY 75 - $100,000; FY 76 - no funds'scheduled
-------
8. AIR TRANSPORTATION SYSTEMS STUDIES
Studies considered in this section are concerned with the inter-
relation of future air transportation needs, technology requirements,
socioeconomic and environmental factors, and aircraft/airport interface,
National Aeronautics and Space Administration
Systems studies being conducted by NASA that have significant
noise relevance are:
Quiet propulsive lift transport technology systems
studies. To identify, through aircraft definition
and transportation systems studies, the problem areas,
configurations and technology for emphasis in future
quiet propulsive lift technology programs, including
flight research.
Short-haul transportation systems analysis. To devel-
op a sound technological base for future decisions re-
lating to the design, development, and operation of
short-haul transportation systems; to examine the re-
lationships between short-haul technology and short-
haul economics, markets, and implementation; to iden-
tify potential viable short-haul airplane concepts and
their design and performance criteria for practical
short-haul transportation systems including considera-
tion of market, economic, and environmental factors.
Analysis of future civil air transportation systems
and concepts. To identify promising aeronautical
systems, determine optimum characteristics, and define
technology requirements and costs associated with such
systems. Studies include general aviation aircraft,
CTOL, STOL, and VTOL transports, advanced subsonic
transonic transport aircraft, and advanced supersonic
transports.
High transonic speed transport (HiTST) system study.
To provide detailed configuration definitions of a high
transonic speed transport concept with design studies
to include fatigue and flutter characteristics of com-
posite structures, low speed stability, and control of
yawed wing for emergency maneuvers, and new engine
technology application for reduced noise.
-------
* Subsonic/Transonic C/RTOL transport technology systems
and design studies. To make technology advances avail-
able for superior subsonic C/RTOL transport aircraft to
satisfy anticipated requirements in the 1980's; to de-
termine the feasibility of utilizing aircraft fuels
other than JP fuel for subsonic cargo and passenger air-
craft; to investigate new approaches to providing more
economical subsonic transport of liquid and solid cargo
in anticipation of the need for increased air transport
of cargo.
Subsonic/Sonic CTOL transport technology propulsion
studies. To study the application of advanced tech-
nology to the improvement of future commercial trans-
port aircraft including consideration of economic
factors involving parameters such as aircraft drag,
propulsion efficiency, cost, and propulsion system
noise and exhaust emissions.
Table 8.1 provides a funding summary of the air transportation
systems studies being conducted by NASA and discussed in the preceding
paragraphs. Additional detail on objectives, approach, and milestones
for each program is provided in the Appendix.
Environmental Protection Agency (EPA)
EPA sponsors studies to support its activities related to aircraft
regulations. The FY 1973 and FY 1974 projects, which are most relevant,
for inclusion here, are listed in Table 8.2.
32
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Table 8.1 HASA NOISE RELEVANT AIR TRANSPORTATION SYSTEMS
STUDIES NOISE RELEVANT PROGRAM COSTS
(Thousands of Dollars)
Descriptive Title
Short-Haul Transporta-
tion Systems Analysis
Analysis of Future Civil
Transportation Systems
and Concepts
High Transonic Speed
Transport System Study
Subsonic/Transonic C/RTOL
Transport Tech. Systems
and Design Studies
Subsonic/Sonic Transpor-
tation Technology
Propulsion Studies
FY 1974
Cross Manpower
R&D Costs Total
150
61 27
15
80
28
30
FY 1975
Gross Manpower
R&D Costs Total
FY 1976
Gross Manpower
R&D Costs Total
30 180
88 120 48 168 120 27
16
110
34
80
80
80
147
80
TOTALS
334 94 428 200 48 248 200 27
227
-------
Table 8.2 EPA AIRCRAFT NOISE SYSTEMS STUDIES
Project Title
Contracting
Organization
Contract
Number
Project
Manager
Key Dates
Start End
Amount,
thousands of
dollars
Aircraft/Airport Opera- Bolt, Beranek 68-01-1835
tions Noise Study & Newman
Installation, Refinement Bolt, Beranek
and Training in Utiliza- & Newman
tion of USAF-NEF
Aircraft/Airport Study:
Legal Analysis
George Washing- 68-01-1834
ton University
Development of Implemen- E. H. Robbins
tation Tools for Admin-
istration of Airport
Noise Regulation
68-01-2266
J. Schettino 4/73
68-01-2265 D. Gray
E. Cuadra
E. Cuadra
2/74 2/75
4/73 9/73
2/74 4/75
182
79
110
33
TOTAL for FY 73 & 74
404
-------
GENERAL AVIATION NOISE RELATED TECHNOLOGY
Many of the noise related programs presented in other sections of
this report have application to general aviation aircraft. In particu-
lar, the NASA programs, Basic Noise Research and Noise Technology, in-
volve studies of propeller noise reduction. DOT/FAA also conducts
studies relevant to general aviation aircraft; however, these are in-
cluded in Section 8 since it is difficult to isolate this activity from
cost and program scheduling data.
National Aeronautics and Space Administration
The title and statement of objective of the NASA programs dedicated
specifically to general aviation aircraft are:
General aviation aerodynamic technology. To develop
and demonstrate advanced technology for general avia-
tion use that will permit the design of future U.S.
aircraft that will be safer, more productive, and
clearly superior to foreign competition.
Quiet, clean general aviation turbofan (QCGAT). To
identify, extend, and demonstrate the technology
applicable to small general aviation turbofans to
achieve future environmental requirements with
economic viability.
Table 9.1 shows the major study categories and the funding in the
general aviation aerodynamic technology program. The Appendix contains
an expanded discussion of this program.
35
-------
Table 9.1 NASA NOISE RELEVANT GENERAL AVIATION AIRCRAFT TECHNOLOGY STUDIES
NOISE RELEVANT PROGRAM COSTS
(Thousands of Dollars)
FY 1974
FY 1975
FY 1976
Descriptive Title
Gross Manpower
R&D Costs Total
Gross Manpower
R&D Costs Total
Gross Manpower
R&D Costa Total
CT-.
Aerodynamics and Crash-
worthiness
General Aviation
Technology
Quiet, Clean General
Aviation Turbofan (QCGAT)
65
200
30
95
60 260 250 198 448 370
90 460
400 136 536
TOTALS
265
90 355 250 198
448
770 226 996
-------
10. REFERENCES
1. Civil Aviation Research and Development Policy Study. Report DOT
TST-10-4, NASA SP-265; Supporting Papers DOT TST-10-5, NASA
SP-265. March 1971.
2. Aircraft Noise Reduction Technology. A report by the National
Aeronautics and Space Administration to the Environmental Protec-
tion Agency for the Aircraft/Airport Noise Study, March 30, 1973.
This report gives a technical treatment of progress, status, and
planned research by NASA relative to aircraft noise. (Unpublished)
3. Federal Noise Effects Research: FY73-FY75. A report prepared by
the Interagency Noise Effects Research Panel, for the U.S. En-
vironmental Protection Agency: EPA Report #600/2-75-001.
March 1975. (31 pages.)
37
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11* GLOSSARY OF ACRONYMS AND TERMS
AMST - Advanced Medium STOL Transport.
ARC - Ames Research Center.
C/RTOL - Conventional/Reduced Take Off and Landing.
CTOL - Conventional Take Off and Landing.
DOD - Department of Defense.
DOT - Department of Transportation.
EPNdB - Effective Perceived Noise Level in dB.
FAA - Federal Aviation Administration.
FAR-36 - Federal Aviation Rule, Part 36.
FRC - Flight Research Center.
FY - Fiscal Year.
HiTST - High Transonic Speed Transport.
JP-Fuel - Jet Petroleum Fuel
JPL - Jet Propulsion Laboratory.
VD - Lift-Drag Ratio.
LaRC - Langley Research Center.
LeRC - Lewis Research Center.
NASA - National Aeronautics and Space Administration.
ONA - Office of Noise Abatement.
QCSEE - Quiet Clean Short-Haul Experimental Engine.
QSRA - Quiet Short-Haul Research Aircraft.
RD&D - Research, Development, and Demonstration.
- Rotor Systems Research Aircraft.
39
-------
RTOL - Reduced Take Off and Landing.
RTOP - Research and Technology Operating Plan.
SAM - Sound Absorbing Material.
SCAR - Supersonic Cruise Aircraft.
STOL - Short Take Off and Landing.
USAF - United States Air Force.
V/STOL - Vertical/Short Take Off and Landing.
VTOL - Vertical Take Off and Landing.
40
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12. APPENDIX - COMPENDIUM OF AIRCRAFT NOISE RELATED
FEDERAL PROGRAM PLANNING AND PROJECT DESCRIPTIONS
This document contains detailed program planning information of
the Federal Agencies' Aircraft noise research, development, and demon-
stration activities. The information and data are presented basically
in the form submitted to EPA through the agencies' representatives on
the Aircraft Noise Research Panel. This document can be viewed as the
status of programs and plans as of July, 1974.
TABLE OF CONTENTS
Page
I NASA PROGRAM DESCRIPTIONS 43
1. NASA Subsonic Conventional Takeoff and Landing 43
Aircraft Noise Programs
a. NASA July 25, 1974 Testimony on Aircraft Noise 59
Programs before the House Subcommittee on
Aeronautics and Space Technology
2. NASA Basic Research and Technology Programs 87
3, NASA Powered Lift Aircraft Noise Technology 101
Programs
4. NASA Rotorcraft/VTOL Noise Technology Program 119
5. NASA Supersonic Cruise Aircraft Noise Technology 137
Programs
6. NASA Air Transportation System Studies 145
7. NASA General Aviation Noise Technology Programs 151
IX DOT AIRCRAFT NOISE PROGRAMS 159
1. DOT/FAA Aircraft Noise Programs 159
2. DOT/FAA July 25, 1974 Testimony on Aircraft Noise 173
Programs before the House Subcommittee on
Aeronautics and Space Technology
41
-------
Page
3. DOT/ONA AIRCRAFT NOISE PROGRAMS 185
III DOD AIRCRAFT NOISE PROGRAMS 195
IV NSF PROGRAMS 215
42
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I. NASA PROGRAM DESCRIPTIONS
1. NASA SUBSONIC CONVENTIONAL TAKEOFF
AND LANDING AIRCRAFT NOISE PROGRAMS
-------
NOISE REDUCTION FLIGHT PROCEDURES EXPERIMENTS
(768-80) Ongoing
Program Objective
Reduce 90 EPNdB approach noise footprint by at least 60% through
scheduled airlines' demonstrations of avionic systems for noise abate-
ment flight procedures.
DOT considers the two-segment approach procedure to be the most promis-,
ing operational noise abatement technique now under evaluation and an
important part of the overall noise reduction program.
Program Targets
NASA will demonstrate operational avionics and flight procedures that
can be used to reduce airport community noise through the following
steps:
Complete six month trunk airline demonstration of two-
segment approach with a B-727 in scheduled air-line
service - November 1973.
Complete six-month trunk airline demonstration of two-
segment approach with a DC-8 in scheduled air-line
service - October 1974.
Demonstrate potential of other operating techniques for
reducing aerodynamic and propulsion noise on approach
and landing - January 1976.
.Program Approach
The NASA program for noise reduction has placed primary emphasis on
the two-segment approach, which offers significant benefits.
For reduced noise impact
At a relatively small cost
With the potential of early implementation
Program activities are closely coordinated with the FAA and the Joint
ODT/NASA Office of Noise Abatement. They are being managed by the
Ames Research Center with participation by the airline industry, airline
45
-------
pilots, avionic manufacturers, and air traffic controllers at several
airports.
Two avionic system concepts are being evaluated. The main differences
between the concepts are the techniques that will be used to establish
the upper segment glide slope guidance. One concept, for aircraft not
equipped with area navigation, will cost approximately $37,000 installed.
The other concept, based on modification of area navigation equipment
already installed in the aircraft, will cost approximately $9,000.
The program involves analysis, simulation, flight test, and in-service
evaluation in two aircraft types: the B-727, and DC-8. The applica-
bility of the procedures over the remainder of the fleet of current jet
transports will be evaluated by analysis and simulations.
Over 1200 two-segment approaches have been made in the B-727 by over
120 pilots from 13 airlines at five airports. Of these, approximately
600 approaches by 58 line pilots have been made in passenger carrying
service.
Preliminary results:
Have obtained line pilot acceptance in one airline in
one type aircraft:
- Procedure has been demonstrated to be safe
- Procedure can be interfaced with today's ATC
environment
- Avionics system provides good navigation accuracy
on upper segment
- No significant increase in pilot workload
- Passenger comfort not affected
Two-segment approach provides approximately 607, reduction
in the 90 EPNdB approach noise footprint area for the B-727.
Research continuing into FY 75 includes the DC-8 in-service evaluation,
investigations of the effects of operating procedures on aerodynamic
and propulsive noise, and development of procedures that achieve maximum
noise reduction.
46
-------
Investigations have been conducted on a preliminary evaluation of the
wake vortex behind and below jet aircraft flying a two-segment approach
in order to determine if any additional hazard exists to following
aircraft.
Need and Relevancy
The NASA in cooperation with the FAA and the airlines has been involved
in developing and evaluating the operational procedures for noise re-
duction for a number of years. The landing approach studies indicated
potentially large noise reductions could be achieved by three noise
reduction approach techniques: the two-segment approach, the energy
management of decelerating approach, and the curved ground tracts
approach. Although it was found that these flight procedures are well
within the performance capability of current day jet transports, they
impose new requirements on the pilot duties and workload, on the pilot
displays, on the guidance and navigation system, on the aircraft con-
trol system, on the ATC flow of aircraft to high density runways, and
possible different wake turbulence effects. NASA decided in 1971 to
embark on a substantial effort to develop suitable avionics for noise
abatement procedures and to obtain sufficient experience so that they
are accepted for routine operations.
In July 1973, the Administrator of the Environmental Protection Agency
submitted a "Report to Congress on Aircraft/Airport Noise" in compli-
ance with the Noise Control Act of 1972. The purpose of the report is
to recommend ways in which the public health and welfare can be pro-
tected from excessive aircraft noise.
The following excerpts from this report reinforce the soundness of
NASA's decision relative to the need and relevancy of procedural
methods of aircraft noise reduction.
"Approximately 16 million persons are presently impacted by aviation
noise in the United States, and in spite of the introduction of quieter
new aircraft, the number will continue to be of major proportion until
the mid-19801s unless aggressive action is taken."
"Aircraft noise around airports is presently a principal constraint on
the future growth of the air transportation system."
"It is evident that there is a need to mobilize available resources
and technology, including those of providing newer and quieter air-
craft for the future, to deal with this problem in a coordinated time-
phased fashion."
47
-------
"If noise levels protective of the public health and welfare are to be
achieved around the Nation's airports in the near future, it will be
necessary to establish a Federal regulatory program which effectively
combines Federal controls on aircraft flight procedures, technology,
and noise control options available to airport operations and local
jurisdictions."
"From the foregoing, it can be seen that a number of noise abatement
flight procedures are available for implementation. Although by them-
selves, they cannot totally resolve the noise problem, they play an
important part in any comprehensive plan for noise abatement."
"The two-segment approach seems to hold the most promise (of several
different noise abatement approach procedures) for significant approach
relief."
"The main objections to two-segment approaches come from ALPA pilots
and some segments of the airline industry. They desire more testing
to be certain that safety will not be degraded by the higher descent
rates in the steep segment."
"EPA also concludes that two-segment approaches in IFR conditions are
technically feasible after installation of equipment currently avail-
able in prototype form. Such approaches are expected to be consistent
with the highest degree of safety upon completion and evaluation of the
current NASA test program and certification of the equipment."
The Noise Reduction Flight Procedures Experiments program is being
conducted by the NASA Office of Aeronautics and Space Technology to
be responsive to the national need to protect the public health and
welfare from aircraft noise.
TERMINAL CONFIGURED VEHICLE OPERATING
SYSTEMS EXPERIMENTS
(768-81) Ongoing
Program Objective
Identify and provide proven technology and operating techniques for
advanced CTOL and RTOL aircraft for reducing approach and landing
accidents, reducing weather minima, increasing air traffic controller
productivity and airport and airway capacity, saving fuel by more
efficient terminal area operations and reducing noise by operational
procedures during the 1976-2000 time period.
48
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An expression by the U.S. scheduled airlines through the Air Transport
Association on the desired direct thrust and content of the government's
aviation research and development efforts proposes a research, develop-
ment and applications engineering effort with three major work areas:
(1) solution of environmental problems; (2) air traffic control
process development and automation; and (3) aircraft and aviation
support systems improvement.
Program Targets
Major targets of this program include technology readiness in the late
1970's for:
Precision 4D flight path control by FY 1976 for
-improved accuracy of time of arrival at runway from
18 sec. to 5 sec.
-decreased spacing between parallel runways from
5000' to 3000'.
Steeper, curved, and decelerating landing approach - FY 1976.
Automatic landings in zero visibility - FY 1977.
Reduction of the impact of aircraft on the environment in
terms of aircraft noise and air pollutions FY 1976.
Landing rates in IFR which approach VRF rates - FY 1977.
Guidance and control capability for reduction in separation
between aircraft on landing approach from 3'and 5 miles to
1 and 2 miles - FY 1976.
Reduction in runway occupancy time from 55 sec. to 25 sec. -
FY 1977.
Avionics which interface with an advanced ATC system - FY 1978.
Greater safety - FY 1979.
Improved productivity by minimizing terminal area delays -
FY 1979.
49
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Program Approach
NASA and FAA are working together on this program, under a joint agree-
ment. The program is being managed by the Langley Research Center with
most of the flight experiments being conducted from Wallops Station.
In comparison with existing transport aircraft, a terminal configured
CTOL or RTOL aircraft should possess improvements in the following
areas: greater flight path flexibility; less pollution and noise;
improved acceleration, deceleration and lift capability; slower approach
and departure speeds; closer spacing without wake vortex hazard; more
accurate position, speed, and time control; less time on the runway,
less sensitivity to wind and weather; greater speed flexibility; safer
and better handling qualities; and reduced operating costs. To define
operational systems needed to produce the above improvements and to i-
dentify areas where technology emphasis should be placed, initial
attention in this program will be placed on analytical and experimental
studies. Later, simulation and flight evaluation will be the primary
tools in carrying out this program.
Flans for the program include research in conjunction with the Micro-
wave Landing System (MLS), now under development by the FAA, and
applying the greater accuracy and reliability .of digital computer tech-
niques to what are presently analog avionic systems. The MLS opens
up many opportunities for improvement in terminal area operations be-
cause the aircraft is freed from the standard one-course ILS approach.
Present aircraft instrument approach systems are not compatible with
MLS.
Flight experiments using advanced displays and performing precision
4D flight paths in a uniquely equipped B-737 aircraft will commence
late in FY 74. This research will continue heavily in FY 75 with
particular emphasis on improving adverse weather approach and landing
capability and safety through use of advanced displays and flexible,
automatic digital flight control and guidance systems. Available and
simulated advanced radio navigation aids will be utilized in flight
tests at Wallops Station. Flight simulation and analysis work will
lead and support flight tests. Feasibility demonstrations of advanced
equipment will be conducted at key points during the program.
Additional details are available in the Dec. 1, 1973 Program Plan
entitled, "Terminal Configured Vehicle Program."
Need and Relevancy
The following excerpts from The National Aviation System Policy
Summary, March 1973, which summarizes the FAA policies for the
50
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development of National Aviation System over the next ten years, clearly
state the need and relevancy of the objectives of this program:
"Thus, in consonance with National Transportation System
goals, the broad technical goals over the next ten years
can be summarized as follows:
Increase airport capacity
Increase airway capacity
Improve airway and airport safety
Minimize system operating costs
Minimize the impact of air transport on the
environment"
"The heart of the present air traffic problem lies at five
high-density terminal locations where congestion and costly
delays occur during adverse weather conditions and regularly
during the peak hours. Without system improvements, the
number of terminals experiencing such congestion is expected
to increase to 21 by 1981."
"Of all the major issues, this (the impact of environmental
concerns on aviation systems development) is potentially
the most important."
"Long range impacts of the energy problem on aviation are
still unclear, but it is quite probable it will act as a
constraint on expanded aviation service."
These positions are supported by many others; for example, the DOT Air
Traffic Control Advisory Committee and the Joint DOT/NASA Civil Avia-
tion Research and Development Policy Study.
Since the problems of safety, adverse weather, noise, congestion, and
fuel wastage manifest themselves most strongly in the high density
terminal area, this program is concentrating on the terminal area per-
formance characteristics of civil transport aircraft. Terminal area
air traffic control is not merely a combination of procedures and
hardware, but is a complex system involving people, aircraft, airports,
and airport neighbors. All elements of the system must be studied in
relation to each other and to their environment. The terminal area
performance characteristics of aircraft are vital parameters in air
traffic control.
If the long-term rate of growth of air transportation continues, airplane
characteristic improvements in combination with planned FAA improvement
in the ground system have the potential benefits of:
51
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Improvement of runway operations by 50 to 150%.
Saving an average of 750,000 gallons of fuel per
transport aircraft per year.
Reducing the cost of delays by %.
Saving passenger time valued at more than $100M per year.
Maximizing the effectiveness of the FAA Third and Fourth
Generation ATC Systems.
In order to provide the system operating technology in a timely and
effective manner, the TCV program will undertake to identify gaps in
the current technology of operating systems (such as displays and
aircraft performance requirements), and generate solutions which will
permit more efficient terminal area operations. It is important that
the TCV program be conducted in a time frame that is compatible with
planned improvements in the National Aviation System. In order that
the advanced airborne technology and systems required to interface
with the future ATC system being developed under FAA leadership are
available by the mid 1980's, they must be essentially demonstrated by
the late 1970's. The planned schedule of TCV activities is designed
to accomplish this purpose.
Safety of aircraft occupants is of fundamental importance in an air
transportation system. Through a 60-plus year history of operations,
accidents have provided clear and sometimes not so clear indications
of hazard areas. With the advent of more reliable jet engines, en
route accidents due to piston engine failure, severe weather encounters,
and in-flight fires as well as takeoff accidents due to engine failure
have declined as major accident prone areas, leaving the approach and
landing phase accounting for more than, half the fatal accidents. Off-
setting higher approach and landing impact speeds as a threat is the
improved structural intagrity of modern aircraft and improved passenger
seat retention. Control systems are more sophisticated, and navigation/
communication is exceedingly complex by 1950 standards, and decision
times for critical events in the landing process are short, all of
which add up to more stress on the pilot's judgement and decision
process. This makes an error in judgement potentially more dangerous
in terms of an accident. A systems analysis will provide a rational
assessment of potential accident-prone areas in flight operations.
TCV experiments will lead to reduced pilot workload by improved flight
deck design, better understanding of crew inter-personal relationships,
and automation. The aft flight deck of the 737 RSFS will provide a
unique facility for man-vehicle (human factors) technology development.
52
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The potential for significant reduction of approach and landing acci-
dents is considered high.
Not only is the activity conducted under this program relevant to our
efforts to ensure future airplanes capability to meet forecast traffic
demand without adverse effect on safety and airport communities, it is
aimed at putting the U.S. industry on a more competitive basis in world
markets of manufactured aircraft and aeronautical equipment.
REFAN PROGRAM
(739-14)
Program Objectives
Provide the technology to obtain a 75 percent reduction in the noise
footprint area of JT8D-powered aircraft (727, 737 and DC-9) which
account for over 60 percent of domestic fleet operations.
Furnish FAA and EPA with the technological and cost data essential
for consideration of rulemaking on engine retrofits.
Program Targets
Major targets of the Re fan Program are the following:
Complete the design of the refanned JT8D engine and
acoustic nacelles for 727 and DC-9 aircraft by
July 1973.
Verify the predicted aerodynamic and acoustic per-
formance of the refanned engine with ground engine
tests starting in February 1974.
Demonstrate the objective of 75 percent noise re-
duction with refanned engines and 727 aircraft
nacelles by ground tests starting in February 1975.
Demonstrate the objective of 75 percent noise reduction
by actual flight tests of a DC-9 aircraft starting
in February 1975.
Final economic and performance data to FAA by
June 1975.
53
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Program Approach
The approach to accomplishing this objective is to develop modifications
for the JT8D engine that can be produced as retrofit kits, develop
nacelles with acoustic treatment for the modified engines, and demon-
strate the noise levels and performance levels of a DC-9 airplane in
flight and a 727 propulsion system in ground tests.
The JT8D engine will be modified by replacing the existing two-stage
fan with a larger diameter single-stage fan employing wide spacing
between the vanes and rotor. The core engine pressure and flow will
be maintained by two booster stages in front of the compressor. The
fan turbine last stage rotor blade will be recambered. These changes
will increase the engine thrust and lower the core jet velocity for
the same cycle temperature. The lower jet velocity will result in
decreased jet mixing noise. Acoustic treatment will be added to fan
ducts and other acoustic devices will be considered to select an opti-
mum engine nacelle. In the interest of minimizing the cost of the
retrofit kit, no modifications will be made to any engine or airframe
components unless they are necessary for or contribute directly to the
substantial reduction of noise.
The program will be conducted through contracts with engine manufacturers,
aircraft manufacturers and airline operators. NASA inhouse effort will
be used both to manage the contracted efforts and to directly support
the program through studies and tests in NASA facilities. The first
phase of the program, completed in June 1973, established the refanned
engine and nacelle definition through analysis, design and limited
component testing. The second phase of the program, starting in July
1973, will culminate in ground tests of a 727 refanned propulsion
system and flight tests of a refanned DC-9 aircraft both in February
1975.
Need and Relevancy
The environmental impact of aircraft noise has been identified as a
critical factor limiting the growth of civil aviation. Vigorous public
reaction to the annoyance of aircraft operations has stifled civil air
system expansion, produced costly litigations, and resulted in operational
constraints which limit airport capacity and constrain aircraft pro-
curement. Demonstration of the refan feasibility provides a basis for
implementation of a refan retrofit which would reduce the noise foot-
print areas of the aircraft principally responsible for the high
community noise exposure by 75 percent. Further, these same modifica-
tions can be introduced in the production of new 727, 737, and DC-9
aircraft to result in quieter, new aircraft.
54
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OBJECTIVE NO. 766-78
ADVANCED ACOUSTIC COMPOSITE NACELLE
FLIGHT PROGRAM
Program Objective
Demonstrate on a modern wide-body transport in airline operation the
application of advanced interwoven acoustic absorbent and composite
structural materials to an engine nacelle which will:
Reduce the noise footprint area of future production
wide-body transport aircraft by 30 percent with no
increase in aircraft weight or fuel consumption or
alternatively reduce aircraft weight and fuel con-
sumption with no increase in noise.
Together with advanced technology engines, reduce
the 90 EPNdB noise footprint area of advanced
technology transport aircraft to 2 square miles with
no increase in aircraft weight or fuel consumption
resulting from the nacelle or alternatively reduce
aircraft weight and fuel consumption together with
some noise reduction.
.Program Targets
Recent materials and structures developments at Langley Research Center
on interwoven acoustic and composite materials offer the promise of
considerable reduction in operating costs. This program will exploit
these materials to:
Complete nacelle concept definition studies and verify
approach by January 1976.
Complete ground tests of an advanced technology
nacelle by early 1979.
Certify an advanced nacelle for airline service on
a wide-body transport by late 1979.
Demonstrate quiet nacelle performance in routine
airline service by 1982.
55
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Program Approach
Current technology using uniform wall treatment basically attenuates
the noise by the addition of acoustic absorbent materials to the
structural materials. A promising advanced technology noise suppres-
sion technique embodies a reflection principle in addition to atten-
uation to decrease noise transmission. This is accomplished by inter-
weaving acoustic absorbent and structural materials in a composite
material form and thereby forming an acoustic structural material.
By using multiple changes in wall acoustic treatment (segmented treat-
ment), lower net transmission is achieved. The performance of the
technique is striking - experimental results indicate about 15dB-
reduction in sound intensity compared to the same weight of metalic
material with added acoustic absorbent material. Utilization of the
acoustic composite material can further eliminate the inlet and duct
splitter rings which are currently used for noise suppression together
with their associated drag and fuel penalties.
The project will be based on FY 1974 studies to determine areas where
the application of composites with integrated acoustic material has
the greatest payoff with respect to weight, cost, and noise reduction.
The experimental program will be carried out in two phases. The first
phase consists of preliminary design of the engine nacelle to be tested.
The second phase will include the detail design, fabrication, and
testing of the nacelle. The program, will: (1) evaluate various
design concepts for the integration of composite materials with nacelle
acoustic treatment in terms of initial cost, noise reduction, weight
reduction, maintenance cost, and feasibility of application to existing
propulsion systems as well as to advanced installations; (2) develop
the technology associated with selected design concepts by means of
analyses, ground tests, and limited flight tests and perform all
analyses and tests required for commercial application; and (3) perform
ground tests, and flight tests in commercial service, of production
composite/acoustic nacelles to provide sufficient data on performance,
maintenance requirements, and maintenance costs to establish aircraft
and airline industry confidence in the application of composites to
engine nacelles.
Overall direction and coordination of the Program will be accomplished
by the OAST Transport Experimental Programs Office. The Langley Research
Center will be designated the lead Center for the project with support
by Lewis Research Center (propulsion activities). Program coordination
with DOT/FAA and with the airlines will be maintained and nacelle
certification will be under the direction of the FAA.
56
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Need and Relevancy
The ICAO World Traffic Forecast for air passenger demand indicates a
potential fivefold increase in air passengers by the mid 1980 period.
The number of air passenger seats required is approximately double the
number now available and on order. While the world fuel crisis may in
time result in modification of this projected growth in demand for air
transportation, the demand will certainly increase.
Market studies indicate that the bulk of this aircraft seat need will
be met by new wide-body type aircraft. Current and quieted narrow-
body aircraft will begin to be removed from service and the world air-
craft fleet will be made up largely of wide-body aircraft certified to
meet current noise regulations. Other types of aircraft such as
advanced technology transports, SSTs, and STOLs will contribute to air
lift capacity but to much less extent than current type wide-body
aircraft.
With such a fleet mix, community noise exposure is expected to again
increase during the 1980 period unless steps are taken now to provide
technology which will permit noise reduction without fuel consumption
penalties. The acoustic composite nacelle flight program is designed
to serve that need.
57
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a. NASA July 25, 1974 Testimony on Aircraft Noise
Programs before the House Subcommittee on
Aeronautics and Space Technology
59
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RESEARCH AND TECHNOLOGY FOR AIRCRAFT NOISE ABATEMENT
Statement of
J. Lloyd Jones
Deputy Associate Administrator for Aeronautics Technology
Office of Aeronautics and Space Technology
NATIONAL AERONAUTICS AND SPACE ADMINISTRATION
Before the
Subcommittee on Aeronautics and Space Technology
Committee on Science and Astronautics
House of Representatives
Mr. Chairman and members of the Subcommittee, I am pleased to have
this opportunity to bring the Subcommittee up to date on NASA's activity
related to the abatement of noise in the present and projected civil
air transportation fleet. As you know, we consider this an important
public matter and have given it considerable attention over an extended
period of time.
Today I will present a brief report on the progress of our work on the
refan retrofit option for civil aircraft certificated before Federal
Air Regulation Part 36 came into effect; and on the result of a meeting
on the Refan Program and related regulatory activity between Dr. Fletcher,
Administrator of NASA, Mr. Barnum, Under Secretary of DOT, and Mr.
Meister, Associate Administrator for Plans of FAA, attending for Mr.
Butterfield, Administrator of FAA, and attended by Mr. Strelow, Acting
Assistant Administrator for Air and Waste Management of EPA, attending
for Mr. Train, Administrator of EPA. I will also report on the progress
made on NASA's Two-Segment Approach Program, the coordination of air-
craft noise abatement programs, and NASA programs to provide data for
the reduction of noise in the near and long term.
Before discussing our programs, I would like to note that NASA is
concerned primarily with the technological aspects of aircraft noise
abatement. The treatment of all the complex factors (economic, social,
operational, and foreign) associated with regulation are the responsi-
bility of other branches of government, noteably DOT, FAA, EPA, and OMB.
61
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REFAN PROGRAM SCHEDULE
NJ
CY 1972
N
CY 1973
M
N
TERMINATE
JT3D
EFFORT
CONTRACT
AWARD
TERMINATE
WORK ON
737
CY 1974
M
M
START
ENGINE
/ TESTS
O
N
CY 1975
M
M
START 727
GROUND TESTS
START DC-9
FLIGHT
TESTS
FIGURE 1
FINAL
DATA
AVAILABLE
NASA RJ75-2326
7-18-74
-------
cr
130
120
PNL.dB
110
100
PEAK NOISE
(200 FT. SIDELINE)
MEASURED
BASE ENGINE
PREDICTED
REFANNED ENGINE\ /
REFANNED ENGINE
5000 10,000
STATIC THRUST, IBS.
15,000
NASA RJ75-2327
7-18-74
FIGURE 2
-------
Thus, the comments and data we present are not the sole basis for
decisions in the complex arena of noise abatement.
REFAN RETROFIT
As you know, NASA's part of the retrofit program is to develop and
assess the costs, effectiveness and technical feasibility associated
with refanning the JT8D-powered fleet. This program has been described
in detail to the Subcommittee in previous hearings. Figure 1 presents
the program schedule discussed with the Subcommittee at its hearings
in December of last year. All of the major milestones are being met.
The testing of refanned JT8D engines began in February as planned.
Our schedule still calls for initiation of detailed ground tests with
the 727 airplane refan hardware in January of 1975, about six months
from now. The DC-9 airplane refan flight tests will start a month
later, in February. An updated assessment of the Phase I acoustic and
performance design estimates for the 737 will be developed after the
727 and DC-9 tests. Final data will be available by June of 1975.
A substantial amount of data on the mechanical, aerodynamic and
acoustic performance of the refanned engines is now in hand. Two
engines have been tested extensively and testing of a third engine
begins this month.
Figure 2 shows a typical result from the refanned engine acoustic
tests, the peak noise level of the engine measured at the 200 foot
sideline. The top curve on the figure shows the data from a standard
JT8D-9 engine plotted against engine thrust. The lower solid and dashed
curves are the measured and predicted noise levels for the refanned
version of the engine. The measured and predicted noise levels are
in good agreement.
On the basis of the engine acoustic results, new baseline aircraft
data, and new analysis procedure, the airframe contractors have revised
their estimates of the noise levels of the DC-9 and 727 aircraft. These
estimates are still under study by the Refan Project Office at the
Lewis Research Center. Although the measured overall noise of the re-
fanned engine was as predicted, the distribution of the noise among the
various engine components was not. The distribution of component noise
affects the calculated aircraft noise. Further acoustic tests at Pratt
and Whitney and further analysis of the acoustic data are needed to
establish confidence in the aircraft noise predictions.
Specific fuel consumption (SFC) is also an important factor in assessing
retrofit options. In the March 1974 Authorization Hearings we noted
that preliminary measurements of SFC for retrofitted engines were higher
than estimates and corrective action was being considered. Minor engine
changes have been made and further tests have been conducted.
64
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The basic predicted improvement in SFC for the uninstalled refanned
engine has been achieved over most of the engine thrust range. At
maximum power the increment of improvement was less than predicted
by about two percent. Furthermore, the absolute level of SFC is higher
than predicted. This is thought to have resulted from the fact that
the SFC of the basic engine that was modified to provide the refan
test engine was higher than that of a new engine. Refanning, there-
fore, resulted in largely achieving the predicted incremental reduction
in SFC but not the absolute level expected. We do not know whether the
same improvement in SFC will be realized for a new engine conversion
to a refanned engine. A new engine, refanned, is being tested this
month and we will soon have the answer to this question.
It should be noted that the tests to date were conducted at sea level
static conditions. The translation of these test data to altitude
cruise conditions is uncertain. The SFC could be high by as much as
the 2 percent experienced at the maximum power conditions. Better
SFC data for altitude cruise will be available some time after August
as a result of wind tunnel flight simulation tests to be conducted at
the Lewis Research Center.
Assuming we achieve our predicted values of SFC at all conditions,
the estimated changes in block fuel due to refanning the 727 and DC-9
aircraft shown in Figure 3 should be realized. For some combinations
of altitude, speed, and distance, fuel is increased as much'as 3 per-
cent and for others it is decreased as much as 1 percent. As you see,
the impact of refanning on fuel usage is- estimated to be small and a
function of specific operating conditions. A refined analysis of
specific airline operations would be required to substantiate gain or
loss for a specific operator.
As we have discussed with you before, the refan technology is a higher
cost technology than sound absorption material alone. The investment
cost for a retrofit of the JT3D- and JT8D-powered fleets with SAM is
estimated to be $667 million, in the 23 airport study of the Joint
DOT/NASA Office of Noise Abatement, whereas a retrofit of the JT3D-
powered aircraft with SAM and the JT8D-powered aircraft with refan is
estimated to be $2.82 billion, or more than four times as much as a
complete SAM retrofit. These numbers are based on assumptions of in-
flation rate and starting schedule for the SAM and refan retrofits
that are necessarily subject to uncertainty. In 1973 dollars, the
cost of a SAM JT3D and refan JT8D retrofit is $1.95 billion.
In addition to the initial investment cost there are other costs
associated with a fleet retrofit that would increase the cost of the
SAM JT3D/Refan JT8D retrofit program. The current estimate in the 23
airport analysis would indicate a total cost of about $5 billion.
These additional costs include consideration of changes in direct
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BLOCK FUEL CHANGES FOR REFANNED AIRCRAFT
-
-
BLOCK
FUEL,
PERCENT
CHANGE
(55-60 PERCENT LOAD FACTOR)
+3 i
4-2
H
-1
-2
15
ALTITUDE, 1000 FT.
14
35
30
200 400 600 800
RANGE, NAUTICAL MILES
727-200
DC-9-32
1000
NASA RJ75-2330
-I _\ O _-» A.
-------
operating cost (DOC) over the projected life of the aircraft, "lost
productivity" resulting from the retrofitted aircraft being unable to
perform maximum range missions because of increased weight, and the
aircraft being out of service during the retrofit installation.
There are sufficient uncertainties in evaluating these additional
factors, excluding the assumed inflation rate and retrofit schedule,
that the $5 billion cost could be over-estimated. These complex
factors are currently being discussed with DOT to develop a realistic
accounting procedure.
We have provided data to DOT, FAA, and EPA on all aspects of the Refan
Program: acoustics, performance, and cost. As the program moves into
the final stages we will continue to provide data needed to these
agencies for their deliberations regarding retrofit.
REFAN PROGRAM/REGULATORY ACTIVITY REVIEW
At our March 6, 1974 hearings before this Subcommittee, we advised
you that the Under Secretary of DOT, and the Administrators of FAA and
NASA were planning a series of meetings to review the progress of the
Refan Program and the plans for related regulatory activity. A meeting
of this group was held this past July 22. At this meeting, the Refan
Program progress was reviewed as well as the results of the Joint
DOT/NASA Office of Noise Abatement study of the effects of various
retrofit and operational techniques for noise reduction at 23 airports.
In addition, the position of DOT/FAA on regulatory action for retrofit
was reviewed.
At this July 22 meeting, it was concluded by DOT/FAA that there was
nothing new to warrant a change in the DOT/FAA position on the retro-
fit NPRM. It was concluded by NASA that the Refan Program should
continue exactly as planned because of the technological advances
provided by the program, the possible use of refanned engines in
derivative aircraft, and the need for keeping the technological option
for lower noise levels in the future.
THE TWO-SEGMENT APPROACH PROGRAM
I will now move on to discuss our two-segment approach activity. We
.have described this program, supported by the FAA, in past testimony.
As you know, the objective of the program is to provide a significant
near-term reduction in the aircraft landing approach noise through the
provision of operational avionics and flight procedures that can be
used safely by airlines in both visual and instrument flight.
67
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I will review for you briefly the program approach, the results of
the 727 in-service flight program, and update you on the in-flight
evaluation with the DC-8 aircraft.
The Two-Segment Approach Program, managed by our Ames Research Center,
is closely coordinated with DOT, FAA, and EPA. Program guidance has
been provided by a Research and Technology Advisory Ad Hoc Panel on
Noise Abatement Flight Procedures. Its members came from DOT, FAA,
aircraft and avionics manufacturers, airlines, and the airline pilots'
association.
Figure 4 shows one version of the two-segment guidance equipment re-
quired in the airplane to permit either manual (flight director) or
automatic (autopilot) two-segment approaches. This airborne equipment
requires ground based distance measuring equipment (DME), co-located
at the instrument landing system (ILS) glide slope transmitter.
Briefly, the two-segment approach technique can be described as follows.
A special airborne computer constructs a preselected upper glide slope
(normally 6°) using barometric altitude and distance information from
the DME. Field elevation is set-in by the pilot before the approach
is initiated. On an approach, the upper glide slope is captured by
the aircraft and the descent initiated. At about 1000 feet above ground
level the computer programs a gradual round out. Then, the lower
nominal 3° glide slope is captured and tracked as on a conventional
approach. At an altitude of about 500 feet, the airplane is stabilized
on the 3° glide slope and goes on to a normal landing.
The cost of the two-segment guidance system, illustrated in Figure 4,
is approximately $40,000 per aircraft for a dual installation. To
add two-segment guidance to an existing three-dimensional area naviga-
tion system, such as shown in Figure 5, would cost approximately $9,000
for a dual installation. For this system the DME need not be co-located
with the ILS glide slope transmitter. The costs noted include the
basic equipment, aircraft modification and installation, check-out spares
and training, and as noted dual installations. Dual installations,
however, may not be required.
The 727 Two-Segment Approach Program
The 727 Two-Segment Approach Program has been completed. It had two
objectives: to develop operational avionics and two-segment flight
procedures for safe use with 727*s in routine scheduled operations;
and, to conduct a six month evaluation in revenue service. The special
avionic equipment illustrated in Figure 4 was used.
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TWO-SEGMENT APPROACH SYSTEM COMPONENTS FOR
NOISE ABATEMENT FLIGHT PROCEDURES PROGRAM
-
c
TWO-SEGMENT APPROACH
COMPUTER
TWO-SEGMENT APPROACH
SWITCHING UNIT
TWO-SEGMENT APPROACH
CONTROLLER
SELECTOR SWITCH
FIGURE
-------
AREA NAVIGATION SYSTEM COMPONENTS MODIFIED
FOR TWO-SEGMENT NOISE ABATEMENT APPROACHES
si
c
FLIGHT DATA STORAGE UNIT
NAVIGATION COMPUTER UNIT
CONTROL DISPLAY UNIT
NASA HQ R074-15419 3 12-12-73
FIGURE 5
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Prior to actual flight tests, extensive flight simulator evaluations
were conducted to assess, evaluate, and assure flight safety. Flight
profile variations, operational abnormalities, and equipment malfunctions
were simulated. Extensive engineering flight tests and guest pilot
evaluations were conducted before initiating the in-service 727 flights
by United Air Lines,
More than 600 two-segment approaches were flown, in the pre-service
phase of the program, about 30 percent of them under instrument-flight
weather conditions. Pilots from 12 airlines, NASA, and the FAA were
involved.
The in-service evaluation commenced on the West Coast in April 1973,
with two-segment approaches being made at Los Angeles, San Francisco,
and Portland. The six-month evaluation was successfully completed on
October 28, 1973.
Fifty-five United pilots participated, 555 two-segment approaches were
flown without incident, and over 40,000 passengers were carried. The
approaches were accomplished uneventfully by the flight crews and un-
noticed by the passengers.
Figure 6 illustrates that the 727, using a two-segment approach, exposes
2.0 square miles of land to noise levels greater than 90 equivalent
preceived noise, decibels (EPNdB), compared to 5.5 for a normal approach,
a 64 percent reduction. The reduced power setting of the two-segment
approach also saves a small amount of fuel, about ten gallons for a
727. An annual saving of about 50 million gallons of fuel would accrue
if all U. S. carriers were making two-segment rather than conventional
approaches.
DC-8 Two-Segment Approach Program
United Air Lines is now conducting an investigation of DC-8-61 two-
segment approaches for NASA. It is considered the most challenging
airplane for two-segment approaches because of its low drag in the
landing configuration. Our tests have confirmed that the recommended
upper segment of the DC-8 two-segment approach should be 5.5° rather
than the 6° attainable with the 727. As shown in Figure 7 the DC-8
On a 5.5° two-segment approach exposes about 5.5 square miles to
greater than 90 EPNdB, compared to 11.6 for a normal approach, a 53
percent reduction.
The modified area navigation system shown in Figure 5 is used to provide
the two-segment approach guidance for the DC-8. This mechanization
provides a low cost option for aircraft already equipped with an area
navigation system.
71,
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NOISE RELIEF FROM TWO-SEGMENT APPROACH
B-727 90 EPNdB IMPACTED AREA
STANDARD ILS-5.5 sq mi »».
TWO-SEGMENT-2.0 sq mi
NOISE IMPACTED AREAS
FIGURE 6
NASA RO74-2482 >3'<
2-15-74
-------
TWO-SEGMENT APPROACH
DC-8 90 EPNdB IMPACTED AREA
STANDARD ILS 11.6 sq mi
TWO-SEGMENT 5.5 sq mi
->.
-
NOISE IMPACTED AREAS
FIGURE 7
NASA HO R074-15029 (1) 7/12/73
(Rev. 1) 12 27-73
-------
In August, in-service evaluation of the DC-8 two-segment approach
system will be initiated with line pilots. This will follow a-three
month engineering flight evaluation period. To date, nearly 800
DC-8 two-segment operational approaches have been made by United in
the engineering flight evaluation period. Early reports indicate
acceptance by the 45 (including 21 guest) pilots that participated in
the program.
Applicability of the Two-Segment Approach to Other Aircraft
Analytical studies by the manufacturers have established the applica-
bility of the two-segment approach to other aircraft in the civil jet
transport fleet. Figure 8 summarizes the noise relief that would be
expected. When these benefits are considered in proportion to the
projected operations of the fleet for 1977, the area impacted by an
approach noise level, of 90 EPNdB or greater, is estimated to be
reduced by about 57 percent.
Wake Turbulence
One anticipated problem with the two-segment approach is the airplane's
wake turbulence, which can cause an upset of a following airplane.
With the two-segment approach, it has been postulated that a closely
following aircraft might not be able to operate clear of the preceding
airplane's trailing wake vortex as often as behind an airplane making
a conventional straight-in approach.
Results of joint NASA/FAA flight tests have shown that the strength
of the wake vortex generated on a two-segment approach is substantially
the same as that generated from conventional approaches. Vortex settling
characteristics also appeared to be about the same. The significance
of these factors with regard to the spacing and other operating require-
ments for following aircraft are under study with the FAA. The FAA
will use these data to help determine its position of the use of two-
segment approaches for noise abatement.
Summary
In summary, as of July 1, 1974, nearly 2000 two-segment approaches have
been conducted with 727 and DC-8 aircraft by about 170 pilots. Guest
pilots have generally started their evaluations with an apprehensive,
skeptical attitude toward the desirability, feasibility and accepta-
bility of two-segment approaches. Typically,- a guest pilot appeared
to have the procedure in-hand by the third practice approach. With
very few exceptions, by the end of their evaluation flights there was
74
-------
APPROACH NOISE AREA REDUCTION POTENTIAL
WITH THE TWO-SEGMENT APPROACH
AIRPLANE
i
B-707
B-727
B-737
B-747
DC-8
DC-9
DC-lO/L-1011
REDUC1ION IN90EPNdB
IMPACTED AREA WITH
TWO-SEGMENT APPROACH
%
57
64
52
39
53
63
44
ESTIMATED
OPERATIONS
IN 1977-%
9
40
10
5
5
18
13
FLEET-WEIGHTED
REDUCTION IN 90
EPNdB IMPACTED
AREA - %
57
FIGURE 8
NASA RO74-2498
2-19-74
-------
a nearly complete reversal of opinion, i.e., from opposed to cautious
optimism and support. Acceptance of the concept by a pilot appeared
to progress in proportion to the number of two-segment approaches flown.
The results of the Two-Segment Approach Program indicate that the
technique is an operationally feasible and safe technique for providing
a significant reduction in aircraft approach noise. A full understand-
ing of the operational implications of wake turbulence for following
aircraft remains to be developed.
AIRCRAFT NOISE PROGRAM COORDINATION
My following comments are directed to the Subcommittee's interest in
the coordination of the Government's programs related to aircraft noise
reduction.
NASA is continuing to work closely with DOT, FAA and EPA, at the staff
level, through working panels, and through the Joint DOT/NASA Office of
Noise Abatement, to help assure that the Government has an integrated
research and technology program directed toward the near and longer term
reduction of aircraft noise.
Through the Joint Office, we have provided EPA with our most recent
internal program planning data and as members of their noise research
and technology program coordination panels, we have met with them as
late as this past month to assist in their coordination effort.
NASA AIRCRAFT NOISE REDUCTION ACTIVITY
We believe that NASA has made and is continuing to make progress in the
development of technology for the reduction of aircraft noise. This
progress is being achieved through research on the understanding,
control and reduction of engine, aircraft and operations related noise.
We are also vitally concerned with the reaction of people and communities
to air transportation noise.
The Civil Aircraft Research and Development (CARD) policy study set a
general goal for the reduction of aircraft noise of 10 dB per decade.
Technologically, this goal is achievable in this decade. However, the
prospects of achieving this goal in the next decade are reduced by
the consideration of technical and practical operating costs. This situ-
ation is illustrated in Figure 9. For near term practical air transport
designs, we believe designers will be able to reduce aircraft noise to
conform to FAR-36 with little increase in direct operating costs (DOC).
In the longer term it is not clear that we can achieve an additional
10 dB noise reduction without a significant and possibly unacceptable
increase in DOC.
76
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AIRCRAFT NOISE REDUCTION
DECREASING
NOISE I
I
EASY EXPLOITATION
LITTLE BASIC
RESEARCH REQUIRED
CURRENT
FUTURE
INCREASING DIFFICULTY
MORE BASIC RESEARCH REQUIRED
NASA RJ75-2331
7-18-74
FIGURE 9
-------
We feel, however, that it is important for us to continue our efforts
to reduce noise and maintain operating efficiency. Our longer term
programs are directed toward these objectives. To illustrate, I will
review selected efforts to provide for future noise reduction, improved
noise prediction, and an understanding of the impact of noise on people.
These programs include: advanced acoustic composite nacelles, airframe
noise reduction, propeller noise reduction, aircraft noise prediction,
and human response to noise.
Acoustic Composite Nacelles
The acoustic composite nacelle program was developed to design and
demonstrate light-weight nacelles constructed of integrated structural
acoustical material. As shown in Figure 10, current nacelle noise
reduction technology involves lining the nacelle with non-load-carrying
sound absorption material. This reduces engine noise, but weight and
fuel consumption are increased. We are exploring the use of advanced
acoustic composite materials which interweave sound absorbent and
structural materials to form a sound absorption structure. Laboratory
studies indicate that for the same nacelle weight at 15 dB reduction
in sound intensity may be possible through the use of acoustic composite
structural material.
Conceptual design studies of such a nacelle were initiated in FY 1974,
The findings from these studies will be verified through laboratory
-investigations during FY 1975, and nacelle designs will be initiated
in FY 1976. We plan to complete ground tests in FY 1979.
The nacelle design will be appropriate for current wide-body transports
so that after completion of ground testing (including flight-qualifica-
tion tests) the nacelle could be demonstrated in flight. The potential
value of this type of nacelle is shown in Figure 11. An acoustic
composite nacelle applied, for example, to a future production DC-10
offers the performance potential of reducing the 90 EPNdB noise foot-
print area by an estimated 30% without a change in airplane weight or
operating cost or, for the same noise performance (footprint), the
aircraft weight could be reduced by about 2700 Ibs., and 1000 Ibs. of
fuel could be saved on a transcontinental flight.
This technology, of course, is applicable to future advanced technology
transports.
78
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APPLICATION OF ACOUSTIC COMPOSITE STRUCTURAL MATERIAL
-
ACOUSTIC COMPOSITE MATERIAL NACELL£
EQUAL
NOISE
LEVEL
ACOUSTIC MATERIAL
METALLIC STRUCTURE
MATERIAL
ADVANCED
TECHNOLOGY
REDUCED:
WEIGHT
FUEL
CURRENT
TECHNOLOGY
INCREASED:
WEIGHT
DRAG
FUEL
NASA HQRG74-15493 (1)
(Rev. 2) 7-18-74
FIGURE 10
-------
00
o
TYPICAL ACOUSTIC COMPOSITE NACELLE BENEFITS
FOR A 3 ENGINE WIDE-BODY TRANSPORT
CURRENT AIRCRAFT
90 EPNdB NOISE FOOTPRINT
100%
WITH APPLICATIONS OF ACOUSTIC COMPOSITE NACELLES
NO CHANGE IN WEIGHT AND FUEL
70%
OR
2700# LESS WEIGHT
10CO# LESS FUEL, TYPICAL TRANSCONTINENTAL FLIGHT
100%
FIGURE 11
NASA HO RG74-15492(1)
(Rev. 3) 7-18-74
-------
Airframe Noise
A relatively new area of concern is airframe noise. Our concern stems
from the fact that noise from landing gears, wings and flaps, body
flow separation and tail surfaces is at levels about 8 to lOdB below
the current FAR-36 requirement as illustrated in Figure 12. Because
future conventional aircraft engine noise at landing may be reduced
some 10 and possibly 15 EPNdB below FAR-36, airframe noise could become
the factor limiting approach noise reduction.
The objectives of our airframe noise reduction program are to identify
and quantify the sources of airframe noise, and to determine the princi-
ples and provide the data for minimizing this noise. A major part of
the work will be accomplished through model studies of components in
quiet wind tunnels and in the new Aircraft Noise Reduction Laboratory
facilities at the Langley Research Center. Flight testing will continue
to support development of data in this critical area. Special studies
will be made to relate airframe noise measurements, made at model
scale in wind tunnels, to full-scale flight test data.
Later phases of the effort will involve studies of noise generation
and its control as related to advanced concepts for high lift devices,
landing gears, other protuberances, and bodies and wings.
j?ropeller Noise Reduction
During testimony on General Aviation in March 1974, the Subcommittee
expressed interest in what NASA was doing to improve propeller design
to achieve better performance and reduce noise. We are approaching
propeller noise from several aspects.
Under a grant to the University of Illinois, effort is being directed
toward providing practical free-propeller design criteria to optimize
planform, airfoil section, twist and camber for minimum noise and maxi-
mum efficiency. The effect of the supercritical airfoil section, on
both noise and efficiency, as applied to propellers, is also under
study. Flight tests of these propellers will be carried out in con-
junction with the Advanced Technology Light Twin (ATLIT) Program during
the second and third quarter of FY 1975.
Noise reduction potential and thrust efficiency of shrouded propellers
are under study. Full scale wind tunnel tests of a modified Cessna 327
incorporating an aft propeller shroud were completed this month. Re-
duction of the data is underway and will provide the basis for decisions
on the feasibility of a subsequent flight demonstration program.
81
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SIGNIFICANCE OF AIRFRAME NOISE
110
106
102
EPNL,
dB
98
94
90
100
FAR PART 36
o
NORMAL APPROACH NOISE, MEAS.
AIRFRAME
NOISE, PREDICTED
^ Mi
\
FAR -10 EPNdB
200
300
400
500
600
700
800
MAXIMUM GROSS TAKEOFF WT. -1000 LB.
NASA RJ75-2332
7-18-74
-------
The same Cessna 327 will be modified to incorporate a Hamilton Standard
"Quiet-Fan" (Q-fan) turbofan engine. Although the Q-fan is expected
to be an expensive system, the noise reduction potential is great. Full
scale wind tunnel tests of the modified airplane, in mid-1975, will
provide a basis for further studies or flight programs.
Aircraft Noise Prediction
Our concern with the design of aircraft for minimum noise generation
or to specific noise standards led to the establishment of an Aircraft
Noise Prediction Office at our Langley Research Center this past year.
The Office with support from other NASA centers, will develop compu-
tational techniques for accurate prediction of operating aircraft noise
levels as perceived on the ground. This capability is essential for
assessing the noise characteristics of aircraft: new designs, aircraft
modifications, proposed noise abatement operational procedures, as well
as the impact of future air transportation systems on airport communi-
ties.
The prediction capability will also provide a basis for identifying
noise reduction technology goals and research needs related to aircraft
components, aircraft design, and airport operations. It will assist
Federal agencies in future rulemaking and regulatory activities, airport
planners in airport development, and airport communities in land use
planning.
Response to Aircraft Noise
The last subject I will comment upon is human response to aircraft
noise. During the FY 1975 authorization hearings, reference was made
to such a study completed at Columbia University. In this research
program the range of noise reduction proposed for retrofits for the
727 airplane was simulated. Figure 13 summarizes the results of the
investigation. An annoyance number of 4 is very annoying. A number
of 0 is not annoying. A reduction of 6 EPNdB represents the level of
noise reduction under the landing approach path expected for the SAM
and anticipated for the refan retrofits for the 727 airplane. From
these test results we conclude that under laboratory conditions signifi-
cant reductions in annoyance can be realized by a 6 EPNdB noise reduction.
In the Columbia study at the 1.1 mile approach point for the untreated
airplane, 72 percent of the subjects were highly annoyed; for the -6
EPNdB case, 34 percent of the subjects were highly annoyed; and for
the -12 EPNdB case, 16 percent were highly annoyed.
83
-------
00
SUBJECTS' RESPONSE TO SIMULATED AIRCRAFT OPERATIONS
4Q COLUMBIA UNIVERSITY STUDY
33.0
2.0
1.0
0
BASE CONFIG.
BASE -6 EPNdB
BASE -12 EPNdB
V
mr
3
i
1
2
3
i
1.1 MILES
2.5 MILES
3.5 MILES
SIMULATED DISTANCE
FROM RUNWAY
THRESHOLD
i
70
80 90
NOISE LEVEL, EPNdB
CORRECTED FOR INDOOR CONDITIONS
100
FIGURE 13
NiSA hQ RBH-15762
P -. - l ' 2! / -
-------
We believe that the experimental tools developed in this program pro-
vide a useful technique for the study of the annoyance of aircraft
noise.
The Columbia study initially was limited to one aircraft type and to
the landing condition, but has been extended to consider several air-
craft types for both landing and takeoff. The results of the extended
investigation should be available early this fall. More detailed
experiments are being planned for the Aircraft Noise Reduction Labora-
tory at Langley. These studies will complement those underway at
Columbia and will assess both the effects of different mixes of aircraft
and different rates of noise exposure.
Attention is also to be given to resolving the differences in the
responses to aircraft noise of various population sub-groups. This
information should provide a basis for the definition of more acceptable
noise environments for airport communities.
We believe that our program will provide the data base needed for near
and longer term action by industry, the public, and responsible govern-
ment groups to evolve toward a more compatible airport community noise
environment. We will continue to work closely with the responsible
government groups, DOT, FAA and EPA to help bring into practical reali-
zation the fruit of our research and technology.
85
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2. NASA
BASIC RESEARCH
AND
TECHNOLOGY
PROGRAMS
87
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OBJECTIVE DOCUMENTATION
Title; Propulsion Noise Reduction
Type of Specific Objective
X Discipline Study System and Experimental Program
Organizational Element Responsibility;
Noise and Pollution Reduction Branch - Harry W. Johnson (Act.)
Statement of Specific Objective and Targets:
Objective; To provide data and a technology base for reducing aircraft
propulsion generated noise with minimum weight, performance and eco-
nomic penalties. Specific targets are:
Obtain experimental and analytical data for a more
accurate understanding of noise generating mechanisms
in simple jet flows which can be used to guide the
technology for reducing jet noise generation. FY
1976 for subsonic jets; FY 1978 for supersonic jets.
Reduce by 60% the currently achievable thrust loss
penalty due to supersonic jet noise suppression
devices to 170 per 5 EPNdB. FY 1977.
Determine the basic effects of forward velocity on
jet noise generation and propagation. FY 1977.
Achieve 4 to 6 EPNdB reduction in fan-stage source
noise (relative to Quiet Engine I fan technology
levels) by means of aeroacoustic design. FY 1977.
Improve the efficiency of acoustic suppression materials
and technology to achieve, for a given dB reduction,
a 507= reduction (relative to 1974 design practice) in
the installation weight attributable to such suppression
treatment. FY 1977.
Demonstrate practical (high subsonic throat Mach
number inlet design concepts to achieve 20 EPNdB
suppression of forward radiated fan noise without
increasing aft radiated noise nor introducting
89
-------
undesirable engine performance, stability and operating
condition limitations. FY 1977.
Determine the noise generation or suppression effects
due to internal and external surfaces which guide or
control jet flows, including effects of shielding and
surface treatment. FY 1977.
Determine the mechanisms responsible for noise emanating
from core noise sources (combustors, struts, turbines)
and establish practical techniques for controlling these
noise sources to optimize acoustic designs of propulsion
systems. FY 1978.
Establish the effects of the random characteristics of
the atmosphere on the propagation of aircraft noise into
the airport community. FY 1977.
Approach;
Propulsion noise reduction aims at providing a technology base and data
for the understanding and reduction of aircraft propulsion component
and system generated noise with minimum weight, performance and economic
penalties. The program at Lewis Research Center is directed at funda-
mental studies of turbo-machinery, jet and jet interaction. Experimental
studies will continue on sonic inlets, fans, nozzles, core suppression
and wing shielding including tests using Quiet Engines A and C. The
program at Langley Research Center emphasizes fundamental studies of
component and jet noise and the effects of atmospheric conditions of
sound propagation. The aircraft Noise Reduction Laboratory, completed
in early 1974, is the focal point for Langley in-house research and
complementary university acoustic research activities. The programs
at Ames Research Center will include wind tunnel tests to measure for-
ward velocity effects. Aircraft static and flyover noise measurements
will be made at Flight Research Center. The Jet Propulsion Laboratory
conducts research on high temperature supersonic velocity jet noise
and the correlation of different noise measurement instrumentation
techniques now in use. Major milestones for Propulsion Noise Reduction
are;
FY 1975 - Demonstrate J-85 noise suppression using a
retractable nozzle in F-106 flight tests.
Early FY 1975 - Complete exploratory studies of noise
propagation and atmospheric attenuation using an instru-
mental tower.
-------
Mid FY 1975 - Complete flight test noise measurements
on supercritical propeller design.
Early FY 1976 - Conduct wind tunnel noise tests on vari-
able pitch Q-Fan for General Aviation Aircraft.
Need and Relevancy;
Aircraft noise is a major constraint to the growth of civil aviation,
and has become a major target for environmental improvement. The
NASA noise reduction program is intended to provide the technology
for reducing aircraft noise ultimately to levels which communities
will find acceptable, and to do so in a manner that permits aircraft
operations to remain economically viable.
OBJECTIVE DOCUMENTATION
Title; Noise Footprint Prediction
Type of Specific Objective
X Discipline Study System and Experimental Program
Organizational Element Responsibility;
Noise and Pollution Reduction Branch - Harry W. Johnson (Act.)
Statement of Specific Objective and Targets
Objective: To establish techniques for accurate prediction of ground
noise levels of operating and future aircraft to establish total
acoustic characteristics, identify parameter sensitivities, and guide
research efforts. Specific targets are:
Select and construct an interim computer program
for noise contour predictions by FY 1975.
Improve the data base capabilities of the interim
program to predict noise contours (footprint areas)
within + 40 percent accuracy (+ 1.5 dB accuracy of
noise contour). FY 1976.
91
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Establish a prediction and design capability to compute
noise contours for current and proposed aircraft systems
based on analytical modeling of individual component
noise sources. FY 1978.
Approach
The Noise Footprint Prediction program at Langley Research Center, with
specific support by the other centers, will evolve computational tech-
niques for accurate prediction of ground noise levels from operating
aircraft to establish acoustic characteristics, identify parameter
sensitivities and guide research efforts.
Major milestones of the Noise Footprint prediction research are:
By FY 1975 - Establish interim aircraft noise prediction
program.
Mid FY 1975 - Establish basic analytical models for key
technical areas in source noise prediction, noise
transmission, and community impact.
Late FY 1975 - First results from the integrated noise
prediction program.
Need and Relevancy
Demands imposed on jet aircraft by recent noise regulations have em-
phasized the need for an accurate noise footprint prediction capability.
This capability is essential not only for evaluating the effect of
proposed noise abatement procedures and aircraft modifications, but
also for evaluating the impact of future aircraft systems on airport
communities. The prediction capability will provide a basis for es-
tablishing noise reduction technology goals and identifying research
needs in the areas of components, aircraft designs, and airport opera-
tions. In addition, the prediction program will assist other federal
agencies in future rulemaking and regulatory activities, and will aid
airport communities in land use planning.
92
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OBJECTIVE DOCUMENTATION
Title; Minimization of Undesirable Aerodynamic Phenomena
Type of Specific Objective
XX Discipline Study System and Experimental Program
Organizational Element Responsibility
Aerodynamics & Vehicle Systems Division - Alfred Gessow
Statement of Specific Objective and Targets
Objective: To understand, and minimize by aerodynamic means, the un-
desirable effects of aerodynamic phenomena such as wake vortex turbulence,
aircraft buffeting and airframe noise. Specific targets are:
Determine by January 1974 one or more aerodynamic
techniques which show promise of effectively elimi-
nating the wake vortex hazard in order to provide FAA
with information with which to set potential require-
ments for operational vortex detection and tracking
systems at airports for safe spacing of aircraft during
landing and takeoff.
Demonstrate in flight by FY 1977 aerodynamic design
techniques which would permit a reduction from the
present 3-5 mile landing separation distance imposed
on transport aircraft by the wake vortex problem to
two miles.
Determine the design principles and provide the
necessary data on airframe (i.e. nonpropulsive)
noise to insure that the CARD policy study goal
of reducing aircraft noise by 10 dB per decade
can be achieved. The technology required for
the first 5 dB reduction to be in hand by FY 1977.
Using unsteady pressure distributions measured on
wing sections in wind tunnels, provide a means for
predicting the intensity of the buffet phenomenon
of combat aircraft throughout their maneuver range
by mid FY 1975. With such predictive capability,
not currently available, provide the design information
1,93
-------
necessary to extend the buffet boundary of combat
aircraft by approximately 100% by FY 1977 and thus
provide the potential for the development of new
aircraft with greater operational capability in
combat situations.
Approach
Aerodynamic factors that control the generation and magnitude of wake
vortex, aerodynamic noise, and aircraft buffet phenomena will be studied
to determine the means by which the detrimental effects can be reduced
or eliminated.
The airframe noise (i.e. the noise generated by an
aircraft in flight with its propulsion system noise
subtracted out) program effort will be concentrated
on determining the source, magnitude, and method of
reducing such noise for large transport aircraft in
the clean and approach (i.e., flaps and landing
extended) configurations. The individual noise
contributions of high-lift devices, separated flow
associated with the landing gear, gear-well cavity
flow, and flaps will be investigated. The program
will be conducted with LRC as the lead Center, aided
by flight research at FRC, and supporting wind tunnel
and basic research at ARC and JPL. Basic noise source
measurements will be made in conventional and quiet
wind tunnels and anechoic chambers with simple wings
and configurations to establish the feasibility and
test techniques for these types of measurements in
inherently "noisy" ground facilities. Airframe noise
prediction techniques will be developed using funda-
mental noise source principals and data correlations.
Far field aerodynamic noise measurements from flight
tests of jet transport aircraft will be compared with
predicted noise levels and corresponding measurements
from wind tunnel tests of scaled transport models for
verification of the ground test techniques. Aerody-
namic design concepts for minimizing airframe noise
will then be defined from analytical prediction
techniques, developed in ground facilities and dem-
onstrated in flight tests.
The wake vortex hazard alleviation program will be
conducted at ARC, LRC, and FRC and will include a
vigorous ground research effort with preliminary
flight tests to develop promising alleviation devices,
-------
and measure detailed vortex structure. The development
of promising vortex alleviation devices or concepts
will require investigations planned to be conducted in
contractor water channels, NASA ground facilities and
in flight. The effectiveness of such aerodynamic devices
or concepts as spoilers, trailing drag devices (splines),
vortex generators steady and pulsed mass injection, and
tailored span load distributions will be investigated.
Ground facility measurements to evaluate the effectiveness
of the alleviation devices include documenting the vortex-
induced rolling moment imposed on trailing aircraft
models, positioned at scaled distances up to about 1%
miles downstream of the generating aircraft models. In
addition, hot-wire probes and LDV instrumentation will
be further developed for obtaining vortex tangential and
axial velocity and core growth measurements. Based on
preliminary results from the on-going ground research
program, aerodynamic devices or techniques which show
promise of significantly reducing the wake vortex strength
include deployment of spoilers and splines, and tailored
span loading to achieve a triangular-like lift distribu-
tion. Plans are to intensify the ground research effort
to further refine and develop those aerodynamic devices,
and to verify and demonstrate the most promising devices
in flight tests using existing NASA aircraft initially
and to later lease a wide body jet transport for final
demonstration.
The buffet program will be conducted at ARC in the
Ames transonic unitary tunnel complex and will be
supported by contractor flight studies and analyses.
Correlations will be made of measured and calculated
buffet alleviation techniquessupercritical wings,
flaps, etc.will be studied. Locations of shock
waves and flow separation will be identified, and
studies of unsteady pressures and forces will be
made. Predictions of aircraft structural response
characteristics during buffet will be developed to
assess the effects of buffet on aircraft design loads.
Major Milestones of the Minimization of Undersirable Aerodynamic Phenom-
ena Program are:
Late FY 1974 - Select candidate vortex minimization devices
or concepts for flight test evaluation.
Mid FY 1975 - Begin flight test evaluation and demonstration
of promising vortex alleviation devices .
95
-------
Mid FY 1975 - Identify individual airframe noise source
contributions on jet transport.
Mid FY 1975 - Develop analytical prediction techniques
for radiated aerodynamic noise from discrete
sources
Mid FY 1975 - Develop capability to predict buffet
intensity of combat aircraft throughout
maneuver envelope.
Mid FY 1976 - Initiate final flight demonstration with
most effective vortex alleviation devices
on wide-body jet transport.
Need and Relevancy
The persistent nature of trailing vortices generated by jet transports
creates a documented safety hazard for closely following aircraft and
severely curtails optimum use of our nations airports. FAA has taken
action to deal with the problem by increasing approach and takeoff
separation distances to 5 miles (from 3 miles) for smaller aircraft
following a wide-body aircraft. This is not a satisfactory long term
solution because of the greatly reduced runway utilization rate, par-
ticularly in view of the heavier jet transports and increased traffic
volume projected for the future. Also, the increased separation
distances cause ground holding delays prior to takeoff and in-flight
holding delays prior to landing during peak traffic periods which waste
precious fuel. Additionally, a major NASA/FAA goal aimed at relieving
air traffic congestion involves as one facet the development and
implementation of a sophisticated, accurate airport-located aircraft
tracking system to allow less separation than presently employed. This
will not be possible as long as the wake vortex hazard continues to
define the minimum separation. The wake vortex hazard research program
will attempt to reduce the present 3-5 mile separation distance to two
miles.
A major CARD policy study goal concerns the reduction of aircraft noise
by 10 dB per decade. Toward this goal, engine quieting efforts are
achieving significant progress. However, recent measurements of jet
transport aerodynamic noise during approach (engines throttled back)
indicate that the noise level associated with the airframe is signifi-
cant (only 10 dB below the FAR PART 36 guideline). Therefore, to realize
full benefits from engine quieting efforts and to ensure that the CARD
policy study goal can be achieved beyond the first step, airframe noise
must be reduced below its current high level.
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Buffeting and buffet induced roll instability at high angles of attack
seriously restrict transonic maneuverability of military aircraft in
the high subsonic speed range where aerial combat takes place. Conse-
quently, to improve odds for victory, buffeting effects must be reduced
to widen the combat envelope of military fighters.
OBJECTIVE DOCUMENTATION
.Title: Acceptance of Aircraft Operations
Type of Specific Objective
X Discipline Study System and Experimental Program
Organizational Element Responsibility
Aeronautical Man-Vehicle Technology Division - R. P. Whitten
Statement of Specific Objective and Targets
Objective: To define and quantify those properties of aircraft noise
exposure that are responsible for causing negative individual and com-
munity response to air transportation systems. Specific targets are
below:
Devise proper methodologies for laboratory and field
studies of human response to aircraft operations.
FY 1975.
Determine effects of multievent noise exposure character-
istics on human response to aircraft operations. FY 1976.
Quantify the effects of background environmental noise
exposure on the human response to aircraft-generated
noise. FY 1977.
Ascertain the effects of aircraft noise on man's speech
production/perception. FY 1977.
Evaluate the effects of aircraft operations on sleep,
relaxation and subsequent performance of people. FY 1978.
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Study the effects of low frequency noise characteristics
generated by present and future aircraft on auditory and
nonauditory responses of people. FY 1979.
Develop a model for reliable prediction of responses of
people to aircraft operations that will satisfy labora-
tory and field conditions. FY 1980.
Approach
Research on the psychophysiological response of humans to aircraft
operations will be conducted primarily in the new Aircraft Noise Re-
duction Laboratory at the Langley Research Center. Sociopolitical impact
analysis of new aviation technology will be conducted by the Ames Research
Center.
Develop a model that will scientifically explain the
composite response of man to aircraft noise. As iden-
tified by the model, improve and/or develop those
methods essential to the conduct ot meaningful labora-
tory studies which simulate the impact of aircraft
operations on the community: Verify the model and the
methods developed for simulation studies by several
field studies.
Obtain data and record it in such a manner that it can
be used for NASA data bank utilization, and for other
federal agencies, i.e., DCT/FAA, EPA.
Design simulation and field studies with a view towards
correlation with specific characteristics of earlier
studies so that proper interpretation and extrapolation
of results can be made.
Need and Relevancy
Information to provide criteria for the prediction of community acceptance
of aircraft operations by people living in communities near airports is
of major importance in the development of noise control technology and
operational procedures for civil aviation. The physical characteristics
of noise and its propagation are fairly well understood; however, scien-
tific data permitting an understanding of the impact of aircraft opera-
tions and noise on the community are sparse. Comprehensive scientific
information on the psychophysiological effects of aircraft operations
and noise is needed to assure the acceptability and effectiveness of
programs designed to alleviate adverse community response to the air
transportation system.
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Because community research is time consuming and expensive, there exists
a need to simulate the real world in a laboratory environment in such a
manner that the laboratory results can be directly related to the opera-
tional world. The benefit of this capability is seen in the savings of
resources and the ability to synthesize operations of future aircraft
systems and then evaluate the degree of acceptance by the airport com-
munities. To achieve this degree of sophistication, further development
is needed in the area of subjective testing methodology to modify existing
or develop new measurement scales. Such scales must be adequate to
properly evaluate responses of people during both awake and sleep and
for indoor and outdoor background noise. There is a special significance
of current research in this area to the programs on advanced aircraft
whose low frequency noise and impulse noise characteristics are not
characterized adequately by existing measures of human response.
Today there exists a climate of general public hostility towards large
visible technologies. A thorough understanding of this social attitude
is needed to allow for accurate economic projections of future aircraft
systems prior to system development. Development of such understanding
would aid in the planning process of integrating a new system into an
existing system.
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3. NASA
PCWERED LIFT AIRCRAFT
NOISE TECHNOLOGY PROGRAMS
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OBJECTIVE DOCUMENTATION
Title; Advanced Powered-Lift Aircraft Aerodynamic Technology
Type of Specific Objective
XX Discipline Study _ System and Experimental Program
Organizational Element Responsibility
Aerodynamics & Vehicle Systems Division - John M. Klineberg
Statement of Specific Objective and Targets
Objective: To develop the aerodynamics and vehicle systems technology
needed to attain the integrated aerodynamic performance, noise, stabil-
ity, control, and handling qualities characteristics required for
viable powered-lift civil and military aircraft designs having overall
aircraft performance and flight characteristics compatible with opera-
tional approach CL's of about 4.5, 90 EPNdB noise, footprint less than
1 sq. mile, and direct operating costs not more than 10% above good
CTOL transports. Specific targets are:
Aero/Acoustic Exploratory Research - Provide, by 1975,
first-order trade-off information on low-speed aerodynamic
performance and noise for augmentor wing (AW) flap systems
(including the use of break-up nozzles and thrust reversers)
and for upper surface blowing (USB) concepts.
Cruise Drag - Provide, by 1976, first-order trade-off infor-
mation to avoid or reduce by half cruise drag penalties of
upper surface blowing systems, indicated for preliminary
analysis to be as great as 10?0 of total drag.
Large-scale Aero/Acoustic Verification - Verify the inte-
grated aerodynamic noise, stability and control character-
istics of representative complete powered-lift transport
configurations models incorporating lobe-nozzle AW concepts
by 1975 and USB concepts by 1976. Advanced systems with
improved nozzles and augmented jet flap designs, will be
verified by 1978.
Handling Qualities and Control Systems - Evaluate the handling
qualities requirements and promising methods of integrating
vehicle aerodynamic and propulsion controls for powered-lift
transports to enable precise flight path and airspeed control
during low-speed terminal-area operation. Result will be the
definition of tentative handling qualities design criteria and
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specific control system concepts by 1975. Also evaluate
by 1976 a hinged plate spoiler system for improving flight
path control and landing dispersion of a low wing loading
nonpowered-lift STOL transport.
Certification Criteria - Define tentative handling
qualities and performance criteria necessary to serve
as the basis for establishing airworthiness standards
and define procedures for demonstrating compliance
with standards. Targets for initial evaluation of
individual system concepts are:
CY
Deflected slipstream 1973
Augmentor Wing 1974
Externally blown flap 1974
Approach
The powered-lift STOL/RTOL aerodynamic programs are conducted at the
Ames and Langley Research Centers. Effort at Ames emphasizes large-
scale wing and model performance and noise tests in the 40- x 80-foot
tunnel, primarily on the augmentor-wing and upper-surface blown flap
concepts; related contracted analytical and experimental studies; and
ground-based motion-simulator flight dynamics investigations. Langley
performance, noise and handling qualities studies are concentrated on
the upper-surface blown flap, involving use of theoretical analyses,
small-scale and large-scale wind tunnel models, static rigs, and ground-
based simulators. The specific approaches for accomplishing each of the
identified targets follow:
Aero/Acoustic Exploratory Research - Ames, in FY 1975,
will conduct diagnostic experimental small-scale tests
in the 7- x 10-foot tunnel and sponsor contractual
investigations of advanced AW flap concepts to develop
fundamental performance, acoustic, and thrust reversal
technology for first-order design trade-off analyses for
systems having superior terminal area performance and
noise. This will include short-element flap systems.
Langley will conduct small-scale and free-flight model
parametric investigations to improve performance,
stability and control characteristics of USB configurations
which utilize the wing for noise shielding; will investigate
fundamentals of USB noise on a static rig with engine exhaust
directed through USB type nozzles over flaps; and will
conduct some USB performance/noise trade-off design studies.
Langley will also complete a series of experimental
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studies to establish reliable tunnel-wall corrections
for powered-lift systems being experimentally investi-
gated at high-lift conditions, and will continue powered-
lift theoretical studies to devise improved flow and
performance prediction methods. Ames will complete an
investigation of turbulent mixing within AW multi-
element nozzles to guide improved nozzle designs.
Cruise Drag - Langley will perform parametric small-
scale wind tunnel evaluations and analyses to
develop by FY 1976 an adequate understanding of how
to reduce cruise penalties accruing from USB instal-
lations. Ames will complete by FY 1975 a contractual
small-scale study to develop cruise augmentor technology.
Large-Scale Aero/Acoustic Verification - On a new
semispan swept wing powered-lift model, Ames in FY 1975
on the static test rig and in the 40- x 80-foot
tunnel will (1) complete the initial evaluation of an
Ames-designed AW concept utilizing advanced multi-ele-
ment lobe nozzles, (2) initiate evaluation of a Boeing
cruise augmentor concept, and (3) initiate evaluation
of a hypermixing ejector flap concept. This research
model will be utilized for several large-scale verifi-
cation tests of dirrerent powered-lift systems over a
3-5 year period. Langley will complete the initial
static and low-speed noise and performance evaluations
of a large-scale USB model (modified Aerocommander) in
FY 1975, using the full-scale tunnel and the lunar-
landing facility (for some of the noise measurements).
A large-scale swept-wing USB model will be investigated
in the Ames 40- x 80-foot tunnel. These large scale
investigations as a whole are required to verify the
integrated aerodynamic, propulsive, acoustic and
structural dynamics characteristics and to provide
valid data for design proposals.
Handling Qualities and Control Systems - Ames, in
FY 1975, will conduct handling-qualities investiga-
tions of representative powered-lift STOL/KTOL
transports using ground-based simulators such as
the FSAA, to provide solution to problems related
to flight-path control and of the transition from
cruise to approach. Ames, also in a joint program
with the FAA, will conduct flight evaluations of a
hinged-plate spoiler system integrated into the pilot's
controls to augment flight path and roll control of a
DHC-6 low-wing-loading nonpowered-lift aircraft. These
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evaluations under STOL operational conditions will
investigate certification implications.
Certification Criteria - In a joint program with the
FAA, Ames in FY 1975 will perform studies on the
FSAA in-house and under contract to provide additional
criteria for establishing handling-qualities and per-
formance certification standards for future STOL/RTOL
powered-lift civil transports. Tentative criteria
will be developed for aircraft using several of the
more promising powered-lift concepts, contributing to
a generalized criteria applicable to all concepts.
Consideration will also be given to the development
of safe flight procedures for demonstrating compliance
with the criteria.
Need and Relevancy
The Joint DOT/NASA Civil Aviation Research and Development (CARD)
Policy Study stressed the urgent requirement to reduce aircraft noise,
to reduce congestion at airport terminals and to evaluate efficient,
quiet short-haul transportation systems as a means towards such ends.
Only 10 percent of the Nation's airports can accommodate today's jet
transports requiring runway lengths of 5,000 feet or longer. Aircraft
with operationally usable approach C^'s of about 4.5 capable of opera-
ting from 2,000 foot runways could be accommodated by 75 percent of
the Nation's airports, and thereby offer tremendous congestion relief
for some currently overcrowded airports. Such aircraft could also help
congestion relief by operating from short new runways within existing
major terminal hubs.
The achievement of this performance in aircraft having acceptable ride
qualities and noise characteristics for the general riding and airport
community public requires the use of efficient, quiet, powered-lift to
provide useable approach lift coefficients up to 5 with noise levels
not exceeding 90 EPNdB over a 1 square mile footprint. The research
and technology efforts in this program are geared toward improving,
evaluating and validating the aerodynamic and noise characteristics
of advanced powered-lift concepts having promise of attaining the
stated overall aircraft performance and noise goals as a part of the
national effort to establish a high-density short-haul air transportation
system.
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C-8 AUGMENTOR WING FLIGHT EXPERIMENT
(766-71) Ongoing
Program Objective
Validate in flight the augmentor-wing powered-lift concept developed in
laboratory programs as a practical means for providing short take-off
and landing capability (under 2,000 foot balanced runway length) to al-
leviate terminal area congestion problems. Assess in flight the handling
qualities of this type of aircraft. Provide a versatile representative
powered-lift aircraft for assessment of navigation and control systems
requirements for safe (precise control with low pilot workload) terminal
area operations foreseen for this class of aircraft.
Program Targets
Documentation by December 1974 of augmentor-wing
proof-of-concept flights to be completed by
May 1974.
STOL operational assessment by U.S. and Canadian
test pilots to be completed by April 1974.
Development by February 1975 of definitive criteria
for control of flight path and airspeed, and for roll
and yaw power for powered-lift transports through
flight confirmation and refinement of results of
analytical studies and piloted simulator experiments.
Development by February 1975 of flight director laws
and integrated controls for transition management
through flight evaluation of a flight director con-
cept system developed by analysis and simulation.
Confirm and extend by 1977, certification criteria
for powered-lift aircraft developed through piloted
simulation.
Initiate by November 1974, main body of STOL operating
systems experiments (supported under separate program),
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Program Approach (Abbreviated Version)
A C-8A aircraft was modified in FY 71 and 72 to incorporate a jet aug-
mentor wing and appropriate jet engines in a joint U.S./NASA - Canadian/
Department of Industry, Trade, and Commerce program. Following con-
tractor check-out flights, the aircraft was delivered in August 1972
to the Ames Research Center where airworthiness and proof-of-concept
flights were initiated. During this phase of testing the vehicle was
further modified to include a powered elevator and the STOLAND avionics
systems to permit handling qualities studies at lower speeds and more
realistic long-term flight experiments on STOL operating systems.
Parallel studies were undertaken under contract using a variable-stabil-
ity Navion aircraft to aid in planning the C-8 flight research program.
The C-8 handling-qualities experiments will begin in mid 1974 following
completion of the proof-of-concept tests and of pilot assessment of the
STOL operational characteristics of the aircraft. The main part of the
handling-qualities criteria studies will be completed by February 1975.
The STOL operating systems experiments will begin in November 1974
utilizing the C-8 augmentor-wing aircraft in a program supported under
a separate project. During the course of the latter experiments, the
C-8 research aircraft will be used to evaluate flight director laws
and certification criteria for powered-lift flight.
Additional details are available in the March 23, 1973 Project plan
entitled "C-8 Augmentor Wing Research Aircraft and Flight Experiment."
Need and Relevancy
OAST has a responsibility to develop short-haul transport technology
for high density civil transportation. The C-8 augmentor-wing research
vehicle is the first jet powered-lift STOL aircraft to operate. It
will therefore enable early examination of low-speed flight and opera-
tional characteristics representative of future STOL/RTOL transports,
which (with rotorcraft and jet VTOL aircraft) are expected to provide
the U.S. with more efficient high-density short-haul systems. Infor-
mation obtained from STOL handling qualities tests with the aircraft
will aid in verifying the results of ongoing and planned ground-based
simulator studies, and in providing the criteria to establish civil
certification requirements for such aircraft. The vehicle, being
equipped with the STOLAND avionics system, will also provide a unique
facility for scheduled general STOL transport operating-systems experi-
ments, to be carried out jointly with DOT in a separate program.
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QUIET, CLEAN, SHORT-HAUL EXPERIMENTAL ENGINE (QCSEE)
(738-13) Ongoing
Program Objective
Design, build and test experimental engines to consolidate and demon-
strate the technology needed for very quiet, clean and efficient pro-
pulsion systems for economically viable and environmentally acceptable
powered lift short-haul air-craft. Program goals translate as follows;
95 EPNdB noise footprint area less than 0.5 sq. mi.
(-10% of DC-10), or 500 ft. sideline = 95 EPNdB.
Emission levels of Experimental Clean Combustor.
Thrust to weight ratio 6 or better.
High bypass ratio engine technology for under-the-wing
and over-the-wing systems: composite, variable pitch,
thrust reversing, low pressure ratio fans with gear
reduction drive for low tip speed.
Program Targets
The program objectives will be met through the following steps:
Source selection and contract award in December, 1973.
Design layout review - June, 1974.
Critical Design Review - January, 1975.
Delivery of first engine to LeRC for in-house testing in
an under-the-wing configuration in August, 1977.
Delivery of second engine to LeRC for in-house testing
in an over-the-wing configuration in December, 1977.
Program Approach
The approach is a competitive procurement, single-contractor experiment-
al engine program managed by the Lewis Research Center. System defini-
tion/optimization studies of powered lift propulsion concepts in FY
1973 formed the hardware program basis. Two full scale engines, one
for under-the-wing installation, the second for over-the-wing will be
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designed, fabricated, assembled, tested, and delivered to Lewis. In-
house acoustic and aerodynamic performance testing in wing/flap system
installations will be conducted to verify system characteristics and
achievement of program goals.
OBJECTIVE DOCUMENTATION
Title; Quiet Short-Haul Research Aircraft (QSRA)
Type of Specific Objective
X System and Experimental Program
Organizational Element Responsibility
Transport Experimental Programs Office - William Gardner/Jack Levine
Statement of Specific Objective and Targets
Objective: To obtain, by means of a low-cost experimental aircraft,
quiet propulsive-lift flight research data on an advanced propulsive-
lift configuration at lift coefficients greater than 4.5, 90 EPNdB foot-
print areas smaller than one square mile, and roll control power greater
than one radian per second^.Specific targets are:
« Provide by the end of FY 1974 a Project Plan and Risk
Assessment which will include the objectives, technical
approach, schedules and cost for the effort and the risk
assessment in achieving the same.
Determine by the end of FY 1974 the airframe and engine
design requirements, schedule and cost to modify an
existing airplane for use as a low-cost quiet, high
performance propulsive-lift research aircraft.
Modify the design, fabricate and assemble by the end
of FY 1976 an existing aircraft with an advanced
propulsive-lift system and perform ground checkout and
limited flight tests of the assembled aircraft by the
third quarter of FY 1977.
Define by the end of FY 1976 and conduct beginning in
the third quarter of FY 1977 appropriate multi-disci-
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pline propulsive-lift flight experiments in areas of
general configuration, handling qualities, noise,
flight dynamics, flight control systems, information
displays, propulsion system, and operating environment.
Generate and verify by FY 1978 the integrated total
vehicle and operating systems technology base from which
design requirements and certification criteria can be
established for practical and efficient quiet propul-
sive-lift civil and military short-haul transports.
Need and Relevancy
Future powered lift short-haul aircraft need quiet, clean, efficient
and economical propulsion systems whose technology is not yet available.
Demonstrations of component and system interactions in credible, full-
scale engines and propulsion installations are needed to establish the
data base to stimulate industry development with acceptable risk, and
to help government establish environmental and operational requirements.
The project will include modification of an existing aircraft into an
advanced quiet propulsive-lift configuration with modified existing
engines to power the aircraft and the use of the aircraft in a flight
research program to achieve the previously stated objective and targets.
Two parallel preliminary design study contracts were awarded on January
3, 1974 to the Lockheed Aircraft Corporation and the Boeing Company
for a nine and one-half month period to determine the most effective
configuration of the quiet propulsive-lift research aircraft. Each con-
tractor will conduct preliminary design of (1) a C-8A Buffalo aircraft
configured with an advanced quieted augmented jet flap (AJF) propul-
sive-lift system, and (2) a contractor-selected aircraft and quiet
propulsive-lift concept. In support of these studies, three separate
engine study contracts were awarded on January 31, 1974 to General
Electric, Allison, and AVCO Lycoming for a two-month period. The engine
contractors will define their engine concepts for the AJF aircraft and
for the configuration alternatives being considered by the airframe
study contractors.
Approximately mid-way in the design studies it is planned that a single
design concept for the research aircraft will be selected by NASA. The
selection will be based on results of the contractor efforts as well
as on our own in-house studies and considerations will be given to the
technical, schedule, and cost risks; the estimated project cost; aircraft
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research capability; industry interest in the approach; and other re-
lated factors. After concept selection the two design studies will
complete preliminary design for the aircraft and provide detailed bud-
getary and schedule estimates for detail design, airframe modification,
engine integration, and contractor tests. Results of these studies will
be utilized as a basis for issuing an RFP to industry for the engines
and for the aircraft. The engine RFP is planned for release in mid-
1974 and the aircraft RFP in late 1974. Flight research will be initi-
ated early in 1977.
The flight research program will be developed in a series of steps
including the refinement of the established flight research objectives
into more detailed and specific objectives, the development of detailed
experiments to achieve these objectives, the preparation of a flight
experiments program plan that orders and integrates the experiments,
and finally, the flight research program itself. The experiments
program will be developed in cooperation with other Government agencies
and interested industry groups and carried out by NASA as an in-house
effort.
The Ames QSRA Project Office is responsible for overall management of
the aircraft modification with support by Lewis Research Center to pro-
vide modified engines for the aircraft. The QSRA Project Office is
also responsible for management of the flight research program with
participation by the other OAST Centers.
Major milestones of the QSRA Project are:
Contract award for aircraft preliminary January 3, 1974
design studies
Contract award for engine support January 31, 1974
studies
Select aircraft design concept 4th Qtr. FY 1974
Contract award for engines for modified 3rd Qtr. FY 1975
research airplane
Contract award for design, fabrication 4th Qtr. FY 1975
of hardware and modifications for
research airplane
Initiate NASA quiet propulsive-lift 3rd Qtr. FY 1977
flight research program
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Initial quiet propulsive-lift flight 4th Qtr. FY 1977
research results available
Technology data base available for use FY 1978
in establishing design criteria and
development of civil commercial air-
craft
Need and Relevancy
The flight research program is necessary in order to reduce the techni-
cal risk associated with the development by industry of both civil and
military propulsive-lift transports and to provide a comprehensive
technical foundation on which Government regulation agencies can estab-
lish realistic criteria for certification of commercial subsonic pro-
pulsive-lift transport aircraft and for enroute and terminal area opera-
tions. A quiet propulsive-lift research airplane must be designed,
built and flown in a research program in order to provide verification
and demonstration of the technical base for the future design, develop-
ment, fabrication and operation of reliable, quiet and economic fan-
jet propulsive-lift transports. Powered lift technology is a key to
community noise reduction, airport congestion relief, and improvement
of civil transport and military tactical airlift.
OBJECTIVE DOCUMENTATION
Title: AMST Prototype Aircraft (769-48)
Type of Specific Objective
X System and Experimental Program
Organizational Element Responsibility
Transport Experimental Programs Office - William Gardner/Jack Levine
Statement of Specific Objective and Targets
Objective: To obtain, through participation in the Air Force AMST
prototype program, propulsive-lift flight research data on straight-
wing externally blown flap configuration at lift coefficients up to
about 3.5, 90 EPNdB footprint areas greater than 11 square miles, and
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l\
roll control power about % radian per second . Specific targets are:
Obtain by FY 1976 flight verification of the detailed
performance predicted by NASA ground based research
data for USB and EBF propulsive-lift aircraft.
Define by the end of FY 1974 and conduct on a non-
interference basis with the Air Force during FY
1976 to the maximum extent possible multi-discipline
flight experiments in areas of general configuration,
handling qualities, flight dynamics, noise, flight
control systems, information displays, propulsion
system, and operating environment.
NASA completes by FY 1978 documentation of the flight
characteristics and evaluation of handling qualities
and operational techniques as related to civil short-
haul operations.
Approach
NASA's direct involvement in the AMST program includes support of devel-
opment of the aircraft and participation, through membership of the
AMST Joint Test Team, in defining and conducting part of the AMST flight
test program. Support of development of the aircraft includes scale-
model tests in various wind tunnels to fill voids in available wind
tunnel capabilities on the part of the Air Force contractors. Further
developmental support is provided through use of the unique ARC Flight
Simulator for Advanced Aircraft for assessing adequacy of stability
and control levels inherent in the AMST designs, operational procedures
and emergency conditions that may influence aircraft configuration and/
or control systems characteristics.
The flight program will be conducted in two stages. In the first stage,
NASA will accomplish cooperatively with the Air Force such technology-
oriented flight research as can be undertaken without interference with
the primary Air Force objectives. Recognizing the Air Force objective
of the evaluation of these prototypes for tactical and logistic military
applications, it is expected that during the Air Force-led flight
program, the time devoted to the acquisition of data of interest both
to the Air Force and NASA (i.e. basic aerodynamic performance, handling
qualities and operational techniques) will be limited. In the second
stage, following completion of the one-year prototype evaluation
currently scheduled by the Air Force, NASA, will assume the primary role
and will conduct additional flight research. This second stage of the
program will complete the documentation of flight characteristics and
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evaluation of handling qualities and operational techniques as related
to civil short-haul operations. Modifications to the aircraft will be
made depending upon a weighing of feasibility and cost, and benefits to
the QPLT Program. It is anticipated that installation of STOLAND in
one of the AMST aircraft would best facilitate the study of advanced
avionics applied to short-haul operations in the terminal area. In
addition to studying integration of advanced avionics with pilot display
and flight control systems, STOLAND would aid in the evaluation of tech-
niques for defining noise abatement flight patterns in the terminal area.
Additional modifications may be made to the aircraft to reduce noise
generated by aero-propulsion systems to permit development of criteria
for noise certification.
Major milestones of the AMST Prototype Aircraft Program applicable to
NASA are:
Initiate Air Force-led flight evaluation 1st Qtr, FY 1976
of the AMST aircraft
Initial propulsive-lift flight research Mid FY 1976
results available for EBF and USB con-
figurations
Initiate NASA-led flight research using Mid FY 1977
the AMST aircraft
Need and Relevancy
In considering the requirements for technology, and operational data to
support development of civil and military transports with the advantages
of improved approach, landing, takeoff, climbout, and airport area low-
speed maneuvering capabilities, the U.S. Air Force and NASA have agreed
that the national needs can best be served through cooperation activity
which assures a close working relationship between the Air Force and
NASA-in the Air Force Advanced Medium STOL prototype (AMST) program
and the NASA Quiet Propulsive-Lift Technology programs.
The Air Force/NASA Memorandum of Understanding on the coordination of
the Air Force and NASA propulsive-lift programs provides both for NASA
participation in the Air Force flight testing of the AMST prototypes
and for subsequent use of these aircraft in a NASA-led flight test
program. These aircraft can be used to accomplish a part of the objec-
tives of the flight test program planned for NASA's quiet propulsive-
lift research airplane to the extent that their performance capabilities
permit.
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STOL OPERATING SYSTEMS EXPERIMENTS
(768-83) Ongoing
Program Objective
Establish a technology base upon which operational STOL short-haul
systems can be based with confidence in the 1978-2000 time period.
Regarding NASA STOL technology programs, the draft Federal Plan for
Short-Haul Air Transportation Improvement states that "The data from
these programs are considered critical to this plan, for this data
provides the basis for assessing which short-haul options are the most
promising from an operational and technology point of view."
Program Targets
In this joint DOT/NASA program, operating systems technology, operating
procedures, and guidance, navigation, and control concepts for high-
density terminal area operation will be demonstrated in the following
steps:
Integrated digital avionics research systems (STOLAND)
available - July 1973.
Synthesize flight paths for STOL independent of CTOL
operations - September 1974.
Initiate flight experiments to provide systems
performance data
- DHC-6 June 1974
- Augmentor Wing C-8 - December 1974.
Initiation of Microwave Landing System (MLS)
validation flight experiments - April 1976.
Benefits which will be demonstrated include:
Noise - 90 EPNdB footprint within airport boundary.
Weather - Low visibility automatic landing capability.
Guidance Accuracy - Maximum touchdown dispersions of
+15 ft. laterally and + 100 ft. longitudinally.
Pilot Workload - Reduced 3070 through automation and
displays.
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Program Approach
This joint DOT/NASA program is being conducted primarily at Ames Re-
search Center, with supporting simulation studies being conducted at
Langley Research Center and FAA's NAFEC.
An integrated digital avionics research system (STOLAND) has been pro-
vided by Ames Research Center. One simulator STOLAND system and two
flight systems have been fabricated. The first flight system has
successfully completed flight acceptance tests in the ARC CV-340 air-
craft and is currently being installed in a DHC-6 Twin Otter. Flight
experiments with this aircraft will begin in June 1974. The second
flight system is being installed in the modified C-8A augmentor wing
STOL research aircraft and flight acceptance tests will be performed
in November 1973. Flight experiments with this aircraft will commence
in December 1974.
Introduction of the Microwave Landing System (MLS), now under develop-
ment by the FAA, will provide better terminal area landing guidance
than is presently available. The MLS will by used by CTOL, STOL and
VTOL aircraft. Consequently, one task to be accomplished in this pro-
gram is to support the FAA in development of the MLS to ensure its suit-
ability for STOL applications. Analysis, field investigations, com-
puter simulations and flight experiments will be conducted to define
realistic criteria for MLS proof-of-concept evaluation and prototype
validations. The field investigations will include ground and flight
tests with the programmable STOLAND avionic system. These investiga-
tions will emphasize MLS performance for terminal area navigation and
approach and landing guidance for low visibility automatic operations.
Flight validation of the K model prototype'system will be completed in
1977.
In addition to the MLS validation, operating systems experiments will
be conducted to provide information to aid in the choice of STOL termi-
nal area guidance, navigation and control system concepts and to define
operational procedures. Steep ascents and descents, tight turns and
slow speed approaches and landings will be studied using analysis,
simulation and flight test. The simulation and flight test experi-
ments will be conducted using the STOLAND avionics system, the DHC-6
Twin Otter and the C-8A augmentor wing research aircraft. The naviga-
tion and landing aids to be used in the experiments are VOR, DME, TACAN
and MODILS (Modular Instrument Landing System).
Improved navigation and guidance will be investigated using an innovative
inertial guidance and navigation concept making full use of digital
computer technology and redundancy management. This strapdown inertial
reference unit (SIRU), now in the design phase, will be delivered to
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ARC in September 1974 for flight acceptance tests in the CV-340. Flight
experiments using a STOL vehicle equipped with both STOLAND and SIRU
will begin in November 1975.
Additional details will be included in the Program Plan to be available
in early 1974.
Need and Relevancy
The Joint DOT/NASA Civil Aviation Research and Development Policy Study
report identified the two most important problems plaguing civil avia-
tion as noise and congestion. Development of a National Short-Haul
Air Transportation System utilizing the capabilities of STOL aircraft
has the potential of reducing the projected terminal area congestion
and noise impact.
The ability of STOL aircraft to operate from runways 3000 to 9000 feet
shorter than those required for CTOL aircraft and containment of the
90 EPNdB footprint within the airport boundary will allow modification
or acquisition of STOL landing facilities with reduced real estate
costs. Advanced navigation, guidance, and control systems will provide
zero visibility landing capability and maximum touchdown dispersions
of +15 ft. laterally and + 100 ft. longitudinally. This will allow
STOL aircraft to interface with the ATC system with minimal interference
and will permit STOL vehicle operations independent of CTOL operations
at existing airports. Reducing the pilot workload by 30% will increase
the safety of operations.
New operating systems criteria and procedures must be established.
Thus, NASA and DOT, in attempting to solve some of the potential
problems associated with STOL navigation, guidance, and air trafic
control, have joined forces in conducting a STOL Operating Experiments
Program which is discussed in "Final Report of the Flight Experiments
Committee of the Joint DOT/NASA Operating Experiments Steering Group,"
dated July 21, 1972.
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4. NASA
ROTORCRAFT/VTOL NOISE TECHNOLOGY PROGRAMS
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OBJECTIVE DOCUMENTATION
Title; Advanced Rotorcraft Aerodynamic Technology
Type of Specific Objective
Discipline Study System and Experimental Program
Organizational Element Responsibility
Aerodynamics & Vehicle Systems Division - John M. Klineberg
Statement of Specific Objective and Targets
Objectives: to determine and improve the performance, dynamic loads,
noise, control, stability, vibration, and handling qualities charac-
teristics of helicopter rotors and rotorcraft configurations in order
to permit the development of rotorcraft having substantially greater
mission and cost effectiveness than current (1973) operational vehicles
in military and civil usage. Specific targets are:
Rotor Tip Vortices - By FY 1975, verify through full-
scale experimental evaluations the projected ability of
both passive and active devices, such as the ogee tip
shape and mass injection concepts, to reduce blade-vortex
impulsive noise about 5 EPNdB compared to conventional
square tip blades for rotors of equivalent thrust level.
Variable-Geometry Rotor - Evaluate the performance and
noise characteristics of one of the current RSRA system
candidates, the variable-geometry rotor concept, analyti-
cally in FY 1975 and experimentally in full-scale static
tests in FY 1975-76.
Controls and Displays for Improved Handling Qualities -
Evaluate in flight the handling qualities improvements
during curved decelerating approaches achievable with
a 3-axis vector velocity command system by FY 1975, and
a non-linear control concept by FY 1976.
Civil Helicopter Technology Assessment - Apply in FY 1975,
1973 state-of-the-art technology on a large transport
helicopter (CH-53) to provide passenger compartment acoustic/
and motion environment and assess suitability for feeder
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line aircraft use, and to provide civil helicopter noise
certification and community acceptance criteria.
Advanced Rotorcraft Design Studies - Define in FY 1975, to
the extent possible in modest design studies incorporating
estimated technology advancements, the broad design and
operational characteristics of large advanced compound
helicopter and tilt rotor transports which could realis-
tically be operational by 1985.
Controllable-Twist Rotor - Verify at full-scale in FY
1975 the ability of a controllable-twist rotor concept
to reduce cyclic vibration 10 percent and improve per-
formance 2 percent, compared to 1973 operational rotor
types.
Flight Controls and Handling Qualities for Unique Military
Helicopters - Through evaluating a hierarchy of helicopter
control systems by 1976, determine the minimum augmentation
requirements for specific military low-level missions,
and develop methods of implementation to minimize the
number and complexity of hardware components. Using
moving base simulation, establish by 1975 the effect of
gross weight up to 250,000 pounds on handling qualities
and flight-control requirements for crane helicopters.
Design Prediction Methods - Validate existing design
predictive methods and modify them where deficiencies
exist to provide the required improved understanding
of interrelated basic factors contributing to rotor-
craft performance, noise, dynamics, and control. The
subjects to be examined include: (1) main rotor/fuse-
lage/tail rotor flow interferences and effects by FY
1975, (2) unsteady flow conditions on rotor blades and
in the rotor wake by FY 1976, and (3) rotor blade and
control system dynamics including feedback by FY 1977.
Tilt-Rotor Control Systems - Develop and demonstrate by
1978 the technology for advanced control systems suit-
able for commerical and military operational tilt rotor
vehicles.
Approach
The NASA rotorcraft aerodynamic programs are conducted at the Ames and
Langley Research Centersin almost all cases jointly with the Army
Air Mobility R&D Laboratory located at each Center. Effort at Ames
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emphasizes large-scale rotor model tests in the 40- x 80-foot tunnel,
ground-based flight simulation studies, and analytical and design
studies conducted primarily under contract. Langley in-house studies
utilize, such facilities as the V/STOL and full-scale tunnels for small-
scale rotor model studies, the whirl tower for large- or full-scale
hover performance and noise evaluations, and available rotorcraft for
flight-dynamics investigations; contracted analytical and experimental
studies are also supported. The specific approaches for accomplishing
each of the identified targets follow:
Rotor Tip Vortices - In the program oriented toward
reduction of rotor tip vortex strength (and therefore
reduction of vibration and noise) rotor tip geometric
variations and mass injection will be studied. In one
phase, Langley will evaluate the characteristics of
full-scale ogee-tip blades on the whirl tower and in
flight on the UH-lH helicopter in FY 1975, and Ames
will carry out coordinated tests of the UH-lH blades
in the 40- x 80-ft. tunnel. Langley will conduct
flight tests to evaluate the mass-injection concept in
FY 1975-76.
Variable-Geometry Rotor - In Langley studies of the
variable-geometry rotor (VGR), also designed for tip
vortex strength alleviation, computer programs will
be improved for the calculation of VGR performance
and dynamics by FY 1975; following complete performance
evaluations of a VGR scale model rotor through wind-
tunnel tests in FY 1974, performance and noise tests
will be made of full-scale models in FY 1975-76 on the
whirl tower.
Controls & Displays for Improved Handling Qualities -
The CH-46 in-flight simulator helicopter will be
utilized in FY 1975 to develop improved design and
certification criteria for rotorcraftand other
VTOL, aircraftprimarily in the areas of handling
qualities and overall low-speed flight character-
istics, such as during decelerating curved approaches.
Advanced flight control systems including a 3-axis
vector velocity command concept will be examined by
early FY 1975 and a non-linear control concept by
early FY 1976. Preparations will be completed for
phasing in a CH-47 in-flight simulator (made available
through the Army) having an improved research capabil-
ity. The SH-3A helicopter will be used to fly pilot-
controlled, simulated IFR VTOL approaches while varying
the electro-optical pilot display parameters (resolution
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field of view, contrast, magnification factor, etc.)
for reduced pilot workload and improved safety.
Civil Helicopter Technology Assessment - The ride
quality improvements achievable from current state-of-
the-art design of a quieted vibration-isolated cabin
in a CH-53 helicopter will be demonstrated at Langely
in FY 1975. Design studies will be continued in FY
1975-77 to define and assess other advanced technology
applications for improving performance, safety,
economy and community acceptance of civil helicopter
transports; flight evaluations of the more promising
applications will be conducted in FY 1976-80.
Advanced Rotorcraft Design Studies - Ames contracted
design studies will be completed in FY 1975 to define
representative tilt-rotor and advanced helicopter
commericial aircraft design models for future short-
haul air transportation. (The studies will enable a
comparison with the characteristics of other STOL
and jet VTOL concepts provided in other similar
contracted studies.) Information on these design
models, derived from analysis, wind-tunnel tests, and
simulation will be used to define their operating
characteristicse.g., noise, fuel utilization, flight
path, pilot workload, and passenger acceptanceduring
approach and landing.
Controllable-Twist Rotor - Ames, in FY 1975, will evalu-
ate the dynamics and performance of a large-scale con-
trollable-twist rotor on a new rotor test rig (RTR)
to be developed for the 40- x 80-ft. tunnel. The RTR
represents a major improved test capability for Ames,
and will be used for a number of large-scale rotor
investigations in future years.
Flight Controls and Handling Qualities for Unique Military
Helicopters - Simulation studies will be conducted at Ames
of a number of low-level helicopter missions of interest
to the Army. A hierarchy of control systems will be in-
vestigated during FY 1975 to establish the minimum aug-
mentation requirements and to develop methods of implemen-
tation. Emphasis will be given to minimizing the number
and complexity of the hardware components, minimizing the
effects of upsets and disturbances, and on developing
techniques for decoupling controls. By 1975, simulation
investigations will be completed to determine the effect
of gross weight up to 250,000 pounds on the handling qualities
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and flight control requirements for crane helicopters
up to the very heavy lift class. Simulation results
will be validated through use of flight results on a
CH-54 helicopter obtained at Langley during FY 1974.
Design Prediction Methods - Langley will conduct ana-
lytical and experimental studies to identify factors
contributing to the aerodynamic, dynamics and noise
characteristics of rotors. University grants and con-
tracted studies will be continued through FY 1979 to
define wake geometry and analytical procedures which
include wake characteristics in predicting airloads,
structural response, rotor control feedback, performance
and noise. Langley in-house experimental studies will
be made in FY 1975-77 to better define unsteady local-
flow and aeroelastic parameters and rotor system
dynamics. Tests will continue in FY 1975 with a highly
instrumented generalized research helicopter model in
the V/STOL tunnel to obtain a better quantitative
understanding of main rotor/fuselage/tail rotor inter-
ference flows and effects. The effectiveness of a
helicopter fan-in-fin in lieu of a tail rotor will be
evaluated in the full-scale tunnel by FY 1976. A
sophisticated rotor noise prediction technique will
also be computerized in FY 1976. Ames will refine
math modeling of tilt rotor dynamics through FY 1975;
will continue contracted generalized studies of tilt
rotor gust response problems and control system suppres-
sion technique through FY 1976; and will develop a
method for computing tilt rotor/wing/empenage aerodynamic
interference in FY 1975-76.
Tilt Rotor Control Systems - A simulator model of a
commercial tilt-rotor transport will be obtained by
1976 for use in simulation studies to define handling
qualities and control system design criteria. Perti-
nent information will be obtained from coordinated
simulation and flight studies supported under the XV-
15 Tilt-Rotor Research Aircraft Program (RTOP 744-28-01).
Need and Relevancy
Rotorcraft have attained wide usage by the military (35 percent of the
DOD aircraft inventory are helicopters and 85 percent of the Army in-
ventory) for application primarily in assault, medical evacuation, air-
crew rescue, aircraft retrieval and ground support missions. There is
likewise a growing use of helicopters in the civil sector for industrial,
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ambulance and police, and short-haul transportation applications.
Despite this wide rotorcraft usage, their full potential is far from
realized in both military and civil sectors due to technology limita-
tions resulting in poor cruise efficiency, inadequate speed and range
capability, poor dynamics and high vibration, bothersome noise, and
inadequate all-weather flight capability. These limitations seriously
impact mission capability, initial and operating (including maintenance)
cost, and passenger and community acceptance. The programs of this
objective are aimed at effective alleviation of the technology limita-
tions to permit the realization of rotorcraft having greater mission
and cost effectiveness for both military and civil needs. An indica-
tion of the relevancy of the programs to military needs is the fact
that about 90 percent of the programs are supported equally in funding
and manpower by NASA and the Army.
OBJECTIVE DOCUMENTATION
Title; Advanced VTOL Aircraft Aerodynamic Technology
Type of Specific Objective
XX Discipline Study System and Experimental Program
Organizational Element Responsibility
Aerodynamics & Vehicle Systems Division - John M. Klineberg
statement of Specific Objective and Targets
Objective: To provide the technology required to enable the development
of viable military and civil aircraft having effective VTOL capability
together with speed, range, operating cost, and mission/operational
capabilities approaching those of 1973 operational medium range military
and civil CTOL aircraft. This requires the development of a thorough
knowledge and understanding of the aerodynamic performance, noise,
control and stability characteristics, and piloting qualities peculiar
to VTOL system concepts. Specific targets are:
Ejector Wing VTOL Aerodynamics - In FY 1975, evaluate
the VTOL aerodynamic performance, stability, and control
of XFV-12A ejector wing configuration. Examine by FY
1976 the performance of advanced high pressure hypermlxing
VTOL ejector-concepts in forward flight transition engines.
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Obtain by FY 1976 a preliminary evaluation of the performance
of VTOL ejectors located chordwise at the root of a low
aspect ratio combat aircraft type wing.
Lift-Fan VTOL Aerodynamics - Verify in FY 1975 through
large and small-scale tunnel tests that a lift-fan VTOL
transport can be configured to achieve satisfactory per-
formance, control and stability characteristics in termi-
nal area operation.
Lift/Cruise Thrust Vectoring - Demonstrate by FY 1975
through large-scale static tests the technology for
rapid response (+ 20% thrust modulation and + 20° thrust
deflection in 0.2 sec.) lift/cruise propulsion system
thrust vectoring/modulation systems whose thrust vector
can be varied in a practical design from 0° (cruise thrust
mode), to 90° (hover lift mode) with no more than 5% thrust
loss, and to 130° for thrust reversal/braking.
Lift/Cruise VTOL Aerodynamics - Demonstrate by FY 1976,
technology for applying basic fluid mechanic phenomena to
improve transition-flight interference effects on per-
formance, stability, and control of selected military
VTOL combat type configurations through wind tunnel
evaluations of small-scale models.
SCS VTOL Aircraft Handling Qualities - Establish by FY
1976 through simulator investigations the envelope of
acceptable approach aspects (relative headings of air-
craft, ship, and wind) for satisfactory handling quali-
ties of VTOL aircraft on Sea Control Ships under various
sea states and weather conditions.
Land-Based VTOL Aircraft Handling Qualities - Devise and
demonstrate by FY 1977 an integrated control system for
all flight phases of high-performance VTOL transport type
aircraft. Verify through X-14 flight tests and related
simulation studies, design criteria for vehicle lateral
control power in hovering by FY 1975.
VTOL Flow Interactions - Provide predictive methods
adequate for design needs by FY 1978 of complex flows
and their interactions (including noise effects) typically
associated with VTOL aircraft having concentrated propul-
sion/lift system inlet and exhaust flows. As one specific
example, a satisfactory analytic method for predicting
vehicle induced lift accruing from lift engine propulsion
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installations in wing mounted pods will be sought in
FY 1976.
Approach
The high performance VTOL aerodynamic programs are conducted at Ames
and Langley. At Ames, the primary emphasis is on large-scale aero-
dynamic performance and acoustic studies, and on handling quality
investigations. Langley concentrates on small-scale model investiga-
tions of aerodynamic performance, stability and control. NASA funding
for the joint USN/USAF, NASA, FAA X-22 handling qualities program has
been directly from Headquarters with technical monitoring by Langley.
The approach toward accomplishing each identified target and the major
milestones is as follows:
Ejector-Wing VTOL Aerodynamics - Langley in FY 1975
will evaluate the VTOL aerodynamic performance, stabil-
ity and control of small-scale wind-tunnel and free-
flight models of XFV-12A VTOL aircraft configurations,
and Ames will test the actual aircraft in the 40- x 80-ft.
tunnel if provided by the Navy. Ames in FY 1975 will
continue exploratory investigation of hypermixing VTOL
ejectors, which will be extended in FY 1976 to advanced
ejectors having pressure ratios perhaps as high as 2 to 3.
Ames in FY 1975 will investigate the feasibility of VTOL
ejectors located axially in the chordwise direction near
the root of low aspect ratio military type aircraft con-
figurations of VTOL performance in FY 1976.
Lift-Fan VTOL Aerodynamics - The characteristics of a
current technology lift-fan civil transport model and
of a military multi-mission lift/cruise fan configura-
tion will be determined in large-scale powered model
tests on the Ames static test stand and in the 40- x 80-
ft. tunnel in FY 1975. Langley in FY 1975 will complete
small-scale model investigations of the performance,
stability, and control of an intercenter VTOL transport
model incorporating a different wing-pod-mounted lift-
fan configuration, and of McDonnel Douglas VTOL transport
design. On the basis of these results, Ames in FY 1976
will initiate the design of a more advanced VTOL trans-
port type model for the 40- x 80- ft. tunnel, having
substantially less required thrust/weight than current
designs, to develop the integrated aerodynamic and acoustic
technology.
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Lift/Cruise Thrust Vectoring - Ames in FY 1975 will complete
a first series of small- and large-scale static tests
of lift/cruise fan nacelles and thrust vectoring vehicle
control systems aimed at developing technology for simple
lightweight systems that can meet the stringent requirements
for large vectoring angular ranges, fast angular and thrust
modulation, high temperatures, and acceptable interactions
of the exhaust flow with the aircraft, ground, and airstream.
Lift/Cruise VTOL Aerodynamics - Langley in FY 1975 will
continue wind tunnel evaluations of small-scale VTOL combat
type aircraft configurations with wing and lift jet rela-
tive positions varied to optimize jet interference effects
on performance, stability and control during transition
flight.
SCS VTOL Aircraft Handling Qualities - Ames will con-
tinue in FY 1975 and complete in FY 1976 a first series
of simulator investigations to establish the envelope
of acceptable approach parameters for satisfactory
handling qualities of VTOL aircraft under manual control
during take-off, approach, and landing on Sea Control
Ships under severe weather conditions. Additional in-
vestigations will extend into FY 1977.
Land-Based VTOL Aircraft Handling jjualities - Research
at Ames toward demonstrating by FY 1977 an integrated
flight control system for high performance VTOL trans-
port type aircraft will include in FY 1975: (1) ana-
lytical and simulation studies of such a control system;
(2) continued X-14 flight investigations to extend and
refine hover control system and handling quality design
criteria determined through simulation; (3) completion
of simulation math models of advanced V/STOL transports
to support transportation systems terminal area effi-
ciency studies and; (4) initiation of a major simulator
study on the FSAA to examine in considerable detail
how best to detect and handle system failures on repre-
sentative VTOL aircraft designs during critical conversion
flight regimes (this effort will extend into FY 1977).
Reporting of the X-22 flight evaluation of VTOL curved
decelerating approaches, monitored by Langley, will be
completed.
VTOL Flow Interactions - Ames by FY 1976 will attempt to
devise satisfactory theoretical methods to predict
induced flows for VTOL podded configurations. Generalized
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studies will continue through FY 1978 at Langley on
VTOL crossflow interferences, and at Ames, on the noise
of VTOL exhaust jets as related to turbulent mixing.
Need and Relevancy
Efficient high-density s"hort-haul civil transportation systems for the
future have a need for quiet efficient vehicles which can operate
over short to modest stage lengths competitively with other forms of
transportation from small inexpensive VTOL ports which can be readily
located to meet transportation demnds with a minimum impact on the
community environment and with an economic advantage to both the travel-
ing public and the communities being served. Likewise, the DOD has a
requirement for future carrier-on-board delivery (COD) logistic and
surveillance type VTOL aircraft which can be operated from small Sea
Control Ships, as well as for VTOL combat aircraft. There is consider-
able commonality in the vehicle technology requirements for both the
civil and military needs. The programs of this objective are oriented
to provide the vehicle aerodynamic and flight dynamics technology re-
quired to develop viable vehicles for such civil and military needs.
TILT ROTOR RESEARCH AIRCRAFT
(744-28) Ongoing
Program Objective
Demonstrate advanced rotorcraft technology for military and civil VTOL
vehicles having twice the cruise speed of the helicopter while retain-
j.ng its efficient hover capability.
Program Targets
Major targets of this program include the following:
Initiate detail design - August 1973.
Critical design review -August 1974.
Fabricate two tilt rotor aircraft - October 1975.
Complete ground testing - May 1976.
Start flight research - June 1976.
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Definitize advanced flight research program -
July 1977.
Program Approach
Under a joint agreement signed November 1, 1971, NASA and the Army are
sharing the funding and management of this program. A jointly staffed
project office is located at the Ames Research Center.
Two contractors participated in a Phase I competitive design and analy-
sis which was the basis for the selection of a Phase II contractor.
The Bell Helicopter Company was awarded a contract on July 31, 1973,
for the design, fabrication, and flight test of two Tilt Rotor Research
Aircraft.
The program will be conducted on an "experimental shop" basis to empha-
size cost and time savings as well as controlling the technical aspects
to insure the aircraft will best meet the research objectives. Prior
to first flight, a comprehensive ground test program will be conducted,
including tie-down and full-scale wind tunnel tests.
Ames1 flight simulators will be utilized to verify aircraft character-
istics and to familiarize Army/NASA operating personnel with normal and
emergency procedures. The initial flight tests will be conducted at
the contractor's facility to verify flight safety and train Army/NASA
flight personnel. NASA facilities will be used for proof-of-concept
flight tests and definition of the advanced flight research program.
Need and Relevancy
Helicopters have been widely accepted for both civil and military mis-
sions where efficient hover and VTOL capability are required. Their
application to a wide range of civil short-haul and military tactical
roles has been restricted, however, because of high dynamic blade loads
and the loss of propulsion efficiency at higher forward flight speeds.
Noise, vibration, high maintenance costs, and poor ride qualities have
also added to the limitation of the helicopter.
For the past twenty years, the Army, Air Force, NASA, and industry have
been pursuing the establishment of a tilt rotor technology base. Based
on in-house studies and analyses by NASA/Army engineers, it was concluded
that the tilt-rotor concept showed the greatest promise for a capability
to meet the military and civil V/STOL needs anticipated in the future.
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ROTOR SYSTEMS RESEARCH AIRCRAFT
(745-79)Ongoing
Program Objective
A unique flight test capability in 1976 for advanced rotor research on
a wide variety of promising new rotor concepts.
This program will expedite improved rotorcraft research through the use
of a specially designed flight test vehicle. Extensive on-board instru-
mentation will provide better research data, and repeated use of the
test vehicle will enable timely and economical completion of rotor
research projects.
Program Targets
Major targets of this program include the following:
Initiate detail design - December 1973.
Critical design review - December 1974.
Fabricate two Rotor Systems Research Aircraft -
September 1975.
Initiate contractor flight test - November 1975.
Aircraft delivery to Government - December 1976.
Initiate NASA/Army rotor research program - January 1977.
Program Approach
NASA and the Army are jointly funding and managing this program under
an agreement signed November 1, 1971. A joint project office is located
at the Langley Research Center where the rotor research program will be
conducted. NASA/Army in-house and two contractor pre-design studies
were used to establish the feasibility of an advanced flight research
vehicle and to define its characteristics, the flight control system,
and the research instrumentation systems.
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An RFP was issued, proposals were evaluated, and Sikorsky Aircraft was
awarded a contract for the design fabrication, and flight test of two
Rotor Systems Research Aircraft.
Supporting research and technology efforts will be conducted, as re-
quired, to support the design effort and reduce the technical risk of
the project. Wind tunnel tests will be conducted and the Flight Simu-
lator at Ames Research Center will be utilized.
The "experimental shop" concept will be used to stress time and cost
savings in addition to controlling the technical aspects to insure the
aircraft will best meet the research objectives.
After a thorough ground test program, the contractor will conduct air-
worthiness flight tests, determine the aircraft characteristics and
handling qualities, and check out the research instrumentation.
The NASA/Army research program will be started shortly after the air-
craft are accepted by the government.
Need and Relevancy
The expanding role of the helicopter in both civil and military appli-
cations has generated requirements which exceed the current state-of-
the-art of rotary wing technology. To date, flight tests of promising
advanced concepts have been conducted by modifying an existing aircraft
or by building a new aircraft for each concept. This approach is time
consuming, costly, and often gives less that good results.
NASA and the Army have been looking for a way to conduct adequate and
timely investigations and demonstrations of advanced concepts in flight
without the excessive time, cost, or data limitations of the "one at a
time" approach. Both agencies have concluded that a specially designed
research aircraft with adequate instrumentation is needed to test ad-
vanced rotor concepts and verify rotorcraft supporting technology. The
Rotor Systems Research Aircraft is planned to fulfull this need.
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ROTOR SYSTEMS FOR RSRA
(766-79) New Start
Program Objective
Select, acquire, and evaluate on the Rotor System Research Aircraft
YRSRA)now being developed jointly by the Army and NASA--three practj-
cal advanced rotor-system concepts. Demonstrate through tests of these
Concepts in the real flight environment the integrated performance,
dynamics and acoustics technology improvements achievable, such as
Increased speed (above 300 knots), with attendant lower vibration levels
Tbv %)» noise (below 95 PNdB at 500 feet), and extended component life
(by 1007=.), leading to community acceptance, improved ride comfort (to
feederline aircraft levels), and reduced direct operating costs (by
20%). Particular objectives will depend in large part on the three
rotor system concepts selected. Concepts currently considered promis-
ing include the:
Aero-acoustic rotor for reduced external acoustic noise
and increased cruise L/D
Variable-geometry rotor for reduced external acoustic
noise and rotor vibration and increased hover efficiency
Composite structures rotor for reduced rotor system
we ight
Variable diameter rotor for increased cruise speed
Controllable twist rotor for increased cruise speed
and L/D, increased hover efficiency and reduced rotor
vibration
Program Targets
The program objectives will be approached through the following steps:
Initial selection of rotor systems by mid FY 1975.
Begin design and fabrication of first rotor system
by late FY 1975, ground tests by mid FY 1977, and flight
tests by early FY 1978.
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Begin design and fabrication of second rotor system
in mid FY 1976, ground tests by late FY 1977, and
flight tests by mid FY 1978.
Begin design and fabrication of third rotor system
by mide FY 1977, ground tests by early FY 1979 and
flight tests by late FY 1979.
Because the program involves evaluating advanced rotor concepts on a
new flight test facility, strong supporting technology efforts will
be conducted during FY 1975-77 to aid in establishing design criteria
for the rotor systems and guiding their development to assure a suc-
cessful program.
Program Approach
The technical approach will encompass four major related elements con-
ducted cooperatively with the U.S. Army:
1. Direct Supportive Research & Technology Activities - This
includes (a) evaluation of advanced technology airfoils and
components which will likely be incorporated into selected
advanced rotor system concepts as described in item 2; (b)
scale model dynamic investigations of some of the candidate
advanced rotor concepts; and (c) correlation of analytical
prediction and flight data obtained as described in item
4.
2. Advanced Rotor System Concept Definition Studies & Selec-
tion - Concept definition studies will be made under con-
tract to serve as the basis for the eventual selection of
the initial three concepts for investigation on RSRA. The
definition study contracts will document information on
concept potential, preliminary design data, development
support requirements, and cost/schedule relationships
necessary for subsequent preparation of proposal requests
and contract award to procure the rotor systems.
3. Advanced Rotor Systems Design & Procurement for RSRA -
This includes the design, fabrication and ground test of
three advanced research rotor systems in a manner to pro-
vide flight hardware consistent with the RSRA flight
schedule. Priorities and sequencing of the hardware de-
velopment will be based in part on concept potential, on
extent of development and full-scale ground test require-
ments, and on timeliness.
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4. Flight Evaluations Utilizing RSRA - Upon delivery of the
RSRA, documentation flight tests will be made to evaluate
system capabilities and provide baseline data for correla-
tion with future test results. Thereupon, extensive flight
investigations will be made of each of the three research
rotor systems provided by this systems technology program.
During the course of evaluating the three rotor systems
per se as they become available, there will be additional
flight evaluations utilizing the unique versatility and
capability of the RSRA to study important broad heli-
copter problem areas such as: (a) control system tech-
nology including feed-back systems for gust alleviation
and ride comfort, (b) rotor/airframe structural dynamic
response, and (c) compound helicopter maneuver character-
istics.
Need and Relevancy
The NASA and Army are jointly developing two RSRA vehicles at a cost
of $33M to provide an efficient, expanded and economic capability (1)
to evaluate potentially superior, advanced technology rotor system
concepts in flight; (2) to investigate rotorcraft systems and charac-
teristics over a much greater envelope of flight conditions than achiev-
able with currently available laboratory facilities or flight vehicles;
and (3) to provide an extensive flight data base to validate many com-
plex rotorcraft design prediction methods. Development of the RSRA
vehicles is being agressively pursued to provide the expanded test
capability for evaluating a number of rotor concepts at a substantial
cost savings compared to the current approach of validating each
advanced concept on separate "one shot" test vehicles. The RSRA pro-
ject is completed upon government acceptance of the aircraft, however,
and this research program is required for utilization of the valuable
national test facilities to achieve the return on their investment in
a cooperative effort with the U.S. Army.
The first RSRA vehicle is scheduled to be delivered to the Langley
Research Center by the mid FY 1977 with its baseline rotor system, and
to be ready for initial evaluation of an advanced research rotor system
by late FY 1977. On the basis of R&T base technology programs to date,
several rotor system concepts appear to warrant the thorough flight
evaluation which RSRA will permit. However, none of the rotor systems
exist in flight hardware suitable for direct use on RSRA. Although
the time requirements for design, fabrication, ground test, and inte-
gration of a complete rotor system on RSRA will vary with different
concepts, a minimum of about two years is anticipated. Therefore, it
is imperative that concept definition studies and evaluations be initi-
ated early in FY 1975 to select the most appropriate rotor systems for
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development, to establish a concept priority which will allow the most
effective development of flight test hardware, and to begin the design/
fabrication of the first research rotor system. The provision and
evaluation of the second and third rotor systems of this program are
timed for maximum effective utilization of the two RSRA vehicles for
all NASA/Army flight investigations requiring the vehicles.
The development of advanced rotor systems and their evaluation of RSRA
contribute directly to the NASA National Goals of providing efficient
short-haul transport technology and establishing the technology for
superiority in military aeronautics. The program will in addition aid
greatly in focusing technology efforts carried out under the NASA Rotor-
craft Research and Technology Base programs which also support the two
National goals mentioned.
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5. NASA
SUPERSONIC CRUISE AIRCRAFT NOISE
TECHNOLOGY PROGRAMS
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OBJECTIVE DOCUMENTATION
Title; SCAR Propulsion Technology
Type of Specific Objective
Discipline Study X System and Experimental Program
Organizational Element Responsibility
Advanced Supersonic Technology/Hypersonic Research Office -
W.S. Aiken, jr.; L. Sternfield
Statement of Specific Objective and Targets
Objective: To establish an expanded supersonic propulsion technology
base in parallel with the expansion of other supersonic disciplinary
technologies which will permit the reduction of noise in takeoff and
landing to levels less than the Douglas DC-10 and Lockheed 1011; re-
duce fuel consumption rates which can make supersonic cruise aircraft
significantly more efficient; and nitric oxide emissions in high al-
titude cruise that are greatly reduced from levels possible with
today's technology. Specific targets are:
By the end of FY 1975, establish noise reduction potential
of suppressors for coannular jets for application to
duct-heating turbofan cycle engines.
By FY 1977, verify the potential of NOx reductions to 90%
less than current engines at supersonic cruise altitudes.
By FY 1977, verify inlet shock stabilization valve concept
operational suitability by YF-12 flight tests.
By FY 1979, synthesize and apply an integrated propulsion
control system to the YF-12.
NASA's fundamental research on supersonic propulsion system problems
is conducted primarily by LeRC, with contributions from ARC in the
noise area and FRC in the area of inlet control systems. Primary
emphasis is placed on the development of engine components and propulsion
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systems which will provide high levels of propulsive efficiency with
reduced levels of noise and pollutant emissions. The secondary em-
phasis is on the development of integrated control systems which will
stabilize inlet shock waves and thus provide for improved propulsion
system performance and reliability.
Noise suppressors developed in the FAA SST Phase II
Follow-on program and in-house LeRC programs will be
flight tested using the Lewis F-106 and also tested
in Ames 40f x 80* wind tunnel. The sources and treat-
ment of coannular jet noise, important for applications
to duct-heating turbofan engines, will be studied by
Lewis leading to later engine tests. Wind tunnel
techniques to be developed by ARC for the prediction
of the effects of forward speed on noise characteris-
tics will lead to testing of powered models of super-
sonic cruise aircraft.
The LeRC will continue the current in-house/contractor
clean combustor program which is aimed at reducing
the NOX emissions at supersonic cruise speeds to levels
which are only 90% of those of current subsonic air-
craft. Tests of candidate combustors will be tested
at flight conditions representative of those of long-
range supersonic cruise aircraft and these tests will
lead to the development of Low NOx combustors suit-
able for use in low-noise engines.
Inlet shock stabilization valve concepts and digital
integrated control techniques will be applied by the
Lewis and Flight Research Centers to the YF-12 air-
craft. The shock stabilization system will be tested
in the Lewis 10' x 10' wind tunnel and subsequent
flight tests will be conducted on a YF-12 which has
been modified to include the new system.
Major milestones of the SCAR Propulsion Technology program are:
Early FY 1975 - Initiate wind-tunnel tests of inlet
shock stabilization valve.
Mid FY 1975 - Initiate studies of augmentor pollution.
Early FY 1976 - Establish noise reduction potential of
suppressors for coannular jets.
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Need and Relevancy
The SCAR Propulsion research is for direct support of the Supersonic
Cruise Aircraft Research program. This work is of primary relevance
to the OAST focus on basic research on supersonic cruise aircraft.
The propulsion system is always a key technology area in the develop-
ment of any advanced aircraft. In the case of supersonic cruise air-
craft, additional constraints imposed by the need to reduce terminal
area noise (less than new widebody civil aircraft) and terminal area
and upper atmosphere pollution (ninety percent less than current
engines at high altitude cruise), while retaining cruise efficiency
for military aircraft and economic viability for civil aircraft,
present a set of interlocking problems which must be addressed through
noise suppression programs, clean combustor programs, and the initia-
tion of research on advanced low-noise engines which permit efficient
operation at both subsonic and supersonic speeds. In addition, since
very precise and complex propulsion controls are required to prevent
major interactions of propulsion system components as well as potential-
ly adverse interactions with airframe control systems, research on the
dynamics and control of supersonic propulsion systems must be conducted
by means of wind tunnel and flight tests.
We expect that the results of this research will provide the background
data which will lead to quieter, cleaner, and more efficient propulsion-
systems for both military and commercial supersonic airplanes.
OBJECTIVE DOCUMENTATION
Title; Supersonic Cruise Aircraft (SCAR) Aerodynamic Performance
~" ~ Technology
Type of Specific Objective
Discipline Study X System and Experimental Program
Organizational Element Responsibility
Advanced Supersonic Technology/Hypersonic Research Office -
W.S. Aiken, Jr.; L. Sternfield
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Statement of Specific Objective and Targets
Objective: To establish an expanded supersonic aerodynamics technology
base in parallel with the expansion of other supersonic disciplinary
technologies which will permit improvements in L/D, reductions in sonic
boom, and the translation of technical advances into integrated air-
craft systems. Specific targets are:
By FY 1977, validation of low-speed high-lift aero-
dynamic performance theories.
By FY 1978, verification of theoretical methods for
rapid analysis of critical design loads.
BY FY 1979, 30% increase in L/D over present state-
of-the-art for aerodynamic configurations meeting
all propulsion system, structure, and control
system restraints.
By FY 1981, 40% reduction in sonic boom during cruise
conditions potentially applicable to far term ad-
vanced supersonic transport designs.
Approach
NASA's fundamental research on supersonic aerodynamic performance is
conducted primarily by the Langley and Ames Research Centers. Primary
emphasis is placed upon evolving supersonic cruise aircraft concepts
which have high levels of supersonic performance, on obtaining suffi-
cient low-speed and supersonic wind tunnel data to permit optimization
of these concepts, and on the development of improved theoretical
methods for use in the design and analysis of both military and com-
mercial supersonic aircraft. The secondary emphasis is on the develop-
ment of a more complete understanding of the sonic boom phenomena which
are so critical to commercial overland supersonic flight.
Integrated supersonic cruise configuration concepts
which show promise of meeting the demanding require-
ments of future long-range supersonic cruise missions
will be developed by LaRC with extensive analyses
and wind tunnel tests. Both "near-term" concepts, which
depend on only small improvements in the related disci-
plines of structures, propulsion, and flight controls
to become viable supersonic cruise aircraft, and "far-
term" concepts which depend on extensive technology
advancements in all areas, will be considered. In
addition, the ARC will give consideration to unconventional
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concepts which might show future promise in an advanced
technology environment.
The purpose of the theory development program is to
fill the voids apparent in the recent United States
SST program. Needs for improved, and more rapid,
means for supersonic cruise aerodynamic design and
analysis methods; more valid means for predicting
critical wing and fuselage design loads; and methods
for analytically assessing the low-speed, high-lift
aerodynamic performance were indicated during this
program. LaRC will conduct contract studies to meet
the needs for better supersonic and loads methods
while ARC will direct a contract study to fill the
need for improved low-speed methods. The goal is
to combine the improved methods into a unified
design and analysis method which is applicable to
most classes of supersonic aircraft.
It is generally accepted that the future market for
commercial supersonic cruise aircraft would be more
than doubled if the sonic boom problem could be
solved of ameliorated. The SCAR sonic boom technology
will be directed towards obtaining a better under-
standing of sonic boom pehnomena and towards evolving
configuration concepts which have low levels of sonic
boom disturbance.
Major milestones of the SCAR Aerodynamic Performance research are;
Early FY 1975 - Complete Cornell University study of
sonic boom phenomena.
Mid FY 1975 - Extend contracts for improved supersonic
loads, and low-speed theory.
Late FY 1975 - Complete transonic tests of arrow-wing
propulsion and pressure distribution
model.
Need and Relevancy
The SCAR Aerodynamic Performance research is for direct support of the
Supersonic Cruise Aircraft Research program. This effort is of pri-
mary relevance to the OAST focus on basic research on supersonic cruise
aircraft.
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Improved aerodynamic performance in all flight regimes is critical in
the development of superior military and commercial airplanes. A thirty
percent increase in L/D would provide the option for an approximate
thirty percent increase in range or payload capability. In the case
of supersonic commercial airplanes, the additional constraint of sonic
boom and the need for high levels of low-speed aerodynamic efficiency
to reduce noise, seriously complicate the aerodynamic design and inte-
gration problems. In order to provide the technology for future super-
sonic cruise aircraft with either military or commercial missions,
advanced configuration concepts must be evolved, advanced theoretical
procedures for use in predicting and optimizing the aerodynamic per-
formance must be validated, and an extensive data base must be obtained
from wind tunnel tests of representative models. The SCAR Aerodynamic
Performance research is directed toward these needs.
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6. NASA
AIR TRANSPORTATION
SYSTEM STUDIES
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SHORT-HAUL TRANSPORTATION SYSTEMS ANALYSIS
The objective of this work is to help develop a sound technological
base for future decisions relating to the design, development, and
operation of short-haul transportation systems. This objective will
be achieved through a related group of studies that: examine the re-
lationships between short-haul technology and short-haul economics,
markets, and implementation; identify potential viable short-haul
airplane concepts and their design and performance criteria for practi-
cal short-haul transportation systems including consideration of
market, economic, and environmental factors; and, perform sufficient
aircraft design to provide a realistic assessment of technical problems
and questions regarding their design, development and operations, and
their development and operational costs. These data will be used to
help define the future direction of productive technical (and system
related) activity for short-haul transportation systems. This in-
vestigation will be performed in-house and under contract.
Two contracted studies (Lockheed and Douglas) to determine the opera-
tional and economic viability of turbofan powered propulsive lift
aircraft for short-haul transportation have been completed. Final
reports will be distributed in June. The current contracts have been
extented to (a) allow Lockheed to optimally design and compare the
OTW/IBF propulsive lift and mechanical flap concepts in terms of noise
impact and operating economics and (b) allow Douglas to determine the
impact on operating economics of the effect of combining terminal
area operations with various engine cycles to minimize community noise
impact for several propulsive lift and mechanical flap concepts.
ANALYSIS OF FUTURE CIVIL AIR TRANSPORTATION SYSTEMS AND CONCEPTS
The objective of this study is to provide systems analyses of future
civil air transportation systems and concepts in order to identify
promising aeronautical systems, determine optimum characteristics, and
define technology requirements and costs associated with such systems.
Studies of general aviation aircraft, CTOL, STOL, and VTOL transports,
advanced subsonic/transonic transport aircraft, and advanced super-
sonic transports will be conducted. Total system studies will be
carried out considering all of the interactions between aircraft, air-
ports, airways, community impact, and economics (both within the avia-
tion industry and on a national basis). In addition, studies of a
short term nature will be conducted in support of the aeronautical
program planning activities of ARC and OAST.
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HIGH TRANSONIC SPEED TRANSPORT (HiTST) SYSTEM STUDY
The objective of this study is to provide detailed configuration defi-
nition of a high transonic speed transport concept. The contract
system study of FY 1973 identified a promising yawed wing aircraft
at the conceptural design level. The study this year will provide
needed definition at a more detailed level, providing in-depth analysis
in several individual new technology areas, and adding credibility to
certain design concepts. Examples of such design studies would include
fatigue and flutter characteristics of composite structures, low speed
stability and control of yawed wing for emergency maneuvers, and new
engine technology applications for reduced noise.
SUBSONIC/TRANSONIC C/RTOL TRANSPORT TECHNOLOGY
SYSTEMS AND DESIGN STUDIES
This work covers systems and design integration studies for subsonic
C/RTOL long and medium-range passenger and cargo transport aircraft.
The objective is three-fold. (1) Make technology advances available
for superior subsonic C/RTOL transport aircraft to satisfy anticipated
requirements in the 1980's. Anticipated requirements include the
need to improve aircraft cruise efficiency not only for better economics
but also for energy (fuel) savings; to alleviate terminal-area conges-
tion; and to reduce aircraft noise and emissions without suffering
economic penalties. (2) Determine the feasibility of utilizing air-
craft fuels other than JP fuel for subsonic cargo and passenger air-
craft as a potential partial solution to a projected shortage of petrol-
eum in the 1990's and to identify aircraft-technology requirements
peculiar to alternate fuels. (3) Investigate new approaches to provid-
ing more economical subsonic transport of liquid and solid cargo in
anticipation of the need for a greatly increased air transport of
cargo.
SUBSONIC/SONIC CTOL TRANSPORT TECHNOLOGY PROPULSION STUDIES
NASA has initiated an effort to study the application of advanced
technology to the improvement of future commercial transport aircraft.
The results were resolved in terms of economic factors involving param-
eters such as aircraft drag, propulsion efficiency, costs, and pro-
pulsion system noise and exhause emissions. Detailed analyses has been
completed through in-house and contract studies and have been documented
in NASA Contractor Reports. Results indicated that the environmental
constraints imposed compromises to the the optimum fixed-area turbofan
cycle with resulting economic penalties. The studies also indicated
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areas where advanced technology would decrease the noise and emissions
and improve the system economics.
Results of recent studies of unconventional cycles have indicated that
to achieve low noise, variable geometry inlets in conjunction with
variable-area exhaust nozzles will be needed. Also, the use of high
throat Mach number inlets appear to offer significant performance and
economic improvement over inlet splitter rings. Several designs,
including hybrid variable geometry cowls, expanding and translating
centerbody types, and translating ring-type inlets were proposed for
further study.
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7. NASA
GENERAL AVIATION
NOISE TECHNOLOGY
PROGRAMS
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OBJECTIVE DOCUMENTATION
Title; General Aviation Aerodynamic Technology
Type of Specific Objective
XX Discipline Study System and Experimental Program
Organizational Element Responsibility
Aerodynamics & Vehicle Systems Division - Roger L. Winblade
Statement of Specific Objective and Targets
Objective: To develop and demonstrate advanced technology for general
aviation use that will permit the design of future U.S. aircraft that
are safer, more productive and clearly superior to foreign competition.
The following targets have been established to provide the advanced
capabilities and design techniques necessary to achieve the stated
objective.
Flight demonstration in FY 1975 of low speed airfoils
with a 30% increase in CLmax maintaining the same or
less cruise drag.
Application of supercritical aerodynamic technology by
all U.S. business jet manufacturers by 1975.
Flight demonstration by FY 1976 of pilot displays and
control systems to improve flight path control and
landing performance with special application to
- pilot training
- pilots who fly infrequently
- landing at unfamiliar airfield
- night landings
- emergency conditions
Provide definitive design criteria, test, and evaluation
techniques by FY 1976 for aircraft that will not spin
unintentionally.
Establish design criteria for airfoil sections and plan-
forms optimized for low noise propellers by FY 1976.
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Approach
Analytical and experimental efforts are directed toward the generation
of design data for safer more productive general aviation aircraft.
Simulators, wind tunnels and when appropriate, experimental aircraft
will be utilized in programs addressing the problems and limitations
unique to the general aviation category of aircraft. Improved safety
and utility are predominate factors; however, user requirements, manu-
facturing and cost limitation and certificability are significant
factors in development and conduct of the technology programs.
Both analytical predictions and wind tunnel testing
have been used to develop a new low speed airfoil
section. The characteristics of the new airfoil show
an increase of 30% in C^^ and a 50% improvement in
L/D when compared to airfoils currently in use.
Experimental flight verification will be accomplished
through the testing of a modified aircraft incorporating
new wings designed with this airfoil section. The
wing design was completed in FY 1973 with fabrication
by a general aviation manufacturer underway in FY 1974.
Detailed flight testing in FY 1975 will provide a
completed data package including analysis, wind
tunnel data, application techniques and flight verifi-
cation.
Supercritical aerodynamic theory, while developed in
the context of large transports and military aircraft,
will be of significant advantage to business jet air-
craft. Classification of supercritical data requires
implementation of specific agreements under which the
necessary access to data can be authorized. Such
agreements, providing data, technical consultation
and NASA wind tunnel validation of the resulting
designs, are in effect with four U.S. business jet
manufacturers. Discussions are underway with the
remaining two U.S. companies concerning similar
arrangements.
Direct modulation of the L/D ratio has been shown to
provide significant improvements in the precision of
flight path control and reduction in touchdown dis-
persion when properly integrated into the pilot's
task. The successful completion in FY 1974 of the
direct drag control (plate spoilers) effort to
demonstrate the feasibility of using spoilers on
powered light aircraft is being followed by a similar
effort on direct lift control in FY 1975 and FY 1976.
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An aircraft modified to incorporate the slot spoiler
lift modulation concept will be utilized to obtain
definitive data on effectiveness and operational
characteristics. Simulation and actual flight tests
of an experimental "breadboard" version of a simple
head-up display presenting information on angles of
attack and sideslip as well as airspeed have shown a
beneficial effect on the landing performance of
selected pilots with considerable experience in light
aircraft. Continuing flight verification of this and an
improved prototype version will be performed with pilots
of lesser skills and experience to demonstrate the
effectiveness of the unit and application in the
operational environment.
The stall/spin problem currently is the largest
single factor in general aviation fatal accidents.
The program initiated at the Langley Research Center
in FY 1973 to define the criteria and design techniques
for spin resistant airplanes is intended to alleviate
that problem. Exploratory investigations will be
conducted at Langley and Ames on both aerodynamic and
avionic methods for preventing stalls and spins.
Wind tunnels, radio controlled models and full scale
aircraft are being used to identify and document
the critical aerodynamic characteristics relative
to spin entry and recovery. Modernization of the
tail damping power factor criteria is a primary
aim of this effort, as is the development and
demonstration of an economically viable radio
controlled model testing technique for preflight
verification of spin characteristics. A compact
and easily-installed spin recovery system employing
monopropellant (hydrogen peroxide) thrusters and
a self contained fuel supply system is to be developed
and flight tested to demonstrate the suitability of
this type of system for basic spin research and possible
use by manufacturers in their spin certification
tests.
Both in-house and university grant efforts are being
directed toward development of modern design criteria
for propellers. Operational and manufacturing compro-
mises have resulted in propellers that currently operate
well below the theoretical maximum efficiencies. During
FY 1975 and 76, concentration will be on application of
advanced aerodynamic theory to optimizing planforms and
airfoil sections for maximum noise. Optimized blade shapes
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will be fabricated from both conventional materials
and composites to investigate potential benefits of the
newer manufacturing techniques.
Need and Relevancy
The impact of general aviation on the air transportation systems in
terms of numbers of operations, flight hours, and people transported
has been well documented. The projected large increases in this ac-
tivity are validated by past history. With 500 million intercity
travelers projected to be using general aviation by 1985, it is impera-
tive that a vigorous technology program be directed at improving the
safety of these operations.
The general aviation industry in the United States currently exports 20
to 30% of its production. This market has been maintained primarily
through the technical superiority of the U.S. manufacturing. Countries
in Europe, South America, and Asia, through government support, are
rapidly developing their general aviation industries. Projections to
the 1985 time period indicate that unless the U.S. industry can gener-
ate aircraft that are technologically superior, the emerging foreign
competition will not only absorb the export market but will make
significant inroads into the domestic market as well.
SPECIFIC OBJECTIVE
Title; Quiet, Clean General Aviation Turbofan
Management Responsibility
David J. Miller/Aeronautical Propulsion Division
Specific Objective
The specific objective of this program is to identify, extend, and
demonstrate the technology applicable to small general aviation turbo-
fans to achieve future environmental requirements with economic
viability.
Targets
Perform studies to define an experimental technology
demonstration program, January 1976.
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Contract award February 1976
Critical design review June 1976
Delivery of experimental engine for test May 1977
Need and Relevancy
The use of small aircraft has the potential to create a more widespread
adverse community reaction to jet noise and pollution than do transport
aircraft. This "is so because minor airports used by small aircraft
are apt to be located near suburban residential areas unprotected by
commercial/industrial buffer zones. Jet powered general aviation air-
craft sales are increasing at a faster rate than the rest of general
aviation aircraft.
Existing FAR 36 noise restrictions probably can be met by new production
aircraft. It is probable that these restrictions will be tightened to
require reduced noise levels for the next generation of aircraft.
EPA emissions standards applicable to subsonic gas turbine engines of
less than 8000 Ib thrust will enforce a more stringent set of criteria
for all engines manufactured after January 1, 1979. No current small
turbofan or turbojet engine can meet these 1979 emission standards.
Approach
Program definition studies will be accomplished during FY 1975 as part
of the R&T Base TecHnology program. The studies, to be performed by
general aviation turbofan manufacturers will:
1. Analyze the applicability of large engine technology
(noise/pollution) to general aviation turbofans.
2. Examine other factors significant in improving the
applicability of small turbofans to general aviation.
A program plan will be included as part of the FY 1975 studies.
The Quiet, Clean, General Aviation Turbofan (QCGAT) program will be a
contracted effort. A single contractor will be competitively selected
for the experimental program. This program will include design, fabri-
cation, assembly, and ground tests of the experimental engine. Further
ground testing will be performed by NASA. Extensive use will be made
of existing engine component technology and existing engine cores in
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order to hold down costs. Cost sharing will be explored.
There is no intention to proceed into a development program for a
flight demonstrator engine.
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II. DOT AIRCRAFT NOISE PROGRAMS
1. DOT/FAA AIRCRAFT NOISE
PROGRAMS
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SOURCE NOISE REDUCTION PROGRAMS
The objective of this program is to develop a noise source pre-
diction capability for all categories of aircraft. This program in-
volves the investigation and determination of the parameters that
cause or influence the actual generation of noise emanating from
aircraft, definition of noise sources and methods of reduction plus
development of guidelines for changes to the engine and aircraft
configuration required to minimize noise. Aircraft noise source ele-
ments are identified as follows:
Turbo machinery
Jet mixing
Combustion/case
Propeller and rotor
Airflow surface interaction
Lift augmentation
Reciprocating engine
Duct acoustic lining
Aircraft configuration noise shielding
Source noise reduction research and development efforts can conven-
iently be described according to aircraft type: CTOL (transonic, sub-
sonic and supersonic) and V/STOL. The schedule of major activities
is described below and is shown in Table 1. A continuing effort to
update and add to current capabilities is planned for both CTOL and
V/STOL aircraft types through both in-house and contract activities.
It is important that the latest technology in noise prediction and
reduction techniques be readily available so that community exposures
can be accurately estimated and noise control can be implemented by
technologically practicable and economically reasonable regulations.
Core Engine Noise Control
The purpose of this project is to provide theoretical and ex-
permental data to assist the designers in developing future aircraft
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Table 1
AIRCRAFT NOISE ABATEMENT SOURCE NOISE REDUC1ION
Program Schedule 1972-1977
Program Elesent/Subprogras | CY
Sou-rce Koiso Reduction 202-551
CTOL Aircraft
Source Noise Prediction & Reduction
Core Engine Noise Control
Prediction of Aircraft Configuration
Effects
General Aviation Aircraft
Retrofit Feasibility
Coeaerclal Jet Aircraft (SAM)
Executive Jet Aircraft
V/STOL Aircraft
Source Solse Prediction and Reduction
Jet Propulsors
Rotary Propulsors
n 73 74 75 75 77
1972
Award
f
Award
V
1973
1974
Continuing
1975
Effort
1976
Gun GVneracor
Report
V
i
Award
Vl
A;'ard ' Report
^ V
1
Report
T7
r
727
T?
707 DC-9
V V
Award
T7
1
I
1
Award
VI
Rcpor t
V
1
Coruinuir
e Effort
V7
Award
V
Report
r?
1977
1
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capable of conforming to lower noise levels than are now required by
FAR Part 36. The effort shall be directed to identifying, evaluating,
and controlling the component noise sources inherent in the core en-
gine (the gas generator) which establishes the limit of effectiveness
of the current noise control state-of-the-art.
For the purpose of this project, core engine noise is defined as
the noise produced by the gas generator portion of the gas turbine
engine either solely or as influenced or amplified by the fan dis-
charge, tail pipe, and/or any other portion of the exhaust system.
Core engine noise shall be assumed to radiate only in the aft engine
quadrant and its sources may be generated either upstream or down-
stream of the tail pipe exit plane. Core engine noise shall not be
assumed to contain compressor generated noise radiating from either
the engine inlet or fan exhaust ducting; Core engine noise, however,
may include compressor generated noise transmitted downstream through
the engine flow passages or fan generated noise enhanced by inter-
action with the core engine noise or gas stream.
Prediction of Aircraft Configuration Effects
The purpose of this project is to study the feasibility of use
of aircraft configuration and engine placement to reduce noise propa-
gation to the ground plus development of prediction procedures for
configurations of practical interest.
General Aviation Aircraft
This project covers a survey and definition of the noise charac-
teristic of all general aviation aircraft plus development of suitable
noise prediction capabilities.
Retrofit Feasibility
« Current Commercial Jet Aircraft - The purpose of this project
is to provide test data to assist in determining whether cer-
tain classes of turbofan propelled airplanes in the current
fleet can be modified for meaningful noise reduction in a
feasible manner. Feasibility relates to three key instructions
contained in Public Law 90-411; that is, the noise abatement
methods must be technologically practicable, economically
reasonable, and appropriate for .the particular type of air-
craft, aircraft engine appliance, or certificate to which
it will apply. The effort is directed to providing acoustical
treatment, designed to conform to specified noise reduction
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goals. The acoustical treatment may be any hardware or mech-
anical device, applied either singly or in combination with
the inlet and primary and secondary exhausts that will either
absorb sound or otherwise effect a noise reduction at the
FAR Part 36 measurement positions. Current retrofit programs
for 727 aircraft will be completed in FY 1973; 707, DC-8,
and DC-9 retrofit programs will be completed in FY 1974. The
effort is directed to providing nacelles that are capable of
being certificated. Results to date indicate that the retro-
fitted aircraft can comply with FAR Part 36.
Executive Jet Aircraft - A retrofit feasibility program cover-
ing business jets is planned to follow the commercial retro-
fit project. The number of this type of aircraft is more
than one-half that of the commercial fleet considered for
retrofit and is growing rapidly. The purpose of this project
is the same as given above for commercial jets. This program
will draw upon knowledge gained and relate closely to the
commercial jet program covered above. It is scheduled for
completion in FY 1976.
V/STOL
V/STOL aircraft have propulsive lift systems that are distinctly
different from conventional aircraft. Both rotary and jet propulsion
systems are being considered. It is anticipated that V/STOL air-
craft (including helicopters) will supply a major segment of the
short haul transportation requirements in the near future. These
aircraft, which are being considered for city center airports, may
cause substantial increases in noise exposure for adjacent urban
areas and also for suburban areas under the cruise path.
This effort is directed to identification, evaluation and con-
trolling component noise sources inherent in V/STOL systems. Both
jet propulsion and rotary propulsion systems will be studied. Pre-
diction techniques will be developed.
OPERATIONAL NOISE REDUCTION PROGRAMS
The objective of this program element is the determination, in-
vestigation and measurement of significant factors which affect the
transmission of noise from its source to the airport community. Ele-
ments are identified as follows:
Aircraft Operational Procedures
164
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c Atmospheric Parameters
Operational noise reduction is a continuing effort through both in-
house and contract activities. Information developed will be used
to update FAR Part 36, and in future noise rules. Projects apply to
certification measurement and compliance.
The operational noise reduction program plan is presented in
Table 2 and elements of the program are discussed below.
Noise Propagation Measurement and Evaluation
This program element will include studies of ground attenuation
and of the importance of temperature and humidity measurements along
the noise propagation path versus ground measurements only in correct-
ing flyover noise measurements to standard conditions as currently
required by FAR Part 36. This project could provide a refinement to
FAR Part 36 and to improved accuracy in calculation of noise exposure
areas.
Noise Measurement
This program involves development of methods and equipment for
noise measurement. The project objectives are to develop noise mea-
surement systems with capabilities suitable for certification research,
studies of noise abatement operating procedures, long-range noise
propagation, and community noise exposure. Certification measurement
capability objectives include commercial subsonic and supersonic
aircraft, general aviation including business jets, plus VTOL and
STOL aircraft.
Increasing air traffic brings with it increasing complexity in
airport noise patterns and as a consequence, more complete automatic
and sophisticated measurements will be needed to determine the extent
of the noise exposure. It would therefore be technologically advan-
tageous to develop noise measurement systems capable of handling ex-
tensive measurement tasks, at greater accuracies, then the conven-
tional systems.
NOISE EVALUATION AND RESPONSE
The objective of this program element is to determine the effects
of noise on individuals and on the community as a whole; to develop
methods required to predict the reaction of communities to noise
resulting from varying numbers and types of aircraft; and to develop
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Table 2
AIRCRAFT NOISE ABATEMENT -- OPERATIONAL NOISE REDUCTION, NOISE EVALUATION AND RESPONSE
Program Schedule -- 1972-1977
cr«
Program Eleaent/Subprograa
Ct
Operational Noise Reduction «*O'2-S5»'2.
Research and Technology Base
Noise Propagation Measurement
and Evaluation
Noise Measurement Systems
~FY
73
1972
74
1973
75
1974
Continuing
76
1975
Effort
77
1976
1977
"
Report Award
*& V
1
L
Report
V
*vard
Report Design Avard
t7 1 V
Install
Ope
acional
I
1
-------
and/or refine acceptable yardsticks for evaluation and rating of var-
ious levels of aircraft noise. The program schedule is included in
Table 2. Elements of noise evaluation and response are identified
as follows:
Noise exposure evaluation
» Community response surveys
Subjective noise evaluation
Psychoacoustic studies
Noise exposure forecasting
Research to improve the technology base in this area is a continuing
effort through both in-house and contract activities.
Current and planned projects are outlined below;
Noise Exposure
Noise Evaluation and Community Response - The purpose of this
project is the development of accurate and comprehensive noise
evaluation criteria suitable for application to all CTOL
aircraft including business jets and also suitable for appli-
cation to V/STOL aircraft.
Psychoacoustic laboratory and field tests will be con-
ducted on response of human beings to aircraft sounds and
noise evaluation measures developed for regulatory purposes
by statistical correlation of test results. Investigations
will be made of the significance of various annoyance factors
such as multiple tones, speech interference, amplitude and
duration of tones, doppler shift, low frequency effects,
transient and impulse effects, and the rate of onset and in-
tensity on duration.
Noise Certification Criteria - Objectives cover development
of techniques for noise measurement and analysis for use in
certification of all aircraft categories, refinements to FAR
Part 36 for CTOL aircraft plus development of criteria for
business jets and V/STOL aircraft. Included are considera-
tions of multi-segment or complex flight paths plus data ac-
quisition and analysis systems. Work will include measurement
and analysis of the aircraft noise and determination of
167
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procedures and equipment which will promote development of
measurement and analysis standards.
SOURCE SONIC BOOM REDUCTION PROGRAMS
FAR Part 91.55 prohibits civil aircraft operations at true flight
speeds greater than Mach 1 to prevent any sonic booms from reaching
the ground. However, it is known that it is possible to fly up to
speeds of Mach 1.4 without causing a sonic boom to reach the ground
under certain conditions. Therefore, a demonstration was conducted
during 1973 utilizing simulated operational techniques for long-
range cross-country supersonic flights at Threshold Mach Number (Be-
tween 1.0 and 1.3) which theoretically did not generate sonic booms
on the ground. This is Phase II of a four phase effort to develop
a definition of the air and ground system requirements for successful
supersonic Thresholds Mach Number operation. During 1974, based on
Phase II results, conduct a SR-71 (YF-12) or F-lll transcontinental
flight at Threshold Mach Number and not produce a sonic boom on the
ground. Define and update the system requirements for boomless super-
sonic transcontinental flight during 1975 through 1977.
OPERATIONAL SONIC BOOM REDUCTION PROGRAMS
This effort will provide, during 1973, two prototype digital
lightweight inexpensive sonic boom recorders for future field use to
provide an improved capability to record signature data during sonic
boom test and monitoring programs. Based on prototype tests results
during 1974, obtain production units for operational test program
during 1975. The FAA will also provide atmospheric sounding aircraft
during joint FAA, NASA, USAF, and NOAA operational programs to obtain
real-time atmospheric data (winds,, turbulence, and temperature) for
use in long-range Threshold Mach Number operational feasibility
studies during 1973 through 1975, i.e., boomless transcontinental
supersonic flights. Program schedules are in Tables 3 and 4.
Sonic Boom Atmospheric Effects
Studies are being conducted to identify measureable features of
the atmosphere, both large scale and small scale, which cause statis-
tical variations in sonic boom measurements. Attention will be given
during 1974 through 1977 to establishment of a correlation between
observed overpressure variability and local atmospheric conditions to
provide a basis for prediction of that variability. The program will
include theoretical and experimental work aimed at determining sonic
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Table 3. SONIC BOOMSOURCE SONIC BOOM REDUCTION, OPERATIONAL SONIC BOOM REDUCTION
PROGRAM SCHEDULE -- 1972-1977
FY
73
74
75
76
77
Program Element/Subprogram
CY
1972
1973
1974
1975
1976
1977
VO
Source Sonic Boom Reduction
Supersonic boomless flight
research
Ft. Worth F-lll/F-8 opera-
tional research boomless flight;
other operational program
Operational Sonic Boom Reduction
Sonic boom signature prototype
digital recording system
Operation, maintenance, and data
collection during operational
programs
Phase I
Phase II
Phase II]
Final
Trans
Phase IV
System Final
RFP Award Report Flight RFP Award Report
V V IV VI V V I V '
Phas
Award
V
>. I
Report
V
Phase II
Report
V
Phase III
Report
V
Final Re
V
Award
V
De- Fielc
livery Test
V V j
2 Prototype
Recorder
V
ort
-------
Table 4
SONIC BOOM -- SONIC BOOM EVALUATION AND RESPONSE
Program Schedule 1972-1977
1
Prograa Elecenc/Subprograa . i CY
Sonic Booa Evaluation a-d Response
Sonic Booa Certification Prograa:
Ambient noise effect on booa loudness
Subjective evaluation of sonic booa
perceived level; startle and coxrcunity
response
Wildlife Animal Response (Ft. Worth)
other operational programs
Effects on structures
Class damage preduction model. Plaster,
Bric-A-Brae, and other oaterial
Response of marine life; follow-on study
Aoplicability of existing calculation
procedures to sonic booa noise
n
73
1972
Awa
V)
74
73
Award
rd
1
75
1974
Final
1
Final Report
i J
Report
1
Award
76
1975
I
1 t
Award Final Report Award
to iv . v
Award
|
Final
Report
S7
1
Award
Award
1
J
Final Ueport
]
final Ueport
V
1
Avard
Award
Final
|
I
Final
77
1976
Final Report
i
Final Report
Report
I
Report
I
1977
-------
boom pressure signatures associated with aircraft operations at or
near Threshold Mach Number.
Sonic Boom Criteria
A sonic boom criteria research program is currently working to
develop better technical and social criteria for sonic boom in accor-
dance with Public Law 90-411 to form definitive guidelines upon which
to base government and industry policies for both the design and regu-
lation of supersonic and transonic commercial aircraft. The objective
is to develop a consistent technical rationale based on the multiple
technical and social criteria found from research that will assist
in revising and updating administrative policies and decisions re-
garding certification limits and provide industry with a design window
for supersonic operations.
Sonic Boom Effects on Structures
Structural damage due to moderate sonic booms has been primarily
centered on damage to glass, plaster and bric-a-brac. Glass breakage
is of primary importance. During 1974 and 1975 this work will de-
velop sonic boom criteria in terms of equivalent response of windows
to such natural forces as wind gusts, thunder and in terms of building
codes applicable to window glass installation. This program will
include flight programs, as well as simulator studies.
Test of Existing Noise Calculation Procedures Applicability to Sonic
Boom
During 1973 and 1974, test the applicability of existing calcu-
lation procedures which scale annoyance and loudness reactions to
steady state, time varying, and impulse noise. The object is to de-
velop a simple method that would apply equally well to a variety of
noises which would then be highly useful for multiple regulatory
missions.
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2. DOT/FAA JULY 25, 1974 TESTIMONY ON AIRCRAFT
NOISE PROGRAMS BEFORE THE HOUSE
SUBCOMMITTEE ON AERONAUTICS
AND SPACE TECHNOLOGY
173
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STATEMENT OF FREDERICK A. MEISTER, ACTING ASSOCIATE ADMINISTRATOR
FOR POLICY DEVELOPMENT AND REVIEW, FEDERAL AVIATION ADMINISTRATION,
DEPARTMENT OF TRANSPORTATION, BEFORE THE HOUSE COMMITTEE ON SCIENCE
AND ASTRONAUTICS, SUBCOMMITTEE ON AERONAUTICS AND SPACE TECHNOLOGY,
JULY 25, 1974, REGARDING AIRCRAFT NOISE ABATEMENT EFFORTS.
Thank you for the opportunity to appear before you today, Mr. Chairman.
I am Frederick A. Meister, FAA Acting Associate Administrator for
Policy Development and Review. Appearing with me today are Charles
R. Foster, Director of the Department of Transportation Office of
Noise Abatement, and Richard P. Skully, Director of the FAA Office
of Environmental Quality.
In passing the Noise Control Act of 1972 the Congress declared it to
be the policy of the United States "to promote an environment for
all Americans free from noise that jeopardizes their health or
welfare." The Congress further authorized and directed Federal agencies
to carry out the programs within their control in such a manner as
to further that declared policy of the United States "to the fullest
extent consistent with their authority under Federal laws administered
by them." Section 7(b) of the Noise Control Act directs the Adminis-
trator of the Federal Aviation Administration to prescribe such regu-
lations as the FAA may find necessary to provide for the control and
abatement of aircraft noise "in order to afford present and future
relief and protection to the public health and welfare." (emphasis
added).
By statute it is the FAA which has the responsibility, after con-
sultation with the Secretary of Transportation and EPA, to prescribe
standards for measuring aircraft noise and for prescribing regulations
for the control and abatement of aircraft noise.
Mr. Chairman, the FAA is taking this Congressional mandate seriously
and is in the process of implementing an aggressive program to control
and abate aircraft noise. As evidence of our resolve to help achieve
a better environment for all Americans, steps have been taken to
double the size of the FAA Office of Environmental Quality. In addi-
tion, the Administrator has recently released a draft FAA Five Year
Environmental Program which defines FAA environmental policy and
delineates a five-year program designated to implement-that policy.
Three parts of our overall noise abatement program relate to the
design and operation of aircraft.
First is the imposition of maximum noise limits for all types of air-
craft to insure that individual aircraft noise levels will not increase
as newer, more powerful aircraft types are designed, and to insure
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that the best available noise reduction technology is included in the
design of all new aircraft. In 1969,the FAA promulgated Federal Avia-
tion Regulation Part 36 which put a lid on the escalation of aircraft
noise levels of new subsonic turbojet transport aircraft. In 1973,
Part 36 was amended to include newly produced aircraft, including those
of older designs not previously covered. As you know, we have pro-
posed a retrofit regulation to cover all large civil transport air-
craft, requiring that older models not previously covered be modified
to lower their noise levels to at least Part 36 limits. That proposal
will be the subject of detailed discussion in a moment. We will soon
promulgate a regulation limiting the noise levels of propeller-driven
airplanes. The final Environmental Impact Statement for this regu-
latory action is in the process of being forwarded to the Council on
Environmental Quality. We have solicited public reaction to our
proposal to establish noise limits for short haul aircraft, and we
are preparing a proposal for noise limits for civil supersonic air-
craft. In this step-by-step manner, we are setting maximum noise
limits for all categories of civil aircraft.
The second step in our program involves the use of approach and depar-
ture operational procedures which will reduce noise impact around
our airports. The FAA views the control of aircraft noise through
the use of operational procedures to be a promising and practical means
for obtaining early noise relief. We have for many years been experi-
menting with takeoff and approach procedures, passive and dynamic
preferential runway procedures, noise abatement routing, and terminal
area handling of aircraft to achieve noise control.
Noise abatement takeoff operating procedures designed to provide maxi-
mum separation between aircraft and the communities overflown were
developed jointly by FAA and ATA and are now in wide use.
Noise abatement approach operating procedures developed jointly by FAA
and NASA include a two-segment glide slope which provides noise re-
duction by use of lower power settings and higher altitudes during
the initial phase of an approach. A few airlines have been using two-
segment approaches safely and efficiently for over one year during
VFR weather conditions. The joint NASA/FAA research on two-segment
approaches has reached the point where in-service operational imple-
mentation is progressing under instrument flight rule (IFR) conditions
as well. In fact, a major airline has conducted in-service operations
for NASA with a B-727 aircraft under VFR and IFR weather conditions.
NASA is currently working with United Air Lines on two-segment ap-
proaches utilizing Douglas DC-8 aircraft. The FAA has recently issued
an Advance Notice of Proposed Rule Making seeking advice and comments
on this two-segment approach procedure. I will give you a rundown
of the comments received to date later on.
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Another means of maximizing aircraft to ground separation distances
to provide community noise relief is to change allowable minimum alti-
tudes. The utilization of higher minimum altitudes as a means of
achieving noise reduction has been implemented and is providing sig-
nificant noise relief. An Advisory Circular was published in August
1972 to deal directly with VFR flight near noise sensitive areas.
phis has resulted in pilots making VFR flights near ^recreational and
park areas, churches, hospitals, schools, and similar areas at higher
altitudes than previously flown and permitted by regulation in order
to reduce aircraft noise impact on the ground.
third step in our program, oriented more for the future, is the
progressive reduction of present permissible noise levels. -We are not
content with present noise levels --we are striving constantly to
improve the state-of-the-art to lower these noise levels. Part 36
limits have now been in effect four and one-half years, and we are
giving serious consideration to proposing a lowering of those limits
to increase their stringency. We will of course continue to support
effective research to develop and demonstrate just what future reduc-
tions may be feasible. And so, in brief, this covers that portion of
olir aircraft noise abatement program relating to the design and opera-
tion of aircraft.
j would like to turn now to a discussion of the retrofitting of the
current commercial jet fleet to meet FAR 36 standards.
technical development of means for quieting the present fleet has
underway for more than six years. This joint industry-government
effort has resulted in the expenditure of well in excess of $100 mil-
lion. The major steps taken in this program were as follows: first,
an early NASA program provided proof of the technical concept of using
gOund -absorb ing materials in nacelles, which I shall refer to as SAM,
co control aircraft noise; second, an FAA nacelle jet suppression and
flight test program was conducted; third, feasibility studies and
flight demonstrations were made, followed by actual certification of
the Boeing 727 and 737 and the Douglas DC-9; and, finally, a decision
^as made that we were ready to initiate formal regulatory action as
required by law. On March 27, 1974, a Notice of Proposed Rule Making
was published which, if adopted, will provide the means of assuring
that all currently available -acoustic technology is applied to in-
service commercial aircraft. The rule would require that subsonic
turbojet aircraft, having maximum weights of 75,000 pounds or more,
co conform to Part 36 noise levels by not later than July 1, 1978.
Behind this proposed rule is our conviction that utilizing the tech-
nology of sound absorbing material in engine nacelles is available now
providing additional, significant relief from aircraft noise.
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Before we embarked upon this rulemaking procedure, Mr. Chairman, we
had to assure ourselves that the SAM nacelle treatment would provide
meaningful relief, that is, we were looking for a reduction in noise
levels which would be sufficient to significantly reduce annoyance
levels for persons living near airports. I would like to point to
three important items of evidence which in my view go a long way
toward dispelling any doubts that the SAM retrofit program would pro-
vide that meaningful relief.
First, it is a fact that today's airport neighbors notice and appre-
ciate the reduced noise levels of the new wide bodied aircraft. These
aircraft meet the same Part 36 noise levels as the older aircraft
would meet with the SAM retrofit.
Second, a joint FAA-Boeing Company project, which culminated in May
1973 flyover demonstrations for members of Congress and the public
at Dulles International Airport, demonstrated that takeoff noise re-
ductions of 11 EPNdB and approach noise reductions of 15 EPNdB were
achievable using nacelles quieted with sound absorbing material on
a JT3D-powered Boeing 707 aircraft. There was general agreement among
those witnessing the flyovers of a B-707 treated with sound absorbing
material in a configuration capable of being certificated and a B-707
without such material, that the noise reduction was highly significant
and clearly perceivable.
Third, a NASA-sponsored approach noise study conducted by Professor
Paul N. Borsky of the Columbia University Noise Research Unit has
concluded that significant reductions in annoyance resulted from the
use of exposure to synthesized nacelle treatments equivalent to a
JT8D-powered Boeing B-727 with the SAM treatment as compared to a stan-
dard B-727 aircraft. Professor Borsky, of Columbia's School of Public
Health, College of Physicians and Surgeons, is one of the world's
leading experts in assessing community response to aircraft noise. He
used test subjects living in the vicinity of Kennedy International
Airport. Significantly, there was a 50% reduction in the number of
test subjects who had expressed highest annoyance to the standard
Boeing 727 aircraft as compared to the acoustically treated B-727.
This 50% reduction was achieved with a difference of 6 EPNdB between
the two aircraft. We would anticipate a very meaningful response for
the Boeing 707 mentioned a few moments ago relative to the Dulles
flyover demonstrations.
I would also like to point out that in addition to the SAM retrofit
it is possible to tailor approach and departure procedures to achieve
even greater relief than can be achieved by SAM. The two-segment
approach procedure and a power reduction on takeoff are examples of
procedures we are investigating.
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Next I would like to give you a rundown of the comments received on
the fleet retrofit NERM and the two-segment approach Advance NPRM.
Nearly 600 comments were received on the retrofit NPRM, of which some
500 were from private citizens and citizen groups. The overwhelming
majority of citizens and citizen groups were for immediate promulga-
tion of the final rule. With regard to the industry* the Air Trans-
port Association and commenting air carriers expressed total opposi-
tion to the proposed rule as written. Particular concern was expressed
over the possibility of performance penalties and the amount of benefit
considering the price tag. Regarding the manufacturers, the Aerospace
Industries Association of America and the Boeing Company, while not
opposing the rule as such, expressed little enthusiasm and support for
an immediate go ahead, while the Douglas Aircraft Company was firm
in its opposition to the rule. The international carrier community,
represented by IATA, and several foreign governments expressed oppo-
sition for several reasons. A further discussion of the international
reaction will be given a little later.
U.S. Airport Operators, whose jurisdictions are facing a total of some
$4 billion in aircraft noise damage claims, strongly endorsed and
urged immediate adoption of the rule. From this group we heard from
some 25 city, county and state airport or transportation authorities
plus the airport operator associations.
Private aircraft owners and operators did not, in general, support
the rule, expressed doubt that SAM would produce appreciable relief
and expressed concern over the program's expense.
We also heard from the Department of State, which expressed concern
over unilateral U.S. action, and the Environmental Protection Agency,
which concluded that the proposed regulation represents a substantial
step in the right direction.
By the way, with regard to comments received on the two-segment approach
Advance NPRM, the line-up was roughly the same. Private citizens, citi-
zen groups, city governments and airport operators favored adoption of
the two-segment approach. Those opposed included ALPA, AOPA, NBAA
and the International interests. Those expressing strong reservations
were ATA, Boeing and GAMA.
There are two basic problem areas associated with putting the retro-
fit rule into effect, namely, the international implications of the
rule and the problem of how the retrofit program should be financed.
I would now like to discuss these two problem areas.
The retrofit NPRM applies not only to U.S. registered aircraft, but
also to foreign civil subsonic turbojet powered aircraft of 75,000
pounds or more that land or takeoff in the United States. The inclusion
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of foreign civil aircraft was considered essential because the air-
ports having the most serious noise problems are generally those served
most frequently by foreign operators. The bulk of comments received
from the international community took strong exception to the pro-
posed rule on the basis that it amounted to unilateral action in an
area which ICAO should coordinate. The Department of State expressed
concern over possible proliferation of conflicting standards affecting
international civil aviation if the United States took unilateral ac-
tion without either reaching agreement through ICAO, or at least by
coordinating plans with other major civil aviation countries.
The international problems associated with the rule are difficult, but
their impact has not been ignored. In fact, last month Administrator
Butterfield met in Montreal with ICAO President Binaghi, the Secretary
General of ICAO, a number of the members of the Secretariat, Council
members and Air Navigation Commissioners. The Administrator made it
clear to Dr. Binaghi that it was not the desire of FAA to act uni-
laterally and that we continued to support a multilateral approach.
He did not, however, commit the United States to multilateral agree-
ment with respect to the retrofit requirement because we are still
considering foreign aircraft operating into the United States for in-
clusion in our aircraft noise reduction actions. We are hopeful that
our actions in this area will stimulate multilateral action similar
to the multilateral action which followed the issuance of Part 36.
The question of financing the retrofit program is central to a deci-
sion to put the proposed rule into effect. We know the program will
be expensive, some $600 to $700 million to retrofit the existing fleet.
I believe this issue, more than any other, accounts for the industry's
lack of support.
In issuing the NPRM we solicited recommendations for financing the
cost of the retrofit program. A number of suggestions were made,
including use of the Airport and Airways Trust Fund, long term, low
interest government loans to private operators, surcharges on passen-
ger tickets and cargo way bills and increased air fares to allow the
carriers to recover costs.
We have reviewed the various financing alternatives, and, while we have
reached no conclusions on the shape of a final plan, some tentative
decisions have been made. First we are opposed to direct Federal fund-
ing; we believe, instead, that the users of our air transportation
system, the passengers and shippers, should, as a matter of principle,
pay for the costs of retrofit. At present we believe that the best
means to achieve this goal would be the establishment of a special
fund, supported by nominal enplanement and cargo way bill surcharges
proportionate to the aircraft modification costs for each segment of
the air carrier industry. Such a plan would cover only domestic
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operations; the international operations of U.S. carriers would have
to be handled separately.
Mr. Chairman, NASA has played a vital role with us in the abatement
of aircraft noise. Through the Joint DOT/NASA Office of Noise Abate-
ment we have an effective vehicle for assuring an integrated research
and technology program. We have both supported and worked with EPA
in its role in coordinating noise research as specified in the Noise
Control Act. The three agencies have worked closely together at the
staff and Administrator levels to marshall the Federal aircraft noise
abatement effort. For example, this Monday I represented Administra-
tor Butterfield, who was appearing before the Senate Appropriations
Subcommittee, in a meeting with Undersecretary Barnum, Administrator
Fletcher and Assistant Administrator Strelow representing Administra-
tor Train, to review our efforts, particularly with respect to the
refan program and FAA's regulatory actions. The DOT/FAA position
expressed at that meeting was that there is more than an adequate tech-
nical and economic basis for a decision at this time to proceed with
regulatory action. Assuming that all objectives of the refan program
would be achieved, the cost-effectiveness picture, in our view, will
be unchanged.
In considering the relative merits of SAM versus refan in our rule-
making efforts, we have considered the following factors as being of
primary significance.
First, the SAM modification offers the earliest meaningful relief.
With reference to time, we believe that completion of a refan retrofit
program would be at least three years behind completion of the SAM
retrofit program.
Second, the refan program does not apply to the noisiest aircraft in
the fleet, the JT3D-powered Boeing 707 and Douglas DC-8.
Third, refan represents at best a promise of future relief since the
present program is limited to flight testing of the Douglas DC-9 and
ground testing of the Boeing 727. No work is presently being done
with the JT8D-powered Boeing 737. Work on the B-737 terminated with
the Phase I design effort. Additional work and funding would be re-
quired for the refanned B-737 to be a candidate for any future rule-
making.
Fourth, the refan program is considerably more costly than the SAM
retrofit program. For example, the SAM retrofit of the entire fleet
is estimated to cost approximately $600 to $700 million for investment
with total program cost over the remaining life of the modified air-
craft approaching $1 billion. In comparison, the combination program
of using refan for JT8D-powered aircraft and the use of SAM for
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JT3D-powered aircraft would cost approximately $2.8 billion for in-
vestment with total program cost of $5 billion. In terms of one air-
craft, the Boeing 727, the cost of refanning would be roughly eight
to ten times the cost of using the SAM retrofit. The B-727 with the
SAM modification provides the same noise reduction on approach as
the refanned B-727.
The relative cost-effectiveness of the two aircraft modification pro-
grams has, as you know, been a part of our 23 U.S. airport analysis.
This effort, begun some time ago, provides the DOT/FAA with information
needed to evaluate a wide range of aircraft and airport noise abate-
ment alternatives. We have completed the 23-airport study, and the
cost-effectiveness results have not changed substantially from those
reported to you last December on the basis of the first six airports.
These results are presented in terms of (1) airport neighbors subjected
to two levels of noise exposure, (2) land areas around the 23 airports
impacted by airport noise, and (3) effective changes in the noise ex-
posure index. All of these indicators provide the same conclusions:
first, the SAM program is significantly more cost-effective than the
potential SAM/Refan program; and, second, effectiveness will be ob-
tained earlier with the SAM program.
For example, with respect to the people removed from the noise exposure
areas of NEF 30 and NEF 40, and looking forward to 1987, the end period
of the study, we find that for an expenditure of $1 billion for SAM,
we remove 125,000 of the 300,000 people that would be residing in the
NEF 40 area. For an expenditure of $5 billion for refanning the JT8D
and SAMming the JT3D, 220,000 people would be removed. An additional
expenditure of $4 billion dollars for the refan/SAM program would
remove 95,000 people from the NEF 40 area. In the NEF 30 contour, the
$1 billion SAM program will remove 600,000 of the 2,700,000 people,
whereas the $5 billion refan/SAM program will remove 1,900,000 people.
In brief, the results of this study are consistent with our earlier
conclusion that the action proposed in our Notice of Proposed Rule
Making on March 27, 1974, will provide the earliest meaningful relief
to airport neighbors through a program which is technologically avail-
able and economically reasonable. I am submitting a detailed Informa-
tion Brief describing the results of this study for the record, Mr.
Chairman. And, Mr. Foster is prepared to provide a brief summary of
this study if you desire.
With regard to the goal of 10 EPNdB reduction per decade identified
in the CARD study, we feel that for this first decade we will be able
to achieve the goal, generally speaking. Looking ahead to the next
and succeeding decades, however, we are reaching the point of diminish*
ing returns with foreseeable technology. We will continue to assess
182
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developing noise reduction technology with the idea of keeping our
regulatory program apace.
In concluding, I would like to make the following remarks.
Noise is a major problem impeding further growth of the air transpor-
tation industry. Aircraft noise has brought increased pressure to
limit flight operations and restrict flight paths as well as to im-
pose night curfews. Airport operators are faced with aircraft noise
related suits involving potential multimi11ion dollar judgments.
Congress recognized this serious impediment to air transportation in-
dustry growth and the serious implications regarding the health and
welfare of the Nation's population when it passed the Noise Control
Act of 1972.
We have developed a retrofit program which offers great promise of
the earliest relief which Congress mandated be afforded. There has
been some concern expressed by Congressional Committees about our
moving ahead with the retrofit rule prior to obtaining the final re-
sults of the refan test to be completed next year. We of course fully
appreciate these views, and before publishing a final rule we will
present to those committees our reasons for moving forward. We feel
confident that we will have their support for any action that we take
to advance our noise abatement program in a cost-effective way. Our
present posture is to continue with the regulatory process to work
toward a resolution of the difficult problems associated with the
proposed rule, such as the financing and international aspects. Only
when we are satisfied that we have solved these problems will we be
in a position to make a final decision on the rule.
Thank you for your attention to this rather lengthy testimony, Mr.
Chairman. I and my associates are available to answer any questions
you may have.
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3. DOT/ONA AIRCRAFT NOISE PROGRAMS
185
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The DOT has university grants for fundamental studies in noise sup-
pression. These studies are briefly described with funding indicated.
1. University of Southern California Contract
DOT-OS-000-2
Title: Modeling Noise
An extremely elaborate and quiet facility has been constructed to
isolate the jet noise sources. The elimination of upstream and
outside noise contamination will allow for accurate measure of
the noise from the jet alone by use of a sophisticated noise
collection reflector-microphone combination connected to a tra-
versing device. The sources or distribution contributing to
the overall jet noise is thus determined. The large scale struc-
ture of jet turbulence is being investigated as a possible major
contributor to jet noise.
Funding: (Thousands of Dollars)
FY 73 FY 74 FY 75 FY 76
75 75 50 50
2. University of Syracuse New York Contract
DOT-OS-20094
Title: Noise Reduction from Supersonic Jet Flow with Co-Axial Jets
The objective of this program is to study the mechanism of jet
noise reduction in co-axial jets when the individual jets are op-
erating under unique conditions that lead to a strong shock forma-
tion and hence to subsonic flow conditions a small distance outside
the nozzle exit. Under these conditions the jet noise is signifi-
cantly reduced below that condition of operation that does not form
into a strong coalesced shock. The specific objectives will be to
(1) verify the existence of the minimum noise condition for larger
jets and to study the scaling laws, (2) establish the effects of
temperature on noise reduction for co-axial jets, and (3) study
those phenomena with 2 and 3 co-axial elements.
Funding: (Thousands of Dollars)
FY 73 FY 74 FY 76
75 75 75
187
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3. California Institute of Technology Contract
DOT-OS-20197
Title: Jet Combustion Noise
The purpose of this study is to investigate experimentally and
theoretically the noise generated by combustion inhomogeneities
as they pass through nozzles or turbine buckets. Theoretically,
it has been shown that a pressure disturbance gets amplified on
passing through a nozzle, likewise a temperature oscillation in
the chamber leads to noise generation and it too gets amplified
on passing through a nozzle or turbine. These factors will be
studied.
Funding: (Thousands of Dollars)
FY 73 FY 74
147 50
4. Massachusetts Institute of Technology Contract
DOT-OS-30011
Title: Acoustic Material Research
The purpose of this study is to determine the characteristics of
acoustic liners in ducts that have an added mechanical inertance
that acts to lower the natural frequencies of Helmholtz resonators
with a given backing depth thus allowing for the absorption of low
frequency acoustic energy in the duct. This development is impor-
tant for application to problems involving the reduction of low
frequency noise from fans and combustion.
Funding: (Thousands of Dollars)
FY 73 FY 74 FY 75
33 35 35
5. The University of Texas at Austin Contract
DOT-OS-4117
Title: Effects of Non-Linearity on Jet Noise Propagation
The purpose of this contract is to study the non-linearity effects
in the propagation of intense noise. Non-linearity causes an in-
creased attenuation of the noise, a spectral redistribution of
the energy, and decreased cross correlation between the source and
receiver waveforms. The question is posed as to whether these
188
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effects are important for jet noise propagation. Specific work
will include conversion of the already existing plane wave analysis
into a spherical spreading one; use of the modified analysis to
predict the propagation distortion for noise from an actual intense
jet noise source.
Funding: (Thousands of Dollars)
North Carolina State University Contract
DOT-OS-40056
Title: On the Origin of Combustion Generated Noise
The objective of the program is to present a theory capable of
explaining the observed characteristics of combustion noise whose
validity does not hinge on the assumptions employed and on the
particular situation considered. Starting from the exact multi-
fluid equations of a reacting gas mixture, the mechanism of com-
bustion generated noise for open and confined flames is identified.
The derivation parallels the procedure employed by Lighthill and
Curie and does not depend on simplifying assumptions. It is shown
that the pressure fluctuation is a sum of two terms. The first is
proportional to the overall density fluctuation and the second is
a linear combination of the density fluctuations of the various
species. At present, a reliable estimate of combustion noise
cannot be made; a complete understanding of the problem first re-
quires the identification of the sources of the noise due to com-
bustion and scaling laws and the effects of confinement on the
propagation.
Funding: (Thousands of Dollars)
FY 74 FY 75 FY 76
25 30 25
General Electric Company Contract
DOT-OS-30034
Title: High Velocity Jet Noise Source Location and Reduction
Program
The overall objective is to investigate the promising suppression
concepts that will result in the greatest nois.e suppression with
189
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the least degradation of performance over flight speed ranges of
interest for the potential types of engine cycles. The theoretical
understanding of these more complex nozzle concepts presents a
great challenge and is a fundamental part of the objective of this
program.
The detailed investigation of the basic phenomena which affect the
source locations, source strength, and noise reduction potential
of high velocity jet noise is directed towards the following pro-
gram objectives:
Investigation of the aerodynamic and acoustic mechanisms
of various jet noise suppressors for subsonic and super-
sonic jets, including scaling effects.
Analytical and experimental studies of the acoustic source
distribution in such suppressors, including identification
of source location, nature and strength, and noise reduc-
tion potential.
Investigation of in-flight effects on the aerodynamic and
acoustic performance of these suppressors.
The results of these investigations will lead to the preparation
of a prediction guide report for predicting the overall charac-
teristics of suppressor concepts, i.e., for models, full-scale
static, and in-flight conditions, as well as a quantitative and
qualitative analytical prediction of the phenomena involved.
The work effort in this program is organized under the following
major categories:
Task 1 - Activation of Facilities and Validation of Source
Techniques
Task 2 - Theoretical Developments and Basic Experiments
Task 3 - Experimental Investigation of Suppression Principles
Task 4 - Development and Evaluation of Techniques for "In-
Flight" Investigation
Task 5 - Investigation of "In-Flight" Aero-Acoustic Effects
on Suppressed Exhausts
Task 6 - Preparation of Noise Abatement Nozzle Prediction
Guide Report.
See Figures 14 and 15 for funding and schedule.
190
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_
HIGH VELOCITY JET NOISE SOURCE LOCATION AND REDUCTION
OVERALL PROGRAM PLAN
MONTHS
TASKS
1 - Activation of Faci-
lities and Valida-
tion of Source Loca-
tion Techniques
Work Plan
2 - Theoretical Develop-
ment and Basic Ex-
periments
Work Flan
3 - Experimental Inves-
tigation of Suppres-
sion Principles
Work Plan
4 - Development/Evalua-
tion of Techniques
for "In-Flight" In-
vestigation
Work Plan
5 - Investigation of
"In-Flight" Aero-
Acoustic Effects on
Suppressed Exhausts
Work Plan
6 - Preparation of
Noise Abatement Noz-
zle Prediction Guide
Progress Reports
Oral Presentations
- 1973 -
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ESTIMATED TOTAL PROGRAM EXPENDITURE SCHEDULE
v£>
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COST IN
MILLIONS
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4.0
3.0
2.0
l.C-
ALL TASKS (1 - 6)
t CUMULATIVE DOLLARS
COST INCLUDES IR & D/GA, ETC.
INTERAGENCY
FUNDING
TOTAL PROGRAM __ _.
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u A S 0 N D
-r-1973
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JFHAMJJ ASOND
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MENTS
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-1976-
-MONTHJ
FIGURE 15
-------
8. Virginia Polytechnic Institute Contract
DOT-OS-50047
Title; Suppression of Multiple Pure Tones
This is a program to evaluate an advanced acoustic concept for
the suppression of multiple pure tones from supersonic jet engine
fans. The concept is based on the dispersion of waves by acous-
tically treating the duct walls to inhibit the exchange of energy
among the harmonics and to counteract the steepening of the waves
due to non-linearity. A detailed parametric study will be per-
formed to determine the optimum linear characteristics.
193
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III. DOD AIRCRAFT NOISE PROGRAMS
195
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DOD JET EXHAUST NOISE PROGRAMS
Department of Defense
Air Force
SUPERSONIC JET EXHAUST NOISE-
PRESSURE MODEL
Bolt Beranek & Newman Inc.
Contract F33615-71-C-1661
Project 3066, Task 14,
Work Unit 02
7/72 to 6/73
Funds $164,000
The overall objective of this program is to develop the technology base
necessary to significantly reduce aircraft propulsion system noise
with minimum associated performance and weight penalties. The speci-
fic technical objectives of this effort are (a) to assess the advan-
tages and disadvantages of various competing mathematical models used
to explain the supersonic jet noise generation process with particular
emphasis on the Ribner/Meecham fluctuating pressure model; (b) to
determine the relative importance of the various jet noise generation
mechanisms for the range of operating conditions typical of the B-l
system; (c) to experimentally demonstrate the advanced instrumentation
techniques required to verify the accuracy of the Ribner/Meecham fluc-
tuating pressure model.
This program involves a comprehensive investigation of all relevant
mechanisms of noise generation and emphasized the interrelationships
between acoustics and engine cycles and between acoustics and exhaust
jet aerodynamics. The experimental investigation features the use of
unique transducers to relate the exhaust fluctuating aerodynamic'pres-
sures to the radiated noise. A large-scale, high temperature (3000° F)
free jet facility will be used to conduct aero/acoustic experiments.
This facility makes it possible to compile a comprehensive and exhaus-
tive catalog showing the inter-relationship between nozzle mean and
fluctuating aerodynamic and acoustic properties of supersonic jet
exhausts.
SUPERSONIC JET NOISE
INVESTIGATION - VELOCITY MODEL
General Electric
Project 3066, Task 14,
Work Unit 03
Funds $164,000
The overall objective of this program is to develop the technology to
significantly reduce supersonic aircraft propulsion system noise with
minimum associated performance and weight penalties. Emphasis is placed
on afterburning and non-afterburning supersonic jet exhaust systems
with operating conditions typical of supersonic transport (SST) and
long range strategic (B-l) aircraft propulsion systems. The specific
technical objective of this research program is to develop a compre-
hensive mathematical model capable of providing aero/acoustic design
197
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data to be used in the development of future supersonic jet exhaust
noise suppressors.
SUPERSONIC JET NOISE Project 3066, Task 14
INVESTIGATION - DENSITY MODEL Work Unit 04
Lockheed, Georgia Funds $199,000
The overall objective of this program is to develop the technology to
significantly reduce supersonic aircraft propulsion system noise with
minimum associated performance and weight penalties. The specific
technical objectives of this program are to numerically solve the
applicable turbulence and acoustic theories which describe jet noise
generation and radiation for the subsonic and fully-expanded supersonic
flow regime and to measure the necessary turbulence and acoustic param-
eters in order to verify the numerical predictions or to supply data
to the turbulence/noise theories as necessary.
GENERAL ELECTRIC/LOCKHEED
Contract DOT-AS-20099 / AF Contracts F33615-73-C-203 1/2
Title: Supersonic Jet Noise (Analytical Model)
The overall objective of this program is to develop a fundamental under-
standing of the mechanisms of jet noise generation. This phase of the
work is limited to sound single nozzles in contrast to the complex
nozzle configurations of suppressor types. The specific technical ob-
jectives are to numerically solve the applicable turbulence and acous-
tic theories which describe jet noise generation and radiation for the
subsonic and fully-expanded supersonic flow regime and to measure the
necessary turbulence and acoustic parameters in order to verify the
numerical prediction or to supply data to the turbulence/noise theories,
as necessary. The program comprised of an experimental and theoretical
effort to predict noise from subsonic and supersonic jets with particu-
lar emphasis on the turbulent mixing region. Development of promising
optical techniques to measure necessary turbulence spectra intensity,
and scales is also included. The objectives are intended to lead to
a unified theory of jet noise. The work will be performed in four
phases:
Phase I - Through review of competing mathematical models.
Phase II - Detailed investigation - relate flow field to acoustic.
Phase III - Investigate effects of upstream perturbations.
198
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Phase IV - Correlation of all results into unified theory.
Contracts are with Lockheed Georgia and General Electric in Cincinnati.
This work was started in 1971 and will be completed in March 1975.
Total funding by DOT is 1.3 million in the following schedule of ex-
penditure.
DOT
DOD/Air Force
JET NOISE REDUCTION FOR MILITARY
RECONNAISSANCE/SURVEILLANCE AIR-
CRAFT
Bell Aerospace Corporation
Project 3066, Task 14,
Work Unit 005
The objective of this program is to evaluate and experimentally demon-
strate a unique quiet propulsion concept for advanced quiet aircraft
systems. The performance and acoustic characteristics of the total
propulsion system will be assessed under this effort.
POD AIRFLOW SURFACE INTERACTION PROGRAMS
Department of Defense
Air Force
NOISE CONTROL BY LIQUID VAPORIZATION
California Institute of Technology
School of Engineering
DF032080
Contract AF-AFOSR-2068-71
7/73 to 6/74
Funds $31,220
Strategic bombardment, tactical operations, and logistic support are
AF functions which require the use of high performance flight vehicles.
The operation of such vehicles produces intense noise from sources
associated with propulsion systems. Because of a lack of a basic un-
derstanding of the physical behavior of sound and the interaction of
sound with the fluid medium it is traveling through, rational noise
control and avoidance is difficult. This noise can cause degradation
in human performance, reduced reliability of structural and equipment
subsystems and increased maintenance. The proposed research will in-
vestigate the behavior of high intensity sound as it interacts with
liquid droplets. Specifically, an analysis will be made of nonlinear
acoustic disturbances In a heterogeneous gas-liquid mixture where transition
199
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between the two phases constitutes an important element of the problem.
Particular stress will be given to the wave steepening beyond the plane
of generation, to the attenuation of duct modes and to the effect of
phase change attenuation on acoustic fields resulting from gas-dynamic
interaction with sharp edges.
AERODYNAMICALLY GENERATED SOUND Project 9781, Task 02
University of Toronto Work Unit 001
This research is directed toward developing a comprehensive physical
model of jet noise which covers generation, convection, refraction,
and spectrum properties. Research is being conducted in the areas of
aerodynamically generated sound and subsonic aerodynamics. In the
area of sound the following projects are being conducted:
(a) Correlation of sound with hot wire measurements in
a jet. A direct correlation between the turbulence
(the cause) and the sound (the effect) is being
attempted.
(b) Shielding flap scheme of jet noise suppression. The
effectiveness of a wing as a shield for jet noise is
being examined experimentally.
(c) Wind noise in vehicles. An experiment is being con-
ducted to determine the relation between the jet flow
over a cavity and the noise generated by the flow.
(d) Model of Mach wave noise emanating from the lip of a
supersonic jet. A mathematical analysis is being made
to delineate the mechanisms of noise generation of a
rocket nozzle.
(e) Extended near-field concept for sonic boom alleviation.
The possibility of delaying the transition of the near
field signature to the far field pressure signature is
being examined. In the area of subsonic aerodynamics the
lift distribution and moment of wing cutting obliquely
through a simulated trailing-vortex of another airplane
is being determined.
200
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Department of Defense
Air Force
DYNAMICS OF VORTICES AND SHOCK-
WAVES IN NONUNIFORM MEDIA
California Institute of Technology
School of Engineering
DF032500
Contract AF-AFOSR-2092-71
Project 9781, Task 02
7/73 to 6/74
Funds $40,900
Aircraft operations in all flight regimes involve vortices in flow field
and wakes. The behavior of vortices has profound influence on aerody-
namic forces and the trailing vortices are the crucial phenomenon in
the notorious aircraft wake turbulence hazard. This effort has made
significant progress in theoretical understanding of vortex motion.
The current effort will extend this work to consider the influence of
various nonlinearities in the equations of motion. Also, water tunnel
experiments will be performed in which the detailed structure of trail-
ing vortices behind lifting surfaces will be studied by means of a
laser doppler velocimeter. The Shockwave aspects of the past research
will also be continued with an experimental investigation of focussed
Shockwave propagation through the focal point. The Shockwave effort
is relevant to improved understanding of super booms. It is hoped
that the experiments will suggest possible simplifications to the ana-
lytical models for focussed Shockwaves.
Department of Defense
Air Force
THEORETICAL AND EXPERIMENTAL
INVESTIGATIONS IN HIGH SPEED
AERODYNAMICS
Cornell Univeristy
School of Engineering
DF001060
Contract F44620-69-C-0063
Code AA
7/73 to 6/74
Funds $165,925
Weapons delivery superiority requires continual refinements in aircraft
and missiles. More complete knowledge of aerodynamics is critical to
such refinements. This is a broad program of research in aerodynamics,
with relevance to low speed performance of tactical aircraft, aero-
dynamic noise and sonic boom minimization, aerodynamic optimization
of aircraft, and high altitude hypersonic flight. Problems are being
studied in the areas of boundary layer flows, including unsteady bound-
ary layer separation and flows with variable viscosity - gas dynamics,
including fluid dynamic processes in gas laser, blast wave experiments,
and rarefied hypersonic leading edge flow - aerodynamic noise, includ-
ing non-uniform cascade theory, non-uniform flow over blunt bodies and
propagation of non-linear waves - supersonic drag with emphasis on
analytical techniques for positioning of nacelles and stores for an
overall optimum area-rule shaping.
201
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Department of Defense
Navy
TIP VORTEX EFFECTS IN ROTARY-
WING AERODYNAMICS
Sage Action Incorporated
DN223260
Contract N00014-72-C-0200
7/72 to 6/73
Funds $48,116
To significantly reduce undesirable rotor blade noise signatures, and
alleviate the blade-tip vortex interaction problem. The role of the
tip vortex in rotary-wing aerodynamics will be investigated and possible
means of control of the tip vortex will be examined. If this explora-
tory effort is successful, an extremely useful technique will be avail-
able for solution of severe rotary-wing aerodynamic, structural, and
noise problems.
The total flowfield including the tip vortex of a model rotor blade
will be investigated by means of an advanced helium bubble flow
visualization technique. Techniques to reduce the blade vortex inter-
ference effects will be evaluated. The new idea in this research of
examining the interference of a tip vortex from a preceeding blade by
means of a second blade positioned upstream in a wind tunnel should
reveal for the first time the violent changes in angle of attack and
stall in the interference region.
Department of Defense
Army
GLARE AND NOISE REDUCTION
OF HELICOPTER ROTOR BLADES
McCoy Electronic Corporation
DAOK3720
Contract DAAK02-72-C-0623
7/72 to 6/73
Funds $25,000
To develop various materials and compositions capable of reducing the
glint, glare, and noise from helicopter rotor blades without impairing
lift or increasing weight or drag.
Task envisions the making of a working model rotor blade upon which an
acoustic surface wave will be generated by means of metal electrode
transducer excited by the acoustic bulk-waves from piezoelectric vibra-
tors (i.e. quartz crystals). The generated acoustic surface wave will
then be propagated along a thin piezoelectric sheet which when lead-
phased should regulate the movement of the bound-vortex layer of air
increasing the rotor blades lift while simultaneously reducing the
glint and glare. In addition, possible method of noise reduction via
bow wave extension and creation of a potential gradient across the
airfoil will be included in the model, but not be capable of demon-
stration.
202
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Department of Defense
Army
UNSTEADY AERODYNAMICS OF BLADE-
VORTEX INTERACTION 6495-E
Massachusetts Institute of
Technology
School of Engineering
DAOB9173
Contract DA-31-124-ARC(D>
471 Code RB
7/73 to 6/74
Fund s Unknown
To study the unsteady aerodynamic mechanisms responsible for helicopter
noise. Improved understanding of the aerodynamic noise generation of
a helicopter could lead to new methods of improving the aerodynamic
performance and decreasing the amount of noise generated by helicopters.
Both are of vital importance in improving the usefulness of the heli-
copter for Army missions.
Approach - work will begin with simpler two-dimensional models and will
be extended to an exact treatment of the three-dimensional problem in
both steady and unsteady flow. The treatment will be concerned pri-
marily with inviscid flow; however, an investigation of the effects
of viscosity will be included in determining the vortex curve bounda-
ries. The approach, while numerical in character, may be described as
exact in the sense that true boundary locations will be accounted for
and the exact solution will be obtained as the computational network
is refined.
Department of Defense
Army
INVESTIGATION OF NOISE GENERATION
ON A HOVERING ROTOR 8704-RN-8704
Boeing Company
DAOC9091
Contract DAHC04-69-0087
7/72 to 6/73
Funds Unknown
To define the noise field generated by a rotor. Investigation of noise
generation of a helicopter rotor is important for the Army's effort to
make its helicopters less noisy for more effective field operations.
This research is important to the Army in that it represents a long
range effort to reduce Army aircraft detection time.
Noise level tests and vortex visualization tests will be made with a
set of rotor blades mounted on a whirl tower. Smoke generation in the
blade and high speed motion picture photography will be employed for
vortex visualization tests. Near and far field acoustical data will
be collected. Following data reduction, an analysis will be made of
the relative levels and frequency distributions of rotational noise,
vortex noise and of any blade slap noise that might occur during tests.
The relative positions of smoke will be evaluated at the points where
the noise is generated as determined from acoustical measurements.
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DOD ROTATING MACHINERY NOISE PROGRAMS
Department of Defense
Air Force
INSTABILITY AND NOISE GENERATION IN
AIR-BREATHING PROPULSION SYSTEMS
Ultrasystems Incorporated
DF032400
Contract F44620-71-C-0104
7/73 to 6/74
Funds $37,661
Effective weapon delivery, defense, reconnaissance, and transport
vehicles require propulsion systems with stable operating characteris-
tics and minimal noise levels. Results obtained from this research
will aid in understanding and controlling combustion instability in
air-breathing main and auxilliary cotnbustors, in providing guidelines
and techniques for modifying the combustion processes for minimum noise
levels, and in establishing criteria for engine design, development,
and control. This research encompasses studies of fundamental physi-
cal mechanisms driving combustion instability, of mechanisms by which
combustion affects the general sound field surrounding an engine, and
of coupling between these mechanisms and combustor operating condi-
tions. Included will be studies of the detailed phenomenological pro-
cesses which determine the nature of the interactions of initially
small disturbances and discrete, discernible combustion zones existing
in the combustor. Existing contractor chemical and fluid mechanical
computer programs will be used in conjunction with data and qualita-
tive observations obtained from laboratory experiments. Particular
emphasis will be placed on fundamental fluid mechanics and combustion
of vortex stabilized combustors, e.g., V-gutter and dump combustors.
A computer model of these processes will be formulated, validated by
experiment, and used as the basis for developing a combustor stability
prediction program based on combustor geometry and operating conditions.
Dominant modes of instability will be predicted and recommendations
made concerning effectiveness of stabilizing measures. Mechanisms by
which combustion affects the general sound field surrounding an
engine will also be investigated and guidelines provided for modifying
the combustion processes to obtain minimum noise levels.
Department of Defense
Air Force
COMBUSTION GENERATED IN
TURBO-PROPULSION SYSTEMS
Georgia Institute of Technology
School of Aerospace Engineering
DF034900
Contract AF-AFOSR-2365-72
7/72 to 6/73
Funds $24,200
For specific missions involving weapon delivery and defense, transport,
204
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reconnaissance and rescue, advanced efficient air-breathing and hybrid
engines are required with minimal noise emission levels to deter de-
tection and avoid aircraft component damage and reduced efficiency of
and hazard to ground and flight personnel. Also to maintain environ-
mental pollution within tolerable limits it is mandatory that air-
craft noise emissions be minimized. This research on fundamental
physical mechanisms and processes involved in combustion noise pro-
duction and transmission in primary and augmentor air-breathing com-
bustors will aid in providing guidelines and techniques for modifying
the combustion process for minimal noise output and development of
effective combustor noise suppressing devices for these advanced en-
gines. This program encompasses theoretical and experimental studies
directed toward isolating the origins and transmission of combustion
noise in turbo-propulsion combustors. Included will be studies of
various aspects of free flame, flameholder flame, and primary combustor
can combustion noise. Sound power output, spectral content and direc-
tionality characteristics will be determined. Scaling rules will be
generated and compared with various theoretical approaches to the
problem. Diagnostic emission measurements will be made to isolate
the origin of combustion noise. Theoretical acoustics will be used
to solve the problems of sound radiation from afterburner and primary
combustors to the surrounding atmosphere.
NOISE GENERATION BY A TRANSONIC Project 9781, Task 02,
COMPRESSOR ROW Work Unit 003
Cornell Aeronautical Laboratory Inc.
The Air Force is presently and will continue to be in the foreseeable
future a large user of high subsonic jet aircraft. The principal means
of propulsion of such aircraft is the high bypass-ratio turbofan engine.
An undesirable byproduct of these engines is the generation of noise
which causes such adverse effects as degradation in human performance,
reduced reliability of structural and equipment subsystems, and in-
creased maintenance cost. The design of vehicle parts and sound-
proofing which alleviate these effects requires accurate definition
of the intensity and occurrence of the noise. In order to partially
fulfill this requirement a theoretical study of the problem of fan-
noise generation in a high bypass-ratio turbofan engine is being made.
The main emphasis in this study is the noise aspect of the three-di-
mensional, transonic flow through a single blade row. A linear acous-
tic theory for the case of non-lifting blades is being applied to the
problem of noise generation. An effort is being made to extend the
theory to lifting blades and to examine the effect of more realistic
duct geometries.
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HIGH INTENSITY SOUND Project 9781, Task 02,
University of Texas Work Unit 002
This research is concerned with investigating the behavior of high-
intensity sound and applying the understanding gained to problems of
interest to technology such as sonic boom, propagation of intense
noise from jet engine compressors, underwater propagation, etc. This
is a theoretical and experimental effort on high-intensity sound and
its interaction with a real media. The purpose of the work,is to study
the phenomena that distinguish nonlinear acoustics from linear acous-
tics and to apply the knowledge gained to physical problems. Specific
topics being studied are;
(a) Stability of the acoustic boundary layer. The
object is to predict the threshold at which a
transition from laminar to turbulent flow takes
place. The frequency dependence of this threshold
is of particular interest.
(b) Standing waves of finite amplitude. Chester's
theoretical predictions are being checked by
experiments.
(c) Quasi-plane-wave mode for finite-amplitude waves
in a tube. Experimental tests are being conducted
to check past theoretical solutions.
(d) Finite-amplitude waves in relaxing media.
(e) Electrical transmission-line analogs of acoustical
propagation problems, such as progressive waves in
relaxing media, random in homogeneous, turbulent
media, or nonlinear media.
SMALL TURBINE ENGINE NOISE REDUCTION Project 3066, Task 14,
Garrett Corporation Work Unit 001
The purpose of this program is to develop the technology base necessary
to effectively reduce the noise signature of existing small turboprop
and turbofan engines. Although the program is primarily aimed at light
aircraft propulsion, the technology generated is directly applicable
to auxilliary power unit silencing. The specific technical objectives
of the effort are to accurately predict the radiated acoustic signature
and aural detectability of existing turboprop and turbofan propulsion
systems in the 80 to 1000 shaft horsepower class for turboprops and the
400 to 5000 pound thrust class for turbofans, to develop effective
methods to minimize propulsion system aural detectability, and to
determine the engine performance and weight penalties associated with
the various suppression methods.
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ROTATING MACHINERY NOISE GENERATION Project 3066, Task 03,
Work Unit 34
The overall objective of this program is to develop an improved under-
standing of noise in axial flow compressors so that design rules may
be formulated for reduced noise. The specific technical objectives
of the effort are:
(a) To develop a direct lifting surface theory for
compressible, linearized flow through a rotating
blade row.
(b) To develop approximate models for noise generation
by rotor-stator interaction.
(c) To correlate results of lifting surface theory with
experiment.
(d) To analyze dominant nonlinear effects in the in-
viscid, three-dimensional flow through a rotating
blade row.
Department of Defense DN123475
Navy Contract N00014-67-0151-0029
Office of Naval Research 473 Subgroup
AIRCRAFT COMBUSTION GENERATED NOISE 7/73 to Cont
Princeton University Funds $64,022
Aerospace, Mech. Sci. Dept.
Within the Navy aircraft, missile and space power and propulsion pro-
gram, this effort offers the possibility of alleviating jet engine
noise by research on nonsteady combustion and gas dynamics phenomena.
This research makes use of past efforts on nonsteady combustion coupled
with nonsteady gas dynamics as applied to aircraft combustor and after-
burner generated noise with emphasis on causes of suppression of such
noise. The study seeks quantitative descriptions of the driving
mechanisms as well as methods of predicting and minimizing such noise.
Special instrumentation will be utilized in conjunction with an ane-
choic chamber and a combustion rig to conduct diagnostic measurements
designed to elucidate sources of sound in a combustor-jet combination,
to measure effects of controlled changes and to observe relationships
between flow pattern and noise characteristics. Concurrent theoretical
report will involve modeling and treat noise generation from turbulent
mixing regions, interactions of such turbulent flow with shock waves
and unsteady rough burning processes. Information will be compared
with typical jet engine firing tests involving various operating param-
eters.
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Department of Defense
Army
INVESTIGATION OF GEARBOX DESIGN
MODIFICATION FOR REDUCING NOISE,
ARMY AIRCRAFT TRANSMISSION SYSTEMS
Mechanical Technology Inc.
DAOC4046
Contract DAAJ02-72-0040
7/73 to 6/74
Funds $26,456
The objective of this program is to identify practical gearbox design
modifications which will help alleviate the gearbox noise problem in
the CK-47 transmission. In addition, analytical methods for predicting
and reducing gearbox noise sidebands will be developed to permit design
analysis of this significant noise source.
Select component modifications, based on Contract DAAJ02-70-C-0035, to
be investigated for noise attenuation in the CH-47 helicopter trans-
mission. Perform vibration calculations so that candidate configura-
tion is optimized from the standpoint of noise and vibration reduction.
Identify modifications having greatest noise reduction potential. Uti-
lizing test results obtained under Contract DAAJO2-71-C-0020. Deter-
mine the mechanamistns producing planet-pass sidebands and then modify
existing computer programs accordingly to develop analytical methods
to reduce sideband amplitudes.
COMPUTERIZED PROCEDURE TO ASSESS
TURBINE ENGINE PERFORMANCE/NOISE
TRADES
Project 3066, Task 14,
Work Unit 06
The objective of this program is to develop an effective design pro-
cedure relating aircraft engine performance and noise. The specific
technical objectives of this program are; (a) to develop effective
uninstaller engine noise prediction methods applicable to current and
future gas tu-bine engines, (b) to develop techniques for the predic-
tion on installed engine noise levels including the effects of special
noise reduction devices, and (c) to develop methods to assess propul-
sion performance and weight penalties as a function of noise level
reduction.
DOD DUCT ACOUSTICS AND SUPRESSION PROGRAMS
SOUND TRANSMISSION THROUGH DUCTS
Project 3066, Task 14,
Work Unit 09 (AF)
The purpose of this effort is to develop a numerical procedure to
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predict the effects of engine ducting on sound propagation. The
specific technical objectives of the effort are to review existing
theoretical and empirical methods for the prediction of sound propa-
gation through and radiation from ducts and to develop a unified gen-
eral theory based on this review. This prediction theory will then
be incorporated into a general computerized procedure to assess tur-
bine engine noise/performance trades.
Department of Defense DAOC4924
Army Contract DAAD05-72-C-0175
DEVELOPMENT OF NOISE 7/73 to 6/74
ATTENUATING SUBSTANCE Funds $19,950
Lehigh University
To develop a paint-like substance which will damp thin panel vibration.
A Latex substance consisting of two layers - a viscoelastic latex IPN
undercoat ing having damping capabilities at the temperature and fre-
quency range of interest and a reinforced plastic constraining layer
which has a high modulus. Steel tests panels will be coated, evalua-
ted, and compared to commercial materials at frequent intervals. The
best paint will be recommended for Army use on material where person- -
nel are exposed.
POD STRUCTURAL RESPONSE AND INTERIOR NOISE PROGRAMS
Department of Defense DAOD4751
Army 7/72 to 6/73
STRUCTURAL MATERIALS WITH DAMPING Funds Unknown
CHARACTERISTICS FOR APPLICATION TO
HELICOPTERS
U.S. Army
The objective is to produce a material that can be used to dampen noise
in helicopters (engine mounts, driveshafts, honeycomb linings).
Titanium-nickel alloys in the 50-50 range will be fabricated and tested
to determine their yield strength and damping capacity. Acoustical
attenuation as a function of frequency (0-20 percent) and temperature
(-60 degrees centigrade to 100 degrees centigrade) will be measured
and by alloying or heat treatment the yield strength and damping charac-
teristics will be optimized. X-ray studies will be made to correlate
the lattice arrangement with the damping characteristics and yield
strength.
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DOD FLIGHT AND INSTALLATION EFFECTS PROGRAMS
Department of Defense
Army
ANALYTICAL STUDIES OF HELICOPTER
ROTOR BROADBAND NOISE GENERATION
10299-E
Sikorsky Aircraft
DAOD8982
Contract DAHC04-72-C-0040
7/73 to 6/74
Funds $33,861
An analytical study will be made to establish a closed form solution
for predicting the broadband noise intensity radiated by helicopter
rotors. This research should develop techniques which will reduce the
aerodynamically generated noise made by helicopters.
Experimental studies will be made of isolated airfoils in an existing
acoustic-wind tunnel. The data obtained and other existing data will
be statistically analyzed to provide an empirical equation which will
then serve as a measure by which the validity of the theoretical equa-
tion will be examined.
Department of Defense
Army
STUDIES IN LOW SPEED FLIGHT
10233-E
Georgia Institute of Technology
School of Aerospace Engineering
DAOD9005
Contract DA-ARO(D)-31-124-
71-G-17
7/72 to 6/73
Funds $120,000
Investigation of problems associated with low speed flight of heli-
copters, such as the hovering rotors, vortex wake, blade slap noise,
rotor flutter, and the instability of tensioned sheets with cutouts.
The Army helicopter program has a definite need to improve the capa-
bility of its helicopters to hover near the ground so as to take off
and land precisely at a surface location with maximum payload. The
present vortex wake and rotor flutter of the vehicle interferes with
ground personnel as well as reduces the payload capability of the
vehicle. Blade slap noise alerts the enemy to the helicopter's pres-
ence and must be reduced significantly to improve the element of
tactical suprise.
(a) Develop a method for calculating vortex wakes in the hovering per-
formance of multi-bladed helicopter rotors, (b) the interaction of the
helicopter blade with the vortex field shed from the preceding blades
as a cause of blade slap, (d) the structural dynamic characteristics
of the rotor-blade system that gives rise to flutter due to the un-
steady air loads on the blade, (C) the instability of thin sheets
with cutouts and cracks.
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Department of Defense Contract DAHC04-69-C-0086
Army 7/72 to 6/73
SYSTEMS STUDY OF HELICOPTER NOISE Funds $73,864
REQUIREMENTS 8713-E
Massachusetts Institute of Technology
School of Engineering
To establish a new methodology for systems analysis which includes
noise criteria and to develop a new wind tunnel facility for making
useful noise measurements on V/STOL aircraft types. It is important
for the Army to reduce the noise levels of its helicopters so that the
missions of surveillance, reconnaissance and target acquisition can
be performed better without giving too much warning of approach to the
enemy. The mission accomplishment may still be performed better if
just the right combination of noise reduction and performance of the
helicopter existed. The question that remains unanswered is - What
is the most desirable combination of these parameters so the mission
effectiveness will be maximized. This project is aimed towards answer-
ing this question.
The initial system studies will be performed, assessing the effect of
noise criteria on mission performance. Experimental data on the noise
radiated by helicopter rotors in high forward speed flight will be
obtained. Emphasis will be in determining the effect of helicopter
operating conditions upon the directivity, frequency content and time
signature of the noise.
DOD SOUND PROPAGATION PROGRAMS
NOISE FROM LINEAR ARRAY Project 1471, Task 02,
OF LARGE TURBOJET ENGINES Work Unit Oil
AFFDL (In-House)
The purpose of this program is to determine the interaction effects of
multiple turbojet exhause noise sources in determining the near-field.
acoustic environment. Data were obtained in the form of sound pressure
levels and frequency spectra at various microphone locations. Analog
data were recorded on tape for later analysis.
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RADIATED NOISE FROM SAILPLANES Project 1471, Task 02,
AFFDL (In-House) Work Unit 013
The objective of this effort is to identify the noise associated with
a powerless aircraft and to relate this noise to area and velocity
parameters of the aircraft. The flyby noise from three sailplanes,
Schweizer 2-32, Schweizer 2-33, and Libelle, has been recorded on tape
and one-third octave and overall bandwidth analyses obtained. The
noise levels from each of the sailplanes follows a sixth power of the
velocity and appear to be directly proportional to the turbulent area
on the wing. A test report has been prepared which presents the re-
sults obtained to date.
Department of Defense DAOC9164
Army Contract DAHC04-74-C-0001
RESEARCH ON HELICOPTER 7/73 to 6/74
NOISE 9372-E Funds $30,615
Cornell University
School of Engineering
To discover, refine and exploit techniques for the analysis and
predictions of aerodynamic noise, in particular the noise produced
by helicopters and similar-AIRTR/fT!, for the purpose of finding tech-
niques for reduction of such noise. The successful field operation
of Army helicopters is jeopardized by the noise environment in three
ways. Helicopter noise increases the vulnerability of both the ma-
chine and crew to ground fire, distracts the crew in the performing
of their duties, and induces sonic fatigue in construction elements.
Thus, this investigation has a high degree of relevance to effective
utilization of rotorcraft since it will identify noise sources and
describe noise propagation relative to helicopters.
DOD PROPELLER NOISE PROGRAMS
PROPELLER TECHNOLOGY Project 3066, Task 12
Significant propeller system technology advancement is an area of
major importance for V/STOL and light aircraft. The propeller tech-
nology task consists of three areas:
(a) lighweight propeller and propeller/gearbox
development;
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(b) improvement of propeller aerodynamic performance
and analytical prediction techniques;
(c) prediction and reduction of propeller and
gearbox system noise.
More specifically, near term areas of concern are: decreasing pro-
peller/gearbox system weight through the use of high strength-to-
weight ratio materials and composites; improving propeller system per-
formance through the application of cyclic pitch and variable geometry;
improving basic airfoil design for optimum performance; determining
accurate static thrust prediction methods; improving noise prediction
techniques through improved basic noise source theory; and improving
propeller noise scaling techniques and noise reduction through utili-
zation of unique propeller designs based on noise source theory
information.
PROPELLER ACOUSTICS RESEARCH Project 3066, Task 12,
Work Unit 07
The overall objective of this program is to experimentally determine
the noise generation mechanisms for low tip speed propeller airfoils.
The specific technical objectives of the effort are: (a) to determine
the relative effects of upstream turbulence, boundary layer fluctua-
tions and vortex shedding on radiated noise, and (b) to experimentally
verify the theoretical prediction models developed under contract
F33615-70-C-1135 and presented in AFAPL-TR-71-55 entitled "Propeller
Noise at Low Tip Speeds."
QUIET PROPELLER CONCEPT EVALUATION Project 3066, Task 12,
Work Unit 08
The objective of this program is to evaluate the noise characteristics
of various tail rotor configurations to determine the noise reduction
potential of various new designs. Variables to be investigated include
number of blades, blade to hub phasing angles and blade length.
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LOW NOISE PROPELLER TECHNOLOGY Project 3066, Task 12,
DEMONSTRATION Work Unit 12
The objective of this exploratory research program is to develop a
reliable design procedure for quiet propellers applicable to reconnais-
sance/surveillance aircraft. The specific technical objectives of this
effort are: (a) to modify existing Air Force propeller noise predic-
tion computer programs to account for forward flight effects, and (b)
to produce a series of design charts that will be useful in design of
future propeller driven quiet aircraft.
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IV. NSF PROGRAMS
Note that these are not
discussed in the main text.
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National Science Foundation GK-33801
Div. of Engineering 4/72 to 4/73
AN INVESTIGATION OF ACOUSTIC Funds $60,000
FEEDBACK FOR THE REDUCTION OF
JET NOISE
University of Michigan
School of Engineering
This project will investigate the part acoustic feedback (resonance)
plays in the generation of noise from supersonic jets with special
consideration given to the possibility of shifting the frequency of
a significant part of the radiated acoustic energy outside the range
of the human ear.
Phase relationships between movements of shock waves and disturbance
created will be determined using ultra-high-speed Schilieren or shadow
photographs. Local flow properties will be measured and the sound re-
flecting and absorbing surfaces in various geometries will be examined.
National Science Foundation GK-37433
Div. of Engineering 3/73 to 8/74
RESEARCH INITIATION-APPLICATION Funds $17,000
OF UNSTEADY AIRFOIL THEORY
Widener College
Graduate School
This research project will investigate the pressure fluctuations on
blade surfaces of a single stage compressor. In particular it will be
clarified whether the chopping effect of blades moving at high speeds
relative to one another without the presence of low momentum flow is
the predominant source of noise or the mere interference of blades
with flow perturbations.
Experimental tests will be aimed to separate the sources of pressure
fluctuations. Using high response pressure transducers a quantitative
answer of the magnitude of these fluctuations is to be obtained. An
integration of these results over the blade surface will give answers
as to the magnitude of the experienced lift fluctuations which will
then be compared with existing theories.
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National Science Foundation GK-5030 A#l
Div. of Engineering 10/71 to 10/72
COMPRESSOR NOISE REDUCTION Funds $19,350
WITH A SONIC INLET
South Dakota State University
School of Arts
The purpose of this investigation is to develop some fundamental
understanding of the aerodynamic-problems associated with the sonic
inlet. Specific emphasis will be given the following: (a) A theo-
retical and experimental verification of a method for optimizing the
design of center body, (b) Experimental investigation of the effects
of splitters and vortex generators on secondary air injections. (c)
Verification of the theoretical studies on shock stability.
National Science Foundation GK-32544
Div. of Engineering 2/72 to 2/73
COMBUSTION GENERATED NOISE Funds $13,950
Georgia Inst. of Technology
School of Aerospace Engineering
A combined experimental-theoretical program will be undertaken to iso-
late the origin of combustion generated noise and to discover appropri-
ate scaling rules associated with this noise. Primary attention is to
be focused on premixed turbulent flames, although several aspects of
diffusion flame noise will also be investigated.
An extension of the principal investigator's original theory of com-
bustion generated noise will be attempted to include the effects of
approach flow turbulence level, directional radiation as caused by
refraction and dipole source effects, and the effects of diffusion
flames. Information gained from this analysis will be used to direct
experiments on free flames. An analysis will also be initiated to
determine the effects of reflecting surfaces on the combustion noise
source behavior. Suggestions for appropriate experimental variables.
will be made to extract the effects of reflecting surfaces.
The data obtained on free flames will be analyzed and compared with
the theory. Correlations will be obtained for sound power output,
directionality, and spectral content. Furthermore, the relation
between the reaction rate fluctuations and the sound power output will
be determined. An analysis will be completed for the radiation of
noise from a flame-containing enclosure to the surroundings. The modi-
fication to sound power output, spectral content and directionality
will be determined as compared with free flame generated noise.
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National Science Foundation GK-34136X
Division 'of Engineering 5/72 to 3/73
RANDOM VIBRATIONS OF ALMOST Funds $44,900
PERIODIC STRUCTURES
University of Illinois
School of Engineering
The first part of this research will consider the random variation of
periodic units from the designed (or norm) configuration. One objec-
tive will be to determine the probability distribution of each natural
frequency and the corresponding normal mode of the structure from the
probability distribution of the varied geometrical and material param-
eters. The investigation will then be extended to the response of such
a structure to random forcing fields. The convected frozen noise field
and convected but slowly changing noise field which have been used as
mathematical models for boundary layer turbulence will be included
among several other types of random excitation.
National Science Foundation GK-34126 Xl
Division of Engineering 4/73 to 3/74
RANDOM VIBRATIONS OF ALMOST Funds $44,100
PERIODIC STRUCTURES
University of Illinois
School of Engineering
The first part of this research will consider the random variation of
periodic units from the designed (or norm) configuration. One objective
will be to determine the probability distribution of each natural fre-
quency and corresponding normal mode of the structure from the proba-
bility distribution of the varied geometrical and material parameters.
The investigation will then be extended to the response of such a
structure to random forcing fields. The convected frozen noise field
and convected but slowly changing noise field which have been used as
mathematical models for boundary layer turbulence will be included
among several other types of random excitation.
This action provides a second year of support for a continuing grant.
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National Science Foundation GK-32585
Div. of Engineering 2/72 to 2/73
ENLARGEMENT OF ANECHOIC CHAMBER Funds $24,800
FOR NOISE RESEARCH
Syracuse University
Graduate School
An existing anechoic chamber facility (wedge-tip to wedge-tip size 12'
x 10' x 9') will be enlarged to 20 feet by 15 feet by 11 feet wedge-tip
to wedge-tip. The enlarged anechoic chamber facility will serve as a
more reliable tool for the noise research listed below, both because of
its greater capacity and lower effective cut-off frequency characteristics,
(a) Noise experiments in a hard room.
(b) Compressor and turbine noise.
(c) Traffic noise control.
(d) Effect of impulsive noise on the auditory system.
National Science Foundation Proposal P2K0644
Div. of Engineering FY 72 - 12 months
PREDICITION AND MEASUREMENT OF Funds $37,800
SOUND PROPAGATION IN LINED FLOW
DUCTS
University of Minnesota
The theoretical portion of this project will include the analysis of
two-dimensional steady flow in a porous wall duct and to initiate a
study of acoustic wave propagation in the same porous duct. The experi-
mental portion will imclude the development of and the measurement of
pressure spectrum in the porous wall ducts.
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TECHNICAL REPORT DATA
(Please readlHttntctioni on the revene before completing)
i. REPORT NO.
600/2-75-003
3. RECIPIENT'S ACCESSIOf*NO.
4. TITLE AND SUBTITLE
Federal Aircraft Noise Research, Development and
Demonstration Programs: FY'73 - FY'75
5. REPORT DATE
March, 1975
6. PERFORMING ORGANIZATION CODE
7. AUTHOH(S)
Interagency Aircraft Noise Research Panel
8. PERFORMING ORGANIZATION REPORT NO.
9. PERFORMING ORGANIZATION NAME AND ADDRESS
Interagency Aircraft Noise Research Panel (RD-681)
Office of Research and Development
Environmental Protection Agency
Washington, D. C. 20460
10. PROGRAM ELEMENT NO.
1GB090
11. CONTRACT/GRANT NO.
12. SPONSORING AGENCY NAME AND ADDRESS
Environmental Protection Agency
Office of Research and Development
Washington, D.C. 20460
13. TYPE OF REPORT AND PERIOD COVERED
Final, FY'73 thru FY'75
14. SPONSORING AGENCY CODE
IB. SUPPLEMENTARY NOTES
EPA Contact: Eugene E. Berkau, 202-755-0449
16. ABSTRACT
The Interagency Aircraft Noise Research Panel was established by the
Environmental Protection Agency to aid EPA in fulfilling its responsibility for
coordinating the Federal noise research activities. This report is the first
prepared by the Panel and provides an inventory of current and planned Federal
aircraft noise RD&D programs. The Federal agencies which sponsor aircraft noise
RD&D are the National Aeronautic and Space Administration, the Department of
Transportation, the Department of Defense, the National Science Foundation, and
the EPA. The report is organized by technical areas with each agency's programs
presented under the appropriate technical area. Emphasis is on fiscal years 1974
and 1975, but summary information on fiscal years 1973 and 1976 is also included.
The Appendix contains detailed programmatic information as furnished by the Federal
agencies on their aircraft related RD&D activities.
17.
KEY WORDS AND DOCUMENT ANALYSIS
DESCRIPTORS
b.lDENTIFIERS/OPEN ENDED TERMS
COSATI I icld/Gloup
Acoustics
Noise (Sound)
Noise reduction
Jet aircraft noise
Jet engine noise
Aerodynamic noise
Research
Research projects
Federal budgets
Federal noise RD&D
Federal noise coordinati
Research program
Aircraft
Transportation
2001
1406
1903
'18. DISTRIBUTION STATEMENT
Release unlimited
19. SECURITY CLASS /Till} Report/
Unclassified
21. NO. OF PAGES
20. SECURITY CLASS (This page)
Unclassified
22. PRICE
SPA Form 2220-1 (*-73)
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