The results, status, and plans of NASA sponsored advanced aerodynamics and active controls technology activities are reported. Development of subsonic, energy efficient transport aircraft technologies is emphasized

Alford, W. J., Jr.

English

NASA Technical Reports Server

ADVANCED AERODYNAMICS AND ACTIVE CONTROLS TECHNOLOGY 
SESSION INTRODUCTION 
William J. Alford, Jr. 
NASA Langley Research Center 
INTRODUCTION 
The purpose of this section is to report on the results, status, and plans 
of NASA sponsored advanced aerodynamics and active controls technology 
activities. 
Since most of the work underway in these areas is focused on development 
of subsonic, energy efficient transport aircraft technologies and is sponsored 
by the Energy Efficient Transport (EET) Element of the Aircraft Energy 
Efficiency (ACEE) Project (refs. 1 and 2), the material to be presented in this 
introductory paper is intended to set the stage for the section by providing a 
synopsis of the EET activities; the titles and authors of the ten section 
papers; and how the efforts represented by the papers are related to the over- 
all EET plan. 
It should be noted that most of the work being reported on has been 
underway for less than a year and, therefore, in-depth or complete results are 
not yet available. 
ABBREVIATIONS 
ACEE aircraft energy efficiency 
ACT active controls technology 
ARC Ames Research Center 
B Boeing Commercial Airplane Company 
DC Douglas Aircraft Company 
DFRC Dryden Flight Research Center 
EET energy efficient transport 
EMS elastic mode suppression 
FLT flight tests 
GA gust load alleviation 
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https://ntrs.nasa.gov/search.jsp?R=19780021104 2020-03-20T13:22:58+00:00Z
IASCW high-aspect-ratio supercritical wing 
IEM integrated energy management 
L Lockheed-California Company 
L.S. low speed 
LaRC Langley Research Center 
M maintainable 
Max. Ben. maximum benefit 
MFLDN 
MLA 
NASA 
NLF 
OAST 
PFC 
R 
mixed-flow, long-duct nacelle 
maneuver load alleviation 
National Aeronautics and Space Administration 
natural laminar flow 
Office of Aeronautics and Space Technology 
primary flight control system 
reliability 
RPRV 
RSS 
R&T 
sew 
W.T. 
WTE 
WTW 
remotely piloted research vehicle 
relaxed static stability 
research and technology 
supercritical wing 
wing load alleviation 
wind-tunnel tests 
wing tip extension 
wing tip winglet 
ENERGY EFFICIENT TRANSPORT PROJECT 
: The 
Aircraft 
EET project is one of the elements of the NASA OAST Advanced Civil 
Systems Technology Program (ref. 2) whose objectives are to: 
524 
"Expedite industry acceptance and application of advanced aero- 
dynamics and active controls technology in an integrated manner 
to achieve energy, economic, and aircraft sales benefits." 
As illustrated in figure 1, the focus of the EET activities is on advanced 
subsonic CTOL aircraft of both the near-term derivative category (i.e., B-747, 
DC-lo, and L-1011) and farther-term, new or advanced derivative aircraft 
(i.e., B-7X7, DC-X-200, and L-RE-1011) category. 
A schedule of the EET technology development and evaluation activities is 
presented in figure 2. The activities consist of NASA-LaRC defined and imple- 
mented (with contractor involvement, as appropriate) advanced aerodynamics and 
active controls efforts and selected concepts contracts with Boeing, Douglas, 
and Lockheed. These activities, which were initiated in 1976, intensified in 
1977 and are expected to continue through fiscal year 1982. Associated research 
and technology resources are slightly in excess of eighty-five million (then 
year) dollars. 
Advanced Aerodynamics 
The advanced aerodynamics activities (fig. 2) focus on three areas: cruise 
conditions, low-speed conditions, and design methodology. 
In the cruise area, high-aspect-ratio supercritical wing airplane models 
have been designed and are being tested in the Langley 8-foot transonic pressure 
tunnel to establish a data base for variations in wing characteristics and con- 
trols. Analytical and experimental activities are also underway to optimize 
wing-winglet geometry and to assess wide-body transport applications of wing- 
lets. Propulsion/airframe integration experiments are planned to minimize. 
interference effects of below-the-wing pylon-mounted nacelles. Early results 
of these efforts are presented in reference 3. 
Current results and status of the cruise aerodynamics activities are con- 
tained in papers 1 and 2 of this section, entitled "NASA Supercritical-Wing 
Technology" by Dennis W. Bartlett and James C. Patterson, Jr., and "Experi- 
mental Results of Winglets on First, Second, and Third Generation Jet Trans- 
ports" by Stuart G. Flechner and Peter F. Jacobs, respectively. These four 
authors are aerospace technologists associated with the LaRC Transonic Aero- 
dynamics Branch. 
In the low-speed area, efforts are underway to define the high-lift system 
requirements for high-aspect-ratio supercritical wing configurations and to 
assess the impact of active controls requirements on high-lift systems. A 
model has been designed, fabricated, and tested in the Langley V/STOL tunnel. 
Another model is being designed for fabrication and testing at higher Reynolds 
numbers in the Ames Research Center (ARC) 12-Foot Tunnel. 
Design methodology developments are aimed at expedi,ting three-dimensional, 
optimum, supercritical wing design capability and mixed-flow-juncture analysis 
methods. The approach, using computer aided design tools, is to: couple 3-D 
525 
boundary layer programs to transonic wing analysis procedures; extend 3-D 
transonic wing programs to operate in a design mode with either constrained 
loading or geometry specifications; and to incorporate non-planar capability 
in the wing programs. There are two papers in this section dealing with 
advanced transonic flow computational aerodynamics. The first is entitled 
r'Recent Experiences With Three-Dimensional Transonic Potential Flow Calculations" 
by David A. Caughey of Cornell, Perry A. Newman of LaRC, and Antony Jameson of 
NYU. This activity was sponsored by NASA in the OAST R&T Base Program (ref. 2). 
The second paper is entitled "Towards Complete Configurations Using an Embedded 
Grid Approach" by Charles W. Boppe of Grumman. This and all of the other work 
being reported on in this section was sponsored by the ACEE/EET Project (ref. 2). 
Active Controls 
Still referring to figure 2, the active controls technology activities 
consist of two major developments: integrated analysis and design techniques; 
and reliable, maintainable flight control systems (ref. 4). 
The objective of the integrated analysis and design techniques activity is 
to evaluate existing analytical and experimental tools for the integrated appli- 
cation of aerodynamics, structures, and controls. The technical approach is to 
design, under contract (NASl-14665, with Boeing-Wichita), a high-aspect-ratio 
supercritical wing incorporating structurally critical gust load alleviation, 
maneuver load alleviation, and active flutter suppression systems. Three aero- 
elastic semispan wings including the control systems will be fabricated. One 
set of two will be flight tested at DFRC utilizing a modified BQM-34E/F 
"Firebee II" RPRV. The other semispan wing will be tested in the Langley 
transonic dynamics tunnel. The expected results of this activity will be a 
comparison and evaluation of the analytical, wind-tunnel, and flight test 
results including: control system performance, loads, flutter, and unsteady 
aerodynamic and aeroelastic characteristics. The design methods to be evaluated 
through test activities are discussed in the last paper of this section, 
entitled "Active Controls Technology to Maximize Structural Efficiency" by 
James M. Hoy of Boeing-Seattle and James M. Arnold of Boeing-Wichita. 
The principal thrusts of the reliable, maintainable flight controls 
systems activity are: design of a cost-effective system, using state-of-the-art 
technology for near-term, non-flight-critical application; and design and 
evaluation of an advanced, reliable, maintainable system for far-term applica- 
tion. Elements of these activities include: (1) a state-of-the-art assessment 
by collecting, analyzing, and documenting current airlines avionics systems 
reliability data, maintenance experience, and operational practices and pro- 
cedures; (2) development and validation of system evaluation models incorporating 
control system reliability and performance, aircraft flight safety, airline 
operations (e.g., route structure, maintenance, delays, etc.) and cost; 
(3) development and evaluation of two advanced fault-tolerant computer systems: 
Stanford Research Institute's Software Implemented Fault Tolerance (SIFT) and 
Charles Stark Draper Laboratory's Fault Tolerant Multiprocessor (FTMP); and 
(4) studies of fault-tolerant flight control system architectures. Early 
results of some of these activities are presented in references 5 toIT. Some 
526 
current results were given in the oral presentation on fault tolerant computer 
technology for active controls. 
Selected Concepts 
To achieve the earlier stated objective of the ACEE/EET Project, a strong 
NASA/industry partnership is being implemented with the technology focus being 
that which NASA and the commercial transport industry mutually agree is most 
relevant for both near-term (current transport derivatives - 1983) and far-term 
(new aircraft design - 1985+) applications. (See fig. 1.) The three industry 
participants are Boeing, Douglas, and Lockheed. As indicated in figure 2, 
selected advanced concepts are being implemented in two phases. Phase I, which 
is currently underway, is illustrated in figure 2 by the activities listed in 
the solid rectangles. These activities are primarily developmental in nature 
lasting through FY-79. Phase II, which is to be initiated this year, is 
illustrated in figure 2 by the dashed rectangles. These activities are pri- 
marily evaluative and demonstrative in nature and are expected to continue 
through FY-82. Ongoing and planned contractual activities with each company 
are described below. 
Boeing.- In Phase I, there are two contractual activities with Boeing. 
One of these has a near-term focus (NASA contract NASl-14741 for selected 
advanced aerodynamics and active controls technology concepts development on a 
derivative B-747 aircraft). The tasks include development and analysis, 
engineering design, and evaluation of wing-tip extensions, wing-tip winglets, 
wing load alleviation, wind-tunnel testing of these various modifications, 
choice of a final configuration, and evaluation and recommendations for further 
work. Some results to date and status of this work are presented in the paper 
entitled "Application of Winglets and/or Tip Extensions With Active Load 
Control on the Boeing 747" by Robert L. Allison, Brian R. Perkin, and Richard L. 
Schoenman of Boeing-Seattle. 
The second Boeing contractual activity has a farther term focus (NASA 
contract NASl-14742 for selected advanced aerodynamic and active control con- 
cepts development). The tasks of this program include: B-747 primary flight 
control system reliability and maintainability study; integrated energy manage- 
ment; natural laminar flow; high-lift characteristics of high-aspect-ratio 
supercritical wings; and a maximum benefit of active controls technology planning 
study. Although a complete status report on these activities is not presented 
herein, some of the more important considerations related to methods of inte- 
grated design to maximize the benefits of active controls are discussed in the 
paper,entitled "Active Controls Technology to Maximize Structural Efficiency" by 
James M. Hoy of Boeing-Seattle and James M. Arnold of Boeing-Wichita. 
Current plans for Phase II include: wind-tunnel testing of the final 
B-747 configuration selected in Phase I and, possibly, some engineering flight 
tests; and an in-depth assessment of the integrated application of ACT followed 
by identification of ACT system design and test requirements. 
527 
Douglas.- In Phase I there are also two contracted activities underway with 
Douglas. The first has a near-term focus (NASA contract NASl-14743 for selected 
winglet and mixed-flow long-duct nacelle development for DC-10 derivative air- 
craft). The tasks include: design and wind-tunnel tests of winglets on a 
DC-10 wing; and analytical and wind-tunnel investigation of the interference 
effects of mixed-flow long-duct nacelles on a DC-10 wing. Early results and 
the status of this work are presented in the paper entitled "Winglet and Long- 
Duct Nacelle Aerodynamic Development for DC-10 Derivatives" by A. Brian Taylor 
of Douglas-Long Beach. 
The second contractual activity has a farther term focus (NASA contract 
NASl-14744 for selected advanced aerodynamic and active control concepts 
development). The tasks include: wind-tunnel testing of a high-aspect-ratio 
supercritical wing; definition and study of an optimum wing-winglet combination; 
definition of a high-lift system for a high-aspect-ratio supercritical wing; and 
assessment of a low-risk stability augmentation system for current and advanced 
transports. The status and results of this work are presented in the paper 
entitled "Advanced Aerodynamics and Active Controls for a Next Generation 
Transport" by A. Brian Taylor of Douglas-Long Beach. 
Current plans for Phase II include: further DC-10 mixed-flow, long-duct 
nacelle and winglets wind-tunnel testing and flight test demonstrations; 
further high-aspect-ratio supercritical wing wind-tunnel testing; and in-depth 
assessment of an active controls transport including the identification of 
system design and test requirements. 
Lockheed.- In Phase I there is a single effort by Lockheed with a near-term 
focus (NASA contract NASl-14690 for accelerated development and flight evaluation 
of active control concepts for subsonic transport aircraft). The tasks include: 
flight test of a wing load alleviation system on an L-1011 aircraft; addition of 
4.5 foot wing-tip extensions and flight tests with a wing load alleviation 
system; and moving-base simulation testing to develop active stability augmenta- 
tion permitting a smaller horizontal tail on future L-1011 derivatives. The 
status and results of this program to date are presented in the paper entitled 
"Development and Flight Evaluation of Active Controls in the L-1011" by 
J. F. Johnston and D. M. Urie of Lockheed-California. 
Current plans for Phase II call for further development and evaluation of 
a wing load alleviation system for subsonic commercial transport aircraft. 
CONCLUDING REMARKS 
Most NASA-sponsored advanced aerodynamics and active controls technology 
development for CTOL transports is embodied in the ACEE/EET project. The other 
papers in this section report selected early results of this program. So that 
their context is clear, this paper has briefly summarized the EET ongoing and 
planned efforts indicating which are represented by the papers that follow and 
outlining the nature of the work not reported. 
528 
REFERENCES 
1. Leonard, Robert W.; and Wagner, Richard D.: Airframe Technology for Energy 
Efficient Transport Aircraft. [Preprint] 760929, Sot. Automot. Eng., 
Nov.-Dec. 1976. 
2. Alford, W. J.: Energy Efficient Transport. Research and Technology Objec- 
tives and Plans. Summary - Fiscal Year 1978 Research and Technology 
Program. NASA-TM-78623, 1977, p. 22. 
3. Bartlett, Dennis W.: Wind-Tunnel Investigation of Several High Aspect-Ratio 
Supercritical Wing Configurations on a Wide-Body-Type Fuselage. NASA 
TM X-71996, 1977. 
4. Hood, R. V., Jr.: The Aircraft Energy Efficiency Active Controls Technology 
Program. AIAA 1977 Guidance and Control Conference, Aug. 1977, 
pp. 279-285. 
5. Dade, W. W.; Edwards, R. H.; Katt, G. T.; McClellan, K. L.; and Shomber, 
H. A.: Flight Control Electronics Reliability/Maintenance Study. NASA 
CR-145271, 1977. 
6. Murray, N. D.: Fault Tolerant Computers for Civil Transport Aircraft. AIAA 
Paper No. 77-1439, Oct.-Nov. 1977. 
7. Advanced Programs Div., Aerospace Corp.: Fault-Tolerant Software Study. 
NASA CR-145298, 1978. 
529 
Figure l.- Energy efficient transport - illustrations of advanced 
subsonic CTOL aircraft. 
530 
ACTIVITY \ FY 
IDVANCEDAERODYNAMIC! 
B CRUISE 
B LOW-SPEED 
m DESIGN METHODOLOGY 
CTIVE CONTROLS 
m INTEG. ANALYSIS & 
DES. TECHNIQUES 
D RELIABLE, 
MAINTAINABLE FCS 
iELECTED CONCEPTS 
BOEING 
0 PHASE I 
l PHASEII 
DOUGLAS 
l PHASE1 
. PHASE II 
LOCKHEED 
0 PHASE1 
0 PHASEII 
77 ] 78 1 79 I 80 I 81 I a2 
I 
REL.& MAINT. 
STUDY 
l lNT.ENERGYMGMT 
*NAT. LAM. FLOW l----- *HIGH LIFT 'MAX.BEN. ACT BASELINE DEF. 
-------__ 
:*-B-7ii ~L$tib$TE l POSSIBLE 
I W.T. FLT.DEMO 
;-ASSESS. OFINTEG. l DES. &TEST 
; _ --A!!L!cI _oFeA_cT_ _ _ _ -REa'T_s.e _ 
. DC-10LONG DUCT 
l DC-lOWINGLETS 
' OPT. SCWI 
' HIGH LIFT 
l REL. STATICSTAB. 
_ _ _ _ _ _ _ _ - _ 
::-bC-iO-L6tiG-Dk! i4AC. FLT DEMO. 
; l DC-lOWlNGLETLOW-SPEED W.T.TEST 
;. HIGH A.R. SCWW.T. TEST 
, l ACT CONF. DEF.*DES.&TEST REQ'TS L _______ ------- ---- 
l L-1011 wLA/ 
TIP EXTEN 
7 DEV. FLT. TEST 
r------- ---- - ------ -_ 
1 l L-loll-500WITH WLA/WTE PRE-CERT. 
L ____ --- --------------- 
Figure 2.- Energy efficient transport - advanced aerodynamics 
and active controls technology development and evaluation 
schedules. 
531 


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