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A GARDADVISOR 01W FOR A KBOWE EARCH & DLEV.OP FW

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AGARD ADiOvR POW 271

Technical Evaluation Report onAerodynamics of Combat AircraftControls and of Ground Effects(L'Mrodynamique des Commandes des Avionsde Combat et des Effets de Sol)

/- - NORTH ATLANTIC TREATY ORGANIZATION

.. .. ..... Distribution and Availability on Back Cover

AGA40271

AIWIORtY GiOl" FOR AEROSM E RESEACH & DEE.OPUNI37 RUE ANCELLE 92200 NEUILIY SUR SEINE FRANCE

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--P DVSR REPORT 271 - ---

Technical Evaluation Report on _ .

Aerodynamics of Combat AircraftControls and of Ground Effects iyu jg.,;

(L'A&odynamique des Comnuandes des Avions !at t ,

de Combat et des Effets de Sol)

by

G.ILRichevChief Scientist, Wright LaboratoryAeronautical Systems Division, US Air Force Systems CommandWright-Patterson AFB, Ohio 45433-6523United States

Edited by

D.H.Peckham 4

Royal Aerospace Establishment, Building 141Famborough, Hants GU14 6TD, United Kingdom

J.LeynaertDirecteur adjoint, Direction Grands Moyens d'EssaisB.P. 72, ONERA, 92322 Chitillon, France MV

This Advisory Report was produced at the request of 0 -the Fluid Dynamics Panel of AGARD.

4 ~ North Atlantic Treaty OrganizationSOrganisation du Trait6 de IAtlantique Nord

1!010 0011"

The Mission of AGARD

Acco o sO rhmeri~mioa cAG.ARDi kwhrng weehe he k a ofeAT O r xi rzbild

-Rcomnding effectie, i for the member na s to use thir reschd and devdapment capabirm for thecomon benefit of the NIATO c mwxt),

J - Po insnac icadiieandiac etd o teMiiCommininefie oro mewea and

dewlomet faiith pwarnregad to t ia-app iaion)

- Co ngwuo smuati v 2&,aoces in the aerospace scknoes re mant to surnethenhin the common defence posture;

-Lm ingthe co-,operaton among member naonsin aeospace reseca and doeopie m;

- Ex.mcale ofscientic and Lremical uorinotil

- Prm-ding assisiac to member nations for the purpose of increasing their scietific and technical potential;

- Rendeingscdentific and techical 2a cas reqtxgsed, to other NATO bodies and to member nations in connectionv6ith research and de'edopment problems in the --rospac field.

The highest authority within AGARD is the National Delegates Board consisting of offidally appointed senior representativesfrom each member"a"&" T mission ofAGARDiscarrid out throug "he Panels witich are compomed of-experts appointedby the National Delegates, the Consultant and Exchange Programme and the Aerospace Applications Stu dies Programme.Theresults of AGARD work are reported to the member nations and the NATO Authorities through the AGARD series ofpublications of which this is one.

Participation in AGARD activities is by invitation only and is normally limited to citizens of the NATO nations.

The content of this publication has been reproduceddirectly from material supplied by AGARD or the authors.

Published July 1991

Copyright 0 AGARD 1991All Rights Reserved

ISBN 92-835-0626-X

Printed by Specialised Printing Services Limited40 Chigwell Lane, Loughton, Essex IGIO 3TZ

Foreword

The complex shzpes ofmoderncoma~t a iin eomimnariou tihctvr-uideniag it-civdpcs ad increasing demandsfor greaer inannm3bfiqy aad coinrola!fliz; A,-n-e ffte-. i the need to improire the aerodiiamc design of airraftcontroks Howeren the basic undensunding ofaeo'in- controks is stil deficient in any areas and =AircAf deVInes armstil iry dependent on resuLt fron w~nd tuanel and figh tests. Thoug coniputmial methods are Protin inceainleffecth- in basic w~ice desitn application to control has mat with limited succes bemase of the dominance of Usediscou and separated-flo effects, %N6k lead to poorer control perfonw=c than predicd. often coupWe w-ith high buffet

It vks the purpose of the !SAiposi=r to rmica, the aerodynamic design of controls at take-off and landing conditons, formaoern narsubsonic~u sonicand supersonicspeeds, forbih angesof anac and yaw and for dep a Mure precnmtion andpos;-stall rnanoeuvrrn Also, part of the S) mposium was coocerned ith noine control dewacms With regard to ground effects,computational andexperimental methods wee aree, and induided jet effects on flo%-fiel forces and intake floAs

Avant-Propos

Les formies complexes des avions de combat modei ies, associ6es aux :omaines de vol qul s'dtendent sans ccsse C-1 auxdemnandes c-roissantes pour une plus grande manoeuvibilit ef em ,as grande contr6labilit6, ont fait croitrc le besoind'ani~liorcr les moycns de conception et de difinition de leurs gouvernes.

Cependant les connaissances de base stir le fonctionnement des gouvemnes sont encore insuffisantes sur bien des points et lesconcepteurs d'avions doivent encorese reposer beaucoup sur les r~sultats d'essais en soufficric ct en vol. Bier1 ,ue les m~thodesde calcul se montrent de plus efficaces pour les projets, leur utilisation pour Ics gouvernes a un succ~s hiptit6 A cause del'importancc des effets visqueux et de la prdsence de d~collements qui conduiscnt A des performances infdrieurcs Ai cclles quisont calcul~es et, en plus, a des niveaux de tremblement c6Ievds.

Cdrnit le but deccc symposium que de faire Ie point sur la d6finition a~rodynamiquc des gouvemnes:

- dans les configurations de d6collage ct d'attcrrissage,

- pour Ics manocuvres en subsonique, transsonique et supersonique,

- pour Ics grands angles d'attaquc et de d6rapagc,

- pour ]a pr4~vcnfion de la misc en vrillc,

- ct pour Ics manoeuvres apr~s d~crochage.

Une pantic du symposium a t6galcmcnt 6t6 consacr~c aux nouveaut~s en mati~re de controlc a6rodynamique.

En cc qui concemne I'cffct de so], Ics mdthodes cxp6rimentales et lcs mcthodes de calcul ont 6t6 pass~cs en revue. Leur aptitude

At 6valeur les effets dejet sur Ics efforts adrodyfiamiques et sur lcs 6coulemcnt d'cntr~c a 6t6 cxamin6e.

D.H. Peckham and J.LeynacitI Co- Chairmen

ContentsI

Page

FrrdoArant-Popohjs

I. Introducfion 1

2. Future Requirements 1

3. Current Control Design xperience 2

4. innovative Control Concepts 3- 4.1 High Ande of Attack Controls 3

4.2 Dynamic and Unsteady Effects 64.3 Thrust Vectoring Controls 6

5. Aircraft Ground Effects 7

6. ConcludingRemarks 8

7. Recommendations 9

8. References 11

I

___iv

1. INTRODUCIION

The first theme of this symposium addressed the issue thatnew requirements are emerging for combat aircraft for offensive anddefensive maneuvers, which include high angles of attack and yaw,and a greatly expanded flight envelope, with high acceleration ratesin all axes of flight.

The second theme of this Conference was ground effects oncombat aircraft aerodynamics and control. This is always important,but much more so when thrust vectoring and reverse is used onlanding approach or for short takeoff.

These two themes were given a thorough examination at theconference through the outstanding papers that were presented, andthe formal and informal discussions that followed.

2. FUWURE REQUIREMENTS

References 2 and 4 clearly showed that new aircraft controlrequirements will be dictated by extreme maneuvers at very highrates; for example, rapid rolling maneuvers around the velocityvector will be used to rapidly change the plane of attack of theaircraft.

During rapid maneuvering, many of the aerodynamic controlsurfaces are undergoing time-dependent separation which caninduce non-linearities in the aerodynamics of the aircraft and itscontrol system. It was pointed out that there was often timesdifficulty in obtaining both dynamic stability and favorable damping,while still maintaining a high level of agility. Active control offorebody, wing, and canard vortices seems to be the key.

Skow, presenting ref 4 paper, pointed out that anotherrequirement for controls, for increased maneuverability/agility inthe aircraft, is the strong requirement for nose down pitchingmoment control at high angle of attack. Nose-down pitch control isneeded to arrest a nose-up maneuver, to quickly unload to reducedG's (to be able to accelerate), and to control pitch-due-to-rollingabout the velocity vector at high angle of attack. It is impossible tokeep the nose pointed precisely unless there is adequate nose-downpitch control. Most configurations have much more nose-up pitchingmoment capability than nose-down authority.

It was pointed out by several authors (refs 2, 4, 11) that animportant factor in controls for agile aircraft is lateral-directionalcontrol at high angle of attack and high alpha rates. To initiatedesired maneuvers, and to stop undesired maneuvers, is oftendifficult because the tail, especially the vertical fin, has decreasedeffectiveness at high angle of attack.

In order to support advancements in fundamental under-standing of controllability at extreme maneuvers, we will need to

I develop new methods of analysis and test. It was pointed out byOrlik-Riickemann in the round table discussion at tie conclusion ofthe conference, that at combined high angles of attack with highangular rates, moderate angles of side slip or larger amplitudes ofmotion, a situation will be reached where the whole stability andcontrol domain will become non-linear and, therefore, no longerdescribable by the relatively simple linear concept of stabilityderivatives. Aerodynamic effects will no longer be superimposable.Experimental evaluation will require a much more robust body ofinformation on cross-coupling effects from rotary and forcedoscillation balances.

3. CURRENT CONTROL DESIGN EXPERIENCE

References 5 through 8 summarized current control designexperience, with emphasis on close-coupled canard/wing interactionsat high angles of attack and at low speed during takeoff and landing.Reference 7 by Hummel and Oelker, is noteworthy for its low speeddata.

Bufacchi, et al (ref 5), pointed out that, even for a relativelyconventional aircraft configuration (Aermacchi AMX), data from thedynamic/rotary balances showed important differences from thestatic balance data. While the fixed balance results often tended tomask the effects of control deflection near the stall, the rotarybalance allowed these to be quantified quite easily. In fact fixedbalance results can be misleading because they tended to show rapidfluctuations due to asymetiy of the stall which could mistakenly beascribed to changes in control effectiveness. The authors of ref 5 alsopointed out that employing differential canard deflections at highangle of attack could be used to improve directional stability.

3

Lovell (ref 6) provided a systematic investigation of variouscanard;, wing and aft-tailplane arrangements, and concluded thatoptimum lift-to-drag ratio is achieved with trailing edge flapsdeflected on a three-surface (canard-wing-tail) configuration.

Ref 8 pointed out that canard-wing configurations can haveundesirable pitch-up (reduced stability) and lateral stabilityproblems when the nose vortex burst is asymmetric, although thelatter problem is not limited to canard configurations. Ref 8 authorsalso found some indications that dynamic (inertia) effects areimportant, especially at high angle of attack.

The general conclusion of this session of the symposiumseemed to be that even though the control and aerodynamiccharacteristics of relatively conventional configurations are wellunderstood at low or medium angles of attack, there are still somesurprises when angles of attack approach stall, or when high onsetrates are experienced. Careful experimental and analytical investi-gations need to be conducted to design the controls for performanceand flight safety.

4. INNOVATIVE CONTROL CONCEPTS

Combat aircraft controls which work well in the "heart of theenvelope" (medium maneuvering levels and medium speeds) areoften deficient in providing responsive control authority in all axes atconditions of high angles of attack/yaw or where high accelerationsabout the axes of flight are required. It is at these conditions whereinnovative control concepts are needed. References 9 through 15addressed various means of aerodynamic control augmentationthrough thrust vectoring, boundary layer suction or blowing, vortexformation/burst control, and geometry shaping or deployment ofspecial surfaces. Properly so, the effects of unsteady aerodynamicswere accounted for in the studies reported, although it is clear thatmuch more work remains, particularly with regard to dynamicstability. Since the control effects are highly non-linear and time-dependent, caution is urged before some of these innovative controltechniques can be considered in combat aircraft design. More data isneeded at full scale Reynolds numbers from flight research.

4.1 High Angle of Attack Controls

4

Staying close to variations in conventional design controlsurfaces such as canards, wing shape, fuselage cross-section andtailplane components, ref 9 by Marks and Hahne showed that themaneuvering envelope could be increased considerably by carefulintegration of the aforementioned control components. Non-axisymmetric fuselage/nose shapes to prevent asymmetric vortexformation improved stability but also introduced negative dampingin pitch. Vertical tail surfaces placed outboard on the wings gavegood lateral-directional stability due, to favorable interference withwing vortices, but could cause aero-elastic problems. In-boardcanting of vertical tails (probably to reduce signature) was found tobe unstable in lateral-directional control, whereas out-boand cantingwas found to be favorable. Skewed hingeline tiperons providedincreased roll control on highly swept, low aspect ratio wings up topost-stall angles of attack, although again there could be structuraland weight issues. All-moveable twin vertical tails provided asubstantial increase in yaw control over conventional rudders andthus extended roll coordination capability to higher angles of attack.However, the adverse roll generated by all-moveable vertical tailscould present a potential problem, depending on the level of rollacceleration required and the roll control available from othersurfaces.

Malcolm, et al, (ref 10) provided a good summary of thepowerful effects of manipulation of the fuselage forebody vortex athigh angles of attack through forebody strakes and by blowing airfrom a simple port (not a slot) on the forebody. Strakes located justabove the horizontal axis of the forebody cross section were found tobe very effective, but would probably have to be "deployable" toavoid drag penalties at lower angles of attack, and to produce yawingmoment at high angles of attack. Forebody blowing experimentsshowed that aft blowing is most effective closest to the tip of theforebody and at a location on the leeward side approximately 135degrees from the windward side, while forward blowing is moreeffective at a farther aft position from the tip at the same meridian.Blowing forward showed that at low blowing rates the yawingmoment was in a direction opposite to the side where blowingoccurred. At higher blowing rates the yawing moment was on thesame direction as the blowing side. Aft blowing produced a yawingmoment in the direction of the blowing side for all blowing rates andthe moment continually increased with increased blowing. The levelof yawing moment could be controlled by variation in the blowingrate on both sides individually. Differential blowing with one side

5

forward and one side aft was very effective in producing controllableyawing moments. It was concluded that the most effective methodto control the yawing moment on the forebody was to minimize thenatural asymmetry with a pair of symmetrically mounted tip strakesand to perturb the vortex system away from the symmetriccondition with blowing on either side. Thus, a combination of fore-body strakes and blowing was found to be the most effective controldevice.

Overall, significant yawing moments (twice that available fromthe rudder at low angles of attack) can be produced at high angles ofattack by either independently moving a pair of forebody strakes orby independently controlling blowing rates from ports located on themodel surface.

Although these results are encouraging, they are based onstatic data at low speed conditions with laminar flow on theforebody. Further research should be conducted on the dynamiceffects and evaluations at higher Reynolds number. A large scaledrop model flight test should be considered.

Roberts and Wood (ref 11), evaluated slot blowing along theleading edge of a delta wing. The wing leading edge was fairly blunt,probably representative of a subsonic combat aircraft, although theresults could, in principle, apply to thinner leading edges. Blowing onone side of the leading edge was found to produce high rollingmoments at angles of attack approaching 50 degrees, so a device ofthis type could be used to augment control to roll about the velocityvector at high angles of attack and to prevent departure or wing rockat high alpha. The same blowing principle, if proven effective atflight conditions, could apply to other control surfaces to increasetheir effectiveness. Blowing rates will need to be evaluated at flightconditions to determine the amount of blowing coefficient (jetmomentum normalized by dynamic pressure times wing area)required. Nevertheless, the results to date are encouraging.

Walchli (ref 12) discussed the unique X-29 forward swept wingconfiguration. Results obtained since this paper was presented at thesymposium have shown that the X-29 is extremely stable andcontrollable about all axes at angles of attack up to 45 degrees. Pitchtransients have been made to 65 degrees where the X-29 vertical tailis virtually ineffective. Ailerons on the forward swept wing are stilleffective, even at this extreme angle of attack, and provide the

6

ability to stabilize the pitch, but not enough to roll about the velocityvector. Apparently the forward swept wing , full authority canardsand the small pitch surfaces adjacent to the vertical tail are moreeffective in flight than was expected from the wind tunnel data.

4.2 Dynamic and Unsteady Effects

Hancock and Mabey (ref 13) provided keen fundamentalinsight into control response for surfaces with attached flow. This isespecially important for aotive controls associated with staticallyunstable aircraft. Another application is design criteria for fluttersuppression systems. For "fast acting" controls, where the time ofdeflection of the control surface is on the order of the flow transittime over the surface, the understanding of unsteady aerodynamiceffects is critical. Computational fluid dynamic analysis, with time-accurate unsteady flow solvers, is being developed in several of theAGARD member nations. Perhaps the phenomena observed byHancock and Mabey, wherein the aerodynamic rise time to attainsteady state conditions was found to decrease abruptly near Mach 1,can be predicted in the not-so-distant future.. Ref 15, Bearman andassociates, gave some encouragement for this possibility with theiranalysis of a rapid spoilr deployment on a two-dimensional airfoil,albeit for incompressible, inviscid flow. Ref 14, by Mabey, et al,evaluated the effects of an unsteady canard flow, such as would bethe case if a canard was used for active control of an unstableaircraft (pitch axis), and found that, for the configurationinvestigated, canard oscillations with one degree amplitude hadvirtually no detrimental effect on the mean flow of the wing. X-29flight experience has essentially verified this conclusion. Thus activecontrol using canards can be considered for combat aircraft althoughtest verification would clearly be required.

4.3 Thrust Vectoring Controls

Thrust vectoring for combat aircraft, using the main engine(s)is now being considered to produce forces and moments in pitch,yaw, roll planes to augment aerodynamic controls, especially in flightregimes where the aerodynamic forces are soft, for example atextreme angles of attack/yaw or during low speed approach tolanding. Ref 1 by Moorhouse, and associates, indicated that an F-15aircraft had been modified to incorporate pitch axis thrust vectoring.Other programs were discussed in the symposium round tablediscussions (ref 24) where combined pitch and yaw vectoring will be

investigated, e.g. modified F-18 and the X-31 enhanced fightermaneuverability technology demonstrator, a joint US-German project.

Since the AGARD symposium, the Short Takeoff and Landing(STOL) and Maneuver Technology Demonstrator F-45 (refl) hasflown, and achieved all the objectives ah.ociated with thrustvectoring/reversing that were described by Moorhouse, et al, (ref 1).The test program showed conclusively that the aircraft flight controlsystem and the propulsion control system could be integrated toachieve significant improvements in performance, maneuverabilityand short field capability.

Mangold and Wedekind (ref 16) addressed some of the sameissues as Ref 1, but with an emphasis on pitch vectoring at highangles of attack. There will be a much stronger need for yaw controlat these conditions because the vertical tail fin is losing effectiveness.Pitch vectoring is needed especially for nose-down pitch control athigh alpha. Thus pitch/yaw vectoring to augment controls is one ofthe key technologies to realize the benefits of enhanced aircraftagility discussed in the opening session of the symposium (refs 1 to4). Ref 18, by Holmes, called special attention to the propulsion-control integration requirements for short takeoff-vertical landing(STOVL) aircraft designs. Correct simulation of engine and airframeis needed to evaluate hot gas reingestion, and controllability near theground.

5. AIRCRAFT GROUND EFFECTS

The second major theine of the symposium, closely related tothe first, was to investigate the influence of ground effects on aircraftaerodynamics and controls. The major influence is during landing ofhigh performance combat aircraft, wherein controllability e: highsink rates and in gusty cross-winds is often an issue. The aircraftlands on a "bubble" of air; the dynamic response of this bubble isinfluenced by the aircraft configuration, weight, lift and attitude, aswell as by the ambient winds. In order to correctly simulate theinteraction between this bubble of air and the aircraft, refs 18-23seemed to agree that the dynamics of landing were important inorder to establish controllability in a high performance combataircraft; thus it is necessary to account for the sink rate whenevaluating ground effects. The F-15 STOL/Maneuver TechnologyDemonstrator now has flight data which bears out this conclusion.

S

Ref 19 (Vidal and Deschamps) described a unique test facilityat CEAT to evaluate ground effezts. The model is guided along a testtrack over a surface of water. Tests on a Falcon 900 executive jettransport showed considemable influence of dynamic ground effects.Rcf 21 (Cocquerez, et al) described a unique free-flight test method,with on-board measurement of forces :o evaluate grcund effects,including the presence of side gusts. Some interesting, non-lineareffects were reported.

Ref 20 (Paulson, et al) concluded that significant differencescan exist between ground effects obtained with and without rate Gfdescent being included (dynamic vs static), especially if vectored orreversed thrust is used prior to touch-down and during roll-out. Theauthors found that including the appropriate rate of descent reducedthe severity of ground effects compared to static testing. They alsofound that the use of a moving belt on the floor of the wind tunnel toelim;inate the boundary layer was less important than simulating therate of descent, in order to determine the correct controllability andlift effects near the ground. Ref 22 verified these general results forthe X-29 configuration, and found that there was less change in liftdue to ground effects when the rate of descent was simulated. Therewas also a nose down pitching moment for the X-29 when dynamiclandings were made, which was not present during static landingsimulations. Finally, ref 23 (Condaminas and Becle) reported on aninvestigation of ground effects for a large commercial transport(A320). Good correlation of forces compared to flight test wasachieved when the wind tunnel floor boundary layer was energizedby blowing. This could indicate that dynamic sink rate simulation isnot as important for large aircraft as it is for small aircraft with lowaspect ratio wings. In other words, the "air bubble" has lessinfluence on the net lift and controllability of a large aircraft.

6. CONCLUDING REMARKS

Because of very high maneuvering rates and accelerations,dynamic stability is much more important than ever before, as is theunderstanding of the dynamics of controls including all the cross-coupling effects. In fact, the basic concept of stability derivativesmay come into question in some very rapid non-linear maneuvers.

An expanded flight envelope of the aircraft will dictate anexpanded controls envelope, requiring a search for favorable

interference between control surfaces and wings in maneuvers.

i9

The engine, and the force it produces, in both direction andmagnitude, is becoming a major control force and moment producer,especially where aerodynamic forces are soft, such as at high anglesof attack, or during short takeoff or vertical landing conditions; hencethe need for flight-propulsion control integration.

Integration of the airframe and its weapon is extremelyimportanL High angle of attack maneuvers, used to bring weapons tobear on the target, will be limited in their effectiveness if theweapons cannot be launched at these conditions. This is an area thatneeds much more research.

Understanding complex ground effects, dynamic as well asstatic, will be crucial to safe, routine operations of military andcommercial aircraft.

In summary, the aerodynamics of combat aircraft controls andof ground effects was given a thorough treatment at the symposium.Complete details may be found in ref 24. These are tough problems,but were addressed by AGARD because stretching the combatmaneuver envelope will enhance offensive and defensive combatcapability. By combining ideas and talents throughout NATO, bymeans of AGARD, we can collectively develop a superior technologybase for combat aircraft of the future.

7. RECONMENDATIONS

Analysis and test of three-dimensional control shapes shouldbe continued to search for means to expand the safe maneuveringenvelope of combat aircraft and weapons in order to increaseoffensive and defensive combat capability.

Dynamic and static stability evaluations should be conductedon complete configurations using new rotary balance and forcedoscillation techniques to determine non-linear control effectivenessover the complete range of maneuvers, including post-stall and highrate (enhanced agility) conditions.

Increased emphasis and resources should be put on time-accurate unsteady flow computational fluid dynamics solutions withappropriate turbulence models, and applied to practical three-dimensional configurations at extreme maneuvers.

Innovative techniques, such as boundary layer and vortexcontrol through blowing, suction and geometrical v~iriatious, shouldbe pursued through full-scale flight test so that they can be usedwith confidence, in future combat aircraft designs.

These recommendations should be pursued to the extentpossible through collaborative efforts among the AG-ARDINATOmember nations.

II

REFERENCES-AGARD-CP-465

1. Noorhotus, D.J., et.al., "Aerodynamic and Propulsive ControlDevelopment of the STOL and Maneuver Technology Demonstrator"

2. Saun ieis, T.B., Tucker, J.H., "CoMbat Aircraft ControlRequire L.ts"

3. Gilbert, "R.P., et.al., "Control Research in the NASA High-AlphaTechnology Program"

4. Chody, J.R., et.al., "Combat Aircyaft Control Requirements forAgility"

5. Bufacchi, B., et.al., "Aerodynamics Control Design: Experienceand Results at Aermacchi"

6. Lovell, D.A., "Some Recent Experimental Investigations intoAerodynamic Aspects of Controls for Canard Combat Aircraft Layouts"

7. Hummel, D., Oelker, H.C., "Effects of Canard Position on theAerodynamic Characteristics of a Close-Coupled Canard Configurationat Low Speed"

8. O'Leary, C.O., Weir, B., "The Effects of Foreplanes of theStatic and Dynamic Characteristics of a Combat Aircraft Model"

9. Marks, B.A., Hahne, D.E., "Innovative Control Concepts andComponent Integration for a Generic Supercruise Fighter"

10. Malcolm, G.N., et. al., "Development of Non-Conventional ControlMethods for High Angle of Attack Flight Using Vortex Manipulation"11. Roberts, L., Wood, N.J., "Control of Vortex Aerodynamics at

High Angles of Attack"

12. Walchli, L.A., "A Look at Tomorrow Today"

13. Hancock, G.J., Mabey, D.G., "Unsteady Aerodynamics of Controls"

14. Mabey, D.G., et.al., "The Steady and Time-Dependent AerodynamicCharacteristics of A Combat Aircraft with a Delta or Swept Canard"

15. Bearman, P.W., et.al., "The Effect of Rapid Spoiler Deploymenton the Transient Forces on an Aerofoil"

16. Mangold, P., Wedekind, G., "Inflight Thrust Vectoring - AFurther Degree of Freedom in the Aerodynamic/FlightmechanicalDesign of Modern Fighter Aicraft"

17. Holmes, M., et.al., "A Propulsion View of Ground EffectsResearch"

12

18. Wedekind, G., Mangold, P., "Aerodynamic Interferences of In-Flight Thrust Reversers in Ground Effect"

19. Vidal, G., Deschamps, J., "Etude De L'Effet De Sol Au Ceat

Exploitation Des Resultats"

20. Paulson, J.W., et.al., "Dynamic Ground Effects"

21. Cocquerez, J.L., et.al., "Etude De L'Effet De Sol Sur MaquetteEn Vol"

22. Curry, R.E., et.al., "An In-Flight Investigation of GroundEffect on A Forward Swept-Wing Airplane"

23. Condaminas, A., Becle, J.P., "Determination De L'Effet De SolSur Les Caracteristiques De L'Avion A320"

24. "Aerodynamics of Combat Aircraft Controls and of Ground

Effects," AGARD CP-465, Madrid, Spain, October 1989

REPORT DOCU3MENETION PAGE

1.Reciien's Refrence 2.Originato'sRefrence 3.Fwtor Reference 4. Security Classificatimof Document

AGARD-AR-271 ISBN 92-835-0626-X UNCLASSIFIED

5. Origiator Advisory Group for Aerospace Research and DevelopmentNortfh Atlantic Treaty Organization7 rueAncelle, 92200 Neuilly sur Seine, France

6.Tide AERODYNAMICS OF COMBAT AIRCRAFT CONTROLS

AND OF GROUND EFFECTS

7. Presented at

8.Author(s)/Editor(s) 1 9. Date

G.K.Richey Edited by D.H.Peckham and J.Leynaert July 1991

10. Author's/Editor's Address 11. Pages

See Flyleaf. 18

12. Distribution Statement This document is distributed in accordance with AGARDpolicies and regulations, which are outlined on theback covers of all AGARD publications.

13. Keywords/Descriptors

Fighter aircraft Aerodynamic characteristicsControl surfaces DesignControl equipment Ground effect

14. Abstract

The papers presented at the AGARD Fluid Dynamics Panel Symposium on ,Aerodynamics ofCombat Aircraft Conti,!s and of Ground Effects.4 are summarized and evaluated. The revieweralso provides some general conclusions relative to the effectiveness of the symposium inaddressing the problems of aerodynamics of combat aircraft controls and ground effects in an erawhen a stretched combat maneuverability envelope is needed to enhance both offensive anddefensive combat capability. Recommendations for future experimental and computational fluiddynamics activities are also provided.

The papers presented at the meeting have been collected in AGARD CP-465(/7)- A , b.

This Advisory Report was produced at the request of the Fluid Dynamics Panel of AGARD.

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0 .. .0

13 0

> U 0.40

5 30 Z