太阳能飞机

MorphingAircraftConcepts,Classifications,andChallenges

NextGenAeronautics,Inc.

2780SkyparkDr.,Suite400,Torrance,CA90505

ABSTRACT

Amorphingaircraftcanbedefinedasanaircraftthatchangesconfigurationtomaximizeitsperformanceatradically

onfigurationchangescantakeplaceinanypartoftheaircraft,ge,wing,

engine,rphingisnaturallythemostimportantaspectofaircraftmorphingasitdictatestheaircraft

performanceinagivenflightcondition,andhasbeenofinteresttotheaircraftdesignerssincethebeginningofthe

flight,prearchefforts(mainlyunder

DARPAandNASAsponsorships)however,arefocusingonevenmoredramaticconfigurationchangessuchas200%

changeinaspectratio,50%changeinwingarea,5ochangeinwingtwist,and20ochangeinwingsweeptolaythe

nggeometryandconfigurationchanges,whileextremely

challenging,canbeconceptuallyachievedinavarietyofways–folding,hiding,telescoping,expanding,and

contractingawing,couplinganddecouplingmultiplewinggments,onceptscanbeclassifiedunderafew

‘independent’categoriesandsub-cat

paperprents:1)areviewofpriorworkleadingtocurrentR&Defforts,2)classificationofmorphingdesigns,and3)a

summaryoftechnicalchallengencounteredindesigningamorphingaircraft.

INTRODUCTION

Ifamorphingaircraftisdefinedmerelyasanaircraftthatchangesitsconfigurationin-flight,itcanbeenthat

efirstsuccessfulcontrolledandpoweredflightbytheWrightbrothers

invohen,controlsurfacesintheformof

aileronsandelevatorshavrmore,inorder

toreducethedrag,alsoe

hesmallchangescanbetechnically

termedasmorphing,theyareeithernecessaryenablersforacontrolledflightorcontributorstotheimproved

ult,thetechnologiesdonotnecessarilyallowanaircrafttoperform

mple,whilealong-enduranceaircraft(Hawk,Fig.1-a)aidedwith

thenecessarycontrolsurfacescanloiteroveratargetforalongtime,itcannotflyathigh-speedlikeX-45(Fig.1-b).

Table1summarizeshowincrea

example,itcanbeenthatforefficientlow-speedflight,theaircraftshouldhavehighaspectratioandlowsweep

rytothis,ore,inorderto

havethesameaircraftflydiversifiedmissions,itshouldbecapableofmakinglargeconfigurationchangesinan

whataircraftdesignersaimtoachievebydevelopingmorphingaircraft

technology.

Wingsarethemostinfluen,theirshapeand

ore,wingmorphinghasbeenofamajor

findveralpreviousdesigns,whichbringsmallandlarge

shapeandsizechangershavealso

attemptedchangingextction,we

veyislimitedtothodesignswhichhavebeeneithertestedin

fter,weclassifythedesignsinveralcategoriesbaduponthebasic

y,weprentthechallengesfacedinthe

designofmorphingaircraft,whichareinadditiontothofoundindesigningaconventionalaircraft.

SmartStructuresandMaterials2004:IndustrialandCommercialApplicationsofSmart

StructuresTechnologies,on,ProceedingsofSPIEVol.5388

(SPIE,Bellingham,WA,2004)·0277-786X/04/$15·doi:10.1117/12.544212

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Table1:Effectsofwinggeometricparametersonaircraftperformance

AirfoilThickness/Chord

Airfoilcharacteristics,laminar/turbulenttransitionAirfoilThicknessDistribution

Improvedlow-speedairfoilperformance

Improvedhigh-speedairfoilperformance

LeadingEdgeRadius

Improvedlow-speedairfoilperformance

Improvedhigh-speedairfoilperformanceRatio

Zero-liftangleofattack,airfoilefficiency,parationbehaviorAirfoilCamber

Preventstipstallbehavior;SpanwiliftdistributionWingTwistDistribution

Wingefficiency(spanwiliftdistribution);InduceddragWingTaperRatio

IncreadcriticalMachno.,dihedraleffectDecreadhigh-speeddrag

IncreadC

Lmax

WingSweep

IncreadRollingmomentcapability,lateralstability

Increadmaximumspeed

WingDihedral

IncreadL/D,loitertime,cruidistance,turnratesDecread:enginerequirements

Increadmaximumspeed;Decreadparasiticdrag

WingAspectRatio

Increadlift,loadfactorcapability

Decreadparasiticdrag

WingPlanArea

EffectsofVariability–allotherparametersunchangedParameter

(a)(b)

Figure1:Widelydifferentaircraftconfigurationsareinvolvedinhighandlow-speedflights:

a)GlobalHawkandb)X-45.

SURVEYOFMORPHINGAIRCRAFT

Inthisction,wepresldbenoted

herethatthisveyhasbeendividedinto

largeandsmallwingmorphingdesigns,fulagemorphing,lowingsubctionprents

examplesineachofthecategories:

ingplanformchange

Here,weincludromtheconventional

wingflapdesignsforlandingandtakeoff,oneofthefirsteffortsinthisdirectionwasthevariablecamberwingdesign

gnedavariablecamberwingforbi-planesandtri-planes,andperformed

structuralandwindtunneltesttovalidatetheconcept(Fig.2,Parker,1920).Themainideaherewastouflexible

wing(oneforbi-planeandtwofortri-plane)inordertosupplementtheliftgeneratedbytherigidwingwhiletheplane

design,onesparwasplacedattheleadingedgeandanotherabouttwo-thirdsofthe

tionbetweenthesparswasmadeflexible,was

ore,

athighspeed,thevariablecamberwingwasplacedinsuchawaythatitalignedwiththeairstreamwithnocamber,and

speed,whentheangle-of-attackoftheplanewasincread,theflexible

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wingexpesultedinacamberedwing

ernaltrussstructurepreventedthewingfromcamberingafteracertain

discusdmeritsanddemeritsofchangingwingsurfaceareaandtheangle-of-incidenceforreducingthe

lleinthenextfewparagraphs,veral

designerslaterconsideredthemorphingideas.

(a)(b)

Figure2:SmoothcamberchangedesignpropodbyParkerin1920:a)variablecamberribdesignandb)vector

diagramoftheforcesforbi-planeinnegativestagger(Parker,1920).

tiontochangeinthe

camber,ignhadachordexpansionmechanismforaone-atermonoplane,and

wasgrantedapatentin1933(Fig.3-a;Burnelli,1933).ThiswingwasudintheBurnelliGX-3aircraft,whichfirst

flewin1929(Fig.3-b).Themainpor

leadingandtrailingedgeportionsmovedoutwardanddownwardinordertochangetheareaandthecamberofthe

ftparalleltotheforwardsparwascontrolledbyahandwheelwhilethatrunningparalleltotherearspar

rtominimizethemovementofthecenterofpressure,the

mechanismwasdesignedinsuchawaythatitprovidedhighermovementintheleadingedgethaninthetrailingedge.

(a)(b)

Figure3:VariableareaandcamberdesignbyBurnelli:a)mechanismasshownintheUSPatent1,917,428(1933)and

b)aircraftBurnelliGX-3fittedwiththevariableareaandcamberwing(1937)

In1937,aevofUSSRdesignedatelescopicwingaircraft,namedRK(Fig.4-a;Shavrov,1994).The

telescopicmechanismconsistedofsixchord-wioverlappingwingctionsthatudtoextendfromeachsideofthe

fulagetill2/escopicpartwasretractedandextendedusingsteelwire,drivenmanually

1941,Bakashaevmodifiedthedesignbyfittingtelescopicwings(Fig.

4-b).design,atelescopicgloveutoextendfromthefulagetocoverthe

trolsurfaceswerelocatedintherearwing,andtheywerenot

edtotheareachangeof44%

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intheRKdesign,theRK-Idesignwasabletochangeitswingareabyasmuchas135%.Thoughtheaircraftdidnot

gointotheproductionpha,thedesignswereconsideredsuccessful.

(a)(b)

Figure4:ev:a)RK(1937)andb)RK-I(1941)

ThefirstvariableincidencewingwasdesignedfortheaircraftXF-91,alsoknownas“Thunderceptor”,byRepublic

AircraftCorporationin1949(Fig.5-a).Theincidenceofwingsofthisrocket-poweredsupersonicaircraftcouldbe

hehighangle-of-attackwasudfortakeoffandlanding,thelowangle-of-attackconfiguration

ghthemaximumspeed

ofthisaircraftwas984mph,itndurancewasquitelow(25min).ThiswasoneofthereasonswhyXF-91wasnotput

intoproductiondespitemakingveralsuccessfultestflights.

Anothervariable-incidencewingwasdesignedin1955byChance-VoughtforF-8Crusader(Fig.5-b).Thewingwas

romprovidinglowspeedtake-offandlandingcapability,italso

enabledthepilottomaintainthefulageparalleltocarrierdeckorrunwayforbettervisibilityintheelevated

tion,theentireleadingedgeandtheaileronscouldbeloweredtoincreatheeffectivecamberofthe

wingandconquentlyreduceapproachandlandingspeed.

(a)(b)

Figure5:Thevariableincidencewingaircraft:a)RepublicXF-91"Thunderceptor"(1949)andb)VoughtF8U

Crusader(1955).

Variablesweepwing(swingwing)

sweepingthewing,helpstheaircraftintake-offand

stattemptinthisdirectionwasmadebyGermanMesrschmitt,whodevelopedP-1101(Fig.6-a)in

epanglecouldbealteredonlyfrom35oto45o,andthattoowhiletheaircraftwasontheground.

In-flightsweepanglechangewasfirstachievedinX-5,builtbyBellAircraftCompanyofUSAin1952(Fig.6-b).The

essfullydemonstratedtheswingwingconceptbyshowing

reduceddragandimprovedperforma

ofthemajorchallengesfacedbythedesignerofX-5wastocompensateforthechangeinthecenterofgravitylocation

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end,theydevelopedamechanismtopushtheentirewing

asmblybyasmuchas27’.

(a)(b)

Figure6:Thefirstswingwingaircraft:a)MesrschmittP-1101(1944)andb)BellX-5(1952).

1952,Grummanbuiltafighter,namedXF10F-1,

whichcouldchangeitssweepfrom13.5oto42.5o(Fig.7-a).Itdemonstratedthehandlingproblemsofswing-wing

aircraft,latersolvedbythedevelopmentoffixedwingroot“gloves”.Italsoudfull-spanslatsandFlowerflaps

extendingover80%heaircraftsufferedfrom

veralairframe,engine,stability,andcontrolproblems,theswingwingtechnologywasproventobeeffectiveand

eofthetwoXF10F-1swasbuiltandtheprogramwasdiscontinuedduetoveraltechnological

difficulties.

ThefirstproductionaircraftwithswingwingcapabilitywasGeneralDynamicsbuiltF-111Aardvark(Fig.7-b).Itwas

developedundertheTacticalFighterExperimental(TFX)programaimedtoproduceasingleaircrafttofulfillaNavy

fleetdefenintercestF-111flewin

ngsfullyextended,theF-111couldtakeoffandlandinaslittleas2,ngsfully

sweptback,itcouldreachaspeedinexcessofMach2.F-111exhibitedaveryhightrimdragatsupersonicspeeddue

slatercorrectedinthedesignofF-14,whichudamoreoutboardpivot

F-111wentintoproductionlinefortheAirForce,it

didencounterveralproblemsduetostructuralfailures,lossofdirectionalstability,enginesurge,andstall(later

solvedbyamajorinletredesign).Theswingwingdesigndidnotstophere,butcontinuedtobethepartofveralhigh

performanceaircraftsuchasMig-23(USSR,1967),GrummanF-14Tomcat(1970),andRockwellB-1BLancer(1983).

(a)(b)

Figure7:Theswingwingaircraft:a)XF10F-1Jaguar(1952)andb)F-111Aardvark(1964).

Theuccessfullyimplementedina

single-atexperimentalsailplanebuiltbyFritzJohlofSouthAfricain1970(Fig.8-a;Stinton,2001).Itachieveda

chordchangeof100%usinganinternal“lazy-tongs”actedthechordtoincreathespeedofthe

configuration,thewinghadhighaspectratioandlowarea,

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thermal,itincreadthewingarea,chordand

cambertoreducethespeedofthesailplanesoastomakeaslowturnintherisingmassofair.

AnotheruniquewingmorphingcanbeeninthedesignofAmes-Dryden-1(AD-1)ObliqueWing,firstflownin1979

(Fig.8-b).,andtherearchwasconductedbyNASA

craftwasdesignedtorotateonitscenterpivot,sothatitcouldbetatitsmost

rspeeds,duringtakeoffsandlandings,thewing

waircraftgainedspeed,thewing

wouldbepivotedtoincreatheobliqueangle,gcouldbesweptinonlyone

direction(righttipmovingforward).Itflew79timesandgatheredflightdataonhandlingqualitiesandaerodynamicsat

differentangularpositionsandspeeds.

(a)(b)

Figure8:Variablegeometrywings:a)variablechordandcambersailplaneJ-5(1970)andb)Obliquewing(1979).

AircraftirstudintheRussianMiG

105-11space-plane,whichflewon11thOctober1976(Fig.9).DesignatedasExperimentalPasngerOrbitalAircraft

(EPOS),thiswingofthisspace-planewasdesignedtobeudasstabilizerbyttingit25oabovehorizontalduring

launch,orbit,ewing,whentinthehorizontalposition,wasdesignedtoworkastheregular

totalofeightflights,endingon1stSeptember1978,furtherdevelopment

ofthisplanewasstoppedaftergatheringdatatocharacterizeitssubsonicaerodynamics.

AmorerecenttelescopicwingdesigncanbefoundinthepatentbyGeversAircraft,Inc(Gevers,1998).Thewingspan

ofthisdesigncanchangeby100%.Thefinalaircraftissuppodtocruiover280mphwhenthewingisretractedand

escopicwingudinthispropodaircraftis

compodofacentralwingctionwithcompletelyretractablehighliftctionswhichareguidedonarollerinaspan-

creasthewingspan,area,er,thelandinggearofthisconceptual

aircraftisdesignedsothatitcantakeoffandlandonsnow,water,scalemodelofthisaircraft

wasalsotestedinawindtunnel(Geverswebsite).

(a)(b)

Figure9:Examplesofmorphingaircraft:a)variabledihedralspaceplaneMiG105-11(1976)andb)Telescopicwing

ofGevers(1998).

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ingplanformchange

Inthisction,wediscussaircraftcapableofsmallwingplanformchanges,

sakeofbrevity,hdesign,forexample,isataillessplaneaircraft

inventedbyShortBrothers&HarlandLtd(Fig.10-a).Firstflownin1953,thisaircrafthadall-movingwingtipsthat

ntendedtotesttheso-called“aero-isoclinic”wing

awastopivotthewingtipssothattheycanmaintainthesameincidenceevenasthewingflexedin

flight(Butler,1999).Thepivotedwingtipsactedbothalevatorsandailerontocontrolthepitch(rotatedtogether)and

roll(rotatedopposite).

AnotherdevelopmentintheareaofrotatingtipwasValkireXB-70,designedbyNorthAmericanin1964(Fig.10-b).

Thewingtip,whichthusfarreprentsthelargestmovableaerodynamicdevice,wasrotatedto25obelowhorizontal

whenflyingbetween300knotstoMach1.4oandto65ofromhorizontalwhenflyingfromMach1.4toMach3+.

Loweringofthewingtipincreadtheverticalarea,speed,itcreatedshock-

wave-generated“compressionlift”thatpartiallysupportedtheaircraftweight.

(a)(b)

Figure10:Wingswithrotatingendparts:a)ShortSB.4Sherpa(1953)andb)ValkireXB-70(1964)

Cambercontrolofwingsusinthe

hetwo,theleadingedgecontrolsurfacesare

-16FightingFalcon,developedbyGeneralDynamicsandfirstflownin1974,usleading

edgeflapstochangethecamberofitswings(Fig.11-a).Thewinghasalsoatof“flaperons”thatcombinestheroles

peronsoperateasconventionalaileronsforcontrollingtheaircraftduringconventional

takeoffsandlandings,theycanbehangeddownbyasmuchas20o,operatingasflaps.

TherecentActiveAeroelasticWing(AAW)programofNASAudtwistingofwingsforprimarymaneuveringroll

controlattransonicandsupersonicspeeds(Fig.11-b).UsinganF/A-18asthetest-bed,thetwistinthewingwascaud

dingedgeflapsofF/A-18weredividedintoparateinboardandoutboard

gments,dingedgeflapofthisaircraftcouldchangefrom10oupto34o

gtheleadingedgeflapsandaileronstotwistthewing,onecouldcreatedesirablerollauthoritywithout

increasingthewingstiffnessandweight.

(a)(b)

Figure11:Exampleofsmallmorphingintheformofcontrolsurfaces:a)movingleadingedgecontrolsurfacesudby

F-16FightingFalcon(1974)andActiveAeroelasticWingProgramofNASA(2002).

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Theconventionalcontrolsurfacesproducediscontinuouscurvatures,ttoproduceasmooth

camberchannghadan

internalmechanismtoflextheouterwingskinandproduceahighcamberctionforsubsonicspeeds,asupercritical

ctionfortransonicspeeds,dingandtrailingedgeflapscould

rotateby0-5oand2-5o,moothnessoftheresultingwingsurface,thedragwasfoundtodecrea

byaround7percentaalflight

temhadfourautomaticcontrolmodes:(1)

ManeuverCamberControl-adjustingcambershapeforpeakaerodynamicefficiency;(2)CruiCamberControl-for

maximumspeedatanyaltitudeandpowertting;(3)ManeuverLoadControl-providingthehighestpossibleaircraft

loadfactor(4)ManeuverEnhancementAlleviation-inpartattemptingtoreducetheeffectsofgustsonairplaneride.

TheAFTI/rautomaticmodesweretestedinflight

withsatisfactoryresults.

(a)(b)

Fig.12:MissionAdaptiveWing(1985):a)installedintheaircraftF-111andb)wingcross-ctionsindifferent

configurations.

Usingcompliantmechanism,edsmoothshapechangeoftheleadingandtrailingedgeflaps

(e).Usingawind-tunnelexperiment,conductedin1998,theynoteda25%increainlift

coefficientsanda51%increainthelift-to-dragratioastheleadingedgecamberwaschangedfrom0oto6o(Fig.13-

a).Similarly,deflectingthetrailingedgefrom0oto6o,theyshowedalowairfoildragof0.006fortheliftcoefficient

rangingfrom0to1.5(Fig.13-b).Thixperimentclearlyshowedtheadvantagesofhavingasmoothwingcamberover

thetraditionaldiscretecontrolsurfaces.

(a)(b)

Figure13:Smoothcamberingusingcompliantmechanism:a)leadingedge(1998)andb)trailingedge.

SmoothcamberingwasalsoappliedinaNorthropUCAVtestmodel(Fig.14;Kudva,2002).Thefinalwindtunneltest

nstratedhighactuationrate(80

deg/c),largedeflection(20o),hinge-less,smoothlycontouredcontrolsurfaceswithchord-wiandspan-wishape

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70differentcontrolsurf

showedanimprovementinrollingmomentcoefficientby~17%rimprovementswereobtained

forpitchingmomentcoefficients.

(a)(b)

Figure14:TheNorthropSmartWing(2001):a)testmodelintheNASAwindtunnelandb)internalstructures.

gemorphing

AnexampleoffulagemorphingcanbeeninConcorde,whichwasbuiltbyAerospatialeandBritishAerospaceand

ingand

take-off,itneededore,itsnowas

droopeddown(5degreesfortake-offand12.5degreesforlanding,Fig.15-a).

morphing

Amorphinginengineconfigurationcanbeufulforaccommodatingchangingspeedoftheaircraftandforchanging

pleofthrustvectoringcanbeeninV22Osprey,whichcantake-offandlandlikea

helicopterand,otherwiflylikearegularairplane.

(a)(b)

Figure15:Examplesofengineandfulagemorphing:a)concord(1969)andb)V22Osprey(2000).

CLASSIFICATIONOFMORPHINGAIRCRAFTTECHNOLOGY

Fromthepreviousction,ally,

wingmorphingcanbeachievedusingveraltechniquessuchashidingonepartunderanother,rotatinggmentsorthe

wholewing,stwobroadergroups

inwhichallthemorphingaircraftwingscanbeendivided:a)roboticdesign,and(b)obotic

design,ore,theroboticwingdesignis

heformerleadstovariablesweep,

variableincidence,andvariabledihedralwings,thelattergivesritoleadingedgecontrolsurface,trailingedgecontrol

surfaces,foldingtip,ganicdesign,theinternalmechanismletstheoverallsizeofthe

ngeinthesizeofthewingcantakeeffecteitherbystretchingthewingorbyslidingapartofthe

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dingwingdesign,someparts

ofesinthiscategoryinclude

telescopingwingwherethecompletewingisdividedintotwopartsinthespan-widirectionandoneparthidesinside

armechanismisappliedfordividingandhidingthewinginthechord-widirectiongivingrito

rconceptthathasbeendemonstratedinthiscategoryistheso-calledglovewing,wheretwo

viousctiongivexampleof

everycategoryprentedinFig.16.

TECHNICALCHALLENGES

Usingconventionalstructure,actuator,skin,engine,andcontroltechnologies,itemsquitedifficulttoaccommodate

differenttypesofmorphingmechanismsinthesameaircraft,andstillkeepitstructurallystrong,lightweight,

controllable,ollowingparagraphs,wediscussthemainissuesconcerningthe

morphingaircraftdesign:

lDesignConfigurations

Unlikethedesignofaconventionalaircraft,amorphingaircraftusuallyinvolvesveraldifferentflightregimesand

ore,thedesignerhastocomeupwithoptimaldesignsforallthoflightconditionsand

mekely,thedesignerwillhaveto

alsoconsiderthemovementofaerodynamiccenterandcenterofgravityduetochangingaircraftconfigurations.

ures

Conventioinspars,ribs,and

nternalstructuremoves,theskinshouldbeableto

,inturn,makestheskinvirtuallyanon-load-carrying

naswellasitsattachmentwiththesubstructureshouldbe

edesigns,thefatigueandhysteresiffectsduetorepeated

Glove

Telescopic

Wing

FoldingTipTEControl

Dihedral

Incidence

Chord

Extension

StretchingSurfacesRotatingSurfacesSlidingSurfaces

Span

Extension

LEControl

RotationofWhole

Wing

Sweep

Smooth

Cambering

WingBox

Surface

LE&TE

Surfaces

LE&TEExtension

Rotationof

Segments

Spoiler

MorphingAircraftTechnology

OrganicDesign

RoboticDesign

Engine

Fulage/Tail

Wing

Area

change

Fig.16:Classificationofmorphingaircrafttechnology

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omplexitiesleadtoaheavierstructureanddemandnew,efficientways

flexibleskindesign,highstrainmaterialswithgoodstructuralproperties

(ticdeformation,fatigue,orenvironmentaleffect)andrequiringlessactuationforceneedstobedeveloped.

ion

Theconfigurationchangeofaircraftin-flightwillrequiretheactuatorstoworkagainstaerodynamicandfrictionforces.

Thisdemandsbiggerandstrongeractuators,whichmaycreatespaceallocationproblems,willneedhighpower,and

ore,itisimperativetofindnewwaysofactuatione.g.,usingaerodynamicforces

forsupplementalactuation,soastominimizethespace,weight,andpowerrequirements.

namics

Theskindesyshoulditprovidesurface

continuity,mple,intheslidingskindesign,onehastomakesure

thatthegapsareminimalandintheflexibleskindesign,thewingshouldhaveminimaldimplingbothinretractedand

er,itisquiteachallengetodesignamorphingwingthatmaintainsoptimalairfoilshapesat

alltheintendedconfigurations.

ls

Therearetwomainchallengesinthecontrolaspectsofamorphingaircraft,whicharenotprentinaconventional

stoaccommodatetheconventionalcontrolsurfaces,whichisdifficultbecauofthemovingsurfaces.

Moreover,inaccommodatingtheconventionalcontrolsurfaces,onehastokeepinmindtheireffectivenessinall

oblemcouldbeovercomebydevelopingnecessarycontrolmechanismsandalgorithmsforusing

ca,themechanismhastobedevelopedthatcanbereliableeven

inaveryhighfrequencyoperationandneedssubstantiallylesspowerwhencomparedtothatneededinchangingthe

ondchallengepertainstointernalcoordinationofthemovingsubstructuresand

actuatorsinordertominimizehuma

parallelordistributedactuatorsareudforincreadreliabilityandbettercontrolauthority,thecontrollershouldbe

programmedtoproviderightsignaltoallactuatorsinatime-coordinatedmanner.

Ifthesameaircraftistoperformdrasticallydifferenttasks,thecurrentapproachtoenginedesign,whichusaspecific

flightgmenttooptimizeitsperformance,nce,thesameengineshouldperformwellboth

inlowandhigh-speedconditions,whichmaynecessitatemorphinginlets,nozzle,etc.

ationofthesubsystems

Evenwhendesignsofskin,mechanism,actuator,powersupply,andwingsubstructurearedeveloped,itisstillaquite

difficulttaer,thesubcomponents

shouldnotcomeinthewaywhentheshapeofwingischanging,andshouldbeaccessibleforrepairandmaintenance.

Sincemorphingaircraftarelikelytobesomewhatheavier,newmaterialandstructuretechnologiesneedstobe

i,thefullbenefitsofthemorphingtechnologywill

notberealized.

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SystemIntegration

•Asmblyinlimitedspace

•Uninhibitedmovement

•Fuelstorage

•Weight

Structures

•Skincapableof

transferringload

•Bendingandtorsional

stiffness

•Weight

Aerodynamics

•SmoothSurface

(nodimplingorgap)

•maintaingoodairfoil

cross-ction

Actuation

•Lowpowerrequirements

(-assistedactuation)

•highefficiency

Engine

•Optimalperformancein

changingflightconditions

Controls

•Asymmetricmorphing

forflightcontrol

•Automaticcontrolof

morphingmechanism

DesignStrategy

•Optimalconfigurations

•Reversiblechanges

•Fuelstorage

•ACshift

CONCLUSIONS

Inthispaper,wesurveyedpastmorphingaircraftdesigns,classifiedthemintodifferentcategories,andprentedthe

issurvey,onecannotethatalmostalltheprevious

designconsideredchangingonlyoneparametertofacilitatetheaircraftflyinginaparticularcondition,ratherthan

tance,theswingwing,glovewing,andthe

telescopicwingdesignschangethesweepangle,chordlength,andwingspan,r,foratruemulti-

missionmorphingaircraft,rtodesignanddevelopa

truemorphingaircraft,oneneedstorethinkalmostallaspectsoftheaircraftdesignincludingskin,ribs,spars,engine,

controlsurface,vesritoveraldesignchallenges,suchasmaintaininggoodaerodynamicprofile,

kinematics,actuation,powersupply,weighmanagement,loadbearingcapabilityofthewing,andtheintegrationofall

thesubsystems,whichneedstobeaddresdbeforeatrulyrevolutionarymorphingaircraftcanbedeveloped.

REFERENCE

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50-55.

,H.F.,1920,“TheParkerVariableCamberWing,”NACAReportNo.77,GovernmentPrintingOffice,

Washington.

li,V.,J.,1933,Aircraft,USPatentNumber1,917,428.

n,D.,2001,TheDesignoftheAirplane,AIAA,Reston,VA.

,J.N.,Sanders,B.,Pinkerton-Florance,J.,Garcia,E.,2002,“TheDARPA/AFRL/NASASmartWing

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Fig.17:Technicalchallengencounteredinthedesignofamorphingaircraft.

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