Development and Whirl Tower Test of the Smart Active Flap Rotor

8/3/2019 Development and Whirl Tower Test of the Smart Active Flap Rotor

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DevelopmentandwhirltowertestoftheSMARTactiveflaprotor

FriedrichK.Straub,DennisK.Kennedy,AlanD.Stemple,V.R.Anand,andTerryS.Birchette

TheBoeingCompany,Mesa,Az85215

ABSTRACT

AfullscaleSmartMaterialActuatedRotorTechnology(SMART)systemwithpiezoelectricactuatedbladeflaps

wasdevelopedandwhirltowertested.Thedevelopmenteffortincludeddesign,fabrication,andcomponenttesting

ofrotorblades,trailingedgeflaps,piezoelectricactuators,switchingpoweramplifiers,andthedata/powersystem.

Simulationsandmodelscalewindtunneltestshaveshownthatthissystemcanprovide80%vibrationreduction,

10dBnoisereductionforahelicopterpassingoverhead,andsubstantialaerodynamicperformancegains.Whirl

towertestingofthe34-footdiameterrotordemonstratedthefunctionality,robustness,andrequiredauthorityofthe

activeflapsystem.

Theprograminvolvedextensivedevelopmentworkandriskreductiontestswhichresultedinarobust,high

performanceactuatorandatightlyintegratedactuator,flap,andbladesystem.Theactuatordemonstratedexcellent

performanceduringbenchtestingandhasaccumulatedover60millioncyclesunderaspectrumofloading

conditions.TheflightworthyactiveflaprotorbladeswerebasedonamodifieddesignoftheFAAcertifiedMD900

Explorerproductionrotorblade.Whirltowertestingwasconductedwithfullrotorinstrumentationanda5-

componentbalance.Therotorwastestedfor13hoursunderarangeofconditions,including7hoursofflap

operation.Flapinputsincludedopenloopstaticanddynamiccommands.Theflapsshowedexcellentauthority

withoscillatorythrustgreaterthan10%ofthesteadybaselinethrust.Variousflapactuationfrequencysweepswere

runtoinvestigatethedynamicsoftherotorandtheflapsystem.Limitedclosedlooptestsusedhubaccelerations

andhubloadsforfeedback.

Provingtheintegration,robustoperation,andauthorityoftheflapsystemwerethekeyobjectivesmetbythewhirl

towertest.Thissuccessdependedontailoringthepiezoelectricmaterialsandactuatortotheapplicationand

meetingactuator/bladeintegrationrequirements.Testresultsdemonstratethefeasibilityandpracticalityofapplying

smartmaterialsforlimitedauthority,activecontrolonahelicopterrotor.Follow-onforwardflightdemonstrations

areneededtoquantifytheexpectedsignificantimprovementsinvibrations,noise,andaerodynamicperformance.Extensionsofthistechnologyareaprimecandidateforon-bladeflightcontrol,i.e.eliminationoftheswashplate.

ThisprogramwasperformedaspartofDARPAsSmartMaterialsandStructuresDemonstrations.Fundingwas

providedbyDARPA,TheBoeingCompany,NASA,andtheU.S.Army.Additionalcostsharefundswereprovided

bytheUniversityofMaryland,MIT,andUCLA.

Keywords:Smartmaterials,piezoelectric,actuator,helicopter,blade,flap,vibrationcontrol,noisecontrol

1.INTRODUCTION

Vibration,noise,andaerodynamicdesigncompromisescontinueasbarrierstofurtherimprovementsineffectivenessandpublicacceptanceofthehelicopter.Bladetrailingedgeflapsactuatedbyin-bladesmartmaterialactuatorshave

emergedasprimarycandidatetodynamicallyalterthebladestructureandapplylimitedauthorityactivecontrolto

achievesignificantimprovementsinrotorcraftperformanceandmissioncapability[1-5].Simulationsandmodel

scalewindtunneltestshaveshownthatthissystemcanprovidemorethan80%vibrationreduction,10dBnoise

reductionforahelicopterpassingoverhead,andsubstantialaerodynamicperformancegains.Resultingbenefits

includeajetsmoothride,improvedcommunityacceptance,aswellassignificantlyimprovedlifecyclecost,

productivity,andfleetreadiness.

PresentedatSPIEsIntl.SymposiumonSmartStructuresandMaterials,SanDiego,CA,March14-18,2004.


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Theoverallprogramobjectivewastodevelopthetechnologyanddemonstratethatsmartmaterialactuatedflapsare

feasibleandpracticalforhighbandwidth,limitedauthorityactivecontrolofahelicoptermainrotor.TheMD900

Explorertwinengine,lightutilityhelicopterwasselectedasdemonstrationvehicle.Itsstate-of-the-art5-bladed

composite,bearinglessmainrotorsystemwasmodifiedtoincludein-bladepiezoelectricactuatorsandtrailingedge

flaps,Figure1.

ConceptdevelopmentanddesignsupporttestswereconductedduringPhaseIofthisprogram[6].Thecurrent

PhaseIIeffortincludeddesign,fabrication,andcomponenttestingofflightworthyhardwareandwhirltowertesting

oftheintegratedsystem.Primarycomponentsofthesystemincludetheblades,flaps,piezoelectricstacksand

actuators,switchingpoweramplifiers,anddata/powersystem.Theirdevelopmentandresultsofthewhirltowertest

arepresentedhere.AdditionaldetailsoftheworkperformedunderPhaseIIcanbefoundinReferences7-17.

2.ROTORBLADEANDFLAPDEVELOPMENT

ThebasiccharacteristicsoftheSMARTrotorareshowninTable1.Primarydesignobjectivesforthemodified

bladeandtheflapweretominimizeactuationrequirements,matchthebaselinebladedynamics,andminimize

weight.Akeyconstraintwastousetheproductionbladetoolingwithonlyminormodifications.Secondarydesign

objectivesweresimplicity,modularity,andtheflexibilityofthebladetoserveasatestbedforalternateactuators.

Thebladedesignwasmodifiedtocarrytheactuatorinsidethesparcavityandtoaddprovisionsformountingtheflap.Ashortlinkconnectstheactuatorandflap.Detailsoftheblade,flap,andactuatorintegrationareshownin

Figures2-4.TheoveralllayoutofthehardwarecomponentsisshowninFigure5.Severalchangesweremadeto

thebladeconstruction,includingreplacementofthreeglassplyswithtwographiteplysinthespar,eliminationof

theouterveilply,anduseoflightweighthoneycombcoreinthemid-sectionoftheblade.Reinforcementswere

addedtoprovideattachmentsfortheactuatorcavityaccesscover,Figure6,theactuatormounts,andtheflap

supports,Figure7.Leadingedgeweightwasaddedtomaintainchordwisebalance,Figure8.Bladeinternalwiring

wasprovidedforactuatordataandpower.

Theflapparameters,Table2,werechosentominimizeactuationrequirements.Becauseoftheflaplength,three

intermediateflapsupportsarerequiredtocarrytheflaploads.Theflapisaerodynamicallybalancedinorderto

lowertheaerodynamichingemomentandthustheactuatorforcerequired.Theflapisalsomassbalanced.For

maximumtorsionalstiffnesstheflapisconstructedusing45deggraphiteplys.Theradiallocationwaschosento

providebothvibrationandnoisereduction.Centrifugalloadsaretransmittedtothebladeusingatension-torsionrod.Aflexiblelinkandarodendbearingtransmittheactuatoroutputtotheflaphorn.Aseriesoftestswere

conductedontheflap,flaplink,andtension-torsionrodtoconfirmpropertiesandtoprovidequalificationdata.

Aprototypeblade,flap,andactuatorwerefabricatedandusedtoconfirmfitandfunction.Integratedtestingofthe

assemblytogetherwithaswitchingamplifierprototypeestablishedthevalidityofthedesign.Actuator/flap

performanceunderarangeofbladedeformationsshowednodegradation.Bladestiffnessandfree-freefrequency

testsconfirmedthatthecompletebladeassembly,includingflapandactuator,closelymatchedthebaselineblade.

3.PIEZOELECTRICACTUATORANDAMPLIFIERDEVELOPMENT

Actuatordesignconsiderationsincludeahighenergydensity,highbandwidthsmartmaterialtomeetactuation

requirements,anefficientmechanismtoprovidestrokeamplificationandminimizelosses,andlowvolume.Inparticulartheactuatorheightmustbesmalltofitinsidethebladespar.Furthermore,theactuatormustberobustand

withstandthebladeelasticdeformationsanddynamicloadingof650gsteadyand30gcyclic.Modelscalerotor

testswereconductedandestablishedthefeasibilityandbenefitsofusingpiezoelectricactuatedbladeflaps[7,8].

Aeroelasticsimulationsshowedthat2degflapdeflectionaresufficientforvibrationreductionathighspeedandfor

noisereduction[6,9,10].Thiscorrespondstoanactuatoroutputof43lband0.032in,includingsomeallowance

forlosses.Fordesignpurposesanominalflapdeflectionof4degwithanactuatoroutputof63lband0.062in


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wereused.Maximumoperatingfrequencywaschosenastherotor(N+1)/rev,i.e.6/revor40Hzforthis5-bladed

rotor,asrequiredforvibrationreduction.

Piezoelectricstackactuatorswereselectedasthedrivingelement.Severallowandhighvoltagestacksweretested

[11-15].Thelatterprovidedbetterperformanceandmoreflexibilitywithrespecttofabricationofdifferent

geometries.Acustommade,highvoltagestackwasselected.Anumberofthesestackswereextensivelytested

underarangeofelectrical,mechanical,andthermalconditions.Bothperformanceandfatiguetestsupto150

millioncycleswereconducted.Fatiguetestswererunatelevatedfieldlevels(2.9kV/mm)andmechanicalpreloads

(6ksi)withoutputs75%largerthancommerciallyavailable.Thesetestsdemonstratedthatdomainwallmovement

withinthepiezoelectricceramicscanbeusedwithoutanysignificantdegradationover150millioncyclesof

operation.

Theactuatormechanismwasbasedonthex-frameconcept[7]withtwoactuatorsworkinginparallel,thusthe2x-

frameactuator.Thetwox-framesareactuated180degout-of-phaseinapush-pullmode.Theactuatorstructure

providesstrokeamplification,ameansforpreloadingthepiezo-ceramicstacks,andprovisionsformountinginthe

blade.Threeprototypeswerefabricatedandtestedtooptimizeperformanceanddurability.Thefirstprototypeused

lowvoltagestacksandvalidatedtheconcept[17].Ithadmarginalperformancebutshowedexcellentrobustness

duringspintesting.Thesecondprototypewasscaledupby15%andusedcustomhighvoltagestacks,Figure9.

Severalfeatureswereaddedtofacilitateassembly,enhancewearcharacteristics,andimprovemountingintheblade.

Athirdprototypewithimprovedstructuralcharacteristicswasdeveloped,Figure10.Itdemonstratedexcellent

performanceduringbenchtesting,Table3,andaccumulated66millioncyclesunderrepresentativeelectricalandmechanicalloadconditions.Thiscorrespondsto560hoursofoperationat5/rev.Theactuatorandbenchtestrigare

showninFigure11.

Aswitchingpoweramplifierwasdevelopedtodrivethepiezoelectricactuator.IGBT(Insulated-GateBipolar

Transistor)switchingat20kHzandcapacitiveenergystorage[18]providedtheefficiencyrequiredtomeetthe

volumeandweightconstraintsforflighttesting.Intermsofpowerdensityitrepresentsafour-foldincrease

comparedtopreviousmodels.Theamplifiermaximumoutputwas-300/+1200Vand3Aforcapacitiveloadsof

4 F.Aprototypeamplifierwasdevelopedandusedtodrivetheflapsystem.Basedontestresults,thedesignwas

enhancedbyaddingnoisesuppressionfilters,providingbetterthermalprotectionforflighttestingonhotdays,and

improvingmodularity.

4.FLIGHTHARDWAREFABRICATIONANDTESTING

Acompletesetof5flightworthyblades,flaps,actuators,andamplifierswasfabricatedforwhirltesting.Inaddition

aspareactuatorandasparebladeforfuturepressureinstrumentationwerefabricated.Fiveactuatorsweretestedon

thebenchtoestablishperformance,stiffness,andnaturalfrequencies.Inadditiontheywererunforonehourtoseat

thecomponents,letthepreloadsettle,andbreakintheflaplinkrodendbearing.Afterinstallationintheblade,the

actuator/flapsystemwasruntoestablishbaselineperformance,naturalfrequencies,andtobreakintheflapbearing

surfaces.Thebladeinstalledactuator/flapsystemnaturalfrequencywas98Hz.Thepitchinertiasofallflapsand

thefree-freefrequenciesandpitchinertiasofthemassbalancedbladeassemblieswerealsodetermined.Theoverall

bladeweightincreasedby5lb,anincreaseof9%inweightand15%inspanwisemomentcomparedtothebaseline

blade.ThechordwiseCGremainedunchangedat27.4%.ThecompletedbladeassemblyisshowninFigure12.

5.WHIRLTOWERTEST

WhirltestswereconductedatMesainawhirlcageusingtheLargeRotorTestStand(LRTS).TheLRTSincludesa

1500HPmotor,transmission,strutassembly,a5-componentrotorbalance,andtherotorflightcontrols,Figure13.

Thisteststandhasbeenusedinanumberofwhirltowerandwindtunneltestsofseveraldifferentrotors.

Testsetupstartedwithinstallationoftheteststand,motor,rotorbalance,androtorhubinthewhirlcage.Forthe

SMARTrotortestahubmounteddataacquisitionandmultiplexingsystem,Figure14,andaslipringforrotordata


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normalforceresults,Figure22,showthatwithharmonicflapinputstherotoractsasafilterandonly5/revbalance

loadsareseen.Applying450Vat5Presultsina5Pnormalforceof550lb,orabout10%ofthenominalsteady

thrust.Thislevelofauthorityatamediumvalueofdrivingvoltageexceedsrequirementsandindicatesthattheflap

systemshouldbeabletoprovidetheexpectedvibration,noise,andaerodynamicimprovementsinforwardflight.

Oneadvantageoftheflapsystemisthatitiscompletelyindependentoftheprimarycontrolsystemandisnotflight

safetycritical.Varioustestswereruntoinvestigatethesystembehaviorwithoneflapinoperativeoratfullstatic

deflection(hardover)withtheotherflapsoperatingnormally.Noproblemswereobserved,butairframevibration

levelswouldcertainlyincreaseshouldsuchaneventoccuronanaircraft.Tofurtherdemonstraterobustness,the

flapsystemwasruncontinuouslyforovertwohourswithoutanyissuesandnodegradationinperformance.After

completionofthewhirltesttheflapsystemwasbenchtested,disassembled,andinspected.Performancematched

datatakenbeforethewhirltestandnosignsofanyinterferenceorunduewearwerefound.

6.SUMMARY

Afullscalerotorsystemwithpiezoelectricactuatedbladeflapswasdevelopedandwhirltowertested.The

developmenteffortincludeddesign,fabrication,andcomponenttestingofrotorblades,trailingedgeflaps,

piezoelectricactuators,switchingpoweramplifiers,andthedata/powersystem.Whirltowertestingofthe34-foot

diameterrotordemonstratedthefunctionality,robustness,andrequiredauthorityoftheflapsystem.

Provingtheintegration,robustoperation,andauthorityoftheflapsystemwerethekeyobjectivesmetbythewhirl

towertest.Thissuccessdependedontailoringthepiezoelectricmaterialsandactuatortotheapplicationand

meetingactuator/bladeintegrationrequirements.Testresultsdemonstratethefeasibilityandpracticalityofapplying

smartmaterialsforlimitedauthority,activecontrolonahelicopterrotor.Follow-onforwardflightdemonstrations

areneededtoquantifytheexpectedsignificantimprovementsinvibrations,noise,andaerodynamicperformance.

Extensionsofthistechnologyareaprimecandidateforon-bladeflightcontrol,i.e.eliminationoftheswashplate.

Specificconclusionsare:

1. Modelscalerotortestsdemonstratedthefeasibilityandbenefitsofpiezoelectricactuatedtrailingedgeflaps.2. Highvoltagecustompiezostackscanbedrivenathighfieldlevelsandmechanicalpreloadwithoutputs75%

largerthancommerciallyavailablewithoutaffectingdurability.

3. Ahighenergy,compactpiezoelectricactuatorforoperationintheruggedrotorbladeenvironmentwas

developed.Performanceanddurabilityweredemonstratedinextensivebenchtests.4. Ahighefficiencyswitchingpoweramplifierwasdeveloped.Powerdensitywasincreasedfour-foldcompared

topreviousmodels.

5. Aeroelasticsimulationmodelsfortheflapsystemweredeveloped.Resultsshowedthat2degreesofflapdeflectionaresufficientforvibrationreductionathighspeed.

6. Theactuator/flapintegrationintothebladewasoptimizedforperformance,weight,matchingbaselinebladedynamics,andusingproductionbladetooling.Fabricationmethodsweredevelopedtoembedactuatorandflap

supportingstructuresaswellasdata/powerwiringintheblade.

7. Therobustnessandcontrolauthorityoftheflapsystemwasdemonstratedinwhirltowertests.Therotorwasfullyinstrumentedandanextensivedatasetofactuatorperformanceandrotorloadswasobtained.

8. Actuatorauthorityexceededrequirements.Flapinducedoscillatoryrotorthrustwasgreaterthan10%ofbaselinethrust.

9. TheSMARTrotorsystemisreadyforforwardflightdemonstrations.

ACKNOWLEDGEMENTS

Drs.EphrahimGarciaandTerryWeisshaar,DARPA,providedthemotivationandfundingfortheeffort.Dr.Gary

Anderson,ARO,providedtechnicaloversightwithsupportfromotherresearchersatU.S.Armylaboratories.Dr.

JanetSater,IDA,providedguidance.Drs.WilliamWarmbrodt(NASA)andCheeTung(U.S.Army)provided

fundingandtechnicaloversight.AtBoeingthefollowingengineers,staff,andsubcontractorsprovidedsupport:


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LouSilverthorn,MikeNothaft,JeffHughes,MikeGamble,DaveDomzalski,JosephJette,andmanyothers.Atthe

UniversityofMaryland,Prof.InderjitChopra,assistedbyJinweiShen,TaeohLee,AndreasBernhard,andNikhil

Koratkarsupportedrotoraeroelasticanalysesandflapactuatorspintesting,andconductedmodelrotorwindtunnel

tests.AtUCLA,Prof.GregoryCarman,assistedbyMilanMitrovichandPaulChaplya,testedPEmaterials.At

MIT,Prof.StevenHall,assistedbyEricPrechtlandDoraTzianetopoulou,conductedmodelrotorspintestsand

supporteddesignofthedoublex-frameactuator.

REFERENCES

1. ChopraI.,StatusofApplicationofSmartStructuresTechnologytoRotorcraftSystems",RAEConference"InnovationinRotorcraftTechnology,London,UK,June1997(republishedinJournaloftheAHSSociety,

Vol.45(4),pp228-252,October2000).

2. FriedmannP.,ThePromiseofAdaptativeMaterialsforAlleviatingAeroelasticProblemsandSomeConcerns,RAEConference"InnovationinRotorcraftTechnology",London,UK,June1997.

3. Straub,F.K.andKing,R.J.,Applicationofsmartmaterialstocontrolofahelicopterrotor,Proc.SPIESymposiumonSmartStructuresandMaterials,SanDiego,March1996.

4. HasegawaY.,KatayamaN.,KobikiN.,NakasatoE.,YamakawaE.,OkawaH.,ExperimentalandAnalyticalResultsofWhirlTowerTestofATICFullScaleRotorSystem,57thAnnualForum,Washington,DC,May9-

11,2001.5. Enenkl,B.,Klppel,V.,Preiler,D.,andJnker,P.,FullScaleRotorwithPiezoelectricActuatedBlade

Flaps,Proc.28thEuropeanRotorcraftForum,Paper89,Bristol,UK,Sept.2002.

6. Straub,F.K.etal.,SmartMaterialActuatedRotorTechnologySMART,Proc.AIAASDMConference,AIAA-2000-1715,Atlanta,GA,April2000.

7. Prechtl,E.,andHall,S.R.,Closed-LoopVibrationControlExperimentsonaRotorwithBladeMountedActuation,Proc.41

stAIAASDMConference,AIAA-2000-1714,Atlanta,GA,April2000.

8. Koratkar,N.A.,andChopra,I.,WindTunnelTestingofaMach-ScaledRotorModelwithTrailingEdgeFlaps,Proc.57

thAHSAnnualForum,Alexandria,VA,2001,pp.1069-1099.

9. Shen,J.andChopra,I.,AeroelasticModelingofTrailing-EdgeFlapswithSmartMaterialActuators,Proc.41stAIAASDMConference,AIAA-2000-1622,Atlanta,GA,April2000.

10. Shen,J.andChopra,I.,AeroelasticStabilityofSmartTrailing-EdgeFlapHelicopterRotors,Proc.42ndAIAASDMConference,AIAA-2001-1675,Seattle,WA,April2001.

11. Mitrovic,M.,G.P.Carman,andF.K.Straub,Electro-MechanicalCharacterizationofPiezoelectricStackActuators,Proc.SPIEConferenceonSmartStructuresandMaterials,SPIEVol.3668,NewportBeach,CA,

March1999,pp.586-601.

12. Mitrovic,M.,GregP.Carman,G.P.andStraub,F.K,DurabilityCharacterizationofPiezoelectricStackActuatorsunderCombinedElectro-MechanicalLoading,Proc.AIAASDMConference,AIAA-2000-1500,

Atlanta,April2000.

13. Mitrovic,M.,G.P.Carman,andF.K.Straub,DurabilityofPiezoelectricStackActuatorsunderCombinedElectro-Mechanical-ThermalLoading,Proc.SPIEConferenceonSmartStructuresandMaterials,Paper4333-

04,NewportBeach,CA,March2001,pp.586-601.

14. Chaplya,P.M.andCarman,G.P.,TheEffectofMechanicalPrestressonDielectricandPiezoelectricResponseofPZT-5HatHighElectricFields,AdaptiveStructuresandMaterialSystems,Orlando,FL,Nov.

2000,pp.327-334.

15. Chaplya,P.andCarman,G.P.,DielectricandPiezoelectricResponseofLeadZirconateTitanateatHigh

ElectricandMechanicalLoadsinTermsofNon-180DomainWallMotion,JournalofAppliedPhysics,November2001,V90Issue10,pp.5278-5286.

16. Hall,S.R.,Tzianetopoulou,T.,Straub,F.K.,andNgo,H.,DesignandTestingofaDoubleX-FramePiezoelectricActuator,Proc.SPIEConferenceonSmartStructuresandMaterials,NewportBeach,CA,

March2000.

17. Clingman,D.J.,andGamble,M.HighPowerPiezoDriveAmplifierforLargeStackandPFCApplications,Proc.SPIEConferenceonSmartStructuresandMaterials,NewportBeach,CA,March2001.


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Table1:Rotorcharacteristics

Rotorblade modifiedMD900

Hubtype bearingless

No.ofblades 5

Radius 203.1in

RotorSpeed 392rpm

Chord 10in

Airfoil HH-10,HH-06

Twist 10deg

Torsionfrequency 5.7/rev

Table2:Flapdata

Radialstation 150186in

Length 36in

Chord 3.5in

Hingelocation 75%ofchord

Hornlength 0.75in

Max.flapangle 6deg

Table3:2x-Frameactuatorcharacteristics

Blockedforce 113lb

Freestroke 0.081in

Maximumwork 2.28in-lb

Voltage 475725V

Weight 2.16lb

Specificwork 1.1in-lb/lb

Actuator

Flap

Blade

Actuator

Flap

Blade

Figure1:MD900bladewithembeddedpiezoelectric

actuatorandtrailingedgeflap

AccessPlateFrame/Balbar

ActuatorMounts

FlapRention Strap

Tension/TorsionRod

Flextural RodEndLinkage

Flap

FlapHinges

FlapFrame

SMARTActuators

A

A

ElectricalConnectors

Outbd FlapSupportw/FlapStop

Inbd FlapSupportw/IntegratedLinkEgressTunnel

Figure2:Blade,flap,actuatordesignintegration

ArcPathofFlapHornSpar

CrossSection

FlapLinkAssembly

Tension-TorsionRod

2-XFrameActuator

ArcPathofFlapHornSpar

CrossSection

FlapLinkAssembly

Tension-TorsionRod

2-XFrameActuator

Figure3:Actuator,flaplink,tension-torsionrod


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ActuatorStacks

Flap

Balbar

FlexturalLinkage

AccessPlateFrame

LinkageTunnel

FoamCore

X-Frames BladeSpar

RodEndBearing

AccessPlate

Figure4:Blade,flap,actuatorcross-section(A-A)

Actuator

Flaps

Access

Cover

TipWeights

Actuator

Flaps

Access

Cover

TipWeights

Figure5:Flapsystemcomponents

SparInnerTorqueWrap

AccessPlateFrame

SparOuterTorqueWrap

LeadingEdge

Weights

SparInnerTorqueWrap

AccessPlateFrame

SparOuterTorqueWrap

LeadingEdge

Weights

Figure6:Bladesparfabrication

SparDetail

HingeAxisAlignmentTool

Inbd FlapSupport

Outbd FlapSupport

Strap

SparDetail

HingeAxisAlignmentTool

Inbd FlapSupport

Outbd FlapSupport

Strap

Figure7:Bladesparandflapsupportdetaillayup

BalanceWeight

AccessPlate

OffsetTool

LeadingEdgeWrap

BalanceWeight

AccessPlate

OffsetTool

LeadingEdgeWrap

Figure8:Leadingedgewrapclosureandbalance

weight

Lowerviewshown

PiezoStackColumn

InboardX-FrameActuator,Assembled

LoadLink

X-FrameActuator,Frames

OutboardX-FrameActuator,Disassembled

FlexureMount

Figure9:2x-frameactuator


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FixedFrame

MovingFrame

Figure10:2x-frameactuatordetails

BenchTestRig

FlapLinkTorsionBar

Spring

InboardX-FrameOutboardX-Frame

BenchTestRig

FlapLinkTorsionBar

Spring

InboardX-FrameOutboardX-Frame

Figure11:Actuatoronbenchtestrig

10in

chord

13Ft13Ft

3Ft

Actuator

Access

Cover

Flap

Figure12:Smartrotorbladeassembly

GearBox

RotorBalance

StrutAssy

1500HP

Motor

Figure13:Largerotorteststand(LRTS)

Figure14:Rotorhubwithdata/powertransferunit


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Figure15:Smartrotorbladeonwhirltower

Figure16:Smartrotoronwhirltower

-4

-3

-2

-1

0

1

2

3

4

0 20 40 60 80 100

RotorSpeed,%NR;Collective*10,deg

FlapDeflection-Average,

Relative

,deg

test11 test12 test18

te st1 1 te st 18

vsRotorSpeed

vsCollective

vsRotorSpeed

vsCollective

Figure17:Flapdeflectionversusrotorspeed(0deg

collective)andcollectivepitch(100%Rpm)withno

powerapplied.

-60

-40

-20

0

20

40

60

-600 -400 -200 0 200 400 600

ActuatorVoltage,V

ActuatorDisplacement,mil

8degcollective

0degcollective

1.5deg

Figure18:Staticactuatordeflectionversusapplied

voltage,at100%Rpm


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-2000

-1500

-1000

-500

0

500

-4 -3 -2 -1 0 1 2 3 4

FlapDeflection,deg

BladeTorsionMoment,in-lb

T51 T71 T130 T165

Figure19:Bladetorsionmomentatfourstations

versusstaticflapdeflection(8degcoll.,100%Rpm)

0

0.5

1

1.5

2

2.5

3

3.5

4

0 1 2 3 4 5 6 7

RotorSpeedMultiple

CyclicFlapDisplacement(Avgof5),deg

300V

400V

450V

Figure20:Flapdeflectionversusexcitation

frequencyforthreevoltagelevels(100%Rpm,8deg

collective,1P=6.53Hz)

0

100

200

300

400

500

600

700

0 1 2 3 4 5 6 7

RotorSpeedMultiple

TorsionMomentSta71,

in-

lb

300V

400V

450V

0V

Figure21:Bladetorsionmomentharmonicsat

station71inattheexcitationfrequencyforthree

voltagelevels(100%Rpm,8degcollective,1P=

6.53Hz)

0

100

200

300

400

500

600

0 1 2 3 4 5 6 7

RotorSpeedMultiple

BalanceNormal,lb

300V

400V

450V

0V

Figure22:Balancenormalforce(thrust)harmonics

attheexcitationfrequencyforthreevoltagelevels

(100%Rpm,8degcollective,1P=6.53Hz)

Development and Whirl Tower Test of the Smart Active Flap Rotor

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