Helicopter drive train modelling for manoeuvre load alleviation

96 Pages·2017·7.03 MB·English

Helicopter drive train
modelling for manoeuvre
load alleviation
B. van Bruchem
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Helicopter drive train modelling for
manoeuvre load alleviation
by
B. van Bruchem
toobtainthedegreeofMasterofScience
attheDelftUniversityofTechnology,
tobedefendedpubliclyonThursdayAugust24,2017at2:30PM.
Studentnumber: 1365223
Projectduration: September1,2015–August24,2017
Thesiscommittee: Dr.Ir.M.Voskuijl, TUDelft,supervisor
Ir.J.A.Melkert, TUDelft,chairman
Dr.F.Yin, TUDelft
Dr.Ir.S.Hartjes, TUDelft
Thesisregistrationnumber:144#17#MT#FPP
CoverimagebyNorthCarolinaandIndianaNationalGuard-CC-BY-2.0
Anelectronicversionofthisthesisisavailableathttp://repository.tudelft.nl/.
Thispageisintentionallyleftblank.
Acknowledgements
ThisreportmarkstheendofajourneythatbeganwithmyinternshipattheConditionBasedMaintenance
centeroftheUniversityofSouthCarolina.Theknowledgeaboutrotorcraftmaintenanceandoperationsthat
Ihavegainedduringthistimeprovedinvaluableforthisresearchproject.
Iwishtothankvariouspeoplefortheircontributiontothisthesis.Firstandforemost,Iwouldliketothankmy
supervisorMarkVoskuijlforhisguidanceandsupportthroughouttheproject.Hisinsightsprovedindispens-
ableforthisworkandhiswillingnesstogivehistimesogenerouslyhasbeenverymuchappreciated.Iwould
liketooffermyspecialthankstoTravisEdwardsandDr. BayoumifromtheConditionBasedMaintenance
centerfortheirassistancewiththedrivetrainexperiment. IwouldalsoliketothanktheLORDcorporation
forprovidingtheTorqueLinksensor. Furthermore,thepracticalinsightsofMartinKeaneyandpilotsfrom
theSouthCarolinaArmyNationalGuardintohelicoptersoperationsareverymuchappreciated.
Iamgratefultomyfamilyandfriendsforsupportingmeandmakingthisjourneypossible.Iwishtothankmy
parentsandmybrotherMaartenfortheirsupportandencouragementthroughoutmystudy.Specialthanks
go to Johan and Rozemarijn Nederend for so generously providing me with a place to say in Delft when I
came back from South Carolina. Furthermore, I would like to thank my friend and fellow student Pieter
Danneelsforthemanyinterestingconversationsduringthetimeweworkedtogether. Ialsowanttoexpress
mygratitudetothefriendswhohelpedmewiththisproject.ThankyouEdwinWijnjaenMartinvanMeijeren
forproofreadingthereportandmakingitbetter. Finally,IwouldliketothankTacoPostmaforguidingme
andhelpingmefinishthisgraduationproject.
B.vanBruchem
Delft,August18,2017
iii
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Abstract
Helicoptersarecomplexandexpensiveaircraftwithaleveloftechnologythatisimmaturecomparedtofixed-
wingcounterparts.Helicopterssufferfromvibratoryloadsstemmingfromthemainrotorandexhibitcontrol
andstabilityproblemsinthelow-speedflightregime. Operatingahelicopternearthelimitsofitsflighten-
velopemayresultinunacceptablehighstructuralloadswhichadverselyaffectswearandtearofdrivetrain
components. Conservativesafetyregulationsleadtohighoperatingcostwhereasignificantpartcanbeat-
tributedtomaintenance.Manufacturersandoperatorsthereforestrivetomakehelicoptersmorecapableand
reliableinanefforttoreduceoperatingcost.Structuralloadalleviationoffersanattractiveoptiontoachieve
thisgoalbyreducingcomponentdamageaccumulationandsubsequentrequiredmaintenance.
ThisthesisinvestigatesstructuralloadalleviationinthetailrotordrivetrainoftheUH-60BlackHawk. The
BlackHawkprovidesacompellingcaseforloadalleviationresearchbecauseofitsevergrowingoperational
weightandresultingincreaseofdrivetrainloadlevels. Furthermore,thelifetimeoftheUH-60istobeex-
tendedsothatitwillflyformanyyearstocome. Currentresearchandapplicationsofrotorcraftstructural
loadalleviationfocusonthemainrotorbutlessattentionisgiventotailrotordrivetraincomponents. This
projectseekstoaddressthisknowledgegapbyinvestigatingmanoeuvresthatresultincriticaldynamicloads
intheUH-60tailrotordrivetrain. Asurveyofpertinentliteratureandinterviewswithhelicopterpilotsin-
dicatethatpedalinputsforleft-handturnsinhoverleadtohighdynamicloadsintheUH-60tailrotordrive
train.
Aflightsimulationmodelisconstructedthatoffersthenovelcapabilitytopredictdynamicloadsintailrotor
driveshafts.Thismodelconsistsofanavailablehighfidelityenginemodelandexistingrotormodelscoupled
byamultibodydynamicstailrotordrivetrainmodelwithpropertiesthatarebasedoncomponentmea-
surementsandCADdrawings. Experimentsareconductedtodeterminetherelationbetweenmanoeuvre
aggressivenessanddynamicloadsintailrotordriveshafts. Basedontheresultsamanoeuvreloadallevia-
tioncontrolstrategyisdevisedtoreducedynamicloadswhileensuringapplicableLevel1handlingquality
requirements.Applicationofthiscontrolstrategywilldecreasedynamicloadsduringleft-handyawmanoeu-
vresinhover. Furthermore,theresultshighlightwhatreductioninloadscanbeachievedforvaryinglevels
ofmanoeuvreaggressiveness.Thesefindingsmayaidinthedesignofflightcontrolsystemsthatincorporate
tailrotordrivetrainloadalleviationobjectives.
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Table of Contents
Acknowledgements iii
Abstract v
ListofTables ix
ListofFigures xi
ListofSymbols xiii
ListofAcronyms xvii
1 Introduction 1
2 Background 3
2.1 SikorskyUH-60BlackHawk. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
2.2 Literaturereview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
2.2.1 Flightsimulationtools. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
2.2.2 Helicopterloads . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
2.2.3 Componentmodellingmethods. . . . . . . . . . . . . . . . . . . . . . . . . . 6
2.2.4 Loadalleviationandlimitprotection . . . . . . . . . . . . . . . . . . . . . . . 7
2.2.5 Handlingqualitiesandrequirements . . . . . . . . . . . . . . . . . . . . . . . 7
2.2.6 Synthesis. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
3 Scopeandobjectives 9
3.1 Researchscopeandaim. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
3.2 Researchobjectivesandquestions . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
4 Criticalmanoeuvres 11
4.1 Literaturesurvey . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
4.2 Expertinterviews . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
4.2.1 AH-64pilotinterviews. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
4.2.2 H-60pilotinterviews. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
4.3 Synthesis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
5 Flightsimulationmodel 19
5.1 Tailrotordrivetrainmodel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
5.2 Enginemodel. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
5.3 MainRotormodel. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
5.4 Tailrotormodel. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
5.5 Modelvalidation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
5.5.1 Hoverperformanceandcontrol . . . . . . . . . . . . . . . . . . . . . . . . . . 24
5.5.2 Responsetocollectivecontroller. . . . . . . . . . . . . . . . . . . . . . . . . . 25
6 Loadalleviationexperiments 31
6.1 Handlingqualitiesrequirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
6.2 Loadmetric. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
6.2.1 Loadtypes. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
6.2.2 Loadseverityandamplificationfactor. . . . . . . . . . . . . . . . . . . . . . . 32
6.2.3 Loadquicknessmetric. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
6.2.4 Loadquicknessapplication . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
6.3 Experimentset-up . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
6.3.1 Controllimits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
6.3.2 Experimentvariables . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
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viii TableofContents
7 Simulationresults 37
7.1 Moderate-amplitudeheadingchange. . . . . . . . . . . . . . . . . . . . . . . . . . . 37
7.2 Effectofmanoeuvreaggressivenessandduration. . . . . . . . . . . . . . . . . . . . . 40
7.3 Effectofhelicopterweight . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42
7.4 Effectofcentreofgravitylocation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44
7.5 Discussionofresults . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44
7.6 Controlstrategies. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44
7.7 Synthesis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46
8 Conclusionsandrecommendations 49
8.1 Conclusions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49
8.2 Recommendations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50
Bibliography 53
A Flightsimulationmodel 57
B Tailrotordrivetrainmodel 59
B.1 Properties. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59
B.2 Validationexperiment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62
C T700-GE-701enginemodel 67
C.1 Modeladjustments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67
C.1.1 Transmission. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67
C.1.2 Fuelflowcontroller . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67
D Mainrotormodel 69
D.1 Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69
D.2 Adjustments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70
D.2.1 Rotorbladelay-out. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71
D.2.2 Inflowmodel. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71
E Tailrotormodel 73
E.1 Modelintegration. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73
E.1.1 Loadapplication. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74
E.1.2 Modeladjustments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74
E.2 Controllimits. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 76