Flight testing and real-time system identification analysis of a UH-60A Black Hawk Helicopter with an instrumented external sling load

120 Pages·1.9 MB·English

by  McCoy, Allen H

NPS ARCHIVE
1997.12
MCCOY, A.
NAVAL POSTGRADUATE SCHOOL
Monterey, California
THESIS
FLIGHT TESTING AND REAL-TIME SYSTEM
IDENTIFICATION ANALYSIS OF A UH-60A BLACK
HAWK HELICOPTERWITH AN INSTRUMENTED
EXTERNAL SLING LOAD
by
AllenH. McCoy
December, 1997
Thesis Co-Advisors: E. Roberts Wood
Mark B. Tischler
Thesis
M18237
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1. AGENCYUSEONLY(Leaveblank) 2. REPORTDATE 3. REPORTTYPEANDDATES COVERED
December 1997 Master'sThesis
4. TITLEANDSUBTITLE 5. FUNDINGNUMBERS
FLIGHT TESTINGAND REAL-TIME SYSTEM IDENTIFICATION ANALYSIS OFA
UH-60ABLACKHAWK HELICOPTERWITHAN INSTRUMENTED EXTERNAL
SLINGLOAD
6. AUTHOR(S)
McCoy, AllenH.
PERFORMING
7. PERFORMINGORGANIZATIONNAME(S)ANDADDRESS(ES) 8O.RGANIZATION REPORT
NavalPostgraduate School NUMBER
Monterey, CA 93943-5000
9. SPONSORING/MONITORINGAGENCYNAME(S)ANDADDRESS(ES) 10.SPONSORING/
U.S. Army/NASARotorcraftDivision, MONITORING
AmesResearch Center, MoffettField, CA94035-1000 AGENCYREPORTNUMBER
11. SUPPLEMENTARYNOTES
Theviewsexpressedinthisthesis arethoseoftheauthoranddo notreflectthe official policyorpositionofthe Departmentof
DefenseortheU.S. Government.
12a. DISTRIBUTION/AVAILABILITYSTATEMENT 12b.DISTRIBUTIONCODE
Approvedforpublicrelease; distributionisunlimited.
13. ABSTRACT (maximum 200 words)
Helicopterexternal airtransportationplaysanimportant role intoday'sworld Forboth military andcivilian helicopters,
external slingloadoperations offeranefficientandexpedientmethodofhandlingheavy, oversizedcargo. With the ability to
reachareasotherwiseinaccessibleby groundtransportation, helicopterexternal loadoperations are conductedin industries such
as logging, construction, andfirefighting, as well as in supportofmilitarytactical transport missions. Historically, helicopter
andloadcombinations havebeenqualifiedthroughflighttesting, requiringconsiderabletimeandcost. With advancements in
simulationandflighttesttechniques, there ispotentialto substantially reduce costsandincrease the safetyofhelicopterslingload
certification. Validatedsimulationtools makepossibleaccuratepredictionofoperational flight characteristicsbefore initial flight
tests. Real time analysisoftestdataimprovesthe safetyandefficiencyofthetestingprograms. Toadvancethese concepts, the
US ArmyandNASA, incooperationwiththeIsraeli AirForceandTechnion, underaMemorandumofAgreement seekto
developandvalidatea numerical model ofthe UH-60 with slingloadanddemonstratea methodofnearreal time flighttest
analysis. Thisthesispresents resultsfromflighttests ofa US ArmyBlackHawkhelicopterwithvariousexternal loads. Tests
were conductedastheUSfirstphaseofthisMOAtask. Theprimary loadwasa containerexpressbox (CONEX). which
containedacompact instrumentationpackage. Theflights coveredthe airspeed rangefrom hoverto 70 knots. Primary
14. SUBJECTTERMS 15. NUMBEROF
Helicopter, External Loads, SlingLoads, FlightTesting, CIFER Real-Time Data Analysis. Helicopter PAGES
HandlingQualities, Helicopter StabilityMargins, UH-60A, BlackHawk 105
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REPORT THIS PAGE OFABSTRACT
UL
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Block 13. ABSTRACT (con't)
maneuvers werepitch androll frequency sweeps, steps, anddoublets. Resultsofthetestdeterminedthe
effect ofthe suspendedloadonboththe aircraft'shandlingqualitiesandit'scontrol system's stability
margins. Includedwerecalculationsofthestabilitycharacteristics ofthe load'spendularmotion.
UtilizingCIFER® software, a methodfornear-real time systemidentificationwasalsodemonstrated
duringtheflighttestprogram.
StandardForm298(Reverse) SECURITYCLASSIFICATIONOFTHIS PAGE
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Approved for public release; distribution unlimited.
FLIGHT TESTING AND REAL-TIME SYSTEM IDENTIFICATION
ANALYSIS OF A UH-60A BLACK HAWK HELICOPTER WITH AN
INSTRUMENTED EXTERNAL SLING LOAD
Allen H. McCoy
Lieutenant, United States Navy
B.S., Georgia Institute ofTechnology, 1989
Submitted in partial fulfillment ofthe
requirements for the degree of
MASTER OF SCIENCE IN AERONAUTICAL ENGINEERING
from the
NAVAL POSTGRADUATE SCHOOL
December 1997

.
DUDLEY KNOX LIBRARY
NAVALPOSTGRADUATE SCHOOL
MONTEREY CA 93943-5',
ABSTRACT
Helicopterexternal airtransportationplaysan importantrole intoday'sworld. Forboth military
andcivilianhelicopters, external slingloadoperationsofferanefficientandexpedient methodofhandling
heavy, oversizedcargo. Withtheabilitytoreachareas otherwise inaccessiblebygroundtransportation,
helicopterexternal loadoperationsareconductedin industries suchaslogging, construction, andfire
fighting, aswell asinsupportofmilitarytacticaltransport missions. Historically, helicopterandload
combinations havebeen qualifiedthroughflighttesting, requiringconsiderabletimeandcost. With
advancementsinsimulationandflighttesttechniques, thereispotentialto substantially reducecosts and
increasethe safetyofhelicopterslingloadcertification. Validatedsimulationtools makepossibleaccurate
predictionofoperational flightcharacteristicsbefore initialflighttests. Real timeanalysis oftestdata
improves the safetyandefficiencyofthetestingprograms. Toadvancethese concepts, the US Armyand
NASA, incooperationwiththe Israeli AirForceandTechnion, underaMemorandum ofAgreement, seek
todevelopandvalidateanumerical model oftheUH-60 with slingloadanddemonstratea methodofnear
real timeflighttestanalysis. Thisthesispresentsresultsfromflighttests ofaUS ArmyBlackHawk
helicopterwithvariousexternal loads. TestswereconductedastheUS firstphase ofthisMOAtask. The
primaryloadwasa containerexpressbox (CONEX), whichcontainedacompact instrumentation
package. Theflightscoveredtheairspeedrangefrom hoverto70knots. Primary maneuverswerepitch
androll frequency sweeps, steps, anddoublets. Resultsofthetestdeterminedthe effect ofthe suspended
loadonboththe aircraft's handlingqualities andit'scontrol system's stability margins. Includedwere
calculationsofthe stabilitycharacteristicsoftheload'spendularmotion. UtilizingC1FER® software, a
methodfornear-real time systemidentificationwas alsodemonstratedduringtheflighttestprogram.
VI
TABLE OF CONTENTS
INTRODUCTION
I. 1
BACKGROUND
A.
1
B. UNITED STATES/ISRAELIMEMORANDUMOFAGREEMENT 3
TESTEQUIPMENT
II. 5
A
HELICOPTERDESCRIPTION
5
1. General 5
2. CargoHook 6
LOADS
B. 7
CONEX
1. 8
2. SolidBlockLoads 9
C. LIFTING SLING 9
D. LOADINSTRUMENTATIONPACKAGE 13
E. HELICOPTERINSTRUMENTATION 14
F. HELICOPTERVIDEO CAMERA 16
III. FLIGHTTESTPROGRAM 17
A. HISTORY 17
B. FLIGHTTESTPROFILE 18
C. DATAACQUISITION 22
rv. DATAANALYSIS 25
A. ANALYSIS TOOLS 25
1. CIFER® 25
2. Derivedand SmoothedVariables Code 28
3. GetData 29
4. XPlot 29
5. MicrosoftEXCEL® 29
B. HELICOPTERHANDLINGQUALITIES 29
1. BandwidthFrequency andPhaseDelay 30
2. DeterminationofBandwidthFrequencyandPhaseDelay 31
Vll
C. CONTROL SYSTEM STABILITYMARGINS 32
1. GainMarginandPhaseMargin 32
2. DeterminationofGainandPhaseMargins 33
D. LOADMOTION ANALYSIS 35
1. PredictingPendulumModeCharacteristics 35
2. DeterminationofPendularMotionfromFlightMeasurements 36
a. LoadAxistoHelicopterAxisTransformationApproximation 36
b. DeterminationofthePendulumModeDampingandNaturalFrequency 37
E. NEARREALTIME ANALYSIS VERSUS POSTFLIGHTANALYSIS 38
V. RESULTS 41
A HELICOPTERHANDLINGQUALITIES 41
B. CONTROL SYSTEM STABILITYMARGINS 47
C. LOADMOTION CHARACTERIZATION 50
D. SIMULATION 52
1. SimulationModel 52
2. ComparisonofTestDatato Simulation 52
VI. CONCLUSIONS ANDRECOMMENDATIONS 55
A. CONCLUSIONS 55
B. RECOMMENDATIONS 56
APPENDKA SIGNALLISTINGFORNASA748, LOAD, AND STRIPCHARTS 59
APPENDDCB. DETAILED DRAWINGS OFTHE 4KBLOCKAND CONEX 65
APPENDDCC. MOATASK8 FLIGHTTESTDATABASE SUMMARY 71
APPENDDCD. PILOT'STESTFLIGHTDATACARD 75
APPENDIXE. NEARREALTIMEDATAANALYSIS PROCEDURES 79
A OVERVIEW 80
B. TYPICAL SCENARIO 80
C STEP-BY-STEPPROCEDUREFORRUNNING CIFER®NEAR-REALTIME 82
APPENDDCF SISOANALYSIS RESULTS SUMMARY 85
LIST OFREFERENCES 87
INITIAL DISTRIBUTIONLIST 89
Vlll