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2.Angle-of-attack,,
3.Pitchrate,,
4.Eulerangle,
5.Altitude,,
6.Rollrate,,
7.Yawrate,,
8.Bankangle,
9.Sidslipangle,
10.Eulerangle,
http://www.77cn.com.cntitude,and12.Longitude.
Linearizationofthetrimmedaircraftproducesa12by12statematrix,.Thelongitudinal
eigenvaluesarefoundbytakingtheeigenvaluesofthesub-matrixofconsistingofthe rst5rowsandcolumnsof.Thelateraleigenvaluesarefoundbytakingtheeigenvaluesofthesub-matrixofconsistingofrowsandcolumns6–9of.
TrimResults
TrimvaluesoftrimvariablesareshowninFigs.5–10.Fig.5showsthat,withtheX-CG
heldtoitsnominalposition,trimcanbeestablishedthroughoutthereferencemissionpro lewithstabilizerde ectionsofnomorethanabout(withcoupledelevatorde ectionsofuptoabout
).Fig.6showsthenominalX-CGschedule(circles)andtheX-CGpositionneededtotrimintheabsenceofstabilatorde ection(x’s).Thehorizontaldash-dotlinesshowtheforward(48%)andaft(54%)X-CGlimitsasgivenin[2,PageB-8].ThenominalX-CGscheduletakesitoutsidetheselimitsduringpartofthesupersoniccruisesegment(Seg.2).ThetrimpositionoftheX-CG,however,exceedstheaftX-CGlimitbothmoreoftenandbyagreateramountthanthenominal.Theelapsedtimeto yfrom ightcondition8to15(thelastconditionbeforetheX-CGexceedsitsaftlimituntilthe rstconditionwheretheX-CGhasreturnedtoitslimit)is10minutes22seconds.Besidesthequestionofwhetheronewouldwanttoexceedthelimitbysomuch,thereisthequestionofwhetheronewouldwanttoincludehighenoughcapacityfuelpumpingsystemstomovetheX-CGthatrapidly.TheX-CGtrimpositionthroughouttheentiredescentandsubsoniccruisephase(Segs.3–5)fallsoutsidetheaftlimit,theexcessbecomingasmuchas6%ofmeanaerodynamicchord.
ThevalueoftrimvariabletotrimtheaircraftisshowninFig.7.Itseemstobequite
insensitivetowhethertheaircraftistrimmedbystabilatorde ectionorX-CGpositioning.Thevaluesoftrimvariablesand,showninFigs.8and9,showonlyslightlymoresensitivitytothetrimmode.
Inthecruisesegments,thepowerleversettingisusedasanadditionaltrimvariable,sup-plementedbyaddingtheconstraintthatthetotalaccelerationshouldbezero().Fig.10
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