Chapter 2 - Flight Manoeuvres

AERODYNAMICSFlightManoeuvresAIM:ReviewtheinteractionofthefourforcesthatactontheaircraftinflightandhowthesewillbeaffectedwithforcemagnitudeUnderstandthedispositionofforcesina:ClimbDescentTurnRevision-ForcesThrustThrustFromthepropellerInthedirectionofflightRevision-ForcesLiftThrustLiftThroughthecenterofpressure(CofP)PerpendiculartotherelativeairflowRevision-ForcesLiftDragThrustDragThroughthecoefficientofdragpointIntheoppositedirectiontoflightRevision-ForcesLiftDragWeightThrustWeightThroughthecenterofgravity(CofG)InadownwardsverticaldirectionWeightGravityistheforceattractingallbodiestotheearthssurfaceWeightisthegravitationalforceofaparticularmassThegreaterthemassofanobjectthegreatertheweightWeightissaidtobeasingleforceactingthroughthecenterofgravityWeightAlwaysactsintheverticaldirectiontothecenteroftheearthTherewillbeweightlimitationsdependingonthestructuralstrengthoftheairframeCenterofGravity(CofG)SinglepointwhereweightsaidtoactWillvarydependingonaircraftloadingWeightatfrontofA/C=forwardCofGWeightatrearofA/C=rearwardCofGAtransferofweight(movingweightfromoneplacetoanother)willhavethesameeffectCofGmustremainwithinlimitsatalltimesduringflightotherwiseitwilleffectthestabilityandperformanceofA/CCenterofGravityCofG100CofGCofG100ThrustPropellorconvertstheenginetorqueintoaforcecalledthrustEachpropbladeisshapedsimilartoanaerofoil.Astheyrotatetheyproduceliftmuchlikeawing.ThisliftactstopulltheaircraftthroughtheairActsindirectionofflightTotalAerodynamicReactionAerofoilscreateliftanddragApropellorsliftbecomespropellorthrustPropellorThrustactsinthedirectionperpendiculartotherotationTotalAerodynamicReactionApropellorsdragiscalledPropellorTorqueForceThedefinitionisresistancetomotionintheplaneofrotationofthepropVerticalComponentofThrustAthighAoA’sThrusthasaverticalcomponentassistingtheLiftproducedbythewingForpracticalpurposesweassumeThrustactsalongtheflightpathAngleVerticalComponentHorizontalComponentActualVectorVectorAdditionItcanbeseenthatifyoudrawaVectorinanydirectionotherthanHorizontalorVerticalitwillbedividedintotwocomponents,aHorizontalComponentandaVerticalComponent.VectorsVectorsubtractionMinusMagnitudesubtractionVectoradditionAddMagnitudeadditionRatioVectorsVectorsareproportionalOnevectorincreasedParallelresultantdrawnRatioremainsconstantForcesinStraightandLevelLift=WeightThrust=DragAircraftinEquilibriumTailplaneNoseUpPitchingMomentL/WCoupleNoseDownPitchingMomentChanginglevelflightspeedL=AoA*VVariationinweightWhenweightdecreases,tomaintainourheightwhatcanwedo?IASandTASIfweclimbataconstantIASwhatwillhappentoTASIncreaseHowevertherelationshipbetweenIASandAoAwillremainunchangedsolongasweightiskeptconstantForcesintheClimbClimb–RequiresFullThrust/PowerLiftWeightThrustDragAircraftinEquilibriumWeightLiftDragThrust/PowerRequiredComponentofWeightParalleltoFlightpathComponentofWeightPerpendiculartoFlightpathAngleHt/ROCDistAngleTypesofclimbsMaxangleofclimbMaximumexcessthrustMaxrateofclimbMaximumexcesspowerFactorsaffectingtheclimbIncreasedweightDecreasedExcessthrust/powerthereforelessclimbperformanceDecreaseddensityDecreasedExcessthrust/powerthereforelessclimbperformanceEffectofWindWindshearForcesinaDescent–GlideZeroThrustThrust=0LiftWeightForwardComponentofWeightbalancingDragAircraftinEquilibriumDistAngleComponentofWeightPerpendiculartoFlightpathAngleTotalDragComponentofWeightParalleltoFlightpathHt/RODForcesinaDescent–GlideInadescentwhatcouldwedotoflattentheflightpath?AddpowerDistAngleComponentofWeightPerpendiculartoFlightpathAngleTotalDragComponentofWeightParalleltoFlightpathHt/RODEffectofweightIfweincreaseweightwemustincreaselift.HowcanweincreaseliftNowwehaveanewairspeedforbestL/Dratio,wearetravelingfasterGliderangewillbeunaffectedEffectofwindForcesinaTurnLiftVectorTilted-VerticalComponentofLiftislostLevelflightwillnotbemaintainedifL1doesnotequalWeightLiftmustbeincreasedtoequalWeight(OrangeArrows)Comparison-Turning30°45°60°LoadFactor=LiftWeightOverbankingWhentheaircraftisinaclimbingturn,theangleofattackontheouterwingissuchthatitisgreaterthantheangleofattackontheinnerwingTheouterwingtravelsfaster,whichwillcreateevenmoreliftonthewingTheaboveresultingfactorswillwanttocontinuebankingtheaircraftintotheturncalledOverbankingItiscommonwhileinaclimbingturntoactuallybeholdingtheaileronintheoppositedirectiontotheturnOverbankingTheoppositeoccursinadescendingturnTheinnerwinghasagreaterangleofattackthantheouterwingTheouterwingtravelsfaster,sothetendencytooverbankinadescendingturnisnotgreatMaintainingBalanceBalanceismaintainedduringturnsbyusingtherudderAbalanced(coordinated)turnwillbemorecomfortableandmoreefficient(lessdrag)SlipTail“slips”intotheturnNotenoughrudder!SkidTail“skids”outoftheturnToomuchrudder!