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PRINCIPLESOFFLIGHTObjectivesAirfoildesigncharacteristicsFourforcesinflightWingtipvorticesandprecautionstobetakenLoadfactorsinairplanedesignAirplanestabilityandcontrollabilityAirfoildesigncharacteristicsWingisalowdragdeviceshapedtogetapositivepressureliftingactionfrombelowandanegativepressureliftingactionfromaboveDragonahandorcarAirfoildesigncharacteristicsAirmoleculesarestationaryandweremovingthroughitTwoneighbormoleculeswanttoendupnexttoeachotheratthetrailingedgeofthewingTheongoingoverthetophastomovefasterBernoullisprincipleWhenafluidsvelocityincreases,pressuredecreasesWingisbasicallyhalfofaventuriLowpressureabovethewing,highpressurebelowAirfoildesigncharacteristicsChordlinerunsfromtheleadingedgetothetrailingedgeAngleofattackCamberisthecurvatureofthewingGenerally,theupperhalfismorecurvedthanthelowerCamberlineiswherealldistancesoneithersideofthelineareequalFourforcesinflightThrustLiftDragWeightThesumofallupwardforcesequalsthesumofalldownwardforcesThesumofallforwardforcesequalsthesumofallrearwardforcesThrustForwardforceproducedbythepowerplantandpropellerThrustmustbeexertedinorderfortheairplanetomoveThrustTomaintainaconstantairspeed,thrustanddragmustbeequalIfinlevelflight,theenginepowerisreduced,thrustdecreasesandtheairplaneslowsdownIfthrustislessthandragtheairplanewilldecelerateuntilitsairspeedisinsufficienttosupportitThrustIfinlevelflight,theenginepowerisincreasedthenthrustincreasesandairspeedincreasesAslongasthrustisgreaterthandrag,theairplanewillaccelerateThrustandAOAStraightandlevelflightcanbesustainedatspeedsfromveryfasttoveryslowMustcoordinateangleofattackandthrustinordertoholdlevelWhenairspeedislow,whatmustwedowithourangleofattacktomaintainlevelflight?IncreaseangleofattackWhy?ThrustandAOAWhenairspeedislow,AOAmustberelativelyhightoincreaseliftIfthrustdecreasesandairspeeddecreases,liftbecomeslessthanweightandtheairplanedescendsDuringstraightandlevelflight,ifthrustisincreased,whatmustwedotoourAOA?DecreaseitIfweincreasethrustwithoutdecreasingAOA,theairplanewillclimbMustdecreaseAOAtokeepliftequaltoweightWeightThecombinedloadoftheairplaneitself,thecrew,fuel,andcargoorbaggageWeightpullstheaircraftdownwardbecauseofgravityOpposesliftandactsverticallydownwardthroughtheairplanescenterofgravityWeightIfinstabilizedlevelflight,whenliftisequaltoweight,theairplanewontgainorlosealtitudeIfliftbecomeslessthanweight,theairplanelosesaltitudeIfliftisgreaterthanweight,theairplanegainsaltitudeLiftProducedbytheeffectoftheairactingonthewingOpposesthedownwardforceofweightL=1/2V2CLSWhichofthesevariablescanwechange?AngleofattackAirspeedLiftAnytimeyoumovethecontrolcolumnforeoraft,theangleofattackchangesAsangleofattackincreases,liftincreaseswithallotherfactorsbeingequalProportionaltothesquareoftheairplanesspeedAnairplanetravelingat200knotshas4timestheliftasthesameairplanegoing100knotsiftheangleofattackandotherfactorsremainconstantLiftPlanecantstayataconstantaltitudeandkeepthesameangleofattackifspeedisincreasedLiftwouldincreaseandtheplanewouldclimbTomaintainthebalanceofliftandweightifspeedisincreased,whatmustwedo?DecreaseangleofattackForeveryangleofattack,theresacorrespondingindicatedairspeedrequiredtomaintainunacceleratedflightDragArearwardforcecausedbydisruptionofairflowbythewing,fuselage,andotherprotrudingobjectsOpposesthrustWhatkindsofdragdowehave?InducedParasiteTotaldrag=induceddrag+parasitedragParasitedragFormdragBasedonthesizeandshapeoftheplane,howwellstreamlinedandamountoffrontalareaParasitedragSkinfrictiondragCausedbyfrictionbetweenafluidandthebodyofthesurfacemovingthroughitParasitedragInterferencedragWhenairflowarounddifferentpartsoftheplaneinteractwitheachotherInduceddragResultofcreatingliftWingtipvorticeswashoverthewingeffectivelybendstheliftvectorbackwardsInduceddragDecreaseswithairspeedThelowertheairspeed,thehigherAOAneededtoproduceliftHighAOAmeanslotsofliftBigpressuredifferentialBigwingtipvorticesLotsofdragWingtipvorticesSpanwiseflowHighpressureairhitsthebottomofthewingandmovesouttothetipLowerpressureattherootduetohighAOAAirgoesfromhigherlowpressuretolowerlowpressureHighpressuretriestogotolowwhichresultsinwingtipvorticesandthepathofleastresistanceisthewingtipInordertocreatelowerpressureandliftontopofthewing,itneedstobeatahigherangleofattackCausesagreaterpressuredifferentialandstrongerwingtipvorticesPlanehastheworstwingtipvorticeswhenitsheavy,clean,andslowWhendoesthisoccur?Whyheavy,clean,andslow?AvoidingwingtipvorticesTakeoffbeforetheplaneinfrontofyouandclimboutonasteeperpathLandaftertheplaneinfrontofyouandcomeinonahigherglidepathVorticessinksoavoidthemAlightquarteringtailwindwillkeepvorticesonarunwaysobecarefulifthisconditionexistsWhatelsecanwedotoreducewingtipvortices?WingletsInterruptwingtipvorticesCanincreasefuelefficiencyathighspeedsby16-26%InduceddragGroundeffectReduceddownwashmeanslessinduceddragCanflyatalowerAOAbecauseverticalcomponentofliftmovesforwardLiftincreasesGroundeffectWhentheairplaneisneartheground,wegetwhatiscalled“groundeffect”Grounddisruptswingtipvortices whichreducesdownwashGroundeffectFeelslikeacushionofairYoullnoticegroundeffectwhentheairplaneiswithinonewingspanofthegroundLoadfactorsinairplanedesignLoadfactoristheratioofthetotalloadactionontheairplanetothegrossweightoftheairplaneAloadfactorof3meansthetotalloadontheplanesstructureisthreetimesitsgrossweightManeuveringspeedMaximumspeedwherefull,abruptcontrolmovementinthepitchaxiswillresultinanaerodynamicstalloftheaircraftpriortoexceedingthedesignloadlimitVA2=VAW2/W1VA2=Maneuveringspeed(atthisweight)At2550lbs,VAis105knotsWhatisVAat2300lbs?99knotsLoadfactorincreaseswithbankangleAsweturn,liftgetssplitinto2components:verticalandhorizontalInordertomaintainaltitude,wemustkeeptheverticalcomponentofliftthesameasitwasinstraightandlevelflightHowdowedothis?EqualandoppositereactionLoadfactorincreaseswithbankangleAirplanestabilityandcontrollabilityControllabilityThecapabilityofanairplanetorespondtothepilotsinputStabilityTheinherentqualityofanairplanetocorrectforconditionsthatdisturbitsequilibriumThetendencytoreturntoequilibrium2kindsofstabilityStaticDynamicStaticstabilityTheinitialtendencytheairplanedisplaysafteritsequilibriumisdisturbedStaticstabilityPositivestaticstabilityThetendencytoreturntotheoriginalstateofequilibriumNeutralstaticstabilityThetendencytocontinueinthenewconditionafterbeingdisturbedNegativestaticstabilityThetendencytocontinueawayfromequilibriumafterbeingdisturbedDynamicstabilityTheoveralltendencyofanairplaneafterbeingtakenoutofequilibriumAssumeallexampleshavepositivestaticstabilityPlanewillattempttoreturntoequilibriumDynamicstabilityPositivedynamicstabilitywillcausetheplanetopitchupthendowninanattempttoreturntoequilibriumwithsteadilydecreasingoscillationsNeutraldynamicstabilitywillcausetheplanetopitchupanddowntoattempttoreturntoequilibriumbutoscillationswillneverchangeNegativedynamicstabilityiswhenthesizeoftheoscillationsincreasesandtheplanemovesfartherfromequilibriumQuestions?
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