CHAPTER 11 Structural Components of Aircraft.....................................................
Aircraftaregenerallybuiltupfromthebasiccomponentsofwings,fuselages,tailunits,andcontrolsur-
faces.Therearevariationsinparticularaircraft;forexample,adeltawingaircraftwouldnotnecessarily
possessahorizontaltail,althoughthisispresentinacanardconfigurationsuchasthatoftheEurofighter
(Typhoon).Eachcomponenthasoneormorespecificfunctionsandmustbedesignedtoensurethatit
cancarryoutthesefunctionssafely.Inthischapter,weshalldescribethevariousloadstowhichaircraft
componentsaresubjected,theirfunctionandfabrication,andalsothedesignofconnections.
11.1 LoadsonStructuralComponents..................................................................
Thestructureofanaircraftisrequiredtosupporttwodistinctclassesofload:thefirst,termedground
loads,includesallloadsencounteredbytheaircraftduringmovementortransportationontheground
such as taxiing and landing loads, towing, and hoisting loads, and the second,air loads, comprises
loadswww.trafalgar.com/USA/DisplayTour?TourID=8642&RegionID=4&CountryID=0&TypeID=0
&LengthID=3&BudgetID=0&TimeID=49&Keywords=&BrochureTypeID=− 1 imposed on the struc-
tureduringflightbymaneuversandgusts.Inaddition,aircraftdesignedforaparticularroleencounter
loadspeculiartotheirsphereofoperation.Carrier-borneaircraft,forinstance,aresubjectedtocatapult
takeoffandarrestedlandingloads:mostlargecivilandpracticallyallmilitaryaircrafthavepressurized
cabinsforhigh-altitudeflying;amphibiousaircraftmustbecapableoflandingonwater,andaircraft
designedtoflyathighspeedsatlowaltitude,suchastheTornado,requireastructureofabove-average
strengthtowithstandtheeffectsofflightinextremelyturbulentair.
Thetwoclassesofloadsmaybefurtherdividedintosurfaceforceswhichactuponthesurfaceof
thestructure,suchasaerodynamicandhydrostaticpressure,andbodyforceswhichactoverthevolume
ofthestructureandareproducedbygravitationalandinertialeffects.Calculationofthedistributionof
aerodynamicpressureoverthevarioussurfacesofanaircraft’sstructureispresentedinnumeroustexts
onaerodynamicsandwillthereforenotbeattemptedhere.Weshall,however,discussthetypesofload
inducedbythesevariouseffectsandtheiractiononthedifferentstructuralcomponents.
Basically,allairloadsaretheresultsofthepressuredistributionoverthesurfacesoftheskinproduced
bysteadyflight,maneuver,orgustconditions.Generally,theseresultscausedirectloads,bending,shear,
andtorsioninallpartsofthestructureinadditiontolocal,normalpressureloadsimposedontheskin.
Conventionalaircraftusuallyconsistoffuselage,wings,andtailplane.Thefuselagecontainscrew
andpayload,thelatterbeingpassengers,cargo,weapons,plusfuel,dependingonthetypeofaircraft
Copyright©2010,T.H.G.Megson. PublishedbyElsevierLtd. Allrightsreserved.
DOI:10.1016/B978-1-85617-932-4.00011-7 351