Introduction to Aircraft Structural Analysis (Elsevier Aerospace Engineering)

11.3 Fabrication of Structural Components 359

Fig.11.7

British Aerospace 146 (courtesy of British Aerospace).

11.3 FabricationofStructuralComponents.............................................................

Theintroductionofall-metal,stressedskinaircraftresultedinmethodsandtypesoffabricationwhich
remain in use to the present day. However, improvements in engine performance and advances in
aerodynamicshaveledtohighermaximumlift,higherspeeds,andthereforetohigherwingloadings
sothatimprovedtechniquesoffabricationarenecessary,particularlyintheconstructionofwings.The
increaseinwingloadingfromabout350N/m^2 for1917–1918aircrafttoaround4800N/m^2 formodern
aircraft,coupledwithadropinthestructuralpercentageofthetotalweightfrom30to40to22to25
percent,givessomeindicationoftheimprovementsinmaterialsandstructuraldesign.
Forpurposesofconstruction,aircraftaredividedintoanumberofsubassemblies.Thesearebuilt
inspeciallydesignedjigs,possiblyindifferentpartsofthefactoryorevendifferentfactories,before
beingforwardedtothefinalassemblyshop.Atypicalbreakdownintosubassembliesofamedium-sized
civil aircraft is shown in Fig. 11.8. Each subassembly relies on numerous minor assemblies such as
sparwebs,ribs,andframes,andthese,inturn,aresuppliedwithindividualcomponentsfromthedetail
workshop.