Introduction to Aircraft Structural Analysis (Elsevier Aerospace Engineering)

13.3 Normal Accelerations Associated with Various Types of Maneuver 391

13.3 NormalAccelerationsAssociatedwithVariousTypesofManeuver..........................

InSection13.2,wedeterminedaircraftloadscorrespondingtoagivenmaneuverloadfactorn.Clearly,
itisnecessarytorelatethisloadfactortogiventypesofmaneuver.Twocasesarise:thefirst,involving
a steady pull-out from a dive and the second, a correctly banked turn. Although the latter is not a
symmetricmaneuverinthestrictsenseoftheword,itgivesrisetonormalaccelerationsintheplaneof
symmetryandisthereforeincluded.

13.3.1 Steady Pull-Out

Letussupposethattheaircrafthasjustbegunitspull-outfromadivesothatitisdescribingacurved
flightpathbutisnotyetatitslowestpoint.Theloadsactingontheaircraftatthisstageofthemaneuver
areshowninFig.13.9,whereRistheradiusofcurvatureoftheflightpath.Inthiscase,theliftvector
mustequilibratethenormal(totheflightpath)componentoftheaircraftweightandprovidetheforce
producingthecentripetalaccelerationV^2 /Roftheaircrafttowardthecenterofcurvatureoftheflight
path.Thus,

L=

WV^2

gR

+Wcosθ

Fig.13.9

Aircraft loads and acceleration during a steady pull-out.