NATIONALAERONAUTICSANDSPACEADMINISTRATION•WASHINGTON,D.C.•DI!CEMBER1974 94035 D.H.HodgesandE.H.DowellAmesResearchCenterandU.S.ArmyAirMobilityR&DLaboratoryMoffettField,Calif NONLINEAREQUATIONSOFMOTIONFORTHEELASTICBENDINGANDTORSIONOFTWISTEDNONUNIFORMROTORBL