Efficient Method for Helicopter Rotor Transient Aerodynamic Response
Wang Hai,Xu Guohua
(National Key Laboratory of Rotorcraft Aerodynamics, Nanjing University of Aeron autics and Astronautics, Nanjing 210016, China)

Abstract: An efficient method is presented to evaluate the rotor transient response to a ramp increase in collective pitch in vertical flight, where the unsteady effects of the blade flap motion and dynamic inflow on rotor thrust are taken into account based on the blade element/momentum theory, which is suitable for analyses of transient variation of rotor thrust, blade flap motion and induced velocity. To validate the proposed method, the calculations for rotor aerodyn amic responses following a step increase in collective for three situations are carried out and compared with the available experimental data. The effects of the offset of blade flap hinge on the dynamic response are examined, and the diffe rent transient responses to the step increase and decrease in collective for an articulated rotor are analyzed comparatively.
Keywords: rotor, helicopter, aerodynamic response, ramp increase in collective.