Control of Helicopter Rotor Blade Dynamic Stall and Hub Vibration Loads by Multiple Trailing Edge Flaps

Abstract

Delaying dynamic stall and reducing rotor-hub vibration loads are important ways to increase the forward speed and improve the flight performances of a helicopter.This paper investigate effective methods for the simultaneous control of the dynamic stall of retreating blade and rotor-hub vibration loads in the high-speed and high load conditions of a helicopter by using multiple trailing edge flaps.Structural dynamic models of the elastic blade and the rigid trailing edge flap are established.The blade section aerodynamic loads are calculated by using the Leishman-Beddoes two-dimensional unsteady dynamic stall model and the trailing edge flap section aerodynamic loads are calculated by using the Hariharan-Leishman two-dimensional subsonic unsteady aerodynamic model.The aeroelastic responses of the rotor system are solved by combining the Galerkin and numerical integration methods.The effective control strategies and control methods of multiple trailing edge flaps are established.The motion laws of the three trailing edge flaps and their control effects on the retreating blade dynamic stall and rotor hub vibration loads are analyzed.The analytical results show that application of the motion of the multiple trailing edge flaps is an effective way to control the retreating blade dynamic stall and the rotor hub vibration loads.