小型共轴式直升机旋翼桨叶铰链力矩研究

从工程实际出发,建立了共轴双旋翼直升机桨叶铰链力矩计算模型.引入Leishman-Beddoes指数函数的半经验公式,建立了二维翼型非定常气动模型;引入干扰因子到Pitt-Peters动态入流模型,建立了反映共轴双旋翼直升机上下旋翼气动干扰的诱导速度模型;从桨叶的挥舞动力学模型出发,利用四阶Runge-Kutta算法求解桨叶刚性挥舞角的数值解,并利用模态叠加法计算桨叶的挥舞向变形.最后,通过对在研共轴直升机的计算得知,上下旋翼桨叶铰链力矩虽然在分量上有所差异,但是总的铰链力矩基本相同;中高速飞行时,上下旋翼桨叶铰链力矩在下倾斜盘累积成为使下倾斜盘前倾的力矩. 

Research on rotor blade hinge moment of a small-scale coaxial helicopter

Based on the engineering reality,a calculation model of the rotor blades hinge moment about coaxial helicopter was set up.An airfoil unsteady aerodynamic model was established by introducing a set of Leishman-Beddoes semi-empirical indicial response formula.The induced velocity model of the aerodynamic interaction between upper and lower rotors of a coaxial helicopter was created by introducing an interferential factor into the Pitt-Peters dynamic inflow model;the Runge-Kutta method was used to obtain the numerical solution of the rigid blade flapping angle,and a modal superposition method used to calculate the distortion of the flapping direction.According to analysis of the coaxial helicopter,the total hinge moment is basically the same,although the partial hinge moments of upper and lower rotors are different.In medium and high speed,the hinge moments of upper and lower rotors are accumulated at the lower swashplate to form a moment making the lower swashplate lean forward.