自转旋翼机跳飞的旋翼诱导速度分布研究

提出了一种自转旋翼机跳飞的旋翼叶素诱导速度随时间和径向站位的分布规律的分析方法.基于叶素理论和动量理论，建立总距突增时旋翼瞬态拉力和动态诱导速度的响应模型，通过NACA试验验证模型有效性.将响应模型引入考虑地面效应的自转旋翼机跳飞动力学模型，以总距突增和地面效应在跳飞中作用时间的起始点作为动力学模型数值求解的分段点求解方程.使用动力学模型对试验样机的跳飞性能进行仿真，并试验验证模型准确度.利用跳飞模型计算出试验样机跳飞中旋翼叶素诱导速度并分析其分布规律.结果表明某站位处诱导速度与时间的关系先呈线性后呈抛物线，某时刻诱导速度与径向站位近似呈线性. 

Distribution Research on Rotor Induced Velocity in Gyroplane Jump Takeoff

A method was proposed to analyze the distribution principle of the induced velocity varying with the jump time and radial stand position in gyroplane. A novel response model was developed based on blade element theory and momentum theory for the dynamic induced velocity and transient thrust of rotor following a rapid blade-pitch increase, and it was experimentally validated with NACA data. Then the response model was introduced into a nonlinear jump takeoff model considering the ground effect of gyroplane. The piecewise numerical solution of the jump model was got by regarding the beginning and ending time as the piecewise point. The simulation results of a small scaled jump takeoff platform show good agreement with experiment data. Finally, the rotor induced velocity distribution of the test platform was worked out with the jump takeoff model. Results show that the induced velocity is a linear then parabola time function at the same radial stand position and an approximate linear function of the radial stand position at the same time.