Flight performance of compound helicopter with twin propellers

A compound helicopter trim model with aerodynamic models of propeller and wing based on flight performance model of helicopter was constructed to investigate the effect of propeller and wing on the performance of compound helicopter with twin propellers. Taking the X-3 helicopter as an example, by adding different configurations of propeller and wing, the changes of each control strategy and attitude angle of the helicopter were given, and the effect of the variable proportions of propeller's thrust and wing's lift on the helicopter power required and helicopter lift-to-drag coefficient was analysed. Result showed that wing was useful to raise obviously peak lift-to-drag ratio, and also reduce collective and lateral cyclic pitch. The propeller could only improve the peak lift-to-drag ratio and reduce the helicopter power required until the flight speed is up to certain speed. The final compound helicopter configurated with propeller and wing could reliably achieve the less helicopter power required just by reasonably distributing thrust and lift, thereby improving the flight performance of the compound helicopter. © 2020, Editorial Department of Journal of Aerospace Power. All right reserved.