Experimental Study on the Application of Flat Spin to Vertical Landing of a Fixed-Wing Small UAV

抄録

The flat spin of a fixed-wing airplane is usually considered to be dangerous, and should be avoided by all means. However, an airplane in a flat spin descends almost vertically and relatively slowly. It can be used as a means of vertical landing, especially for a small fixed-wing unmanned aerial vehicle. Controlling the impact speed to the ground and touchdown position is necessary to realize the application of flat-spin landing. A large pitch-up moment generated by the combination of an all-flying tail and the gyro precession due to the yawing motion generated by the so-called P-factor of the propeller rotation was found to be effective not only for the rapid entry into flat spin, but also to control the pitch attitude and rate of descent during a flat spin. In this paper, the results regarding the relationships among the deflection angle of the all-flying tail, the rotational speed of the propeller, the spin rate, and the rate of descent obtained by flight tests using a small unmanned aerial vehicle are presented as fundamental knowledge towards the realization of practical flat-spin landing.