Vertical landing of a fixed-wing UAV using the flat spin

This paper studies a feasibility of a novel landing method especially in a limited space for an ordinary Unmanned Aerial Vehicle (UAV) using the flat spin. Use of the combination of an all-flying tail with large deflection angle has been found effective for quick intentional flat spin entry, and the higher propeller rotational speed as well as the high all-flying tail deflection angle has been also found effective for flatter or even positive pitch attitude during the spin. One of the key issues to realize flat-spin landing is to control its descent path toward the desired landing point. The influences of change in pitch attitude on the descent path are examined in flight tests, and the periodic pitch attitude change caused by the deflection of the all-flying tail with full throttle was found effective for the descent path control.