Quad Tilt Wing VTOL UAV: Aerodynamic Characteristics and Prototype Flight

A QTW VTOL UAV, featured tandem tilt wings and propellers mounted at the mid-span of each wing, is one of the most promising UAV configurations having both a VTOL capability and high cruise performance. A small prototype QTW UAV has been constructed to prove the concept and full transition between vertical and horizontal flight has been successfully demonstrated under remote manual control. The essential aerodynamic characteristics of the QTW derived from wind tunnel data are summarized in this paper, and a tandem wing concept which achieves both hovering and cruising stability has been applied to design the prototype UAV. A flight control system allowing continuous control through all flight phases enabled a pilot to perform vertical take-off, accelerating transition, cruise, decelerating transition and hover landing, with sufficient flying qualities.