Aerodynamic Design and Characterization of a Quad Tilt-Wing UAV via Wind Tunnel Tests

Abstract

This paper presents aerodynamic design and characterization of a new quad tilt-wing unmanned aerial vehicle [Sabanci University unmanned aerial vehicle (SUAVI)] through wind tunnel tests and provides experimental data for the design of similar aerial platforms. SUAVI is capable of vertical takeoff and landing (VTOL) and horizontal flight, and it can perform both indoor and outdoor surveillance. Aerodynamic design of the vehicle directly affects its operational performance, including flight stability and flight duration in vertical, transition, and horizontal flight modes. Selection of the propulsion system and determination of the shape of the fuselage and the wings are done in an optimal manner by taking several aerodynamic criteria into account. Flow simulations reveal that the rear wings are affected by the downwash of the front wings. To solve this problem, the rear wings are placed at a higher incidence angle than the front wings. Wind tunnel tests are performed to measure the lift and drag forces and pitching moments for level flight in the entire speed range. Furthermore, the rear and front motor throttle settings and the wing incidence angle combinations for the nominal flight are measured and tabulated. To eliminate undesired spanwise air flows at the wing tips, several winglets with different shapes and sizes are introduced, and the optimum winglet is developed by several simulations and experiments. Some of the results presented in this paper are novel contributions to the literature and can be used in the design of new hybrid unmanned aerial vehicles (UAVs).