Vector ducted propeller aerodynamic modeling and verification testing

Abstract

The tail-sitter aircraft has the advantages of both high-speed cruise and capability of the take-off and land vertically, high-performance control laws usually rely on the accurate flight mechanics model, while its flight aerodynamic modeling is a complex problem. This paper analytically develops an aerodynamic model of its propelling system based on first principles, including three components of a propeller, a vector duct, and eight slipstream vanes. This model can give the propeller’s induced velocity, power, thrust, and moment, also considers the augmented effect of ducted, and the lift and drag forces of vanes. Moreover, a propelling system test bed is built to measure the forces and moments along the body frame, which is composed of the tail-sitter prototype, power, communication link, upper system, and servo drive device. In addition, experimental results show the effectiveness of the model in estimating the thrust and torque with different angles of control vanes, the measured thrust is consistent with the calculated values, and the steering performance of each vane is further examined. The moments exerted on the two axes are linear with the vanes angles, and the symmetry is also well, which is convenient for flight controller design for this type of tail-sitter aircraft.