Aerodynamic Modeling of the Wing-Propeller Interaction for a Tail-Sitter Unmanned Air Vehicle

Abstract

This paper considers the aerodynamic modeling of a twin-engine tail-sitter unmanned air vehicle that relies on wing- and fin-mounted control surfaces submerged in the propeller slipstreams for control during low-speed vertical flight The aerodynamic forces on this vehicle are predicted using a full azimuthal blade-element solution for the propellers combined with a fixed-wake panel-method model of the vehicle itself. When the flow components determined from the propeller solution are superimposed on the external flowfield and integrated with the panel-method model, the aerodynamic forces can be determined for the full vehicle, including slipstream effects, which are dominant in low-speed flight. The modeling described in this paper has been used extensively for multidisciplinary optimization work, as well as in the construction of a comprehensive aerodynamic database for the vehicle. This database encompasses all the aerodynamic force and moment coefficients and their derivatives for over 4300 separate flight conditions and has been extensively used for vehicle simulation and control design purposes.