Aerodynamic investigations of the Freewing Tilt-Body UAV

Abstract

The Freewing UAV by Freewing Aerial Robotics Corporation has demonstrated stability, gust alleviation, and near VTOL characteristics. However, limitations in existing analytic models constrain the development of model-based autopilots and design refinements. Presently, there is a need to further evaluate the vehicle's aerodynamic properties and control characteristics to enable the development of a reliable analytical model to be used in flight control. A 20% scaled model of the Freewing Tilt-Body vehicle was developed and tested to evaluate its aerodynamic properties and the effects of self-induced flows on the performance of the aircraft. Wind tunnel tests for validation and evaluation of various flight conditions and configurations were carried out. Particular attention has been paid to evaluating high angle of attack flight. The wind tunnel model is fully powered with moveable control surfaces and is instrumented with transducers for real time measurements of Freewing and propeller motion. An external three component balance is used for force and moment measurements as well as multi-hole probes for flow surveys. The tests were conducted using Aero View, a multi-media interactive flow-diagnostics environment.