Testing study on aerodynamics and control characteristics of a small unmanned tilt rotor

It is very difficult to determine the aerodynamics and control characteristics theoretically for tiltrotor aircraft because of multi-flight modes, complexity of aerodynamic interactions, and redundancy of control surfaces. Especially for the tilting flight mode, the layout of the aircraft is transformed between the helicopter mode and the fixed-wing airplane mode with the nacelle driven rotor system tilting. In order to investigate the aerodynamics and control characteristics, the full-span and full-envelop flight modes of a small unmanned tilt rotor are tested in wind-tunnel prior to flight. The un-powered test is mainly determining the flight characteristics with different attack angles, nacelle angles and forward speeds. The powered test is focused on the aerodynamic interactions among rotor, wing and flaperon wing, with and without wings, as well as the efficacy manipulation of the collective aileron and elevator. According to the experimental data, the full-envelop flight control characteristics for the tiltrotor is deduced, improves aircraft designing, and provides a priori knowledge for successful flight tests.