France’s Supaero aeronautics university and the University of Arizona, Tuscon, have successfully flown a tail-sitting micro air vehicle (MAV) through a full cycle of take-off and transition to horizontal flight. The remotely controlled flights were carried out last month at a Supaero facility, and included both indoor and outdoor testing.
The design could result in a smaller version: “We could do this with a 15cm [6in] span instead of 30cm,” University of Arizona professor of aerospace and mechanical engineering Sergey Shkarayev told the US-European MAV competition and workshop in Toulouse, France on 17 September.
The Zimmerman (or elliptical) wing MAV has a 30cm span, with its power train comprising twin electric motors driving twin coaxially mounted, contra-rotating propellers. The propellers each have a 15 x 10cm pitch. The air vehicle is able to rotate on its axis by applying differential power to each rotor. Each engine can deliver 12,000rpm, with a combined power draw of 60W, although 100W is available.
A single propeller would have resulted in inadequate torque, resulting in only the turning of the MAV body and no lift, according to development team researchers. The airframe also incorporates a rudder and two ailerons.
The project is being funded by the US Air Force's Research Laboratory and its European office of aerospace research and development.
The air vehicle’s mission would be to conduct urban operations, including inside buildings. The MAV needs to be able to fly at low speed, hover and carry out rapid target zone ingress and egress. Shkarayev said that prior to adoption of the tail sitter concept, both tiltrotor and thrust-vectoring MAV designs were also considered.
Source: Flight International