'Embedded' coaxial rotor fixed wing tail sitter is French MAV focus

Source: Flightglobal.com
This story is sourced from Flightglobal.com

A micro air vehicle (MAV) the size of an apple that is rolled into a building, rights itself, takes-off from a tail-sitting position and flies through the interior sending back images, is the goal of researchers at Toulouse, France-based Institut Superieur de l'Aeronautique et de l'Espace.

A 35cm (13.7in) diameter prototype embedded coaxial rotor MAV has been test-flown by ISAE researchers. The MAV has an outer wire structure within which is embedded a coaxial rotor tail sitter vehicle with its flaps within the rotors' slipstream.

The wires for the rotors' motors are passed through the wire structure and the payload is at its base. In future the development team wants to avoid the through-shaft system associated with coaxial rotors and the payload's location may change.

"We are working on a 20cm diameter 100g (3.52oz) prototype," says ISAE aerodynamics professor, Jean-Marc Moschetta. Tail sitters are an option for a fixed wing vehicle that can hover, fly slowly and transition to rapid forward flight.

The tail-sitting MAV design was one of a several types analysed by Moschetta's team. MAV tilt rotor, tilt wing and tilt body systems have also been evaluated for hovering fixed wing vehicles. While the tilt rotor option was rejected early on, the study's conclusion was that the tilt body variant was preferable to tilt wing.

The ISAE work will be aided next year by the installation of a 4.5m (14.7ft)-wide, 19m-long wind tunnel designed for MAVs.