The Demon is a UAV designed by BAE Systems, as part of its "FLAVIIR" project. It has a novel aerodynamic control system which uses engine exhaust and bleed air to provide the aerodynamic forces usually provided by flaps, ailerons and elevators. It has been called the world's first "flapless" plane. It first flew, from Walney Island, off the coast of Cumbria, UK on 17 September 2010.
The unique circulation control system could be employed to reduce the size of the wing on widebody airliners. Its developers hope that the new design could reduce noise, cut fuel and lower maintenance costs. For military fast jets the technology might help to achieve greater stealth.
The so-called "fluidic flight controls" guide air from a rectangular exhaust nozzle over upper and lower Coandă effect surfaces to establish pitch. For roll control, bleed air is blown over a Coanda surface installed on the trailing edge of the wing. By controlling boundary layer conditions, the fluidic controls can also provide greater lift or drag on take-off and landing.