UK-developed single-seat aircraft uses tilt-wing technology to transition to forward flight
Tethered tests of a privately developed single-seat vertical take-off and landing (VTOL) aircraft are due to start in the UK next week.
The Kestrel VTOL prototype uses electrically powered ducted fans for vertical and horizontal flight. Developer Kestrel Aerospace - formed in September 2003 and based in Staffordshire - aims to sell the Kestrel for around £75,000 ($134,000).
Chief technology officer Simon Scott says that, although the single-seater is being tested, "it could be the unmanned-air-vehicle version that will arrive sooner rather than later". The company also plans to develop a cargo variant that uses twice as many ducted fans.
The prototype Kestrel VTOL has a paraglider petrol engine that generates 40kW of electricity. This is used in conjunction with a battery and a high-power capacitor. The energy generated on board powers the avionics and the two ducted fans on the tilting wing, which sits atop the airframe and is moved by electrical actuators. There are two impeller electrical motors within each ducted fan. One motor powers the small impeller and, above that, a more powerful motor turns the larger impeller.
This combination of counter-rotating large impellers and small impellers is key to the design, says Scott. Once hovering, the tilt wing moves to an angle of 60° and the thrust from the smaller impeller is diverted horizontally, giving forward thrust.
The cockpit interior is complete and the ducts arrive this week and next week. Scott will not disclose the funding the company has raised so far, but says: "New investors are waiting for the tethered tests to be completed."
ROB COPPINGER / LONDON
Source: Flight International
