The UK's Kestrel Aerospace is one of a number of specialist technology companies with personal air vehicle (PAV) prototypes waiting in the wings. Kestrel has designed a single-seat aircraft based around its patented electrically-powered vertical take-off and landing propulsion system (Flight International, 18-24 May 2004).
The Stoke-on-Trent-based business, founded 18 months ago by former soldier Simon Scott, has won a contract to supply its propulsion system to Californian wireless communications airship developer Sanswire, and is about to put an unmanned air vehicle, using the same technology, on the market in the next few months. Scott says the PAV prototype - which weighs 295kg (650lb) without a pilot - will be ready for hover testing within six months.
In the Netherlands, Spark Design is seeking investors to raise €10 million ($12.7 million) to build its proof-of-concept motorcycle gyrocopter chimera. Known as the personal air and land vehicle (PALV), its designers say it would use the Renesis rotary engine from Mazda's MX-8 sports car and reach 108kt (200km/h) on land and in the air, produce 70dB in noise, use its V/STOL capabilities on roads and fly below 4,000ft (1,220m). If it is certificated, Spark Design would have it manufactured in Canada under licence for the US market for cost reasons.
At the other end of the PAV spectrum is the UK-designed personal twinjet Jetpod P-200. With computational fluid dynamics analysis conducted by City University, this wholly composite vehicle is said by its developer, UK-based Avcen, to have a planned certification date of around 2008. Although there are unmanned air vehicle and military versions of the Jetpod, it is the P-200 that would operate as a commuter's vehicle.
The strangest design of the European designs, however, is the most advanced in terms of proof-of-concept vehicle development and flight testing. Known as the Fanwing, it was unveiled by its inventor, Patrick Peebles, at the 2004 Farnborough air show. Neither a fixed-wing aircraft nor a rotorcraft, it has a 2.2m bladed rotor on a horizontal axis that acts as a thick wing. These blades, rotated by an engine at up to 2,000RPM, suck in air and push it up and over the wing, providing lift. This strange mode of operation was proven to be possible in tests at Imperial College in London in 2002. Its inventor's plan is to have future versions with enough power to take off vertically and operate like a helicopter. Peebles is upgrading the engine from a two-cycle alcohol unit to a four-cycle petrol motor, providing sufficient power to achieve a short take-off and landing capability. He is hoping to gain government support following successful trials with the new engine later this year. He is approaching the US government for funding to develop the Fanwing as a UAV.
In the USA, California-based inventor Attila Melkuti is working on a vertical take-off and landing PAV, dubbed the AMV 211, powered by a ducted fan. The 2.38m-diameter fan is driven by a 440shp (330kW) Mazda rotary engine, and mounted horizontally to provide vertical lift. Louvred ducts beneath the fan will be used to vector the thrust, while the entire vehicle will pitch at an angle of around 26¡ for forward flight.
NASA-supported projects, with Small Business Innovative Research grants, include Barnaby Wainfan's Facetmobile and Jay Carter's CarterCopter. The Facetmobile is a delta-shaped blended-wing design, similar to the Lockheed Martin F-117, and reportedly inspired by the Dyke Delta, a home-built delta-winged aircraft from the early 1960s. The CarterCopter is a high-speed autogyro design with a pusher propeller and weighted rotor tips to increase stability at low rotation speeds. The Texas-based company has flown the aircraft to speeds of 150kt (280km/h), but continues to encounter development problems having suffered a series of crashes in test flights.
A veteran of the PAV concept, Paul Moller, continues his crusade to develop the ducted-fan M400 Skycar, having briefly flown a demonstrator powered by eight 150shp rotary engines in California last year. The developer has run into financial problems, however, having been forced to settle a suit filed by the US Securities and Exchange Commission for selling unregistered securities.
Other ducted lift-fan PAV projects either in development or seeking fresh support include the Macro Industries SkyRider X2R and Urban Aeronautics X-Hawk. Israel-based Urban Aeronautics has completed more than 10h of hover tests of its CityHawk concept demonstrator, and aims to develop medevac and police patrol X-Hawk variants. The "Hawk" vehicles use a patented vane-control system to duct thrust from dual lift fans, and are similar in concept to the Piasecki V2-8 "Flying Jeep".
Huntsville, Alabama-based Macro Industries is, meanwhile, "seeking investors" for its vertical take-off and landing SkyRider X2R concept.
GUY NORRIS / LOS ANGELES & ROB COPPINGER / LONDON