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The Williams X-Jet, created by Williams International, was a small, light-weight Vertical Take Off and Landing (VTOL) system powered by a modified Williams WR-19-A7D turbofan aircraft engine designated WR-19-7 after minor modifications. This vehicle was nicknamed "The Flying Pulpit". It was designed to be operated by and carry one person and controlled by leaning in the direction of desired travel and adjusting the power. It could move in any direction, accelerate rapidly, hover, and rotate on its axis, staying aloft for up to 45 minutes and traveling at speeds up to 60 miles per hour (100 km/h). It was evaluated by the U.S. Army in the 1980s, and was deemed inferior to the capabilities of helicopters and small unmanned aircraft.
Other VTOL systems developed by Williams International included a jet-powered flying belt developed in 1969, which was powered by a Williams WR19 turbofan, and the WASP I (Williams Aerial Systems Platform) developed in the 1970s, which was powered by the more powerful WR19-9 BRP5 (rated at 670 lbst and a great SFC of just .47lbs/lb/hr).
Specifications (X-Jet) 
- Crew: One pilot
- Length: ft (m)
- Wingspan: ft (m)
- Height: 4 ft 0 in (1.22 m)
- Footprint: 4 ft² (0.4 m²))
- Wing area: ft² (m²)
- Empty weight: 401 lb (182 kg)
- Loaded weight: 550 lb (250 kg)
- Max. takeoff weight: lb (kg)
- Powerplant: 1 × modified Williams WR-19 turbofan, 570 lbf (2.6 kN)
- Maximum speed: 60 mph (96 km/h)
- Range: endurance of 30-45 minutes ()
- Service ceiling: 10,000 ft (3,049 m)
- Rate of climb: ft/min (m/s)
- Wing loading: lb/ft² (kg/m²)
- Thrust/weight: 1.11
US PATENT NUMBER 4,447,024 for this Airborne Vehicle and Technical Information and Drawings is available at the USPTO. The WASP II uses a slightly modified and derated version of the WR-19-A7D (600 lbs thrust class micro turbofan engine which is designated WR19-7 (rated at 570 lbst) after minor modifications and a slight derating. Modifications to the WR-19-A7D included Accessory (replaced Pyro starter with electric/air start) and exhaust system modifications. No internal modifications to the counter-rotating micro turbofans were performed. The first manned untethered flight was made in April 1980. Ray Le Grande is one of the WASP II Operators trained by Williams International to fly the WASP II.
- Display information at Museum of Flight in Seattle, Washington.
- Guardian article
- The History of North American Small Gas Turbine Aircraft Engines by Richard A Leyes II and William A Fleming (ISBN 1-56347-332-1 Copyright 1999)
See also 
- Aircraft of comparable role, configuration and era