The Williams X-Jet, created by Williams International, was a small, one-man, light-weight, Vertical Take Off and Landing (VTOL) aircraft powered by a modified Williams F107 turbofan aircraft engine designated WR-19-7 after some minor modifications. The vehicle was nicknamed "The Flying Pulpit" for its shape, apparently. It was designed to be operated by / carry one person and dirigible by leaning in the direction of desired travel together with the modulation of its input power. It could move in any direction, accelerate rapidly, hover and rotate on its axis, stay aloft for up to 45 minutes and travel at speeds up to 60 miles per hour (97 km/h). It was evaluated by the U.S. Army in the 1980s, but was deemed inferior to the capabilities of helicopters and small, unmanned aircraft and so the development of the X-Jet was discontinued.
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 X-Jet's predecessor, the WASP I (Williams Aerial Systems Platform) which developed in the 1970s and was powered by the more powerful WR19-9 BRP5 (rated at 670 lbs thrust and a great SFC of just .47 lbs/lb/hr). The US PATENT NUMBER 4,447,024 is designated for the Williams X-Jet. Technical information and drawings are available at the United States Patent and Trademark Office. The WASP II uses a slightly modified and derated version of the WR-19-A7D which yields 600 lbs thrust from its micro turbofan engine and is designated WR19-7 ― rated at 570 lbs thrust, after minor modifications and said derating. Modifications to the WR-19-A7D included accessories (replacement of 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 conducted in April 1980. Ray Le Grande is one of the WASP II operators trained by Williams International to fly the X-Jet.