Williams X-Jet
{{Short description|Single-person lightweight aircraft}}
{{No footnotes|date=March 2014}}
File:Williams X-Jet - side view.jpg
The Williams X-Jet, created by Williams International, was a small, single-person, 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. It was designed to carry one operator and to be controlled by leaning in the direction of desired travel and by modulating engine output 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 United States Army in the 1980s, but was deemed inferior to the capabilities of helicopters and small, uncrewed 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 was developed in the 1970s and was powered by the more powerful WR19-9 BRP5, rated at 670 lbf (2.98 kN) thrust and a specific fuel consumption of 0.47 lb/lbf·h (13.31 g/kN·s).
{{US patent|4447024}} was issued 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, yielding 600 lbf thrust from its micro turbofan engine and is designated WR19-7, rated at 570 lbf 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 crewed, 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.
Specifications (X-Jet)
{{Aircraft specs
|ref={{citation needed|date=March 2020}}
|prime units?=kts
|crew=1
|length ft=3
|length in=
|length note=approx.
|width ft=
|width in=
|width note=
|height ft=4
|height in=0
|height note=
|empty weight lb=401
|empty weight note=
|gross weight lb=550
|gross weight note=
|max takeoff weight lb=
|max takeoff weight note=
|fuel capacity=
|more general=
|eng1 number=1
|eng1 name=Williams F107
|eng1 type=turbofan engine
|eng1 lbf=570
|eng1 note=(modified)
|max speed kts=52
|max speed note=
|max speed mach=
|cruise speed kts=
|cruise speed note=
|never exceed speed kts=
|never exceed speed note=
|range nmi=
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|ferry range nmi=
|ferry range note=
|endurance=30–45 minutes
|ceiling ft=10000
|ceiling note=
|climb rate ftmin=
|climb rate note=
|time to altitude=
|wing loading lb/sqft=
|wing loading note=
|fuel consumption lb/mi=
|thrust/weight=1.11
|more performance=
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}}
See also
Notes
{{Reflist}}
References
- Display information at Museum of Flight in Seattle, Washington.
- [https://www.theguardian.com/science/2000/sep/14/technology2 Guardian article]
- [https://www.nationalmuseum.af.mil/ nationalmuseum.af.mil]
- 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)