Boeing X-50

infobox Aircraft
name = X-50
type = gyrodyne unmanned aerial vehicle

manufacturer = Boeing



caption = First flight of the Boeing X-50A
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The Boeing X-50 Dragonfly, formerly known as the Canard Rotor/Wing Demonstrator, is a gyrodyne unmanned aerial vehicle that was being developed by Boeing and DARPA to demonstrate the principle that a helicopter's rotor can be stopped in flight and act as a fixed wing. The X-50A builds upon the work of the Sikorsky S-72 X-Wing program of the 1980s by designing the vehicle as a multi-mode aircraft from the ground up. The X-50A is one of two projects funded by DARPA in its "Heliplane" program.

Development

The X-50A was a joint program between Boeing and DARPA, with each paying for half the development costs. The X-50A is powered by a single conventional turbofan engine. For rotary-wing mode, the engine's exhaust is diverted to nozzles in the tips of the rotor blades. When the aircraft transitions to full forward flight, the engine exhaust is directed through a nozzle at the rear of the aircraft and the rotor is locked into a fixed position and functions as a conventional wing.McKenna, James T. "One Step Beyond", "Rotor & Wing", February, 2007, page 54] Two proof-of-concept aircraft were built as part of the program. The X-50A's maiden flight took place on 24 November, 2003.

Crashes

During the third flight of the prototype X-50A, on 23 March, 2004, the vehicle crashed, as a result of cross-coupling in the controls.

A second, improved prototype (Ship 2) was then built. On its sixth of 11 planned test flights, Ship 2 was completely destroyed in a crash at the Yuma Proving Grounds on April 12, 2006. Subsequent investigation revealed that the aircraft's fuselage was subject to an aerodynamic pitching moment of extreme sensitivity. Both airspeed and rotor wake would produce a nose-up pitching motion that was greater than the flight controls could compensate for.

Outcome

Neither aircraft was able to achieve transition to full forward flight mode during the portions of the test flight program that were completed. In September, 2006, DARPA recognized the inherent design flaws and withdrew funding for the program.

pecifications

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empty weight kg=574
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gross weight kg=645
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eng1 type=Williams Research F-112
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max speed kmh=700
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cruise speed kmh=278
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* Tail unit span: 2.47m
* Fuel weight: 66kg
* Max payload: 91kg

ee also

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* Sikorsky X-Wing

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References

External links

* [http://www.boeing.com/news/frontiers/archive/2002/may/ts_pw.html Boeing press release]
* [http://www.boeing.com/phantom/news/2005/q4/nr_051205a.html Boeing press release 2]
* [http://www.boeing.com/companyoffices/gallery/images/military/unmanned/dvd-128-01.html Large image of the X-50A]
* [http://avia.russian.ee/helicopters_eng/boeing_x-50-r.html Information about X-50A]
* [http://people.nas.nasa.gov/~aftosmis/publications/aiaa2001-0997.pdf Additional technical information]