Boeing X-50
Encyclopedia
The Boeing X-50A Dragonfly, formerly known as the Canard Rotor/Wing
Demonstrator, was a gyrodyne unmanned aerial vehicle
that was developed by Boeing
and DARPA to demonstrate the principle that a helicopter's rotor
could be stopped in flight and act as a fixed wing. The X-50A built 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 was one of two projects funded by DARPA in its "Heliplane" program.
Neither of the two prototype aircraft ever successfully transitioned to full forward flight. DARPA withdrew funding for the X-50 program in late 2006 due to inherent design flaws.
engine. For rotary-wing mode, the engine's exhaust was diverted to nozzles in the tips of the rotor blades. When the aircraft transitioned to full forward flight, the engine exhaust was directed through a nozzle at the rear of the aircraft and the rotor was locked into a fixed position and functioned as a conventional wing. Two proof-of-concept aircraft were built as part of the program. The X-50A's maiden flight took place on 24 November 2003.
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.
Canard Rotor/Wing
The Canard Rotor/Wing is a class of VTOL aircraft capable of both fixed-wing and rotary-wing flight. For vertical take-off, hovering, low-speed flight, and vertical landing, the main airfoil is spun like a helicopter's rotor by directing the exhaust from a jet engine through thrust nozzles in the...
Demonstrator, was a gyrodyne unmanned aerial vehicle
Unmanned aerial vehicle
An unmanned aerial vehicle , also known as a unmanned aircraft system , remotely piloted aircraft or unmanned aircraft, is a machine which functions either by the remote control of a navigator or pilot or autonomously, that is, as a self-directing entity...
that was developed by Boeing
Boeing
The Boeing Company is an American multinational aerospace and defense corporation, founded in 1916 by William E. Boeing in Seattle, Washington. Boeing has expanded over the years, merging with McDonnell Douglas in 1997. Boeing Corporate headquarters has been in Chicago, Illinois since 2001...
and DARPA to demonstrate the principle that a helicopter's rotor
Helicopter rotor
A helicopter main rotor or rotor system is a type of fan that is used to generate both the aerodynamic lift force that supports the weight of the helicopter, and thrust which counteracts aerodynamic drag in forward flight...
could be stopped in flight and act as a fixed wing. The X-50A built upon the work of the Sikorsky S-72 X-Wing
Sikorsky S-72
|-See also:-External links:* * *...
program of the 1980s by designing the vehicle as a multi-mode aircraft from the ground up. The X-50A was one of two projects funded by DARPA in its "Heliplane" program.
Neither of the two prototype aircraft ever successfully transitioned to full forward flight. DARPA withdrew funding for the X-50 program in late 2006 due to inherent design flaws.
Development
The X-50A was a joint program between Boeing and DARPA, with each paying for half the development costs. The X-50A was powered by a single conventional turbofanTurbofan
The turbofan is a type of airbreathing jet engine that is widely used for aircraft propulsion. A turbofan combines two types of engines, the turbo portion which is a conventional gas turbine engine, and the fan, a propeller-like ducted fan...
engine. For rotary-wing mode, the engine's exhaust was diverted to nozzles in the tips of the rotor blades. When the aircraft transitioned to full forward flight, the engine exhaust was directed through a nozzle at the rear of the aircraft and the rotor was locked into a fixed position and functioned as a conventional wing. 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
Fuselage
The fuselage is an aircraft's main body section that holds crew and passengers or cargo. In single-engine aircraft it will usually contain an engine, although in some amphibious aircraft the single engine is mounted on a pylon attached to the fuselage which in turn is used as a floating hull...
was subject to an aerodynamic pitching moment
Pitching moment
In aerodynamics, the pitching moment on an airfoil is the moment produced by the aerodynamic force on the airfoil if that aerodynamic force is considered to be applied, not at the center of pressure, but at the aerodynamic center of the airfoil...
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.Specifications
- Tail unit span: 2.47m
- Fuel weight: 66 kg
- Max payload: 91 kg
See also
- Unmanned aerial vehicleUnmanned aerial vehicleAn unmanned aerial vehicle , also known as a unmanned aircraft system , remotely piloted aircraft or unmanned aircraft, is a machine which functions either by the remote control of a navigator or pilot or autonomously, that is, as a self-directing entity...
- Aerial reconnaissanceAerial reconnaissanceAerial reconnaissance is reconnaissance that is conducted using unmanned aerial vehicles or reconnaissance aircraft. Their roles are to collect imagery intelligence, signals intelligence and measurement and signature intelligence...
- Sikorsky X-WingSikorsky S-72|-See also:-External links:* * *...
- SurveillanceSurveillanceSurveillance is the monitoring of the behavior, activities, or other changing information, usually of people. It is sometimes done in a surreptitious manner...