Wednesday, April 2, 2008

United States Department of Defense - V-22 Osprey


The V-22 Osprey is an American joint service, multimission, military tiltrotor aircraft with both a vertical takeoff and landing (VTOL) and short takeoff and landing (STOL) capability. It is designed to perform missions like a conventional helicopter with the long-range, high-speed cruise performance of a turboprop aircraft. The V-22 was developed by Bell Helicopter Textron, which manufactures it in partnership with Boeing Helicopters. The initial operators are the United States Marine Corps and Air Force. The FAA classifies the Osprey as a model of powered lift aircraft.
The Osprey is the world's first production tiltrotor aircraft, with one three-bladed proprotor, turboprop engine, and transmission nacelle mounted on each wingtip. For takeoff and landing, it typically operates as a helicopter with the nacelles vertical (rotors horizontal). Once airborne, the nacelles rotate forward 90° in as little as 12 seconds for horizontal flight, converting the V-22 to a more fuel-efficient, higher-speed turboprop airplane. STOL rolling-takeoff and landing capability is achieved by having the nacelles tilted forward up to 45°. For compact storage and transport, the V-22's wing rotates to align, front-to-back, with the fuselage. The proprotors can also fold in a sequence taking 90 seconds.
The V-22 is equipped with a glass cockpit, which incorporates four Multi-Function Displays (MFDs) and one shared Central Display Unit (CDU), allowing the pilots to display a variety of images including: digimaps centered or decentered on current position, FLIR imagery, primary flight instruments, navigation (TACAN, VOR, ILS, GPS, INS), and system status. The flight director panel of the Cockpit Management System (CMS) allows for fully-coupled (aka: autopilot) functions which will take the aircraft from forward flight into a 50-foot hover with no pilot interaction other than programming the system.
The V-22 is a fly-by-wire aircraft with triple redundant flight control systems. With the nacelles pointing straight up in conversion mode at 90° the flight computers command the aircraft to fly like a helicopter, with cyclic forces being applied to a conventional swashplate at the rotor hub. With the nacelles in airplane mode (0°) the flaperons, rudder, and elevator fly the aircraft like an airplane. This is a gradual transition which occurs over the entire 96° range of the nacelles. The lower the nacelles, the greater effect of the airplane-mode control surfaces.
The Osprey is armed with one 0.30 in (7.62 mm) machine gun pointing rearward that can be fired when the loading ramp is lowered. A GAU-19 three-barrel 0.50 in (12.7 mm) gatling gun mounted below the V-22's nose has also been studied for future upgrade. BAE Systems is also developing a remotely operated turreted weapons system for the V-22.

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