V-22 Osprey

The V-22 Osprey is a joint service, multi-mission aircraft with vertical take-off and landing (VTOL) capability. It is designed to perform VTOL missions like a conventional helicopter while also having the long-range cruise abilities of a twin turboprop aircraft.

The Osprey is the world's first production tiltrotor aircraft with a 38 ft (12 m) rotor, engine, and transmission nacelle mounted on each wing tip. It can operate as a helicopter when taking off and landing vertically. Once airborne, the nacelles rotate forward 90 degrees for horizontal flight, converting the V-22 to a high-speed, fuel-efficient turboprop airplane. The wing rotates for compact storage aboard ship.

The United States Marine Corps is the lead service in the development of the V-22 Osprey. The Marine Corps version, the MV-22B, will be an assault transport for troops, equipment and supplies, and will be capable of operating from ships or from expeditionary airfields ashore. The US Navy's HV-22A will provide combat search and rescue, delivery and retrieval of special warfare teams along with fleet logistic support transport. The CV-22A operated by the United States Special Operations Command (USSOCOM) will conduct long-range special operations missions. The V-22 Osprey will replace the Marine Corps CH-46E and CH-53D as well as several types of the Special Operations Command H-53, H-47, H-60, and C-130 series aircraft.

The Osprey's development process has been long and controversial. The first flight occurred in March 1989. Since then however there have been four significant failures during testing – a crash in 1991, a second in 1992 that killed seven, a third in April 2000 that killed nineteen, and a fourth in December 2000 that killed four. Problems identified in all of these mishaps have been addressed by the V-22 program office and advocates of the program are optimistic that the aircraft is mature enough for fleet operations. Currently (as of Nov 2004) the V-22 is scheduled to begin its next operational evaluation in March 2005; this should be the final operational test before a milestone decision is made to begin full rate production. The Osprey's lift capacity and high cost have also been heavily criticized. Advocates of the program point to the Osprey's ability to carry troops and freight faster, further, and much higher than conventional helicopters.

Experienced aerodynamicists have pointed out that a propellor or rotor does not provide much motive force, but only stirs the air around it, unless there is windflow into it. A conventional airplane develops sufficient speed on the runway to guarantee good airflow into the propellor (or jet engine) by takeoff time. A conventional helicopter sets into motion a large air mass that is drawn downwards into the rotor, before rising. An aircraft that attempts to pivot its engines while aloft is subject to thrust failure because of the paucity of airstream arriving at the rotors from the newly selected aspect.

Planned purchases include 360 for the Marine Corps, 48 for the Navy and 50 for the Air Force and 4 for the Texas Air National Guard.

General Characteristics

• Primary Function: Vertical takeoff and landing (VTOL) aircraft
• Contractor: Bell-Boeing
• Propulsion: Two pivoting Rolls-Royce/Allison AE 1007 engines
• Main rotor diameter: 38 ft (11.58 m)
• Blades per rotor: Three
• Weight: 60,500 lb (27 t) max gross weight
• Ceiling: 25,000 feet (7,600 m) service ceiling
• Speed: 272 knots (500 km/h) cruise
• Armament: Provisions for two .50 cal cabin guns or 7.62 x 51 mm miniguns