V-22 Osprey

The V-22 Osprey is a joint service, multi-mission military 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 typically operates as a helicopter with its nacelles vertical (rotors horizontal) for takeoff and landing. Once airborne, the nacelles rotate forward 90 degrees in as little as 12 seconds for horizontal flight, converting the V-22 to a high-speed, fuel-efficient turboprop airplane. STOL, rolling-takeoff and landing capability is achieved by having the nacelles tilted forward up to 45 degrees. For compact storage aboard a ship, the wing rotates (about the z-axis), and the proprotors fold in a sequence that takes between 90 and 120 seconds.

Because of the extreme downdraft of the propellers, Marines cannot rappel out the side doors as on conventional helicopers. Moreover, the engines block the firing arc of side-mounted machine guns. Marines will use the rear ramp to exit and a ramp gun mount is in development. A chin-mounted turret has also been proposed.

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 planned, but as yet unfunded, U.S. Navy V-22 will provide combat search and rescue, delivery and retrieval of special warfare teams along with fleet logistic support transport. The CV-22 operated by the United States Special Operations Command (USSOCOM) will conduct long-range special operations missions, combat rescue, among other special missions. The V-22 Osprey will replace the Marine Corps CH-46E and CH-53D. However, it will not replace the Air Force's MH-53 PAVE LOW helicopters.

The Osprey was developed and is built jointly by Bell Helicopter Textron, who manufacture and integrate the wing, nacelles, rotors, drive system, tail surfaces, and aft ramp, as well as integrating the Rolls-Royce engines; and Boeing Helicopters, who manufacture and integrate the fuselage, cockpit, avionics, and flight controls. Portions are manufactured in Philadelphia, Pennsylvania, and Amarillo, Texas. Final assembly and delivery occurs in Amarillo. The joint development team is known as Bell-Boeing.

The Osprey's development processes have been long and controversial. When the development budget, first set at $2.5 billion in 1986, had reached $30 billion in 1988, then Defense Secretary Dick Cheney zeroed out the budget, but was overruled by Congress. The first flight occurred on March 19, 1989. Since then, however, there have been four significant failures during testing[1]:

* On June 11, 1991, a miswired flight control system led to two minor injuries when the left nacelle struck the ground while the plane was hovering 15 feet in the air, causing it to bounce and catch fire.

* On July 20, 1992, a leaking gearbox led to a fire in the right nacelle, causing the plane to drop into the Potomac River in front of an audience of Congressmen and other government officials at Quantico, killing all seven crewmen and grounding the plane for 11 months.

* On April 8, 2000, two Ospreys, loaded with Marines to simulate a rescue, attempted to land at Marana Northwest Regional Airport in Arizona. They descended unusually quickly from an unusually high altitude; the second Osprey, descending at over 2,000 feet per minute (600 m per minute) with a forward speed of under 45 miles per hour, suddenly stalled in its right rotor at 245 feet, rolled over, crashed, and exploded, killing all nineteen on board. The official cause was determined to be vortex ring state (VRS), a fundamental limitation on vertical descent in helicopters, which resulted in public questioning of whether the fundamental premise of the aircraft might be fatally flawed. At the time of the mishap, however, the Osprey's flight operations rules restricted the Osprey to an 800 feet per minute (240 m/min) descent at lower than 40 knots (74 km/h) airspeed (restrictions typical of helicopters, as well); the crew of the aircraft in question exceeded this operating restriction threefold. Another factor that may have triggered VRS was their operating in close proximity, which is believed to be a risk factor for VRS in helicopters. The military claims that subsequent testing has shown that the Osprey, and the tiltrotor in general, is less susceptible to VRS; the conditions are easily recognized by the pilots; recovery from VRS requires a more natural action by the pilot than recovery in helicopters; the altitude loss is significantly less than for helicopters; and with sufficient altitude (2000 feet or more), VRS recovery is relatively easy. They also claim recognition of and recovery from VRS is easily trainable for new pilots. As a result of testing, the Osprey will have a descent envelope as large or larger than most helicopters, further enhancing its ability to enter and depart hostile landing zones quickly and safely. Osprey has also dealt with the problem by adding a simultaneous warning light and voice that says "Sink Rate" when the Osprey is close to VRS. Critics believe the current solution is inadequate; some question whether this will limit effectiveness in combat zones that require fast and sudden maneuvers, and where they will frequently be operating in close proximity to other Ospreys.

* On December 11, 2000, a hydraulic leak crippled an engine; a previously undiscovered error in the aircraft's control software caused it to decelerate each time in response to the pilot's eight attempts to reset the software to compensate for the dead engine, and the plane fell 1,600 feet into a forest, killing all four aboard.

Adding to the program's problems, the Osprey squadron commander at New River, Lieutenant Colonel Odin Lieberman, was recorded by a crew member telling his crew they needed to falsify maintenance records to make the plane appear more reliable, saying "We need to lie or manipulate the data, or however you wanna call it".

On December 12, 2000, the Osprey was grounded indefinitely. The Pentagon gave the project two years grace before cancellation. A staff shakeup led to the appointment of Air Force colonel Craig Olsen as program manager and Ken Baile as assistant chief engineer, and a new focus on eliminating problems, rather than reaching paper milestones.

The Osprey completed its final operational evaluation (OPEVAL) in June 2005. The OPEVAL was extremely successful; events included long range deployments, high altitude, desert and shipboard operations. It is claimed that 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. Critics state that the aircraft will never be mature enough for fundamental design flaws and that the V-22 is inherently dangerous because of its flawed side-by-side rotor design, although in-line tandem rotor CH-46 and CH-47 helicopters have been operational for over 30 years.

On June 3, 2005, the United States Marine Corps helicopter squadron, HMM-263, was stood down to begin the process of transitioning to the MV-22 Osprey, and reactivated March 3, 2006 as the first MV-22 squadron, re-designated VMM-263.

On September 28, 2005, the Pentagon formally approved full-rate production for the Osprey. The current plan is to boost production from 11 a year to 24 to 48 a year by 2012. Planned production quantities include 360 for the Marine Corps, 48 for the Navy, 50 for the Air Force. The US Army, originally the lead service for the then-named JVX program, is also a candidate for possible applications.

On December 8, LtGen Amos, the commanding general of the 2nd Marine Expeditionary Force, accepted the delivery of the first fleet of MV-22s. This aircraft is being delivered to HMM-263; the former helicopter squadron is currently undergoing transition training. The Osprey will enter operational service with the Marine Corps in 2007.

On December 12, 2005, the Pentagon announced that the procurement budget for the USMC V-22's would be reduced by $1.1 billion over the production run. The plans for the USAF were unaffected.

On July 8, 2006, the Pentagon announced plans to buy two new V-22's within the 2007 military budget outlined by President George W. Bush and his cabinet.

At Royal International Air Tattoo (RIAT) of 2006 the V-22 Osprey flew for the first time in the UK.

Israel has shown interest in the purchase of an undisclosed number of MV-22's, but an official order has not been placed or approved.

Plans of using it in Iraq in 2007 has been revealed by the manufacturer Boeing

General characteristics

* Crew: 3
* Capacity: 24 troops
* Length: 57 ft 4 in (17.5 m)
* Rotor diameter: 38 ft 0 in (11.6 m)
* Wingspan: 46 ft in ( m)
* Height: 17 ft 11 in (5.5 m)
* Disc area: 9,100 ft² (840 m²)
* Wing area: ft² ( m²)
* Empty weight: 33,140 lb (15,032 kg)
* Loaded weight: 47,500 lb (21,500 kg)
* Max takeoff weight: 60,500 lb (27,400 kg)
* Powerplant: 2× Rolls-Royce AE 1107C-Liberty turboshafts, 6,150 hp (4,590 kW) each


* Maximum speed: 275 knots (316 mph, 509 km/h)
* Cruise speed: 214 knots (246 mph, 396 km/h) at sea level[6]
* Combat radius: 370 nm (430 mi, 690 km)
* Ferry range: 2,417 nm (2,781 mi, 4,476 km)
* Unrefueled range: 879 nm (1,011 mi, 1,627 km)
* Service ceiling: 26,000 ft (7,925 m)
* Rate of climb: 2,320 ft/min (11.8 m/s)
* Disc loading: 5.2 lb/ft² (26 kg/m²)
* Power/mass: 0.259 hp/lb (427 W/kg)Permission is granted to copy, distribute and/or modify this document under the terms of the GNU Free Documentation License, Version 1.2 or any later version published by the Free Software Foundation; with no Invariant Sections, with no Front-Cover Texts, and with no Back-Cover Texts.
Virtual Magic is a human knowledge database blog. Text Based On Information From Wikipedia, Under The GNU Free Documentation License. Copyright (c) 2007 Virtual Magic. Permission is granted to copy, distribute and/or modify this document under the terms of the GNU Free Documentation License, Version 1.1 or any later version published by the Free Software Foundation; with no Invariant Sections, no Front-Cover Texts and no Back-Cover Texts. A copy of the license is included in the section entitled "GNU Free Documentation License".

Links to this post:

Create a Link

<< Home