Since the 1980s, the U. S. military has been looking for a new generation of vertical take-off and landing (VTOL) aircraft to replace the conventional helicopters in use. Such a machine would be able to rise and land vertically, like a helicopter, but assume a high-speed flight profile like a regular aircraft. The Bell Corporation had been attempting to address this very problem since 1958, and in 1987, it began fielding the first of five V-22 prototypes. This is a medium-sized aircraft capable of carrying 24 fully armed troops at high speed and over long distances. And, because it takes off and lands like a helicopter, prepared airstrips are not necessary. The secret lies in the large turboprop engines on each wingtip, as they can tilt upward or forward as the situation demands, changing the flight profile from a helicopter to an airplane, then back again. The Marine Corps expressed considerable interest in this new machine for obvious tactical reasons, and Congress voted funding for it to acquire 360 machines.
The first VM-22 Ospreys were delivered in 1997 for training purposes, although two high-profile accidents took the lives of 19 marines and crew members in 2000. The Osprey program was halted temporarily until problems could be resolved, which added greater credence to complaints that it was dangerous and overpriced. However, continued testing and refinement led to the first Osprey overseas deployment in January 2009, when 12 machines were assigned to Iraq as part of Operation IRAQI FREEDOM. In the fall of 2009, Marine Medium Tiltrotor Squadron 263 deployed in Afghanistan as part of Operation ENDURING FREEDOM, and it completed its first combat troop landing at Now Zad on December 10 of that year. The MV-22 program has been shrouded in controversy since its inception but, now that the bugs have been ironed out, it is a reliable and efficient addition to Marine Corps tactical aviation.
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In the mid-1980s the U. S. DoD funded comprehensive evaluations of the Bell-Boeing XV-22 Osprey, which melded the vertical lift of a helicopter with the cruise speed of a fixed-wing turboprop aircraft. The program called for extensive use of composite materials in order to construct a lighter and stronger aircraft. A progeny of both the Boeing VZ-2 and the Bell XV-15, the V-22 featured two Allison T406 6,140-horsepower turboshafts installed in the tips of slightly forward- swept wings, powering twin counter-rotating, three-bladed composite 36-foot proprotors. The swiveling engine nacelles allowed the Osprey to lift off to a hover and accelerate into forward flight in less than twelve seconds. A sturdy retractable landing gear supported the aircraft for ground operations.
Initially the U. S. Army managed the JVX project, but in January 1983 the U. S. Navy assumed stewardship of the program. In June 1985, DoD let a contract for six flying prototypes and several static test mock-ups. The U. S. military services anticipated a requirement for 913 V-22s of several variants. To replace its CH-46 fleet, the USMC expected to order 552 MV-22A assault aircraft, each capable of transporting up to twenty-four combat-loaded Marines. The Army wanted 231 similar aircraft. The USAF foresaw a requirement for eighty CV-22 special operations long-range transports. Along the same lines the Navy submitted a need for fifty HV-22A aircraft for SAR, special warfare, and fleet logistical support. The Navy also expected to order an additional 300 Ospreys equipped for ASW. For shipboard storage, engineers designed the Osprey’s wings to fold fore and aft along the fuselage, with the folded blades and engine nacelles rotating and folding parallel to the wings and fuselage.
On March 19, 1989, after a long series of simulated test-stand flights, the first V-22 lifted off vertically for a twelve-minute flight. The Osprey completed its first transition from a hover to horizontal flight on September 14. By May 9, 1990, two additional machines had completed their test flights. In June 1991 the fifth XV-22 sustained considerable damage in a nonfatal crash on its first flight. A more calamitous event occurred on July 21, 1992, when the fourth ship crashed, killing all seven aboard. The Bell-Boeing team experienced a number of vibration and engine fuel control problems that caused the XV-22 program to fall well behind schedule. Additionally, a funding fight between DoD and Congress created a shortage of funds that precluded completion of the sixth aircraft; its parts were used as spares for the other five prototypes. Although only the USMC remained in the program, Congress finally agreed to fully fund the MV-22A Osprey in September 1994. Five aircraft, representing production models, began test flights on February 5, 1997. The USMC received its first Osprey in 1999 and began operational testing. A series of accidents, however, including one in April 2000 that killed nineteen Marines, again halted the program for a short period. A USMC accident report indicated that pilot error had caused the April 2000 crash, when the pilot inadvertently entered a condition called vortex ring state. In that situation a rotor system continues to recirculate disturbed air, causing the rotorcraft to settle in its own rotorwash.
The MV-22A’s 57-foot fuselage carried up to twenty-four troops, or twelve litters plus medical attendants, or 20,000 pounds of internal cargo, or a 15,000-pound slingload. The fuselage had a large rear loading ramp to facilitate handling or large and wheeled cargoes. The Osprey cruised at 100 knots in the helicopter mode and 315 knots in the airplane configuration. The aircraft had a service ceiling of 26,000 feet and a range of 500 nautical miles without auxiliary fuel. The V-22 could also be refueled by its air-to-air refueling probe. If the MV-22A projects continue as planned, the USMC will receive 425 of the aircraft.
Variants
V-22A
Pre-production full-scale development aircraft used for flight testing. These are unofficially considered A-variants after the 1993 redesign.
CV-22B
U.S. Air Force variant for the U.S. Special Operations Command (USSOCOM). It conducts long-range special operations missions, and is equipped with extra wing fuel tanks, an AN/APQ-186 terrain-following radar, and other equipment such as the AN/ALQ-211,[189][190][191] and AN/AAQ-24 Nemesis Directional Infrared Counter Measures. The fuel capacity is increased by 588 gallons (2,230 L) with two inboard wing tanks; three auxiliary tanks (200 or 430 gal) can also be added in the cabin. The CV-22 replaced the MH-53 Pave Low.
MV-22B
U.S. Marine Corps variant. The Marine Corps is the lead service in the V-22’s development. The Marine Corps variant is an assault transport for troops, equipment and supplies, capable of operating from ships or expeditionary airfields ashore; replacing the Marine Corps’ CH-46E and CH-53D fleets. The aircraft has received the latest modifications in the Block C upgrade.
EV-22
Proposed airborne early warning and control variant. The Royal Navy studied this AEW variant as a replacement for its current fleet of carrier-based Sea King ASaC.7 helicopters.
HV-22
The U.S. Navy considered an HV-22 to provide combat search and rescue, delivery and retrieval of special warfare teams along with fleet logistic support transport. It chose the MH-60S for this role in 2001. Naval Air Systems Command’s 2011/2012 V-22 Osprey Guidebook lists the HV-22 for the U.S. Navy with the USAF and USMC variants.
SV-22
The proposed anti-submarine warfare variant. The U.S. Navy studied the SV-22 in the 1980s to replace S-3 and SH-2 aircraft.
