the Secretary of Defense and Navy administration opposed the tiltrotor project, but congressional pressure proved persuasive. The Navy and USMC were given the lead in 1983. The JVX combined requirements from the USMC, USAF, Army and Navy. A request for proposals was issued in December 1982 for preliminary design work. Interest was expressed by Aérospatiale, Bell Helicopter, Boeing Vertol, Grumman, Lockheed, and Westland. Contractors were encouraged to form teams. Bell partnered with Boeing Vertol to submit a proposal for an enlarged version of the Bell XV-15 prototype on 17 February 1983. Being the only proposal received, a preliminary design contract was awarded on 26 April 1983. The JVX aircraft was designated V-22 Osprey on 15 January 1985; by that March, the first six prototypes were being produced, and Boeing Vertol was expanded to handle the workload. Work was split evenly between Bell and Boeing. Bell Helicopter manufactures and integrates the wing, nacelles, rotors, drive system, tail surfaces, and aft ramp, as well as integrates the Rolls-Royce engines and performs final assembly. Boeing Helicopters manufactures and integrates the fuselage, cockpit, avionics, and flight controls. The USMC variant received the MV-22 designation, and the USAF variant received CV-22; this was reversed from normal procedure to prevent USMC Ospreys from having a conflicting CV designation with aircraft carriers. Full-scale development began in 1986. On 3 May 1986, Bell Boeing was awarded a US$1.714 billion contract for the V-22 by the U.S. Navy. At this point, all four U.S. military services had acquisition plans for the V-22. The first V-22 was publicly rolled out in May 1988. That year, the U.S. Army left the program, citing a need to focus its budget on more immediate aviation programs. In 1989, the V-22 survived two separate Senate votes that could have resulted in cancellation. Despite the Senate's decision, the Department of Defense instructed the Navy not to spend more money on the V-22. As development cost projections greatly increased in 1988, Defense Secretary Dick Cheney tried to defund it from 1989 to 1992, but was overruled by Congress, which provided unrequested program funding. Multiple studies of alternatives found the V-22 provided more capability and effectiveness with similar operating costs. The Clinton Administration was supportive of the V-22, helping it attain funding. Flight testing and design changes The first of six prototypes first flew on 19 March 1989 in the helicopter mode and on 14 September 1989