The Boeing Vertol XCH-62 was a prototype heavy-lift helicopter which never really took off. Either figuratively or literally. It was designed for the US Army in the early ’70s. Mainly because the US military were a little envious of the Soviet heavy-lift helicopters – such as the Mil Mi-26 – which could carry a considerably heavier payload than the Boeing CH-47 Chinook – the United States’ largest helicopter, both then and now.
The contract for the XCH-62 prototype was awarded in 1973. The rotor diameter was to be a colossal 28 meters (92 ft) – slightly longer than its fuselage length of 27.2 meters (89 feet 3 inches). Its widely-spaced landing gear would allow it to straddle heavy cargoes such as armored vehicles, and still carry twelve troops within its slender fuselage.
The intended power source was a trio of Allison XT701-700 turboshafts, each rated at 8,079 horsepower. Unfortunately, the power proved to be a little too much for the transmission, and in 1975, when the aircraft was in the final stages of construction, the engineers had to go back to the drawing board to redesign stronger gears. This delay meant the aircraft never went for its first scheduled test flight. And by August 1975 US Congress had decided to cut funding for the project.
The almost-finished prototype was put into storage at the the US Army Aviation Museum at Fort Rucker, Alabama. However in the mid-1980s NASA in collaboration with DARPA briefly toyed with the idea of finishing the XCH-62 and taking it for some experimental flights. But yet again, budget constraints soon put an end to the idea. The largest helicopter outside of the USSR was well and truly dead.
The XCH-62 was kept in storage until as recently as 2005, when the aircraft was uncemoniously scrapped. Some components were saved and now reside at the Helicopter museum in Weston-super-Mare in the United Kingdom.