The Sikorsky S-73 /ref> was a proposed aircraft design to meet the
United States Army
The United States Army (USA) is the primary Land warfare, land service branch of the United States Department of Defense. It is designated as the Army of the United States in the United States Constitution.Article II, section 2, clause 1 of th ...
requirement in 1970 for a Heavy Lift Helicopter (HLH) capable of carrying , a lifting capacity more than twice that of Sikorsky's most powerful helicopter at that time.
The Sikorsky's S-73 design was an enlarged version of the successful
CH-54
The Sikorsky CH-54 Tarhe is an American twin-engine heavy-lift helicopter designed by Sikorsky Aircraft for the United States Army. It is named after Tarhe, an 18th-century chief of the Wyandot people, Wyandot Indian tribe whose nickname was "T ...
/ S-64 with a simplified and improved single main rotor powered by three General Electric TF34-58 turboshaft engines rated at a combined . A crew of five would operate the aircraft from the forward cockpit with pushbuttons replacing the traditional cyclic stick and collective lever. Behind the cockpit an aft cabin provided capacity for 12 combat troops.
Sikorsky submitted their design in February 1971, then in May the Army declared the
Boeing Vertol XCH-62
The Boeing Vertol XCH-62 (Model 301) was a triple-turbine, heavy-lift helicopter project designed for the United States Army by Boeing Rotorcraft Systems, Boeing Vertol. Approved in 1971, one prototype reached 95% completion before it was cancel ...
winner of the contract, ending the Sikorsky S-73 program.