The
Sikorsky S-56 was developed to meet a U.S. Marine Corps
requirement for a large assault helicopter. The S-56 had two
nacelles on either side of the fuselage that held both the piston
engines and retractable landing gear. The prototype first flew
in 1953.
The S-56 was delivered to the Marine Corps as the HR2S.
The U.S. Army designated their version the H-37 Mojave.
Later versions could lift 11,000 lbs of cargo or 36 fully armed
troops.
