Sikorsky CH-37 Mojave

CH-37 Mojave HR2S-1 Deuce
H-37 Mojave of the US Army in flight.
Role	Cargo helicopter Type of aircraft
National origin	United States
Manufacturer	Sikorsky Aircraft
First flight	18 December 1953
Introduction	July 1956
Retired	Late 1960s
Status	Retired
Primary users	United States Army United States Marine Corps
Number built	154[1]
Developed into	Sikorsky S-60 Westland Westminster

The Sikorsky CH-37 Mojave (company designation S-56) is an American large heavy-lift military helicopter of the 1950s. It entered service as the HR2S-1 Deuce with USMC in 1956, and as the H-37A Mojave with the U.S. Army that same year. In the early 1960s the designation was standardized to CH-37 for both services, with the HR2S-1 redesignated as CH-37C specifically.

Developed in the early 1950s with its first flight in 1953, it filled a 1950 Navy requirement for an assault helicopter. The design includes a front loading ramp with side opening clam shell doors on the nose. It is powered by two radial piston engines. It served well into the 1960s in active military service including in Indochina before being replaced, and many ex-military models went onto civilian service in the 1970s. This was the biggest helicopter in the world to enter service at the time, and one of the earliest twin engine models. It was known for being noisy but earned a good reputation for reliability. The Navy also adapted it to carry a naval radar, with two entering service as HR2S-1W.

The design lead to a production attempt as the Westland Westminster in the United Kingdom; prototypes were produced, but it did not go into full production. The S-56 was also the basis for the S-60 Skycrane helicopter prototype.