The CH-53 was the product of the U.S. Marines’ “Heavy Helicopter Experimental” (HH(X)) competition begun in 1962. Sikorsky’s S-65 was selected over Boeing Vertol’s modified CH-47 Chinook version. The prototype YCH-53A first flew on 14 October 1964. The helicopter was designated “CH-53A Sea Stallion” and delivery of production helicopters began in 1966. The first CH-53As were powered by two General Electric T64-GE-6 turboshaft engines with 2,850 shp (2,125 kW) and had a maximum gross weight of 46,000 lb (20,865 kg) including 20,000 lb (9,072 kg) in payload.
Variants of the original CH-53A Sea Stallion include the RH-53A/D, HH-53B/C, CH-53D, CH-53G, and MH-53H/J/M. The RH-53A and RH-53D were used by the US Navy for mine sweeping. The CH-53D included a more powerful version of the General Electric T64 engine, used in all H-53 variants, and external fuel tanks. The CH-53G was a version of the CH-53D produced in West Germany for the German Army.
The US Air Force’s HH-53B/C “Super Jolly Green Giant” were for special operations and combat rescue and were first deployed during the Vietnam War. The Air Force’s MH-53H/J/M Pave Low helicopters were the last of the twin engined H-53s and were equipped with extensive avionics upgrades for all weather operation.