The experiences of the Korean War, during which helicopters for the first time operated extensively in transporting troops and equipment to the battlefield, prompted the Marine Corps to seek procurement of a true heavy-lift capability platform. The result was the HR2S (later designated CH-37), which for the decade following its first flight on December 18, 1953, held the distinction of being the largest rotary-wing aircraft flying outside of the Soviet Union. Although capable of carrying over 20 combat troops, the aircraft proved its greatest value in the transport of vehicles and cargo, loaded and unloaded through clam-shell nose doors. An innovative design in the evolution of rotary-wing aviation, the Mojave was the first production helicopter to incorporate five main rotor blades, retractable landing gear, and auto stabilization. The type also featured a folding tail boom to better allow for shipboard operations, Marine Corps planning of the day incorporating the use of escort carriers to support amphibious assaults.
The “Deuce,” as the helicopter was nicknamed, was ungainly in appearance, with two engine nacelles extending out from the fuselage. Crews took to painting the fronts of them with white circles, which gave them the appearance of eyes when viewing the Mojave head on. The type entered squadron service in mid-1956, demonstrating its capabilities almost immediately by establishing three world records during the period November 9-11, 1956, by carrying an 11,050 lb. payload to an altitude of 12,000 ft., lifting 13,250 lb. to over 7,000 ft., and covering a 3-kilometer course with a speed of 167.2 M.P.H. Despite this success, the Commandant of of the Marine Corps expressed doubts about the HR2S to meet specifications, noting that its combat radius and ability to hover out of ground effect (hovering at a height above the ground of less than the helicopter’s rotor diameter) was less than anticipated. The result was a dramatic reduction in the number of HR2Ss procured with a total of 55 eventually entering service when planned production totaled over 150.
By the time U.S. Marines went ashore at Da Nang, Republic of Vietnam, in March 1960, only two of the Marine Corps’ twenty helicopter squadrons still flew the “Deuce,” now designated the CH-37. The demands of the widening combat operations in Southeast Asia extended the life of the Mojave, which had not lived up to the expectations the Marine Corps had for it a decade earlier. With so many helicopters deploying to the Western Pacific, CH-37s filled the void by deploying with the Caribbean Ready Force, marking the first and only time a full squadron of “Deuces” served at sea in the role envisioned for the helicopter. Some CH-37s deployed to Vietnam and while their size made them vulnerable in the air assault mission, their heavy lift capability proved useful in retrieving downed helicopters from the combat zone and returning them to Marine airfields. They also provided cargo transport and by the time that last CH-37 departed Vietnam in May 1967, the type had logged over 5,300 combat hours and transported 12.5 million lb. of cargo.
Interestingly, two variants designated the HR2S-1W and fitted with a large diameter radar scanner in the nose were procured by the Navy in 1957, as a possible airborne early warning platform. The Marine Corps embarked on a similar experiment with a CH-37 fitted with bulbous, dielectric radome for use as a radar patrol aircraft. Neither service operated them in this capacity.
The museum’s CH-37A (Bureau Number 145864) entered service in August 1958, as part of the last batch of HR2S-1s produced by Sikorsky Aircraft Division of United Aircraft Corporation. The following month it joined its first squadron, Marine Helicopter Transport Squadron (Medium) (HMR(M)) 463 at Marine Corps Air Station (MCAS) Santa Ana, California. The following year it joined HMR(M) 462 for a period of a few months before shifting to HMR(M)-461, its service in the latter squadron including operations from the carrier Lake Champlain (CVS 39). Assigned to Marine Heavy Helicopter Squadron (HMH) 462 in May 1962, the aircraft's final squadron service was with Headquarters and Maintenance Squadron (H&MS) 26 at MCAS New River, North Carolina, during 1966. Placed in storage at Davis Monthan Air Force Base, Arizona, the museum's aircraft was acquired by Keystone Helicopter Corporation, which used it and other former military CH-37Cs for external load construction work, including the transportation and erection of power line poles. Keystone Helicopter Corporation eventually donated it to the museum, flight delivering it to Pensacola in 1981.
Manufacturer: Sikorsky Aircraft Division of United Aircraft Corporation
Dimensions: Length: 64 ft., 3 in.; Height: 22 ft.; Rotor Diameter: 72 ft
Weights: Empty: 20,831 lb.; Gross: 31,000 lb.
Power Plant: Two 1,900 horsepower Pratt & Whitney R-2800-54 engines
Maximum Speed: Maximum Speed: 130 M.P.H. at sea level; Service Ceiling: 8,700 ft.; Range: 145 miles
Crew: Two pilots and the capacity for 20 troops, 24 litters, and useful load of 11,000 lb.