Sikorsky CH-34 Choctaw Helicopter

The CH-34 Choctaw cargo and light tactical transport helicopter (Sikorsky Model S-58) was a lengthened and more powerful version of the H-19 Chickasaw cargo helicopter. The CH-34 could carry up to 16 troops or eight litters and a medic in the MedEvac role. The CH-34 entered service with the U.S. Army in April 1955 and rapidly became the principal Army transport helicopter, with 437 CH-34A/B/C models in inventory by 1970. ARVN acquired the CH-34 but it was not used by the U.S. Army in Vietnam. The Marine Corps version (UH-34D Seahorse or HUS-1) was the primary Marine utility/assault helicopter used in Vietnam and by the CIA Air America in Laos. Other variants were modified for Search and Rescue or other specialized roles.

The U.S. Navy procured the Sikorsky Model S-58 as the anti-submarine HSS-1 Seabat. It was also licensed and manufactured in Great Britain (with a turbine engine) where it was named the Wessex.

Sikorsky CH-34 Choctaw Helicopter in Flight.
Sikorsky CH-34 Choctaw Helicopter in Flight.

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Sikorsky CH-34 Choctaw

The CH-34 Choctaw had a single four-bladed main rotor and a four-bladed metal tail rotor. Although it was very robust and generally liked and respected by its crews, there were design flaws exposed by combat experience in Vietnam. The high cockpit made it an obvious target. The drive shaft created a partition that made it difficult for crew chiefs to come to the aid of injured cockpit crew. The H-34's magnesium skin resulted in very intense fires, and contributed to significant corrosion problems. The airframe was also too weak to support most of the weapons that allowed the UH-1 Huey to become an effective ad-hoc gunship.

Sikorsky CH-34 Choctaw Specifications and Performance

Rotor diameter 56 ft.
Length 46 ft. 9 in.
Height 14 ft. 3.5 in.
Max Weight 14,000 lb.
Armament None
Engine 1525 hp Curtis-Wright R-1820-84 Cyclone (radial pistons)
Maximum speed 123 mph.
Cruising speed 98 mph.
Range 280 mi.
Service ceiling 9,500 ft.

Specifications and Performance differ across the large number of variants of the Sikorsky S-58 (H-34) helicopter. The table above is correct for the SH-34J (US Navy) converted to the Search and Rescue HH-34J (USAF) as described here. The US Army versions CH-34A and CH-34C have the maximum speed tabulated as 150 knots (172.6 mph) in TM 55-1520-202-10, the Operator's Manual for that helicopter.

Thanks to Robert Quillen for help with this information.

Sikorsky CH-34 Choctaw helicopter
Sikorsky CH-34 Choctaw helicopter.

CH-34 Choctaw helicopter, Fitzsimons Army Hospital, Aurora, CO, 13 September 1956
CH-34 Choctaw helicopter, Fitzsimons Army Hospital, Aurora, CO, 13 September 1956.

Technicians work on a Marine HUS-1 / CH-34 Seahorse helicopter on the beach at Cua Viet, Vietnam, 1 October 196
Technicians work on a Marine HUS-1 / CH-34 Seahorse helicopter on the beach at Cua Viet, Vietnam, 1 October 1966.

Marine HUS-1 / CH-34 Seahorse helicopter on the runway at Dong Ha, Vietnam, 1 July 1967
Marine HUS-1 / CH-34 Seahorse helicopter on the runway at Dong Ha, Vietnam, 1 July 1967.

An air-to-air left front view of a Marine HUS-1 / CH-34 Seahorse helicopter over Cua Viet, Vietnam, 1967
An air-to-air left front view of a Marine HUS-1 / CH-34 Seahorse helicopter over Cua Viet, Vietnam, 1967.