Sikorsky began work on the S-58 in 1951 as a general purpose utility machine and as a more capable anti-submarine platform for the US Navy, to follow the
S-55. It differed principally in a larger cabin area directly under the main gearbox - still driven by an oblique shaft from the nose mounted engine - the considerably more powerful R-1820-84 piston radial. It had a 4 bladed main rotor, a lower level foldable boom on which was mounted the port-side 4 bladed tail rotor and a tripod undercarriage (with tail wheel). It first flew in prototype on 8 Mar 1954 and the first production airframe flew on 20 Sep 1954.
| Model | Year | History |
| XHSS-1 | 1953 | Sikorsky S-58 prototype anti-submarine helicopter desigmated XHSS-1 by USN. Four built.
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| HSS-1 / SH-34G Seabat | 1954 | Sikorsky production S-58 for anti-submarine warfare, desgnated HSS-1 / SH-34G by USN.
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| HUS-1 / UH-34D Seahorse | 1954 | HUS-1/UH-34D Seahorse was the utility version of the HSS-1/SH-34G Seabat with early bent leg / torsion bar undercarriage. Production began in 19 ...
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| CH-126 Choctaw | 1955 | Sikorsky S-58B (H-34A) in Canadian service
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| H-34A Choctaw | 1955 | US Army variant. Conversions to H-34C. Redesignated CH-34A in 1962. Many transferred to South Vietnam Air Force and Thailand.
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| S-58B | 1955 | Commercial/Export designation for H-34B (Basic H-34A with detail changes)
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| HUS-1L / LH-34D | 1956 | Factory winterized version of HUS-1 used by VXE-6 for Operation DEEP FREEZE support in Antartica. Seven produced.
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 SA S-58 | 1956 | |
| S-58C | 1956 | |
| H-34G.I | 1957 | |
| HSS-1F / SH-34H | 1957 | Sikorsky HSS-1 fitted with two GE YT-58 turbine engines as test bed for HSS-2 prototype. Redesignated SH-34H in Oct62.
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| HUS-1A / UH-34E | 1957 | Basic HUS-1 but equipped with amphibious pontoons. They can also carry an external fuel tank. Re-designated UH-34E in 1962
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| HUS-1Z / VH-34D Seahorse | 1957 | |
| VH-34A/C Choctaw | 1957 | |
| HSS-1N / SH-34J Seabat | 1958 | Night/Bad weather version of the HSS-1 with improved avionics and autopilot, re-designated SH-34J in 1962
Many airframes later converted to UH-34J by removal of ASW gear.
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| Westland Wessex | 1958 | the sikorsky s-58 (ff 8 mar 1954) entered usn service late 1955 as the hss-1. this looked a good bet for the uk admiralty, which had been searchi ...
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| H-34G.II | 1959 | |
| HH-34F Seahorse | 1959 | Original designated HUS-1G, search & rescue version of HUS-1 / UH-34D Seahorse for US Coast Guard. Six built
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| CH-34C Choctaw | 1962 | Improved H-34A for US Army and export under MDAP.
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| UH-34G Seabat | 1962 | Conversion of HSS-1 / SH-34G by US Navy into utility version by removing ASW equipment.
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| H-34G III | 1963 | |
| S-58D | 1964 | |
| S-58T | 1970 | First flight on August 1970, the S-58T is an old airframe converted to turboshaft power using different versions of the Pratt & Whitney Canada ...
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| HH-34J Choctaw | 1971 | Former US Navy aircraft transferred to AFRES rescue squadrons
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