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.
Specifications
| Engine | 1 x Wright R-1820 1000 shp |
|---|---|
| Capacity | 2 + 18 |
| Length (m) | 17.27 |
| Height (m) | 4.36 |
| Blades | 4 |
| Rotor diam. (m) | 17.07 |
| Disc area (m2) | 228.54 |
| Weight (kgs) | Empty: 3500 Max: 5900 |
| Speed (km/h) | Cruise: 156 Max: 198 |
| Range (km) | 400 |
| Ceiling (m) | 2900 |
Derivatives & Versions
| XHSS-1 | 1953 | Sikorsky S-58 prototype anti-submarine helicopter desigmated XHSS-1 by USN. |
| HSS-1 / SH-34G Seabat | 1954 | Sikorsky production S-58 for anti-submarine warfare, desgnated HSS-1 / SH-34G by USN. |
| 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. |
| CH-126 Choctaw | 1955 | Sikorsky S-58B (H-34A) in Canadian service |
| H-34A Choctaw | 1955 | US Army variant. |
| S-58B | 1955 | Commercial/Export designation for H-34B (Basic H-34A with detail changes) |
| HUS-1L / LH-34D | 1956 | Factory winterized version of HUS-1 used by VXE-6 for Operation DEEP FREEZE support in Antartica. |
| → 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. |
| HUS-1A / UH-34E | 1957 | Basic HUS-1 but equipped with amphibious pontoons. |
| HUS-1Z / VH-34D Seahorse | 1957 | Presidential helicopter |
| VH-34A/C Choctaw | 1957 | VIP variant used by White House |
| HSS-1N / SH-34J Seabat | 1958 | Many airframes later converted to UH-34J by removal of ASW gear. |
| → Wessex | 1958 | the sikorsky s-58 (ff 8 mar 1954) entered usn service late 1955 as the hss-1. |
| 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. |
| CH-34C Choctaw | 1962 | Improved H-34A for US Army and export under MDAP. |
| UH-34G Seabat | 1962 | Conversion of HSS-1 / SH-34G by US Navy into utility version by removing ASW equipment. |
| 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 PT6T engine. |
| HH-34J Choctaw | 1971 | Former US Navy aircraft transferred to AFRES rescue squadrons |