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 searching for a machine with sufficient power and endurance to be able to complete all three phases of anti-submarine warfare; hunt for, find and then destroy submarines. westland obtained a licence to build the s-58 in 1956. one s-58 was bought and modified with a 1100shp napier gazelle turbine engine, which ff 17 may 1957. 2 pre-production airframes built, ff 20 jun 1958 which became the wessex has.1.
the has.3 (a 1600shp gazelle mk 165 engine) and hu.5 (twin couled gnome turbine engines) were improved has.1s for the rn.
westland also produced the mk.31 for the ran (27), the mk.52 for iraq (12), mk.53 for ghana (2), the mk.54 for brunei (2) and the mk.60 as a civilian version of the raf hc.2 for bristow helicopters to serve offshore platforms in the north sea.
| Wessex HAS.1 || 1961 |
| Wessex HAS.31 || 1962 || Export version of Wessex HAS.1 for Royal Australian Navy. Twenty-seven Mk.31A examples delivered with more powerful 1,540 shp Napier Gazelle NGa ... |
| Wessex HU.5 || 1963 || Military transport version of the Wessex HC.2 for the Royal Navy. |
The Wessex HU.5 was a development of the HAS.1, replacing its single Gazelle engine with a pair of coupled Gnome turbines (similar to the RAFs HC ...
| Wessex HC.2 || 1964 || The Wessex HC.2 was an improved version of the Wessex HAS.1, designed for battlefield tactical support. To achieve the lift required (armed troop ... |
| Wessex Mk.54 || 1964 || Military transport version of the Wessex HC.2 for the Sultan of Brunei Air Force, 2 built. |
| Wessex Mk.60 || 1964 || Civil utility transport version of the Wessex HC.2 for Bristow Helicopters, 20 built. |
| Wessex HAS.3 || 1965 || Improved ASW version of Wessex HAS.1 with more powerful 1,600 shp NGa.18 Mk.165 Napier Gazelle turboshatft engine. Three prototypes built and 42 ... |
During 1965, Rolls Royce bought out the Napier engine company (manufacturers of the Gazelle), which resulted in a shortage of engine spares and s ...
| Wessex Mk.52 || 1965 || Military transport version of the Wessex HC.2 for the Iraqi Air Force, 12 built. |
| Wessex Mk.53 || 1965 || Military transport version of the Wessex HC.2 for the Ghana Air Force, 2 built. |
| Wessex HCC.4 || 1969 || Based on the robust and highly versatile RAF Wessex HC.2, the HCC.4 was given a VVIP interior, and had a special navigation systems fit, which in ... |
| Wessex HAR.2 || 1976 || This version of the Wessex was created for use on UK SAR duties in the mid 1970s, being used to start the replacement of the Whirlwind HAR Mk10 o ... |