The Westland WS-61 Sea King is a British licence-built version of the American Sikorsky S-61 helicopter of the same name, built by Westland Helicopters. The aircraft differs considerably from the American version, with Rolls-Royce Gnome engines (licence-built General Electric T58s), British made anti-submarine warfare systems and a fully computerised control system. The Westland Sea King was also produced as the Commando troop transport version for export.
Design and development
Westland Helicopters, which had a long standing licence agreement with Sikorsky to allow it to build Sikorsky's helicopters, extended the agreement to cover Sikorsky Sea King soon after the Sea King's first flight in 1959. In 1966 the British Royal Navy selected the Sea King to meet a requirement for an anti-submarine warfare (ASW) helicopter to replace the Westland Wessex , placing an order with Westland for 60 Sea Kings on 27 June 1966. The prototype and pre-production aircraft were constructed with Sikorsky-built components. The first Westland-built aircraft, the first production aircraft for the Royal Navy, designated the Sea King HAS1, first flew on the 7 May 1969 and was delivered to the navy in the same year.
By 1979, the Royal Navy had ordered 56 HAS1s and 21 HAS2s to meet the anti-submarine requirements, these were also outfitted for carrying out the secondary role of anti-ship missions. Over 300 Westland Sea Kings were produced, the last to be built at Westland were Mk 43B SAR versions for the Royal Norwegian Air Force. The last of the Royal Navy's Sea Kings in the ASW role was retired in 2003, being replaced by the AgustaWestland Merlin HM1. The Airborne Surveillance and Control (ASaC) (formerly Airborne Early Warning) variant is expected to be replaced in time for the two Queen Elizabeth -class aircraft carriers, sometime in the 2010s. The types in contention are a Merlin derivative, a V-22 Osprey variant or a derivative of the E-2C Hawkeye. The UK is also expected to replace the HC4 and Search and Rescue variants in the 2010s.
The basic ASW Sea King has been upgraded numerous times, becoming the HAS2 , HAS5 and HAS6 , the latter of which has been replaced by the AgustaWestland Merlin ASW helicopter. Surviving aircraft are having the mission equipment removed and the aircraft are being used in the utility role.
Crew: Two to four, depending on the mission
Length: 55 ft 10 in [ 30 ] (17.02 m)
Rotor diameter: 62 ft 0 in (18.90 m)
Height: 16 ft 10 in (5.13 m)
Disc area: 3,020 ft² (280 m²)
Empty weight : 14,051 lb (6,387 kg)
Loaded weight: 21,000 lb (9,525 kg)
Max. takeoff weight : 21,400 lb (9,707 kg) (overload weight)
Powerplant : 2 × Rolls-Royce Gnome H1400-2 turboshafts , 1,660 shp (1,238 kW) each
Propellers: Five bladed rotor
Maximum speed : 129 mph (112 knots, 208 km/h) (max cruise at sea level)
Range : 764 mi (664 nmi , 1,230 km)
Service ceiling : 10,000 ft [ citation needed ] (3,050 m)
Rate of climb : 2,020 ft/min (10.3 m/s)
4× Mark 44 , Mark 46 or Sting Ray torpedos , or 4× Depth charges