Westland WESSEX HAS.3 XT257

	Rotor span: 56 ft Service ceiling: ‘low level’ Length: 65 ft 10 in Max speed: 135 mph Max weight: 12,600 lb Engine: 1,600 hp Napier Gazelle 18
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Helicopters began to be used by the military in large numbers in the early 1950's, and one way for Britain to expand its fleet quickly was to build American designs under license. So it was that Westland Helicopters of Yeovil built the Sikorsky S-55 helicopter in the mid 1950's as the Whirlwind, with Westlands making a number of improvements to the design over the years. The Whirlwind served in large numbers with the Army, Navy and Air Force, and to follow on Westlands built the Sikorsky S-58 as the Wessex, again being used in large numbers by all services.

The Wessex was initially ordered by the Royal Navy for use in the anti-submarine role, for which the helicopter was based on an Aircraft Carrier or the stern of a Destroyer. A S-58 with its piston engine was first flown by Westlands in May 1957, but this was soon modified to be powered by a Napier Gazelle turboshaft engine, which improved performance and range. The first Yeovil built Wessex flew in June 1958, and deliveries to the Royal Navy commenced in April 1960. The helicopter entered full squadron service in July 1961, with a total of eleven squadrons operating the initial HAS.1 version. Improved radar equipment and extra engine power, plus the ability to carry wire-guided missiles, led to the HAS.3 version which entered service in January 1967. Apart from a development batch of three, all HAS.3 airframes were conversions of the earlier mark. When the HAS.3 entered service, a number of earlier HAS.1’s were made available for commando duties, being used operationally in Borneo. The HAS.3 remained in squadron service until December 1982, being replaced by the Sea King which possessed a much greater range. Locally, Wessex were based at RNAS Portland, often being seen flying along the Dorset coast.

The Wessex was also ordered by the RAF as the HC.2 for troop transport duties, being equipped with a twin coupled Gnome turboshaft engine which gave operational improvements over the Gazelle. The prototype flew in January 1962, entering service at Odiham in February 1964, the type seeing action in Aden and the Far East. Seventy four were produced, serving around the world with the RAF, with a number later being converted for Search and Rescue duties to replace the Whirlwind. A similar version was ordered by the Royal Navy for use by Commando Forces as the HU.5, first being delivered to the Navy in December 1963, and entering operational service the following October. Six squadrons used the HU.5 until 1987 when they were finally replaced by Commando versions of the Sea King. Operations had originally begun to wind down by the early 1980’s, but the Wessex was called back into action during the Falklands War of 1982, providing a vital role in ferrying troops from ship to shore. The public will also recall them for their use in the spectacular battle sequences at the end on Yeovilton’s Annual Air Show. There were two other Wessex built for the RAF – the HCC.4 version for use by the Queens Flight, entering Royal service in June 1969. Bristow Helicopters used the Wessex for North Sea oil exploration work, and the HAS.1 version was also purchased by the Royal Australian Navy. In all 382 Wessex were built by Westland Helicopters.

XT257 was a pre-production version of the HAS.3 built by Westlands early in 1965 (c/n WA241). As such, it never saw operational service with the Royal Navy, spending its flying career on development flying. 1966/67 saw it at A&AEE Boscombe Down testing flight control systems and radio evaluation. It's flying days were over by 1980, and it was passed to the RAF for use as an instructional airframe (8719M) at No.1 School of technical Training at Halton. Changes within the RAF saw it move to the new No.1 S of TT at Cosford early in 1995. At some stage it acquired the yellow colour scheme of a RAF HAR.2 rescue variant - which it never was. Sold to a private owner in West Sussex in 1998, XT257 arrived by road in January 2005 for display at the Museum.