Whirlwind | |
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A Royal Air Force Whirlwind HAR.10 of the RAF Search and Rescue Force | |
Role | Helicopter |
National origin | United Kingdom |
Manufacturer | Westland Aircraft |
First flight | August 1953 |
Introduction | 1954 |
Primary users |
Royal Navy Royal Air Force |
Produced | 1953–1966 |
Number built | 360+ |
Developed from | Sikorsky H-19 |
The Westland Whirlwind helicopter was a British licence-built version of the U.S. Sikorsky S-55/H-19 Chickasaw. It primarily served with the Royal Navy's Fleet Air Arm in anti-submarine and search and rescue roles.
In 1950, Westland Aircraft, already building the American Sikorsky S-51 under license as the Westland Dragonfly, purchased the rights to manufacture and sell Sikorsky's larger Sikorsky S-55 helicopter. While a Sikorsky-built pattern aircraft was flown by Westland in June 1951, converting the design to meet British standards (including the provision of a revised main-rotor gearbox), was time consuming, and the first prototype British aircraft, registered G-AMJT, powered by the 600 hp Pratt & Whitney R-1340-40 Wasp did not fly until August 1953. This was followed by ten Whirlwind HAR.1s, which entered service shortly afterwards. They served in non-combat roles, including search and rescue and communications functions. The HAR.3 had a larger 700 hp Wright R-1300-3 Cyclone 7 engine.
The performance of early versions was limited by the power of the American Wasp or Cyclone engines, and in 1955, the HAR.5, powered by an uprated engine, the Alvis Leonides Major, flew for the first time. This was followed by the similarly powered HAS.7, which became the first British helicopter designed for anti-submarine warfare in the front-line when it entered service in 1957. It could either be equipped with a dipping Sonar for submarine detection or carry a torpedo, but could not carry both simultaneously, so sonar equipped "Hunters" were used to direct torpedo armed "Killers". The HAS.7 was powered by a 750 hp (560 kW) Alvis Leonides Major 755/1 radial engine. It had a hovering ceiling at 9,400 ft (2,900 m) and a range of 334 miles at 86 mph. In 1960 Westland introduced a Whirlwind powered by the 1,000 hp Bristol Siddeley Gnome turboshaft, the greater power giving much improved performance over the earlier piston-engined variants. The Gnome featured an early computer controlled fuel system that removed variations in engine power and made for much easier handling by the pilot.