Westland WS-51 Dragonfly
|Dragonfly HR.3 of 705 Naval Air Squadron Royal Navy in 1955|
|Role||Rescue or communications helicopter|
|First flight||5 October 1948|
|Primary users||Royal Navy|
Royal Air Force
|Developed from||Sikorsky H-5|
Design and development
In December 1946 an agreement was signed between Westland Aircraft and Sikorsky to allow a British version of the S-51 to be manufactured under licence in the United Kingdom. These would be powered by the 500 hp Alvis Leonides radial engine. A modified version was also developed by Westland as the Westland Widgeon, but it was commercially unsuccessful.
The Dragonfly entered service with the Royal Navy in 1950 in the air-sea rescue role. A number were also used by the Royal Air Force for casualty evacuation. It was replaced in British service by the Westland Whirlwind, another derivative of a Sikorsky design, in the late 1950s.
Fifty-one civilian WS-51s were produced. Examples were used by Pest Control Ltd for crop spraying and others were flown as executive transports by Silver City Airways, Evening Standard Newspapers and Fairey Aviation. Exported aircraft operated in Japan, Belgian Congo, Mexico and Norway.
- Westland/Sikorsky WS-51
- Dragonfly HR.1
- Air-sea search and rescue helicopter for the Royal Navy powered by a 540 hp (400 kW) Alvis 50 radial piston engine. 13 built, some modified later as HR.5s.
- Dragonfly HC.2
- Casualty evacuation helicopter for the Royal Air Force similar to the commercial Mark 1A, 2 built.
- Dragonfly HR.3
- Air-sea search and rescue helicopter for the Royal Navy. Similar to the Dragonfly HR.1, but fitted with all-metal rotor blades, 71 built some later modified as HR.5s.
- Dragonfly HC.4
- Casualty evacuation helicopter for the RAF similar to the Dragonfly HR.3 with all-metal rotor blades, 12 built.
- Dragonfly HR.5
- Air-sea search and rescue helicopter for the Royal Navy similar to the Dragonfly HR.3. Modified from HR.1 and HR.3.
- Westland-Sikorsky WS-51 Mk.1A
- Civil transport helicopter powered by a 520 hp (388 kW) Alvis Leonides 521/1 radial piston engine. Built by Westland in the United Kingdom, 36 built.
- Westland-Sikorsky WS-51 Mk.1B
- Civil transport helicopter powered by a 450 hp (336 kW) Pratt & Whitney R-985 Wasp Junior B4 radial piston engine, 15 built.
Military and government operators
- Royal Air Force
- Royal Navy
- Dragonfly HR.1 VZ962 on display at the Ta'Qali Museum, Malta.
- Dragonfly HR.3 WG725 in Nowra, New South Wales, Australia
- Dragonfly HR.5 VX595 on display at the Fleet Air Arm Museum, Somerset, United Kingdom
- Dragonfly HR.5 WG719 on display at The Helicopter Museum, Somerset, United Kingdom.
- Dragonfly HR.5 WG724 on display at the North East Aircraft Museum, Tyne and Wear, United Kingdom.
- Dragonfly HR.5 WG751 on display at the Chatham Historic Dockyard, Kent, United Kingdom.
- Dragonfly HR.5 8-1 on display at the Aviodrome, Lelystad, Netherlands.
- Dragonfly HR.5 WH991 on display at the Yorkshire Air Museum, North Yorkshire, United Kingdom.
- Dragonfly HR.5 WN493 on display at the Fleet Air Arm Museum, Somerset, United Kingdom.
- Dragonfly HR.5 WN499 on display at AeroVenture, South Yorkshire, United Kingdom.
- Dragonfly HR.5 WP495 on display at RAF Museum Cosford, Shropshire, United Kingdom. Marked as G-AJOV.
- Dragonfly HR.5 on display at the Sri Lanka Air Force Museum, SLAF Ratmalana, Sri Lanka.
- Westland/Sikorsky S-51 Dragonfly on display at the Museu Eduardo André Matarazzo, Bebedouro, SP, Brazil.
- Westland-Sikorsky WS-51 Mk.1A H1-4/96 (cn WA/H/120) at Royal Thai Air Force Museum, Don Muang AFB, Thailand
- Westland-Sikorsky WS-51 Mk.1B 11503 on display at the Yugoslav Aeronautical Museum, Belgrade, Serbia.
Specifications (Dragonfly HR.1)
Data from 
- Crew: 1 (pilot)
- Capacity: 3 (passengers)
- Length: 57 ft 6½ in (17.54 m)
- Main rotor diameter: × 48 ft 0 in (14.63 m)
- Height: 12 ft 11½ in (3.95 m)
- Main rotor area: 1809.56 ft2 (168.11 m2)
- Empty weight: 4380 lb (1987 kg)
- Gross weight: 5870 lb (2663 kg)
- Powerplant: 1 × Alvis Leonides 50 radial piston, 540 hp (403 kW)
- Maximum speed: 95 mph (153 km/h)
- Range: 300 miles (483 km)
- Service ceiling: 12,400 ft (3780 m)
- Jackson, 1974, pp 618–619
- "Worlds Helicopter Market 1968 pg. 50". flightglobal.com. Retrieved 16 June 2018.
- "THE WORLD'S AIR FORCES 1955 pg. 658". flightglobal. Retrieved 18 October 2014.
- "World Air Forces 1955 pg. 631". flightglobal.com. Retrieved 2 February 2015.
- James 1991, p. 308.
- Jefford 1988, p. 134.
- "Westland S-5I". Flightglobal Insight. 1953. Retrieved 18 October 2014.
- Howard/Burrow/Myall 2011, pp.11–35
- "Westland Dragonfly HR5 (WN493)". Fleet Air Arm. Retrieved 28 January 2015.
- "THE WORLD'S AIR FORCES 1955 pg. 668". flightglobal. Retrieved 18 October 2014.
- "Helicopters in Civil Operation pg. 388". flightglobal. 21 March 1958. Retrieved 18 October 2014.
- "Westland Dragonfly". Demobbed. Retrieved 1 February 2015.
- Orbis 1985, page 3080
- The Illustrated Encyclopedia of Aircraft (Part Work 1982–1985). Orbis Publishing.
- Howard, Lee; Burrow, Mick; Myall, Eric (2011). Fleet Air Arm Helicopters since 1943. Air-Britain Historians Limited. ISBN 978-0-85130-304-8.
- Jackson, A.J. (1974). British Civil Aircraft Since 1919 – Volume Three. Putnam & Company Limited. ISBN 0-370-10014-X.
- James, D (1991). Westland Aircraft since 1915. London: Putnam Aeronautical Books. ISBN 9780851778471.
- Jefford MBE, Wg Cdr C G (1988). RAF Squadrons. A comprehensive record of the movement and equipment of all RAF squadrons and their antecedents since 1912. Shrewsbury: Airlife. ISBN 1-85310-053-6.
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