Westland WS-51 Dragonfly

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WS-51 Dragonfly
Westland Dragonfly HR.3 WG723 706 Sq BAG 20.08.55 edited-2.jpg
Dragonfly HR.3 of 705 Naval Air Squadron Royal Navy in 1955
Role Rescue or communications helicopter
Manufacturer Westland Aircraft
First flight 5 October 1948
Introduction 1950
Status Retired
Primary users Royal Navy
Royal Air Force
Produced 1949–1954
Number built 133
Developed from Sikorsky H-5
Variants Westland Widgeon

The Westland WS-51 Dragonfly helicopter was built by Westland Aircraft and was a licence-built version of the American Sikorsky S-51.

Design and development[edit]

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.

Operational history[edit]

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.[1]


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[edit]

 Hong Kong
 United Kingdom
British European Airways Sikorsky S-51 in 1953

Civil operators[edit]

 United Kingdom


WS-51 Mk.1A in Royal Thai Air Force Museum in December 2014

+data [12]

Specifications (Dragonfly HR.1)[edit]

Westland Dragonfly HR3

Data from [13]

General characteristics

  • 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)

See also[edit]

Related development

Related lists



  1. ^ a b c d e Jackson, 1974, pp 618–619
  2. ^ "Worlds Helicopter Market 1968 pg. 50". flightglobal.com. Retrieved 16 June 2018.
  3. ^ "THE WORLD'S AIR FORCES 1955 pg. 658". flightglobal. Retrieved 18 October 2014.
  4. ^ "World Air Forces 1955 pg. 631". flightglobal.com. Retrieved 2 February 2015.
  5. ^ James 1991, p. 308.
  6. ^ Jefford 1988, p. 134.
  7. ^ a b "Westland S-5I". Flightglobal Insight. 1953. Retrieved 18 October 2014.
  8. ^ a b c d e f Howard/Burrow/Myall 2011, pp.11–35
  9. ^ a b "Westland Dragonfly HR5 (WN493)". Fleet Air Arm. Retrieved 28 January 2015.
  10. ^ "THE WORLD'S AIR FORCES 1955 pg. 668". flightglobal. Retrieved 18 October 2014.
  11. ^ "Helicopters in Civil Operation pg. 388". flightglobal. 21 March 1958. Retrieved 18 October 2014.
  12. ^ "Westland Dragonfly". Demobbed. Retrieved 1 February 2015.
  13. ^ 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.

External links[edit]