Westland WS-51 Dragonfly

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

WS-51 Dragonfly
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

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.

Operational history

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]

Variants
Westland/Sikorsky WS-51
Prototype.
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.

Operators

Military and government operators
 Ceylon
  • Royal Ceylon Air Force[2]
 Egypt
 Italy
 Thailand
 United Kingdom
British European Airways Sikorsky S-51 in 1953
 Yugoslavia
  • SFR Yugoslav Air Force[10]

Civil operators
 Belgium
 Japan
 United Kingdom

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

Brazil

Japan

Malta

Netherlands
HR.5 on static display at the Aviodrome in Lelystad, Netherlands.

Serbia

Sri Lanka

Thailand

United Kingdom
HR.1 at the FAA Museum in Yeovilton, England.

Venezuela
  • HR.3 on static display at the Museo Aeronáutico de Maracay in Maracay, Aragua.[29]

Specifications (WS-51 Mk.1A)
Westland Dragonfly HR3

Data from Jane's all the World's Aircraft 1955–56[30]

General characteristics

  • Crew: 1
  • Capacity: 3 pax (useful load 530 lb (240 kg)
  • Length: 57 ft 6.5 in (17.539 m) overall
  • Fuselage length: 41 ft 1.75 in (12.5413 m)
  • Height: 12 ft 11.375 in (3.94653 m)
  • Empty weight: 4,366 lb (1,980 kg)
HR Mk.1 , HC Mk.4 4,380 lb (1,990 kg)
HC Mk.2 4,450 lb (2,020 kg) including stretcher panners
  • Gross weight: 5,700 lb (2,585 kg)
HR Mk.1, HC Mk.2, HC Mk.4 5,870 lb (2,660 kg)
  • Max takeoff weight: 5,870 lb (2,663 kg)
  • Fuel capacity: 83 imp gal (100 US gal; 380 l) in 2 fuselage tanks
  • Powerplant: 1 × Alvis Leonides 521/1 9-cylinder air-cooled radial piston engine (6lb boost), 520 hp (390 kW)
  • Main rotor diameter: 49 ft (15 m)
  • Main rotor area: 1,885 sq ft (175.1 m2) (Mk. 1A, Mk.1B, HR Mk.3 and HC Mk.4)
  • Rotor diameter (HR Mk.1 and HC Mk.2) 48 ft (15 m)
  • Rotor area (HR Mk.1 and HC Mk.2) 1,809 sq ft (168.1 m2)

Performance

  • Maximum speed: 103 mph (166 km/h, 90 kn) at sea level
HR Mk.1 , HR Mk.3 95 mph (83 kn; 153 km/h)
HC Mk.2 , HR Mk.3 88 mph (76 kn; 142 km/h)
  • Cruise speed: 85 mph (137 km/h, 74 kn)
HC Mk.2 , HC Mk.4 78 mph (68 kn; 126 km/h)
  • Range: 300 mi (480 km, 260 nmi) in still air with 20 minutes fuel reserves
HC Mk.2, HC Mk.4 275 mi (239 nmi)
  • Service ceiling: 11,000 ft (3,400 m)
HR Mk.1 12,400 ft (3,800 m)
HR Mk.3 13,200 ft (4,000 m)
  • Hover ceiling OGE: 6,000 ft (1,800 m)
HC Mk.2 4,600 ft (1,400 m)
  • Hover ceiling IGE: 8,000 ft (2,400 m)
HR Mk.1 5,600 ft (1,700 m)
HR Mk.3 7,000 ft (2,100 m)
  • Best rate of climb HR Mk.1: 800 ft/min (4.1 m/s) at sea level
  • Best rate of climb HR Mk.3: 1,000 ft/min (5.1 m/s) at sea level
  • Vertical rate of climb HR Mk.1: 50 ft/min (0.25 m/s) at sea level
  • Vertical rate of climb HR Mk.3: 200 ft/min (1.0 m/s) at sea level
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See also

Related development

Related lists

References

Citations
  1. 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. "Westland S-5I". Flightglobal Insight. 1953. Retrieved 18 October 2014.
  8. Howard/Burrow/Myall 2011, pp.11–35
  9. "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. "きたかみ号". Misawa Aviation & Science Museum. Retrieved 26 April 2020.
  13. "Main Exhibition Hangar". Malta Aviation Museum. Retrieved 15 June 2019.
  14. "Westland Dragonfly". Demobbed. Retrieved 15 June 2019.
  15. "Airframe Dossier - Sikorsky-Westland Dragonfly HR.3, s/n WG752 RN, c/n WA/H/062". Aerial Visuals. Retrieved 15 June 2019.
  16. "Сикорски С-51Мк-IB". Aeronautical Museum Belgrade. Archived from the original on 3 April 2016. Retrieved 15 June 2019.
  17. "Airframe Dossier - Sikorsky-Westland Dragonfly 1A, s/n CH501 SLAF, c/n WA/H/137". Aerial Visuals.
  18. "Building 5". Royal Thai Air Force Museum. Archived from the original on 26 October 2013. Retrieved 15 June 2019.
  19. Darke, Steve (26 December 2016). "ROYAL THAI AIR FORCE MUSEUM, DON MUEANG" (PDF). The Thai Aviation Website. Retrieved 15 June 2019.
  20. "Airframe Dossier - Sikorsky-Westland Dragonfly HR.5, s/n VX595". Aerial Visuals. Retrieved 15 June 2019.
  21. "[Untitled]". The Helicopter Museum. Archived from the original on 30 October 2018. Retrieved 15 June 2019.
  22. "Exhibits". North East Land, Sea and Air Museums. Retrieved 15 June 2019.
  23. Crick, Darren; Edwards, Martin; Cowan, Brendan (29 June 2015). "RAAF A80 Sikorsky S-51 Dragonfly [and] RAN Westland Dragonfly". ADF-Serials. Retrieved 15 June 2019.
  24. "c/n wa/h/061". Helis.com. Retrieved 15 June 2019.
  25. "Westland – Sikorsky Dragonfly HR.5". Yorkshire Air Museum. Retrieved 15 June 2019.
  26. "Westland Dragonfly HR5 (WN493)". Fleet Air Arm Museum. Retrieved 15 June 2019.
  27. "Aircraft List". South Yorkshire Aircraft Museum. Retrieved 15 June 2019.
  28. "OUR EXHIBITS". Morayvia. Retrieved 15 June 2019.
  29. "Airframe Dossier - Sikorsky-Westland Dragonfly HR.3". Aerial Visuals. Retrieved 15 June 2019.
  30. Bridgman, Leonard, ed. (1955). Jane's all the World's Aircraft 1955–56. London: Sampson Low, Marston & Company, Ltd. pp. 105–106.

Bibliography
  • 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, 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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