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1943

Sikorsky R-5 / HO2S

The first helicopter to be built in large numbers was a derivative of the Sikorsky R-5, which started out as a tandem two-seater. The first of five prototypes flew on 18 August 1943 powered by a 450hp Wasp Junior radial. This was followed by 25 YR-5A pre-production models, two of which were assigned to the Navy under the designation HO2S-1. While production of the R-5A was getting under way (34 built), five pre-series aircraft were converted into the R-5E, which had dual control, while at least 20 modified R-5As were later given new, 600hp Wasp Junior engines and redesignated R-5D. From the latter, the S-51 was developed, with a slightly enlarged four-seat cabin and a tricycle landing gear. The first commercial helicopter designed by Sikorsky, it first flew on 16 February 1946 and was certified a month later by the Civil Aviation Agency and delivered to the first customer in August. It was sold to United Air Lines and Los Angeles Airways.

A total of 300 S-51s were built, some with 450hp engines, others with 600hp engines and larger diameter three-blade rotors. The military versions were designated R-5F (11 to the USAF), H-5G (38 fitted with a rescue hoist), H-5H (17 with amphibious wheel/pontoon landing gear), HO3S-1 and S2 (90 in all, naval rescue version). The S-51 had a three-blade articulated rotor, the blades of which could be folded back to facilitate stowage. The first aircraft had manual pitch control; this was later replaced by a hydraulic system. The cabin diameter was also increased.

In 1947, Westland acquired the license to build the S-51 in Britain and produced 139 up to 1953. The British version, named the Dragonfly, had a 550hp Alvis Leonides engine.

G.Apostolo "The Illustrated Encyclopedia of Helicopters", 1984

Sikorsky R-5

Technical data for R-5A

Crew: 1, passengers: 1, engine: 1 x Pratt & Whitney R-985-AN-5 rated at 336kW, rotor diameter: 14.6m, fuselage length: 12.4m, height: 3.9m, take-off weight: 2220kg, empty weight: 1715kg, max speed: 145km/h, cruising speed: 130km/h, rate of climb: 4.4m/s, service ceiling: 4300m, range: 370km

Sikorsky R-5

Sikorsky R-5 / HO2S

Comments 
polo, e-mail, 16.06.2011

which helicopters would have been used? How many would the aircraft carry.

don, e-mail, 03.06.2010

built in England under licence 1947, too late for the war it would have to be the R-4 it activly flew in ww II, the S-51 was used in Los Angeles Airways to deliver mail,replaced by the S-55 (1950 odd to 1975)

Ryan Short, e-mail, 09.05.2009

A lot of that would've depended on the scenario. If it was still occupied territory at the time it would have most likely been carried out by British Lysander aircraft and could've only carried maybe two persons out at a time. If it was more front-line action it would likely be a light liaison aircraft like a Taylorcraft Auster carrying one person.

kiran, e-mail, 20.04.2009

will u send me model sketch of your project let me know something about your project please

Jan, e-mail, 13.03.2008

My 9th grade son is writing a WW II story for his language arts class. He has British airmen rescuing a group of airmen outside a French town using helicopters. Would that have been done, and if so, which helicopters would have been used? How many would the aircraft carry?

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