A80 Sikorsky S51
The Sikorsky S51 commercial helicopter first flew on 16 February 1946, and was a development of the USAF Sikorsky R5 of 1943. In USAF service the S51 became their 5F until June 1948, when "R" designations were re-categorised as "H". Consequently, the commercial S51 then became the military H5F. However, in the interim, the RAAF purchased a Sikorsky helicopter under Order USA No. R5F S5-5127. This was the first helicopter ordered for the RAAF, although experiments had been carried out during World War II with a Cierva C30A Autogiro, VH-USR, at RAAF Base Laverton.
The Sikorsky S51, as it became known in RAAF service, was received at No 1 Aircraft Depot (1AD) on 3 October 1947 as A80-1. Extensive trials were then carried out at the Aircraft Research and Development Unit, during which time the helicopter was damaged on a number of occasions, before it was allotted to No 21 Squadron on 27 November 1951. However, a few days later it crashed in the Murray River and was held by No 21 Squadron until it was delivered to 1AD on 19 August 1952 for conversion to components.
Late in 1950 two more S51 helicopters were ordered as A80-374 and A80-636. They arrived at 2AD on 17 May 1951, and were allotted respectively to Nos 22 and 23 Squadrons. On 6 November 1952 A80-636 transferred to No 22 Squadron, but it crashed on 10 December 1952 and was scrapped at 2AD on 8 April 1953. A80-374 operated with No 22 Squadron until 21 June 1955, when it was transferred to 2AD.
On 10 November 1955, the name Dragonfly (the RAF title for the S51) was authorised for A80-374 but it continued to be known as the S51. In 1961 the helicopter was allotted to No 81 (Fighter) Wing and, in 1964, A80-374 became an instructional airframe at RAAF Wagga. The aircraft is now held in the collection of the RAAF Museum.
TECHNICAL DATA: Sikorsky S51 Helicopter
DESCRIPTION:Communication and casualty evacuation helicopter. Pilot and three passengers or two stretcher cases. Metal structure with metal rotor blades.
One 450 hp Pratt and Whitney R985 radial engine.
DIMENSIONS:Rotor diameter 14.93 m (49 ft); fuselage length 12.57 m (41 ft 3 in); height 3.94 m (13 ft).
Empty 1715 kg (3780 lb); loaded 2263 kg (4989 lb).
Max speed 166 km/h (90 kt); Cruising speed 137 km/h (74 kt); Climb 15 mins to 10,000 ft (3048 m); Service ceiling 14,400 ft (4389 m); Range 579 km (313 nm).
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