Country of origin:

United States of America

Description:

General-purpose utility helicopter

Power Plant:

One 336 kw (450 hp) Pratt & Whitney R-985-AN-5 Wasp Junior nine-cylinder air-cooled radial engine

Specifications:

History:

Developed from the Sikorsky R-4 (the Vought Sikorsky Model 316A), which was the first helicopter produced for the US armed services in quantity, the Vought Sikorsky Model 327 followed the design layout, with main and tail rotors shaft-driven from an engine in the fuselage, but was a completely new design.  Four prototypes were first ordered on 18 August 1943, a fifth prototype being ordered later.  Seating two in tandem, two of the prototypes were later re-designated XR-5A after being fitted with British equipment.  It was operated by the US Navy as the H02S-1 and H03S-1.

Twenty-six machines, known as the YR-5A, were ordered for USAAF service trials, and 34 R-5As were built.  The latter quantity had provision for a litter carrier on each side of the fuselage, and this type was the first helicopter to enter service with the US Air Rescue Service. Twenty-one R-5As were modified to R-5D standard by the addition of a second passenger seat, a rescue hoist, auxiliary fuel tank, a nose-wheel and the Pratt & Whitney R-985-AN-5 Wasp Junior engine.  The YR-5E was the XR-5A fitted with dual controls.

From the military Sikorsky R-5, the S-51 commercial helicopter was developed.  The prototype was flown for the first time on 16 February 1946.  The production machine differed from the R-5 by having a larger rotor, four seats in the cabin, a nose-wheel in place of the tail-wheel, and the gross weight increased from 2,189 kg (4,825 lb) to 2,812 kg (6,200 lb).  Eleven S-51s were obtained by the USAF as the F-5F.  The S-51 was the first helicopter licensed for commercial operations in the USA.  It was built under licence in the United Kingdom by Westland as the Dragonfly with a 388 kw (520 hp) Alvis Leonides 50 engine.  A total of 300 S-51s was built, a number having a 447 kw (600 hp) engine.

Three S-51s were obtained for the RAAF (serials A80-1, A80-374 and A80-636).  The first was handed over to Australian personnel at the Sikorsky plant and shipped to Australia on the SS Spitfire on 30 June 1947.  As A80-1 it was assembled and commenced trials on 11 December at ARDU, one of its first public appearances being the conveyance of Santa Claus to a Christmas Party at RAAF Point Cook, VIC.  It made a number of interstate flights in 1948 giving displays as part of Air Force Week in the days when the RAAF had regular open days and air shows.  In 1949 it conducted trials with fire services in May, and in October conducted crop dusting trials at Laverton, VIC.

On 25 April 1950 two more S-51s were ordered, delivery being taken in New Jersey, USA and they were shipped to Australia on the Pioneer Isle in March 1951.  They were assembled at No 2 AD at Richmond, NSW, A80-374 going to Laverton in 1951 and A80-636 to No 23 Squadron at Archerfield, QLD.  At that time it seemed all RAAF helicopters were to receive the series serial A80-, and A80-2 was allotted to a Bristol Sycamore. In the event the Sycamore serial A80-2 was changed to A91-1.

Subsequently three S-51s operated from Laverton, Schofields, NSW and Archerfield, being close to the capital cities so they could take part in rescue, flood relief and bushfire operations.  In December 1951 A80-1 was allotted to No 21 Squadron but crashed into the Murray River near Tocumwal, NSW on 4 December 1951 when it hit power lines across the river and was destroyed.  A80-636 operated with No 23 Squadron from August 1951, later going to No 22 Squadron at Schofields where it was damaged in an accident on 10 December 1952, later being converted to components.

A80-374, after spending some time with the ARDU in 1951, went to No 22 Squadron and on 1 August 1951 became the first helicopter to fly under the Sydney Harbour Bridge.  In February 1953 it went to No 21 Squadron at Laverton and was flown in a search for uranium for the Minerals Department.  In 1954 it went to No 22 Squadron, but in 1955 it became unserviceable at No 2 AD.  In November 1960 it went to No 2 OCU at Williamtown, NSW where it stayed until its life of type expired in June 1963. It finished its flying days assisting during floods in the Hunter Valley during that year.  It later became an Instructional Airframe with the RAAF School of Technical Training.  It spent some time as a static display aircraft for RAAF recruitment before being transferred to the RAAF Museum at Point Cook where it was restored and placed on display in 1974.

During the Korean War in the 1950s a couple of US Navy HO3S-1 (Code UP-28) helicopters were stationed on board HMAS Sydney and flown by a American crew on rescue missions whilst the carrier was operating its Hawker Sea Furies and Fairey Fireflies.  Serials of these machines included 122714 (c/n 5196) named Honey Bucket and 124350 (c/n 51210) which later became a civil aircraft, N5557A.  The type has also been seen in New Zealand. An HO3S-1 (124335) was on board the USS Tarawa when it visited Wellington in 1954; and another was on board a Unitd States icebreaker when it visited Wellington, NZ in 1957.