AP 118 · No. 10 Section II · Aircraft Plate 85 / 161

Plate 85 of 161 · Second World War · Training and liaison helicopter

Sikorsky Hoverfly I

Hoverfly I (R-4B), painted as ‘KK995’, the RAF Museum’s Sikorsky Hoverfly I, which the museum’s own history identifies as KL110, built as R-4B 43-46596 and assembled at Hooton Park in February 1945, flown by the Helicopter Training Flight at Andover, the Transport Command Development Unit and on the King’s Flight mail runs at Balmoral, then by 705 Squadron of the Royal Navy and the College of Aeronautics at Cranfield, presented to the museum in 1966 and refurbished at Bicester in 1967–68 with parts of KK995, whose identity it has carried ever since: the first helicopter in quantity production and the first in RAF and Royal Navy service, a two-seat trainer and liaison helicopter with a 38 ft three-blade fabric-covered main rotor, a Warner R-550 Super Scarab radial buried behind the side-by-side glazed cabin, a long tapering tail boom ending in an open truss that carries a three-blade anti-torque rotor on the starboard side, and fixed main wheels on splayed struts with a tail wheel under the boom, shown standing level with the blades parked and drooping: olive drab upper surfaces and sides over light blue-grey undersides, a white ‘E’ on each side behind the cabin and a smaller one on the band across the nose, Type C1 roundels on the tail boom with ‘KK995’ in black behind them, yellow and black hazard stripes round both cabin doors, grey main blades and black tail rotor blades with yellow tips.

3D model

Turn it over

A procedural model built in Blender from published dimensions, drawings and photographs, painted as ‘KK995’, the RAF Museum’s Sikorsky Hoverfly I, which the museum’s own history identifies as KL110, built as R-4B 43-46596 and assembled at Hooton Park in February 1945, flown by the Helicopter Training Flight at Andover, the Transport Command Development Unit and on the King’s Flight mail runs at Balmoral, then by 705 Squadron of the Royal Navy and the College of Aeronautics at Cranfield, presented to the museum in 1966 and refurbished at Bicester in 1967–68 with parts of KK995, whose identity it has carried ever since: the first helicopter in quantity production and the first in RAF and Royal Navy service, a two-seat trainer and liaison helicopter with a 38 ft three-blade fabric-covered main rotor, a Warner R-550 Super Scarab radial buried behind the side-by-side glazed cabin, a long tapering tail boom ending in an open truss that carries a three-blade anti-torque rotor on the starboard side, and fixed main wheels on splayed struts with a tail wheel under the boom, shown standing level with the blades parked and drooping: olive drab upper surfaces and sides over light blue-grey undersides, a white ‘E’ on each side behind the cabin and a smaller one on the band across the nose, Type C1 roundels on the tail boom with ‘KK995’ in black behind them, yellow and black hazard stripes round both cabin doors, grey main blades and black tail rotor blades with yellow tips. Drag to orbit, scroll or pinch to zoom · download .glb (976 KB)

Data plate

Specification

First flight, number built and top speed are for the whole family (); engine, crew and dimensions are for the Hoverfly I (R-4B) modelled here.

History

The Hoverfly I

Igor Sikorsky proved the single main rotor and small tail rotor layout with his VS-300, which first left the ground in September 1939. The Army Air Forces ordered a two-seat development, the XR-4, which first flew on 14 January 1942 and that May was flown from Stratford, Connecticut, to Wright Field in Ohio over five days, the longest cross-country helicopter flight made at the time.

The R-4 became the first helicopter built in quantity: 131 were made, most of them R-4Bs with the more powerful Warner engine. They were used to train the first military helicopter pilots in the United States, flew from ships in Coast Guard trials, and in April 1944 an R-4 of the 1st Air Commando Group in Burma made the first helicopter rescue behind enemy lines.

About fifty went to Britain under Lend-Lease as the Hoverfly I. The RAF’s Helicopter Training Flight at Andover taught its first helicopter pilots on them from 1945, and the Royal Navy flew them with 705 Squadron at Gosport and for trials at sea until the larger Westland-built Dragonfly replaced them around 1950.

This airframe

Hoverfly I ‘KK995’

KK995The airframe modelled

The RAF Museum’s Hoverfly is displayed as KK995 ‘E’, the code KK995 carried with the Helicopter Training Flight at Andover in 1945, but the museum’s own records identify it as KL110, built as R-4B 43-46596 and assembled at Hooton Park in February 1945. KL110 flew with the Helicopter Training Flight and the Transport Command Development Unit, carried mail for the King’s Flight at Balmoral, then served with 705 Squadron of the Royal Navy and the College of Aeronautics at Cranfield, which presented it to the museum in 1966. It was refurbished at Bicester in 1967–68 using parts of KK995, which had been struck off for spares in 1948, and took that serial from them. The model shows it as displayed in London: olive drab above and light blue-grey beneath, a white ‘E’ on each side and on the band across the nose, Type C1 roundels and the black serial on the tail boom, yellow and black hazard stripes round the cabin doors, grey main blades parked and drooping, and black tail rotor blades with yellow tips.

See it at Royal Air Force Museum London

Where to see one

In the gazetteer

The gazetteer records the Hoverfly I in 2 UK collections. The airframe modelled here is marked.

Every airframe and serial All 161 plates

Profiles and models are procedural interpretations built in Blender from published dimensions, three-view drawings and photographs of each airframe. Treat the museum aircraft as the reference.