July 31, 2007

Fairey FB-1 Gyrodyne helicopter

In April 1946 Fairey announced a private-venture project for a rotary-wing aircraft, to be built to a new concept originated by Dr. J.A.J. Bennett who had joined the company the previous year. Dr Bennett had assumed control of the Cierva Autogyro Company in 1936, following the death of Juan de la Cierva, and Bennett's ideas were based on the combination of a lifting rotor plus an asymmetric propeller mounted on a stub wing, which would counteract yaw and provide thrust, lessening the loading on the rotor.

Fairey FB-1 Gyrodyne helicopter was a British experimental compound aircraft used a propeller set on the end of a stub wing to provide both propulsion and antitorque reaction.

The Gyrodyne was a compact and streamlined helicopter weighing just over 2000kg and powered by a 525hp Alvis Leonides radial engine, the power from which could be transmitted in variable ratios to a three-blade rotor just over 15m in diameter and to the anti-torque propeller on the starboard tip of the stub wing. The Gyrodyne behaved like a helicopter, but the same propeller also provided the necessary thrust for forward flight, when the aircraft looked almost like an autogyro.

A government contract to Specification E.4/46 was awarded for two prototypes with the first Fairey Gyrodyne exhibited as an almost complete airframe at White Waltham on 7 December 1946.

On 4 December 1947, the first of the two prototypes took off from White Waltham airport, and continued to build up flying time until March 1948 when it was dismantled for a thorough examination. The second prototype, basically similar to the first but with more comfortable interior furnishings befitting its role as a passenger demonstrator, was flying by the time of the next SBAC Display, in September 1948, at Farnborough. The first prototype was re-assembled and, following further test flying, took part in an attempt to set a new world's helicopter speed record in a straight line.

On 28 June 1948, flown by test pilot Basil Arkell, the Gyrodyne made two flights in each direction over a 3km course at White Waltham, achieving 200km/h, enough to secure the record. An attempt was to be made in April 1949 to set a 100km closed-circuit record, but two days before the date selected a rotor head fatigue failure resulted in the crash of the aircraft at Ufton, near Reading, killing the pilot, F.H. Dixon and his observer.

The subsequent grounding of the second Gyrodyne for an investigation was only to be expected, and the aircraft did not appear again until 1953. The extensively modified second prototype, renamed Jet Gyrodyne, flew in January 1954; it had two blade-tip jets, fed with air from two compressors driven by the usual Alvis Leonides radial. The Jet Gyrodyne had been completely redesigned to provide data on Fairey's big project, the Fairey Rotodyne.

An example of the Gyrodyne is on display at the Museum of Berkshire Aviation, Woodley, Reading.

Source: Wikipedia

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