Fairey FB-1 Gyrodyne - Testing and Evaluation

Testing and Evaluation

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 reassembled and, following further test flying, took part in an attempt to set a new world 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 2 mi (3 km) course at White Waltham, achieving 124 mph (200 km/h), enough to secure the record. An attempt was to be made in April 1949 to set a 62 mi (100 km) closed-circuit record, but two days before the date selected a poorly machined flapping link in the rotor hub failed during flight and resulted in the crash of the aircraft at Ufton, near Reading, killing the pilot, Foster H. Dixon and observer, Derek Garraway.

The Gyrodyne had been selected for use by the British Army for use in Malaya, beating both the Westland/Sikorsky S.51 Dragonfly and Bristol 171 Sycamore, with an order for six approved by the Treasury at the time of the accident. Though the Gyrodyne's projected performance was significantly better than that of the Dragonfly, and was expected to be in service earlier than the Sycamore, the crash of the first prototype delayed the development programme and the Army, having no other choice, acquired three S.51 Dragonflies, followed by Sycamores at a later date.

The second Gyrodyne was grounded during the accident investigation which determined flapping hinge retaining nut failure due to poor machining as the cause. The extensively modified second prototype, renamed Jet Gyrodyne, flew in January 1954. Though retaining the name "Gyrodyne", the Jet Gyrodyne was a compound gyroplane, and did not operate on the same principle as the original aircraft. It had a two-blade rotor manually controlled with cyclic and collective pitch mechanisms that acted directly on each rotor blade; and was driven by tip jets fed with air from two compressors driven by the Alvis Leonides radial engine. Pusher propellers, one mounted at the tip of each stub wing, provided yaw control through differential collective pitch, and thrust for forward flight. The Jet Gyrodyne was constructed to provide rotor drive and operational data for the Fairey Rotodyne compound gyroplane.

The Jet Gyrodyne is on display at the Museum of Berkshire Aviation, Woodley, Reading.