It was good to see the photograph and letter on the Cierva autogyro, sent in by S. W. Layfield. The engine is indeed an Armstrong Siddeley, a 140 h.p. Genet Major, IA, in fact. The aircraft depicted is a Model C30A, by A. V. Roe Ltd. This craft had a top speed of 110 m.p.h. and a cruising speed of 95 m.p.h. with a range of 280 miles. The take-off run being about 12 yards.
It may be of further interest that Senor De La Cierva accepted an invitation extended by the British Air Ministry, in 1925, to demonstrate the capabilities of his autogyro in Britain. The display took place during October of that year, at the Royal Aircraft Establishment at Farnborough, on Laffan’s Plain, which, incidentally, is where Cody conducted his early aviation experiments.
The machine, AC6A, based on an Avro 504K fuselage, was powered by a La Rhone 120 h.p. engine, driving a standard airscrew. Initial rotor momentum was gained by pulling a rope wound on to the base shaft. Later models used the slipstream effect to start the rotor, this was achieved by deflecting the stream upwards, with the elevators and box tailplane locked in a near vertical position. This method in turn gave way to the more positive shaft drive from the engine through a clutch.
During the demonstration at Farnborough, the C6A autogyro, piloted by Captain F. T. Courtney, attained a level speed of 68 m.p.h., fully loaded, and completed a perfect drop from 500 feet, with the engine switched off. The performance was witnessed by the Air Minister of the period, Sir Samual Hoare, and other top brass.
Later, two autogyros were ordered by the Ministry from Avro, followed by many more through the years. Eventually, the Royal Air Force formed No. 539 Squadron to operate the type. This unit was disbanded towards the end of 1945.
The sad loss of Senor De La Cierva, on December 9th, 1936, when the KLM DC2 in which he was a passenger crashed shortly after take-off from Croydon, resulted in autogyro development tapering off.
The type is still in use today, of course, but the machines are much smaller. It would be interesting if any reader could contribute some information regarding the operation record of No. 529 Squadron. I believe their base was at Halton.