an outmoded technology?

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1 The autogyro an outmoded technology? Aviation News Above: Famous for his flying displays with Little Nellie (G-ARZB), a WA-116, in the James Bond film You Only Live Twice, Ken Wallis sits in the diminutive autogyro, now grounded due to restrictive air safety requirements. (Photos, Aviation News except where stated) The autogyro is a rotary winged aircraft that uses a propeller for forward motion and a freely rotating, unpowered, rotor for lift. Was the autogyro merely a stepping-stone to the helicopter and is it therefore outmoded technology? Retired aerodynamicist and aircraft designer Arthur W J G Ord-Hume thinks not and tells us why. THE quest for vertical flight via a powered rotor pre-dates the autogyro by many years, with Leonardo da Vinci among the first with the idea in the 15th century. It periodically occupied the minds of others down the years. The first recorded ascent in a rotary winged flying machine was made by Etienne Oemichen on April 14, 1924 but such pioneering efforts were blighted by a common defect uncertainty of control. Getting into the air was the easy bit. Maintaining control and following a desired path was another. The autogyro was the newcomer into this arena of experiment. It was the creation of Spanish-born Juan de la Cierva, a brilliant mathematician who taught himself his own special branch of aerodynamics through prolonged experiment and much trial and error. Cierva invested only in the perfection of a rotor system. For the rest he cut costs and used readily available components from existing aeroplanes which, shorn of unnecessary parts, gave him a head start in construction. His first

2 attempts used modified Spanish military trainers for the basic airframe but soon he changed to the more readily available Avro 504. Below: Established by Earle Spangenburg Eckel near Washington, NJ, this unique Autogiro Port displays (right) a Pitcairn autogyro together with its designer. (Photo, Donald A Eckel courtesy of MMP Books) Nevertheless the difficulties he faced were daunting. At that time he had not learned to fly and he had to find a competent pilot to conduct his experiments. Unfortunately, his early autogyros had a tendency to self-destruct, simply rolling over on the ground before ever getting into the air. Only after six distinct designs did he succeed in achieving a controlled flight in a straight line followed by a circuit of the military airfield outside Madrid where he had based his experiments. Cash shortage forced Cierva to look for foreign backers. The French were interested but diffident. He tried two British companies, Westland and Vickers. The Yeovil firm saw no future in the autogyro but Vickers sent a team to Madrid to evaluate his work. Chief designer Rex Pierson was impressed and back at Weybridge they carried out their own wind-tunnel tests. These did not match Cierva s own findings so Vickers backed off. Meanwhile, the Air Ministry learned of the young Spaniard who had a machine with rotary wings that actually flew. The scientific research director, Harry Wimperis, decided to invite Cierva and his machine to Farnborough, where both could be put through their paces under the critical eyes and control of the Royal Aircraft Establishment.

3 Above: The close-up of a VPM M-16, an Italian designed autogyro produced by a factory near Milan, displays the engine, drive, transmission and rotor essential elements in this unique form of aircraft where, perhaps surprisingly, simplicity has ensured safety at a high level. Juan de la Cierva and his C.6bis soon anglicized as C.6a arrived at Farnborough on October 4, But Cierva s demonstration pilot had fallen ill before departure. To make matters worse, Cierva spoke no English. Fortunately some while earlier he had met the accomplished British pilot Frank Courtney in Madrid, where they had conversed in French. Cierva telephoned Courtney who henceforth undertook the early demonstration and test flying. To Cierva s credit he quickly learned English and even learned to fly, finally becoming his own

4 test pilot. The path to success was nowhere straightforward and the Farnborough trials were protracted and failed to gain the vital military interest everybody needed. In America, industrialist Harold Pitcairn was an enthusiast for rotary-winged flight and, having had a meeting with Cierva, they became close friends and business partners. Pitcairn formed The Autogyro Company of America and, with Cierva s backing, he developed his own autogyro. Denied a military contract back home, Cierva found strong industrial backers and a private company was formed, known as Hanworth Air Park, in West London. Cierva never made his own aircraft but most came from the factory of A V Roe, first at Hamble and then Manchester. The Cierva Company (registered as the Cierva Autogiro Company) wanted a machine that could enter production and it was here that problems arose. Pressed by his co-directors for such a machine, Cierva proved himself a perfectionist and perpetual improver. As soon as a suitable design seemed on the horizon, changes were needed. The final models in which he had a hand were the C.30 series but even these were subject to constant alteration. Although many C.19 and C.30 machines were made, they were at least twice the price of a fixed wing aeroplane. Meanwhile Cierva s relationship with his own company was becoming strained. His co-directors saw the future was in helicopters and they were already looking at permanently powered rotors. In a curious move that has never been fully explained, Juan de la Cierva made over all his autogyro patents to Harold Pitcairn in Philadelphia. Pitcairn would attend all the Cierva Company meetings in London and keep everybody fully aware of progress in America. Juan de la Cierva was killed in Hillcrest Road, Croydon, when the DC-2 in which he was flying as a passenger crashed in fog on December 6, This heralded a sea change in the conduct of the Cierva operation. The German designer Otto Reder was brought in to take the company further. Reder produced the C.40, which gained some military interest after its first demonstration in February Below: The Cierva Autogiro Co and Avro had a long association with the type including purchase by the RAF in 1934 of ten Cierva C.30A Rota aircraft designated Avro Type 671. This example, HM580, is preserved at the Imperial War Museum at Duxford.

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