Juan de la Cierva
In the twenties and thirties there was a flying machine which at that time excited much attention and gave a strong stimulus to the development of rotor aircraft, but which today is almost as good as forgotten. By its inventor it was designated as an “Autogiro”.
The Spaniard aircraft constructor was born in 1895 and had interested himself since 1919 in the problems of Short Take Off and Landing. He worked out the principles of the autogiro himself, the principles whereby the wing is replaced by a rotor. After an initial start with a motor placed in the fuselage, the rotors are set in motion by themselves, and after a short time, the autogiro can lift off. From the formulation of these basic principles to the actual completion of an airworthy machine was a long haul.
Initially the autogiros simply flipped over, until at the end of 1922, de Cierva replaced the rigidly-fixed rotor blades with ones hinged at the rotor head. Therefore the flapping-hinge was introduced which later helped the helicopter to make a breakthru. Thru the flapping-hinge the different forces of lift were so equalized that the autogiro could rise into the air.
The first successful flight of a Cierva autogiro took place on 9. January 1923 in the vicinity of Madrid when the pilot Gomez Spencer took the prototype C4, powered by a 100 hp Le Rhone rotating engine, on a 4 kilometer long flight, during which he reached a speed of 60 km / h. With it the spell was broken and de la Cierva developed further types in quick succession. On the invitation of the British Air Ministry, he demonstrated his C 6A type, (which was built from the fuselage of an Avro 504K trainer) at Farnborough in October 1925.
In 1926, de la Cierva settled in Britain and, with the aid of Air Commodore Lord Weir, he founded the Cierva Autogyro Company in Hanworth. In 1931 appeared the best-known type - the C 19, which had a speed range of 40-170 km/h. In 1932, de la Cierva received the Great Gold Medal of the FAI. In various firms in Britain as well as abroad, Cierva autogiros were built under license.
In Deutschland, the Focke-Wulf works in Bremen produced the C 19 and C 30 under license, about forty of the latter being produced. In the USA it was the firm of Pitcairn and Kellett who produced the machines under license. Juan de la Cierva learnt how to fly in 1927 and managed on 18. September 1928 a great personal success, when he flew in his own autogiro CL 8 from London-Croydon to Paris-Le Bourget, thereby achieving the first crossing of the English Channel/Manche in an autogiro.
Further technical developments were constantly worked on. A hop start was developed for take-off - with the brakes applied the rotor is connected to the motor, causing the autogiro to leap several meters into the air, the engine is quickly switched to the main propeller and the autogiro will climb at a steep angle.
An important property was missing from the autogiro admittedly - it was not possible to hover over a fixed point. It was also not possible to move backwards or sideways. Properties which were left to the helicopter, allowing it to become the predominant rotor machine. On 9. December 1936, Juan de la Cierva lost his life in the crash of a passenger aircraft at Croydon.
His autogiros experienced a period of success in both the civil and military areas. In the USA in 1939, Eastern Air Lines used a Kellett Autogiro to operate a service in Philadelphia between the head post office and the airport.