An autogyro, also known as a gyroplane or gyrocopter, is a type of rotorcraft that uses an unpowered rotor in free autorotation to develop lift. Forward thrust is provided independently, by an engine-driven propeller. While similar to a helicopter rotor in appearance, the autogyro's rotor must have air flowing across the rotor disc to generate rotation, and the air flows upwards through the rotor disc rather than down.
Juan de la Cierva y Codorníu, 1st Count of la Cierva was a Spanish civil engineer, pilot and aeronautical engineer. His most famous accomplishment was the invention in 1920 of the first helicopter called Autogiro, a single-rotor type of aircraft that came to be called autogyro in the English language. In 1923, after four years of experimentation, De la Cierva developed the articulated rotor, which resulted in the world's first successful flight of a stable rotary-wing aircraft, with his C.4 prototype.
The Avro 504 was a First World War biplane aircraft made by the Avro aircraft company and under licence by others. Production during the war totalled 8,970 and continued for almost 20 years, making it the most-produced aircraft of any kind that served in the First World War, in any military capacity, during that conflict. More than 10,000 were built from 1913 until production ended in 1940.
The Cierva C.30 was an autogyro designed by Juan de la Cierva and built under licence from the Cierva Autogiro Company by A V Roe & Co Ltd (Avro), Lioré-et-Olivier and Focke-Wulf.
Le Rhône was the name given to a series of popular rotary aircraft engines produced in France by Société des Moteurs Le Rhône and the successor company of Gnome et Rhône. They powered a number of military aircraft types of the First World War. Le Rhône engines were also produced under license worldwide.
Morane-Saulnier MoS-50 was a French parasol configuration trainer aircraft built in 1924. The twin-seat aircraft was of wooden construction and was one of the last aircraft to have a rotary engine, a 97 kW (130 hp) Clerget 9B.
The Pitcairn OP-1 was the first rotary-wing aircraft to be seriously evaluated by any of the world's major air forces. The machine was not a helicopter, nor an airplane, but an autogyro. Pitcairn's model was never put into production for any military.
The Le Rhône 9J is a nine-cylinder rotary aircraft engine produced in France by Gnome et Rhône. Also known as the Le Rhône 110 hp in a reference to its nominal power rating, the engine was fitted to a number of military aircraft types of the First World War. Le Rhône 9J engines were produced under license in Great Britain by W.H. Allen Son & Company of Bedford, and in Germany by Motorenfabrik Oberursel.
The Clerget 9B was a nine-cylinder rotary aircraft engine of the World War I era designed by Pierre Clerget. Manufactured in both France and Great Britain, it was used on such aircraft as the Sopwith Camel. The Clerget 9Bf was an increased stroke version.
The Cierva Autogiro Company was a British firm established in 1926 to develop the autogyro. The company was set up to further the designs of Juan de la Cierva, a Spanish engineer and pilot, with the financial backing of James George Weir, a Scottish industrialist and aviator.
The Cierva C.8 was an experimental autogyro built by Juan de la Cierva in England in 1926 in association with Avro. Like Cierva's earlier autogyros, the C.8s were based on existing fixed-wing aircraft fuselages – in this case, the Avro 552.
The Cierva C.17 was a British experimental autogyro built by Cierva Autogiro Company in England in 1928, in association with Avro. It was an attempt to build upon the successful Cierva C.8 design using the smaller, more streamlined fuselage of an Avro Avian IIIA as a starting point. The type was found to be underpowered, and when the first attempt at fitting a more powerful engine still did not result in acceptable performance, the design was abandoned.
The Cierva C.19 was a 1930s British two-seat autogyro, designed by Spanish engineer Juan de la Cierva. It was built by Avro as the Avro Type 620. It proved to be the most successful and widely produced of the early de la Cierva designs.
The Kellett KD-1 was a 1930s American autogyro built by the Kellett Autogiro Company. It had the distinction of being the first practical rotary-wing aircraft used by the United States Army and inaugurated the first scheduled air-mail service using a rotary-wing aircraft.
The Pitcairn PA-34 and Pitcairn PA-33, given the United States Navy (USN) designation Pitcairn OP-2 and United States Army designation Pitcairn YG-2 respectively were reconnaissance auto-gyros designed and built in 1936 for evaluation.
The Avian 2/180 Gyroplane was a two-seat, single-engine autogyro built in Canada in the 1960s. Several prototypes were built but production was not achieved.
The Besson H-3 was a French civil touring triplane flying boat designed by the Marcel Besson company of Boulogne. One aircraft was built and the type did not enter production.
The Cierva C.29 was a five-seat British cabin autogyro built in 1934 as a joint venture between Westland Aircraft and Cierva. The rotor system and rotors were designed by Cierva and the fuselage by Westland. It was powered by a 600 hp (447 kW) Armstrong Siddeley Panther II engine with a two-bladed tractor propeller; the engine also drove the three-bladed rotor via a clutched shaft. The C.29 suffered from ground resonance during ground running and was not flown. It was later acquired for evaluation by the Royal Aircraft Establishment but it was unable to cure the resonance problem and the autogyro was scrapped in 1939.
The Westland CL.20 was a two-seat autogyro designed and built by Westland Aircraft between 1934 and 1938. One flying prototype and six airframes were built, which had control problems and insufficient lift. Before these problems could be solved the programme was abandoned and the prototype was scrapped in 1938.
The Cierva C.7 was an experimental autogiro designed by Juan de la Cierva and built in the late 1920s.
