The Cierva C.8 was an experimental autogyro built by

Juan de la Cierva Juan de la Cierva y Codorníu, 1st Count of la Cierva (; 21 September 1895 in Murcia, Spain – 9 December 1936 in Croydon, United Kingdom) was a Spanish civil engineer, pilot and a self taught aeronautical engineer. His most famous accomplish ...

in England in 1926 in association with

Avro AVRO, short for Algemene Vereniging Radio Omroep ("General Association of Radio Broadcasting"), was a Dutch public broadcasting association operating within the framework of the Nederlandse Publieke Omroep system. It was the first public broad ...

. Like Cierva's earlier autogyros, the C.8s were based on existing fixed-wing aircraft fuselages – in this case, the Avro 552.

Design and development

The first example, the C.8R (known to Avro as the Type 587) was a rebuild of the C.6D, fitted with stub wings and paddle-shaped main rotor blades. This was followed by the new-built C.8V (or Type 586) that was eventually converted back into an Avro 552 after testing. The next model was the definitive C.8L prototype (or Type 575). The Mark II was based on the Lynx-engined Avro 504N two-seat trainer.''Flight'' 5 July 1928, p. 543 By now, Cierva's efforts were attracting the attention of buyers. The first customer was the British

Air Ministry The Air Ministry was a department of the Government of the United Kingdom with the responsibility of managing the affairs of the Royal Air Force, that existed from 1918 to 1964. It was under the political authority of the Secretary of State ...

, which placed an order for a machine in 1927. This was completed as the Type 611, test flown by Bert Hinkler at Hamble and then delivered to the

Royal Aircraft Establishment The Royal Aircraft Establishment (RAE) was a British research establishment, known by several different names during its history, that eventually came under the aegis of the Ministry of Defence (United Kingdom), UK Ministry of Defence (MoD), bef ...

by Cierva himself in Britain's first cross-country rotorcraft flight on 30 September that year. The next example was purchased by Air Commodore James G. Weir, chairman of Cierva, and flown in the 1928 King's Cup Air Race before being used to make demonstration flights around continental Europe. The two final C.8s were sold in 1928, one to the Italian government, and one to American

Harold Pitcairn Harold Frederick Pitcairn (June 20, 1897 – April 23, 1960) was an American aviation inventor and pioneer. He played a key role in the development of the autogyro and founded the Autogiro Company of America. He patented a number of innovations ...

, who would go on to purchase manufacturing rights for the United States. The C.8W bought by Pitcairn would make the first autogyro flight in the United States at

Willow Grove, Pennsylvania Willow Grove is a census-designated place (CDP) in Montgomery County, Pennsylvania, United States. A community in Philadelphia's northern suburbs, the population was 15,726 at the 2010 census. It is located in Upper Dublin Township, Abington To ...

, on 18 December 1928. The C.8W is the oldest autogyro in the United States. As of 2007, two examples are extant: Weir's machine preserved at the Musée de l'Air et de l'Espace in Paris, and Pitcairn's at the

National Air and Space Museum The National Air and Space Museum of the Smithsonian Institution, also called the Air and Space Museum, is a museum in Washington, D.C., in the United States. Established in 1946 as the National Air Museum, it opened its main building on the Nat ...

in Washington, DC.

Variants

;C.8R: C.6D fitted with new wings and rotor blades, powered by a 97-kW (130-hp)

Clerget Clerget-Blin (full name being ''Société Clerget-Blin et Cie'') was a French precision engineering company formed in 1913 by the engineer and inventor Pierre Clerget and industrialist Eugène Blin. In 1939, the company was absorbed into the ''G ...

engine. (1 converted) ;C.8V: Two-seat model, powered by a 134-kW (180-hp)

Wolseley Viper The Wolseley Viper is a British-built, high-compression derivative of the Hispano Suiza HS-8 liquid-cooled V-8 engine, built under licence by Wolseley Motors during World War I. It powered later models of the S.E.5a, SPAD VII and other Brit ...

piston engine. ;C.8L: (4 built) ;C.8L Mk II: Fitted with short-span wings, powered by an

Armstrong Siddeley Lynx The Armstrong Siddeley Lynx is a British seven-cylinder aero engine developed by Armstrong Siddeley. Testing began in 1920 and 6,000 had been produced by 1939. In Italy Alfa Romeo built a licensed version of this engine named the Alfa Romeo ...

IV radial piston engine. The aircraft took part in 1928 King's Cup Air Race. Built in the United Kingdom as the Avro Type 617. (1 built) ;Weymann-Lepère C.18: Version of C.8L Mk II built under license in France. ;C.8L Mk III: Two aircraft built for the Italian government in 1928. ;C.8W: Powered by a 168-kW (225-hp) Wright Whirlwind radial piston engine. This version was built for Harold Frederick Pitcairn. Original designation C.8L Mk IV. (1 built)

Specifications (C.8 Mark II)

References

;Notes ;Bibliography * * *
NASM website

Cierva C.8
– British Aircraft Directory

External links

{{Cierva aircraft 1920s British experimental aircraft Single-engined tractor autogyros Aircraft first flown in 1926 C.8