The ADC Cirrus is a series of British aero engines manufactured using surplus

Renault Renault S.A., commonly referred to as Groupe Renault ( , , , also known as the Renault Group in English), is a French Multinational corporation, multinational Automotive industry, automobile manufacturer established in 1899. The company curr ...

parts by the Aircraft Disposal Company (ADC) in the 1920s. The engines were air-cooled, four-cylinder inline types. They were widely used for private and light aircraft.

Design and development

The Cirrus engine originated in

Geoffrey de Havilland Captain (British Army and Royal Marines), Captain Sir Geoffrey de Havilland, (27 July 1882 – 21 May 1965) was an English aviation pioneer and aerospace engineer. De Havilland, The aircraft company he founded produced the de Havilland Mosquit ...

's 1924 search for a powerplant suitable for the light two-seat sports biplane which would become the

de Havilland Moth The de Havilland Moths were a series of light aircraft, sports planes, and military trainers designed by Geoffrey de Havilland. In the late 1920s and 1930s, they were the most common civilian aircraft flying in Britain, and during that time eve ...

. No engine existed at the time with a suitable level of power combined with a low weight. The Aircraft Disposal Company, also known as Airdisco and ADC, were producing the low-cost Airdisco V8 which had been developed by

Frank Halford Major Frank Bernard Halford CBE FRAeS (7 March 1894 – 16 April 1955) was an English aircraft engine designer. He is best known for the series of de Havilland Gipsy engines, widely used by light aircraft in the 1920s and 30s. Career Educate ...

from their large stocks of war surplus Renault V8 aero engines. De Havilland realised that half of this engine would make an air-cooled four-cylinder inline engine of just the right size at low cost. He persuaded Halford to undertake its design and development. The cylinders, pistons, con-rods and gearing were taken from the Renault, with the valve gear based on the Airdisco, and a new five-bearing crankshaft and cast crankcase were designed. It became the first Cirrus engine, and the first air-cooled four-cylinder inline aero engine to go into quantity production. The original Cirrus engines were all designed by Halford and built by ADC. The Cirrus I passed its 50-hour

type rating A type rating is an authorization entered on or associated with a pilot license and forming part thereof, stating the pilot's privileges or limitations pertaining to certain aircraft type. Such qualification requires additional training beyond ...

in 1925. De Havilland launched his product as the Cirrus Moth and it proved a winning combination. The engine was soon adopted for other aircraft. Later versions named the Cirrus II, and Cirrus III were produced, each with slightly greater displacement and power (Cirrus II - 85 hp, Cirrus III - 90 hp).Gunston 1989 ADC ceased manufacture when it ran out of surplus Renault engines around 1928.

Subsequent manufacture

When ADC ran out of parts, manufacture of the Cirrus III was taken up by Cirrus Aero Engines, also based at

Croydon Croydon is a large town in South London, England, south of Charing Cross. Part of the London Borough of Croydon, a Districts of England, local government district of Greater London; it is one of the largest commercial districts in Greater Lond ...

. The Cirrus III was also adapted and improved by American Cirrus Engines, who manufactured it under license.

Variants

;Cirrus I :(1925) ;Cirrus II :(1926) ;Cirrus III :(1929)

Applications

''List from Lumsden'' except where noted. The list includes trial installations where a different engine was principally adopted.

Cirrus

Cirrus I

Avro Avian The Avro Avian is a series of United Kingdom, British light aircraft designed and built by Avro in the 1920s and 1930s. While the various versions of the Avian were sound aircraft, they were comprehensively outsold by the de Havilland Moth and ...

* Avro Baby * de Havilland DH.60 Moth * Short Mussel * Westland Widgeon

Cirrus II

* de Havilland DH.60 Moth *

de Havilland DH.71 Tiger Moth The de Havilland DH.71 Tiger Moth was a British single-seat monoplane, designed to research high-speed flight and to test replacement engines for the Cirrus. Only two were built. Design and development It was a low-wing monoplane based on t ...

* Piaggio P.9 * Short Mussel * Westland Widgeon * Bloudek XV Lojze

Cirrus III

* Blackburn Bluebird * Cierva C.17 * de Havilland DH.60 Moth *

* Dudley Watt D.W.2 * Emsco B-4 Cirrus * Koolhoven FK.41Jackson p.190 1973 * Klemm L.26 * Klemm L.27 * Short Mussel * Simmonds Spartan * Spartan Arrow *

Westland Wessex The Westland Wessex is a British-built turbine-powered development of the Sikorsky H-34. It was developed and produced under licence by Westland Aircraft (later Westland Helicopters). One of the main changes from Sikorsky's H-34 was the rep ...

* Westland Widgeon

Engines on display

*A preserved ADC Cirrus II is on display at the

Science Museum (London) The Science Museum is a major museum on Exhibition Road in South Kensington, London. It was founded in 1857 and is one of the city's major tourist attractions, attracting 3.3 million visitors annually in 2019. Like other publicly funded ...

Specifications (Cirrus I)

References

Notes

Bibliography

* The Aviation Ancestry Database of British Aviation Advertisements 1909–1990
Cirrus advertisements
(retrieved 23 April 2020). * Gunston, Bill. ''World Encyclopaedia of Aero Engines''. Cambridge, England. Patrick Stephens Limited, 1989. * * * Lumsden, Alec. ''British Piston Engines and their Aircraft''. Marlborough, Wiltshire: Airlife Publishing, 2003. . * Taylor, Douglas R. ''Boxkite to Jet: The Remarkable Career of Frank B. Halford''. Rolls-Royce Heritage Trust. 1999. . * {{Cirrus aeroengines 1920s aircraft piston engines Cirrus