Grace's Guide is the leading source of historical information on industry and manufacturing in Britain. This web publication contains 133,099 pages of information and 210,772 images on early companies, their products and the people who designed and built them.
Note: This is a sub-section of Blackburn Aeroplane and Motor Co.
ADC Cirrus engines were originally built by ADC Aircraft until Cirrus Aero Engines Limited was formed in 1927. The company became Cirrus-Hermes in 1931 when it was bought by the Cirrus Hermes Engineering Co and later became the Cirrus Engine Section of Blackburn Aircraft Limited in 1937, operating as a separate division until production ended in the post-World War II era.
The first Cirrus engine has been the 90 hp (67 kW) Cirrus I, which passed its 50-hour type rating in 1925. It was the first air-cooled inline engine, a design by Frank Halford that proved extremely popular for light aircraft. The basic layout (using one cylinder bank of an ADC Airdisco V-8 engine) was quickly copied by a number of other manufacturers. 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).