Cirrus Engine

Cirrus Engine (Cirrus Aero Engines Limited) was a British aircraft engine manufacturer, known for their line of 4-cylinder air-cooled vertical inline engines for general aviation use. 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 Hermes Engine Company and later became the Cirrus Engine Section of Blackburn & General Aircraft Limited in 1934, and operated as a separate division until production ended in the post-World War II era.

Cirrus's first product was 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 that proved extremely popular for light aircraft. The basic layout 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.

After purchase by Hermes the Cirrus Hermes I, II, III & IV were produced ranging in power from 105 hp to 140 hp depending on type. A distinguishing feature is all Cirrus engines afterward were inverted.

Designs

* Cirrus Minor
* Cirrus Major