Cirrus engine was created by Major Frank Halford for Captain de
Havilland in 1924. Major Halford was working at the British
government Aircraft Disposal Company (Airdisco) where there
were 30,000 surplus engines.
Halford used the pistons and cylinders from half
of a Renault V-8 and built a new in-line 4-cylinder engine. De
Havilland flew the new engine in the prototype DH.60 Moth in
Cirrus was bought by Hermes Engine Company in the
late 1920s and then by Blackburn Aircraft in 1934. The Cirrus
name was lost after World War II.