Grace's Guide is the leading source of historical information on industry and manufacturing in Britain. This web publication contains 126,800 pages of information and 199,893 images on early companies, their products and the people who designed and built them.
Cirrus-Hermes Engineering Company, of Purley Way, Waddon, Croydon
1931 Acquired Cirrus Aero Engines Company.
After purchase, the Cirrus Hermes I, II, III & IV were produced ranging in power from 105 hp to 140 hp depending on type. The later Cirrus engines were designed to run inverted.
1933 Constructors of low-powered four in line air cooled aero engines. Works: London Air Port, Croydon, Surrey. Registered Office: 274 Gresham House, Old Broad Street, London, E.C.2.
1933 Patent - Improvements relating to inertia starters for internal combustion engines.
1936 On the formation of Blackburn Aircraft Ltd, Cirrus-Hermes Engineering was an associated company but was not brought into the Blackburn group because its new products (engines) were still in the development phase
1937 Blackburn acquired the Cirrus-Hermes company and started producing aircraft engines - the Blackburn Cirrus range.
1937 Advert for Aero Engines. 90 h.p. "Cirrus Minor" Aero Engine. 150 h.p. "Cirrus major" Aero Engine. Both of the above are 4-cylinder-in-line inverted air-cooled engines. (Engineering/Metals/Quarry, Roads and Mining/Transport - Stand No D.921) 
1937 Aero engine manufacturers. "Cirrus" and "Cirrus Hermes" Aero Engines.