Blackburn Aircraft Limited was a British aircraft manufacturer from 1914 to 1963 that concentrated mainly on naval and maritime aircraft.

The Cirrus and Hermes or Cirrus-Hermes are a series of British aero engines manufactured, under various changes of ownership, from the 1920s until the 1950s. The engines were all air-cooled, four-cylinder inline types, with earlier ones upright and later designs inverted.