page_title: Cirrus aero engines
section_title: Variants
hierarchical_section_title: Cirrus aero engines / Variants
caption_attribution_description: English: Cirrus Hermes I engine in Roe IV replica, Shuttleworth collection
context_page_description: 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.
  The first Cirrus design was created for the planned de Havilland Moth light aeroplane and, when it appeared in 1925, created the market for private flying. It and its successors were widely used for private and light aircraft from that moment on.
context_section_description: Cirrus I
  (1925)
  Cirrus II
  (1926)
  Cirrus III
  (1929) Introduced by ADC, also manufactured by Cirrus Aero Engines.
  American Cirrus III
  (1929) Improved variant of the Cirrus III, built under license.
  American Cirrus Hi-drive
  Inverted, with direct and geared drive options.
  Hermes
  (1929). Later as Hermes I. Introduced by Cirrus Aero Engines, also manufactured by Cirrus-Hermes.
  Hermes II
  (1930).
  Hermes IIB
  (1932). First inverted engine
  Hermes III
  (1932). Upright
  Hermes IV and IV A
  (1930). Inverted. The Hermes IV A with opposite-handed rotation was introduced around 1934.
  Cirrus Minor
  (1935). Later as Cirrus Minor I. Inverted. Introduced by Cirrus Hermes, also manufactured by Blackburn.
  Cirrus Minor 100 hp
  (1944). Inverted.
  Cirrus Minor II
  (1945). Inverted.
  Cirrus Major
  (1935). Later as Cirrus Major I. Inverted. Introduced by Cirrus Hermes, also manufactured by Blackburn.
  Cirrus Major 150 hp
  Inverted.
  Cirrus Major II
  (1945). Inverted.
  Cirrus Major III
  (1945) Inverted.
  Blackburn Cirrus Midget
  (1938). Prototype. Not manufactured.
  Blackburn Cirrus Bombardier
  (1948). Fuel injection.
caption: Hermes I in Roe IV replica
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