Blackburn Cirrus Major

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Cirrus Major
Right side view of a Cirrus Major III installed in an Auster J/5G
Type Air-cooled 4-cylinder inline piston engine
National origin United Kingdom
Manufacturer Blackburn Aircraft
First run 1936
Number built c.700

The Blackburn Cirrus Major is a British, four-cylinder, inline aircraft engine that was developed in the late 1930s.

Design and development[edit]

The Blackburn Cirrus Major started life as a development of the original ADC Cirrus series of aircraft engines which progressed through a number of variants, each with slightly different displacement and power outputs. The Cirrus series was later bought by Cirrus Aero-Engines (later known as the Cirrus-Hermes Engine Company) which produced the Cirrus Hermes I, II, III and IV, again each differing slightly in displacement and power.

In 1934 Cirrus was bought again by the Blackburn Aircraft company and later that year the Cirrus Minor was produced. In 1935 the Cirrus Major entered production.


Cirrus Major III showing Cirrus logo cast into crankcase
Cirrus Major I
135 hp
Cirrus Major II
148 hp variant.
Cirrus Major III
Higher compression engine with an increase in output to 150 hp (116kW).


Specifications (Cirrus Major I)[edit]

Data from Lumsden[1]

General characteristics

  • Type: Inline air-cooled inverted 4-cylinder
  • Bore: 4.72 in (120 mm)
  • Stroke: 5.51 in (140 mm)
  • Displacement: 385.64 cu in (6.31 L)
  • Length: 50 in (1270 mm)
  • Width: 17.5 in (444 mm)
  • Height: 30 in (762 mm)
  • Dry weight: 310 lb (141 kg)


  • Valvetrain: 1 inlet and 1 exhaust valve per cylinder
  • Fuel system: 1 Claudel-Hobson carburettor
  • Fuel type: 73 octane petrol
  • Cooling system: Air-cooled


See also[edit]

Related development
Comparable engines
Related lists



  1. ^ Lumsden 2003, p.89.


  • Gunston, Bill (1986). World Encyclopedia of Aero Engines. Wellingborough: Patrick Stephens. p. 40. 
  • Lumsden, Alec. British Piston Engines and their Aircraft. Marlborough, Wiltshire: Airlife Publishing, 2003. ISBN 1-85310-294-6.