The Blackburn Cirrus Major is a British,

inline-four A straight-four engine (also called an inline-four) is a four-cylinder piston engine where cylinders are arranged in a line along a common crankshaft. The vast majority of automotive four-cylinder engines use a straight-four layout (with the ...

aircraft engine An aircraft engine, often referred to as an aero engine, is the power component of an aircraft propulsion system. Most aircraft engines are either piston engines or gas turbines, although a few have been rocket powered and in recent years many ...

that was developed in the late 1930s.

Design and development

The Blackburn Cirrus Major started life as a continued evolution of the original Cirrus and Hermes series of aircraft engines which had been in production for the last decade. C. S. Napier, son of engine designer

Montague Napier Montague Stanley Napier (14 April 1870 – 22 January 1931) was an English automobile and aircraft engine manufacturer. His grandfather, David Napier (1785–1873), had moved to London from Scotland and by 1836 had established an engineering comp ...

, was Technical Director and Chief Designer for Cirrus-Hermes Engineering when he began work on two new engines, the Cirrus minor and the larger Cirrus Major. The engines were still under development when the company was bought by the

Blackburn Aeroplane & Motor Company Blackburn () is an industrial town and the administrative centre of the Blackburn with Darwen borough in Lancashire, England. The town is north of the West Pennine Moors on the southern edge of the Ribble Valley, east of Preston and north- ...

, moved to a new factory at Brough in Yorkshire and renamed Cirrus Hermes Engineering."The 'Cirrus Major'", ''Flight'', 13 June 1935. Supplement."A New Small Engine", ''Flight'', 28 February 1935, pp.218-9. Like all the Cirrus engines, the Major was an air-cooled inverted four-cylinder inline design. Aimed at the same market for a robust, reliable and affordable light aircraft engine, it retained many proven design features of the originals while making many improvements. Cylinder barrels were of forged steel while the individual heads were of light alloy. Unlike the Minor, the Major retained the established long bolts which passed through the barrels to secure the heads to the crank case, as well as the general layout of the heads from the Hermes IV A, which remained in production alongside. Pistons and con-rods were of light alloys, with a steel crankshaft. Direct drive to the propeller, without reduction gearing, helped to keep engine revs low and reliability high. The single carburettor was a Claudel Hobson AV.48D. In 1935 the Cirrus Minor entered production and the Major followed soon afterwards. Two years later, with its product range now rationalised and the new engines settled in the marketplace, the company was brought into its parent as the Cirrus Engines Division of

Blackburn Aircraft Blackburn () is an industrial town and the administrative centre of the Blackburn with Darwen borough in Lancashire, England. The town is north of the West Pennine Moors on the southern edge of the Ribble Valley, east of Preston and north- ...

Variants

;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).

Applications

Specifications (Cirrus Major I)

References

Notes

Bibliography

Oldengine.org
* * Lumsden, Alec. ''British Piston Engines and their Aircraft''. Marlborough, Wiltshire: Airlife Publishing, 2003. . {{Cirrus aeroengines Air-cooled aircraft piston engines Blackburn aircraft engines 1930s aircraft piston engines Inverted aircraft piston engines