Blackburn Cirrus Major

The Blackburn Cirrus Major was the British manufacturer Blackburn Aircraft a piston aircraft engine for general aviation. Was derived from the engine Cirrus Hermes IV, the predecessor of the company Cirrus Engines Ltd.. was produced from 1929.

1936, the four-cylinder OHV engine was first introduced. He then found wide use. In the same year the series production began. A key design feature were turned from solid material suspended air-cooled cylinder of high-alloy steel. The cylinders were attached to its base flange with four bolts each centered on the crankcase. Per cylinder, there was an inlet and an armored with stellite exhaust valve. The cylinder heads were made ​​of aluminum and are connected by pins with the twelve cylinders. The Slipper aluminum pistons had 2 compression rings and one oil scraper ring. The connecting rods were forged Hiduminium. The forged and fully machined crankshaft consisted of a high strength steel alloy. She was supported in bearings made of white metal with steel shells. The shear forces of the direct-driven propeller were taken from a radial ball bearing in the front of the crankcase. This was made ​​from an aluminum alloy, the upper lid was made electron. The camshaft ran directly in the casting of the crankcase and was driven by a spur gear. For the mixture supply came a downdraft carburetor Claudel - Hobson used, which had an automatic Gemischvorwärmung. The lubrication was carried out by a dry sump recirculation system, for which a piston pump with suction and pressure level caused. For the two systems of ignition B.T.H. was be used. On request, the ignition system could be delivered completely shielded. The fuel supply was ensured by Amal duplex fuel pump. On the back cover of the appliance electric starter, vacuum pump, generator and a filter device could be mounted.

The Cirrus Major was installed only in the Blackburn B-2, a school biplane with an unusual juxtaposition of the seats. 1939 was added the increased performance in their execution Cirrus Major II, which was built by General Aviation and Miles in several of its aircraft. The further uprated Cirrus Major III was introduced in 1945. Of all versions were built together about 700 pieces.

Specifications

Major I Major II Major III Bore mm 120 120 120 Stroke mm 140 140 140 Displacement l 6.3 6.3 6.3 Compression 5.1:1 5.8:1 6.5:1 Length mm 1250 1072 1080 Width mm 444.5 465 429 Height mm 762 777 754 Weight kg 136 147 156 Starting power PS/min-1 135/2300 150/2450 155/2450 Travel service PS/min-1 125/2100 138/2200 145/2200 References

  • "British Piston Aero Engines and Their Aircraft ," Alec Lumsden, ISBN 1853102946
  • Jane's all the world 's aircraft 1945
  • Piston aircraft engines, Hans Giger, ISBN 3613010895
  • Propeller engine
  • Line engine (aviation )
British Thomson-Houston
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