Siddeley Puma

The Siddeley Puma was an aircraft engine of the British manufacturer Siddeley Deasy. It was a water-cooled 6- cylinder in-line engine.

The engine was an evolution of Galloway Adriatic, which did not come in large numbers due to manufacturing difficulties. In January 1917 Siddeley began to improve the design of the original engine. The engine was initially called " Siddeley 1S ", but then got the name " Puma ". There was an OHC engine with a camshaft driven by a vertical shaft, the one inlet and two exhaust valves per cylinder operated. The exhaust valves are operated by bucket tappets, while the intake valves via rocker arms. The cylinder blocks and cylinder heads were cast in aluminum. The pistons ran into retracted steel bushings. The large aluminum parts also constitute the main problem in the manufacture, since they often had unacceptably air pockets and thus could not be used. At times, the reject rate was 90 %. Another problem that had to be solved was through burning exhaust valves.

The engine had a dry sump with one pressure and a return pump. The mixture was prepared by two Zenith carburetors, which also allowed a leaner mixture. The dual ignition system was working with two spark plugs per cylinder and two magnetos. As a fuel, a mixture of 80 % gasoline and 20 % of benzene was prescribed.

In August 1917 the series production began. A total of 11,500 engines were ordered, of which up to December 1918 4288 piece could be delivered. The further delivery was canceled because of the war's end. The engine has been used in a number of different planes.

Of 1918 there was a modified version with higher power, increased when both the connecting rod and the exhaust valves were improved. The goal is to operate the engine with a compression ratio of 5.4:1, could not be reached, so that the compression ratio of the original 4,95:1 was left.

A report based on the Siddeley Puma 12-cylinder engine was the Siddeley Pacific.

Specifications

  • Cylinders: 6 Row
  • Bore: 145 mm
  • Stroke: 190 mm
  • Displacement: 18,832 cc
  • Compression ratio: 4,95:1
  • Length: 1775 mm
  • Width: 610 mm
  • Height: 1107 mm
  • Weight: 308.5 kg

Swell

  • ( Janes ) All the worlds aircraft. 9, 1919, ZDB - ID 958040-2.
  • Alec Lumsden SC: British Piston Aero Engines and Their Aircraft. Airlife, Shrewsbury 1994, ISBN 1-85310-294-6.
  • Propeller engine
  • Line engine (aviation )
Siddeley-Deasy Aluminium
78101
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