ARMSTRONG SIDDELEY CHEETAH IX
The Armstrong Siddeley Cheetah series of aircraft engines were British designed in 1930 and produced from 1935 until 1948 when fifteen variants totalling 37,200 units had been built.
They were seven cylinder supercharged air cooled radial engines, that demonstrated dependable reliability that culminated in the RAF certificating it as the first engine to run for 1,200 hours between overhauls.
The Cheetah engine series were used extensively to power training aircraft pre, and during WW2, and also powered the Avro Anson, an operational reconnaissance / bomber aircraft in early WW2, and later went on to be used as a twin engine training machine in the Empire Air Training Scheme (EATS) during the war years.
The RAAF operated 1,028 Avro Ansons between 1936 and 1944, 937 of them were used in the EATS between 1940 and 1944, and were powered by the Cheetah 1X engines. The Avro Anson was Britain's first twin engined aircraft with a retractable undercarriage (manually operated by 130 odd turns of a large handle). In addition 391 Airspeed Oxfords, dedicated twin engine training aircraft, were imported into Australia for use in the EATS and were powered by Cheetah X engines.
TECHNICAL DATA - Cheetah 1X
Bore and Stroke
Power to weight ratio
7 cylinder supercharged, air-cooled radial direct drive engine
5.25in (133mm) and 5.5in (140mm)
834 cu in (13.65 L)
1 Inlet and 1 exhaust popet valve per cylinder
centrifugal, 5.4/1 reduction
Take off - 338hp @2,100rpm at sea level and 345hp @2,425rpm at 8,000ft (2,400m)