Bristol Centaurus

Centaurus
Preserved Bristol Centaurus engine
Type Piston aircraft engine
Manufacturer Bristol Aeroplane Company
First run July 1938
Major applications Hawker Tempest
Bristol Brabazon
Hawker Sea Fury
Number built c.2,500


The Centaurus was the final development of the Bristol Engine Company's series of sleeve valve radial aircraft engines, an 18-cylinder, two-row design that eventually delivered over 3,000 hp (2,200 kW).[1] It was introduced into service late in World War II, and was one of the most powerful aircraft piston engines to see service.

The Royal Navy Historic Flight currently operates a Hawker Sea Fury, powered by a Bristol Centaurus.

Design and development

Like most Bristol Engines designs, the Centaurus was based on the mechanicals of an earlier design, in this case the "classic" 5.75 in (146 mm) piston from their original 1918 Jupiter. The Jupiter piston was still in use in the contemporary 14-cylinder Hercules, which was being brought into production during the design of the Centaurus.

The Centaurus had a cylinder swept volume of 3,272 in³ (53.6 l), close to that of the American Wright Duplex-Cyclone large radial, making the Centaurus one of the largest aircraft piston engines to enter production, while that of the Hercules was 2,363 cubic inches (38.7 l). The nearly 40 percent higher capacity was achieved by increasing the stroke from 6.5 to 7 in (170 to 180 mm) and by changing to two rows of nine cylinders instead of two rows of seven but the diameter of the Centaurus was only just over 6 percent greater.[2]

The cylinder heads had an indentation like an inverted top hat, which of course was finned but it was difficult to get air down into this hollow to adequately cool the head. During the development stage the engineers contacted ICI Metals Division, Birmingham, to enquire whether a copper-chromium alloy with higher thermal conductivity, would have sufficient high temperature strength to be used for this purpose. Tests were successful and with the same volume of cylinder, these modified heads enabled the horsepower per cylinder to be raised from 110hp to 220hp.

Sleeve valve closeup from a Bristol Centarus Mark 175.

Bristol maintained the Centaurus from type-testing in 1938[2] but production did not start until 1942 owing to the need to get the Hercules into production and improve the reliability of the entire engine line. Nor was there any real need for the larger engine at this early point in the war, when most military aircraft designs were intended to mount engines around 1,000 hp. The Hercules' approximately 1,500 hp was better suited to the existing airframes.

Cross Section of a Bristol Centarus Mark 175

The Centaurus did not see service until near the end of the war, first appearing on the Vickers Warwick. Other wartime, or just-postwar, uses included the Bristol Brigand and Buckmaster, Hawker Tempest and Sea Fury, the Blackburn Firebrand and Beverley. The engine also saw post-war use in civilian airliners, including the ill-fated Bristol Brabazon. By the end of the war in Europe, around 2,500 examples of the Centaurus had been produced by Bristol.[2]

The most powerful version of the Centaurus was intended for the Blackburn Beverley transport aircraft. Using direct fuel injection, it achieved a remarkable 3,220 hp but was never fitted.[3] A projected enlarged capacity version of the Centaurus was designed by Sir Roy Fedden; cylinders were produced for this engine but it was never built. Known as the Bristol Orion (a name used previously for a variant of the Jupiter engine, and later re-used for a turboprop) this development was also a two-row, 18 cylinder sleeve valve engine, with the displacement increased to 4,142 cubic inches (67.9 l)[4] (6.25x7.5), nearly as large as the American Wasp Major four-row, 28-cylinder radial, the largest displacement aviation radial engine ever placed in quantity production.

Variants

The Centaurus was produced in 34 variants ranging from the 2,000 hp (1,490 kW) Centaurus I to the 2,405 hp (1,793 kW) Centaurus 663 for the Airspeed Ambassador airliner. The most powerful variants to enter service were the 2,625 hp (1,957 kW) Centaurus 170, 173, 660, 661 and 662.[5]

Applications

Bristol Centaurus powered Fairey Spearfish

Note:[6]

Survivors

The Royal Navy Historic Flight operates a Hawker Sea Fury powered by a Bristol Centaurus.[7]

Engines on display

Preserved Bristol Centaurus engines are on public display at the following museums:

Specifications (Centaurus VII)

A Centaurus with cylinders removed exposing the sleeve valves.

Data from Lumsden[8]

General characteristics

Components

Performance

See also

Related development
Comparable engines
Related lists

References

Notes

  1. ↑ Gunston 1989, p.33.
  2. 1 2 3 Bridgman (Jane's) 1998, p. 270.
  3. ↑ Flight magazine, 11 May, 1956 Retrieved: 12 December 2014
  4. ↑ Gunston 2006, p.152.
  5. ↑ Lumsden 2003, pp.125-128.
  6. ↑ List from Lumsden
  7. ↑ Royal Navy Historic Flight - Aircraft Archived June 15, 2009, at the Wayback Machine. Retrieved: 5 August 2009
  8. ↑ Lumsden 2003, p.125.

Bibliography

  • Bridgman, L, (ed.) (1998) Jane's Fighting Aircraft of World War II. Crescent. ISBN 0-517-67964-7
  • Gunston, Bill. Development of Piston Aero Engines. Cambridge, England. Patrick Stephens Limited, 2006. ISBN 0-7509-4478-1
  • Gunston, Bill. World Encyclopedia of Aero Engines. Cambridge, England. Patrick Stephens Limited, 1989. ISBN 1-85260-163-9
  • Lumsden, Alec. British Piston Engines and their Aircraft. Marlborough, Wiltshire: Airlife Publishing, 2003. ISBN 1-85310-294-6.
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