Sunbeam Pathan

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Sunbeam Pathan
Type 6-cyl. In-line, water-cooled, diesel, piston engine.[1]
Manufacturer Sunbeam[1]
Designed by Louis Coatalen[1]
First run 1929[1]
Number built prototypes only[1]
Developed from Sunbeam Dyak[1]

The Sunbeam Pathan, also known as the Sunbeam P.1, was a 1920s British diesel aero engine.[1][2]

Design and development[edit]

Louis Coatalen, Sunbeam engine designer, started work on a diesel powered aero-engine, that would be suitable for use in airships, in 1928.[2] Using his experience with both aero-engines and auto-mobile diesel engines, the result, given the company designation P.1, was based on the Dyak.[2] Given the name Pathan, a prototype engine was displayed at the 1929 Olympia Aero Show, but attracted no orders.[2]

Using the same bore and stroke of the Dyak (120mm x 130mm - 4.72in x 5.12in ), the Pathan was a water-cooled six-cylinder in-line diesel engine with a cubic capacity of 8.8l (537cu in). Rated to give 100 hp (74.6 kW) @ 1,500rpm the engine was fitted with a new type of fuel injection system allowing cold starts without other assistance.[1]

The engine did not enter production as the British Airship Programme was cancelled, and with no need for the engine only prototypes were built.[1][2]

Coatalen continued the development of Diesel engines after he left Sunbeam and returned to France, developing the Coatalen V-12 Diesel engine with limited success, due to the German invasion of 1940 halting further work.[1]


Data from [1]

General characteristics

  • Type: 6-cylinder, inline diesel engine
  • Bore: 4.72 in (120 mm)
  • Stroke: 5.12 in (130 mm)
  • Displacement: 537 cu in (8.8l)


  • Fuel system: Direct fuel injection
  • Fuel type: Diesel oil
  • Oil system: Dry sump, pressure fed
  • Cooling system: Liquid-cooled


  • Power output: 100hp at 1,500 rpm
  • Specific fuel consumption: 0.169l/kW/hr (0.4 pints/hp/hr)
  • Oil consumption: 0.0127l/kW/hr (0.03 pints/hp/hr)

See also[edit]

Related lists


  1. ^ a b c d e f g h i j k Brew, Alec (1998). Sunbeam Aero-engines. Shrewsbury: Airlife Publishing. ISBN 1-84037-023-8. 
  2. ^ a b c d e "Sunbeam Overhead Cam Engines". Archived from the original on 2008. Retrieved 2009-12-12.