The Sunbeam Sikh was a large slow running V-12 piston engine, intended to power airships, under development at the time of the Armistice.

[1] At the end of the First World War there was an expectation that Britain would continue the development of airships to provide air travel throughout the British Empire.

To power the expected airships Louis Coatalen designed the large Sikh V-12 engine delivering 800 hp (600 kW) at only 1,400 rpm, from 64.13 litre (3,913 in3) displacement in a 60-degree V12 configuration, with six valves per cylinder operated by rockers actuated by overhead camshafts.

[1] To power smaller airships or Blimps, Coatalen used one cylinder bank to create the Sikh II aka Semi-Sikh, a straight six-cylinder developing 400 to 425 hp (298 to 317 kW) @ 1,400 rpm.

The Sikh III was displayed at the 1929 Olympia Aero Show, generating interest due to its large size, weight and power.