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

Armistice An armistice is a formal agreement of warring parties to stop fighting. It is not necessarily the end of a war, as it may constitute only a cessation of hostilities while an attempt is made to negotiate a lasting peace. It is derived from the La ...

Design and development

At the end of the

First World War World War I (28 July 1914 11 November 1918), often abbreviated as WWI, was one of the deadliest global conflicts in history. Belligerents included much of Europe, the Russian Empire, the United States, and the Ottoman Empire, with fightin ...

there was an expectation that Britain would continue the development of airships to provide air travel throughout the

British Empire The British Empire was composed of the dominions, colonies, protectorates, mandates, and other territories ruled or administered by the United Kingdom and its predecessor states. It began with the overseas possessions and trading posts esta ...

. To power the expected airships Louis Coatalen designed the large Sikh V-12 engine delivering at only 1,400 rpm, from 64.13 litre (3,913 in³) displacement in a 60-degree

V12 V12 or V-12 may refer to: Aircraft * Mil V-12, a Soviet heavy lift helicopter * Pilatus OV-12, a planned American military utility aircraft * Rockwell XFV-12, an American experimental aircraft project * Škoda-Kauba V12, a Czechoslovak experim ...

configuration, with six valves per cylinder operated by rockers actuated by overhead camshafts. Bench testing of this impressive engine began in 1919, passing

Air Ministry The Air Ministry was a department of the Government of the United Kingdom with the responsibility of managing the affairs of the Royal Air Force, that existed from 1918 to 1964. It was under the political authority of the Secretary of State ...

acceptance tests in time for one to be displayed at the

1919 Paris Aero Salon Events January * January 1 ** The Czechoslovak Legions occupy much of the self-proclaimed "free city" of Pressburg (now Bratislava), enforcing its incorporation into the new republic of Czechoslovakia. ** HMY ''Iolaire'' sinks off the c ...

and the 1920 Olympia Aero Show where it generated much interest, due to its size, but no production orders. Competition to power what little airship production there was came from the

Rolls-Royce Condor The Rolls-Royce Condor aircraft piston engine was a larger version of the Rolls-Royce Eagle developing up to 675 horsepower (500 kW). The engine first ran in 1918 and a total of 327 engines were recorded as being built. Variants ''Note:'' ...

and the

Napier Cub The Napier Cub was an unusual and very large experimental 16-cylinder 'X' pattern liquid-cooled aero engine built by the British engine company D. Napier & Son. The Cub was the only Napier 'X' engine design. First flown on 15 December 1922 ...

. Development work continued till the engine produced by 1923. To power smaller airships or

Blimp A blimp, or non-rigid airship, is an airship (dirigible) without an internal structural framework or a keel. Unlike semi-rigid and rigid airships (e.g. Zeppelins), blimps rely on the pressure of the lifting gas (usually helium, rather than hydr ...

s, 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. As with the Sikh, the market for airship engines dried up after the war, so no production Sikh II engines were built. In the late 1920s large airships were in favour again, so Coatalen revised the Sikh and developed the Sunbeam Sikh III for the

R100 His Majesty's Airship R100 was a privately designed and built British rigid airship made as part of a two-ship competition to develop a commercial airship service for use on British Empire routes as part of the Imperial Airship Scheme. The ot ...

and

R101 R101 was one of a pair of British rigid airships completed in 1929 as part of a British government programme to develop civil airships capable of service on long-distance routes within the British Empire. It was designed and built by an Air Mi ...

airship families. Retaining the bore, stroke and displacement of the earlier engine, detail refinements included five valves per cylinder and enclosed valve-gear. The Sikh III was displayed at the 1929 Olympia Aero Show, generating interest due to its large size, weight and power. After the

disaster the large Empire airships were abandoned, and the airship market for Sunbeam engines disappeared for a second time, leaving the Sikh III with no orders. No Sikh engines of any version were sold.

Variants

;Sikh :The original 800 hp airship engine intended for use by airships to be developed after the war, which were cancelled. ;Sikh II :Following his previous practise Coatalen developed a straight six version of the Sikh, using a single bank of cylinders. Also intended for airships to be developed after the war, the Sikh II was cancelled when the airships did not materialise.(32.1L / 1,957 in³) ;Semi-Sikh :Alternative name for the Sikh II. ;Sikh III :In the late 1920s, renewed interest in airships, which spawned the Empire Airship programme, also encouraged development of engines to power the airships with. The Sikh III was one of these; closely following the Sikh in construction, major differences included two inlet valves instead of three and enclosed valve-gear.

Specification (Sikh III)

References

Bibliography

* Brew, Alec. ''Sunbeam Aero-Engines''. Airlife Publishing. Shrewsbury.

External links

* {{Sunbeam aeroengines

Sikh Sikhs ( or ; pa, ਸਿੱਖ, ' ) are people who adhere to Sikhism, Sikhism (Sikhi), a Monotheism, monotheistic religion that originated in the late 15th century in the Punjab region of the Indian subcontinent, based on the revelation of Gu ...

1920s aircraft piston engines Airship engines