Sunbeam Sikh
| Industry | Aircraft engines |
|---|---|
| Founded | 1919 |
| Founder | Louis Coatalen |
| Products | Aircraft engines |
The Sunbeam Sikh was a sizable, low-speed V-12 piston engine created specifically to provide power for airships during the period surrounding the Armistice.
Design and development
Following the First World War, Britain envisioned a significant expansion of airship transportation throughout the British Empire. To fulfill this requirement, Louis Coatalen engineered the Sikh V-12, which produced at 1,400 rpm from a 64.13-litre (3,913 in³) displacement arranged in a 60-degree V12 configuration. The design incorporated six valves per cylinder actuated by overhead camshafts.
Initial bench testing commenced in 1919, with the engine successfully passing Air Ministry acceptance evaluations. It was exhibited at both the 1919 Paris Aero Salon and the 1920 Olympia Aero Show, where its considerable dimensions attracted notice; however, it did not achieve any production contracts. Rivalry from engines such as the Rolls-Royce Condor and Napier Cub influenced this outcome. Development efforts persisted until 1923, by which time the Sikh attained .
For smaller airships and Blimps, Coatalen designed the Sikh II—also known as the Semi-Sikh—a straight six-cylinder powerplant generating between 400 and 425 hp (298 to 317 kW) at 1,400 rpm. Despite this, a downturn in post-war demand prevented any Sikh II units from entering production.
In the late 1920s, renewed enthusiasm for large airship projects led Coatalen to develop the Sunbeam Sikh III for use on the R100 and R101 airships. While retaining the original bore, stroke, and total displacement, this iteration introduced enhancements including five valves per cylinder and enclosed valve gear mechanisms. Presented at the 1929 Olympia Aero Show, it garnered attention due to its impressive size and output. The tragic R101 accident subsequently caused Britain to terminate its Empire airship program, removing any market for the Sikh III.
Ultimately, none of the Sikh engine variants progressed to mass production.
Variants
- Sikh
- The initial 800 hp engine designed for post-war airship applications that were eventually cancelled.
- Sikh II
- A straight-six derivative of the Sikh developed by Coatalen for similar cancelled airship initiatives (32.1L / 1,957 in3).
- Semi-Sikh
- An alternative designation for the Sikh II.
- Sikh III
- Produced in the late 1920s during revived interest in airships under the Empire Airship programme. This model resembled the original Sikh but featured two inlet valves instead of three and incorporated enclosed valve gear.
Bibliography
- Brew, Alec. Sunbeam Aero-Engines. Airlife Publishing. Shrewsbury.
External links
- Sunbeam Overhead Cam Engines – Wolverhampton Museum of Industry (archived)