The Bristol Mercury is a British nine-cylinder, air-cooled, single-row, piston radial engine. Designed by Roy Fedden of the Bristol Aeroplane Company it was used to power both civil and military aircraft of the 1930s and 1940s. Developed from the earlier Jupiter engine, later variants could produce 800 horsepower (600 kW) from its capacity of 1,500 cubic inches by use of a geared supercharger.
Bristol Mercury
Mercury license built by NOHAB
Side view showing valve gear detail.
Bristol Mercury VII on display at the Shuttleworth Collection
The radial engine is a reciprocating type internal combustion engine configuration in which the cylinders "radiate" outward from a central crankcase like the spokes of a wheel. It resembles a stylized star when viewed from the front, and is called a "star engine" in some other languages.
Radial engine in a biplane
Master rod (upright) and slaved connecting rods from a two-row, fourteen-cylinder Pratt & Whitney R-1535 Twin Wasp Junior
Continental radial, 1944
Pratt & Whitney R-1340 radial mounted in Sikorsky H-19 helicopter