The Bristol Hercules is a 14-cylinder two-row radial aircraft engine designed by Sir Roy Fedden and produced by the Bristol Engine Company starting in 1939. It was the most numerous of their single sleeve valve designs, powering many aircraft in the mid-World War II timeframe.
Bristol Hercules
Hercules fitted to a Vickers Varsity on display at the Newark Air Museum
Bristol Hercules in Aviation Museum Kbely, Prague
Bristol Hercules engine. Note the absence of pushrods on the cylinders. Each cylinder has two exhaust ports on the front (short L-shaped tubes) and three intake ports on the back supplied through a single manifold.
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