Radial engine

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Radial engine operation relies on coplanar cylinders, necessitating a unique connection method. The master-and-articulating-rod assembly links pistons to the crankshaft. In a five-cylinder radial, the uppermost piston directly attaches to the crankshaft, while others connect to rings around the master rod. This design allows for increased capacity without diameter growth. Four-stroke radials maintain consistent firing patterns for smoother operation. An odd number of cylinders per row ensures a one-piston gap between combustion and compression strokes, enhancing uniform motion. Radial engines typically use fewer cams compared to other types, with the camshaft ring spinning slower in the opposite direction and serving all cylinders with fewer cams required than inline engines. Overhead poppet valves are common, while some smaller radials use individual camshafts for each cylinder. Sleeve valves, seen in Bristol Hercules and Centaurus engines, offer quieter performance but require tight manufacturing tolerances.