Air-cooled engine

An air-cooled engine dispenses with a liquid coolant system and instead relies on air moving directly over metal cooling fins or other exposed hot surfaces to carry heat away from the cylinders and heads. The fins increase the surface area available for heat transfer, and the cooling air may flow naturally as the engine or vehicle moves or be pushed across the engine by a dedicated fan, depending on the design. Compared with liquid-cooled engines, air-cooled designs are simpler and lighter because they eliminate the radiator, coolant reservoir and connecting hoses and piping that a liquid cooling system requires. This simplicity makes air cooling a common choice for motorcycles, general aviation aircraft engines, and small portable equipment such as chainsaws, lawn mowers and portable generators, wherever keeping weight and mechanical complexity down matters more than the precise temperature control a liquid system can offer.