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Piston engine

A crankshaft converts the backwards-and-forwards (reciprocating) motion of the piston into circular (rotational) motion. Here the...Read More >>A crankshaft converts the backwards-and-forwards (reciprocating) motion of the piston into circular (rotational) motion. Here the crankshaft is shown in red, the pistons in grey and the cylinders in blue. The flywheel, to which the propeller unit is connected, is shown in black. In a flat engine, the cylinders are arranged on both sides of a single crankshaft. It is otherwise known as the boxer, or horizontally-opposed engine. Until the invention of jet engines in the 1930s, planes were powered by piston engines turning propellers. Nowadays, usually only light aircraft have piston engines. The kind of piston engine most often used is called a flat engine. It has two banks of cylinders, containing the pistons, opposite one another. The pistons are connected to a horizontal crankshaft.  A flat engine is sometimes known as a boxer engine, so-called because each pair of pistons moves in and out simultaneously, like boxers clashing their gloved fists together before a fight.



The kind of piston engine most often used in a light aircraft is called a flat engine, pictured here. It has two banks of...Read More >>The kind of piston engine most often used in a light aircraft is called a flat engine, pictured here. It has two banks of cylinders opposite one another. The pistons (1) are connected to a horizontal crankshaft. (2)

How it works

A kind of internal combustion engine, a piston engine is very similar to engines used in road vehicles. A mixture of fuel and air is sucked into the engine’s cylinders. The mixture is ignited and the resulting explosions push down pistons inside the cylinders. These turn a crankshaft, which is connected to the propeller. The kind of piston engine most often used in a light aircraft is called a flat engine. It has two banks of cylinders opposite one another. The pistons are connected to a horizontal crankshaft.
A light aircraft engine
A propeller spinning, sucking air around it backwards, pulling the blades forwards

Propeller

A piston engine runs at maximum power for a few minutes during taking off. It then switches to a cruise setting, about 65–75% of full power.

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