Plain English Meaning

The most common type of small-airplane engine. Fuel burns inside cylinders, pushing pistons back and forth, and that motion is turned into the spinning motion that drives the propeller.

Full Definition

Piston-driven internal combustion engines used to power most light airplanes, in which fuel and air are burned inside cylinders to push pistons up and down. The pistons' linear motion is converted by a crankshaft into the rotary motion that turns the propeller.

Context Anchor

Seen in fuel, oil, engine operation, and preflight discussions for many small propeller airplanes.

Derivation

' comes from the Latin 'reciprocare', meaning 'to move back and forth'. It describes the back-and-forth motion of the pistons inside the cylinders, which is the defining feature of this engine type compared with , where parts only .