A type of engine, used mainly to power aircraft, in which a spinning compressor drives air into a set of combustion chambers where it is heated strongly, causing it to expand. The expanding air spins a turbine that turns the compressor, and leaves the rear of the engine through a jetpipe. The force with which the hot air leaves the engine is matched by a force equal in magnitude and opposite in direction (Newton’s third law), and it is this that propels the vehicle.