Plain English Meaning

The propeller doesn't just push air straight back — it twists the air into a spiral. That spiraling air wraps around the fuselage and hits the tail off-center, which tries to push the nose to one side. The pilot uses the rudder to keep the nose straight.

Full Definition

The corkscrew-shaped flow of air that the propeller pushes back along the fuselage. As the propeller turns, it accelerates air rearward in a rotating spiral that wraps around the airplane and strikes the vertical tail (typically on the left side for engines that turn clockwise as viewed from the cockpit), producing a yawing tendency that the pilot must correct with rudder.

Context Anchor

Pilots encounter this term in discussions of , , , and or .