Slipstream
[1] The term slipstream also applies to the similar region adjacent to an object with a fluid moving around it.A slipstream created by turbulent flow has a slightly lower pressure than the ambient fluid around the object.The most noticeable effect resulting from the formation of a spiral slipstream is the tendency to yaw nose-left at low speed and full throttle (in centerline tractor aircraft with a clockwise-rotating propeller.)This effect is caused by the slipstream acting upon the tail fin of the aircraft: The slipstream causes the air to rotate around the longitudinal axis of the aircraft, and this air flow exerts a force on the tail fin, pushing it to the right.To counteract this, some aircraft have the front of the fin (vertical stabilizer) slightly offset from the centreline so as to provide an opposing force that cancels out the one produced by the slipstream, albeit only at one particular (usually cruising) speed, an example being the Hawker Hurricane fighter from World War II.