Propeller blade angle of attack (left) and propeller blade angle of attack change with aircraft pitch change, demonstrating asymmetrical load (right)
P-factor, also known as asymmetric blade effect and asymmetric disc effect, is an aerodynamic phenomenon experienced by a moving propeller,[1] wherein the propeller's center of thrust moves off-center when the aircraft is at a high angle of attack. This shift in the location of the center of thrust will exert a yawing moment on the aircraft, causing it to yaw slightly to one side. A rudder input is required to counteract the yawing tendency.
- ^ Willits, Pat, ed. (2004) [1997]. Guided Flight Discovery: Private Pilot. Abbot, Mike Kailey, Liz. Jeppesen Sanderson, Inc. p. 3-49. ISBN 0-88487-333-1.)