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TORQUE & P-FACTOR



On single engine aircraft from the pilots’ perspective, “torque” is the left turning tendency of an engine aircraft. Torque is made of four types of twisting motions around one of the three axes of an aircraft.

  • Torque

  • Corkscrew slipstream

  • Gyroscopic Action

  • P-Factor

Torque:

Let’s go back and back at Newton’s third law, which is “for every action, there is an equal and opposite reaction”. As for aircraft the engine components and propeller are revolving in one direction, while an equal force is trying to rotate an aircraft in an opposite direction, this is called torque.



Corkscrew slipstream:

Corkscrew or spiraling slipstream is the air from the propeller rotating around the fuselage of the aircraft. During takeoff or when reaching a power-on stall, the rotating air impacts the left side of vertical tail surface, which causes a yawing motion on the aircraft.



Gyroscopic Action:

In this case when a force is placed on a rotating propeller to deflect it out of its plane of rotation, the result is a force 90 degrees ahead and in the direction of rotation, which causes a yawing motion.


P-Factor:

P-Factor is caused by the aircraft propeller during high angle of attack (AOA). The downward moving blade takes a greater “bite” of air, than the blade that is moving upward. This causes the trust to move over to the right, causing the aircraft to yaw to the left around the vertical axis.


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