Which factor is primarily responsible for the downward blade producing more thrust at high AOA?

• A. Asymmetric propeller loading (P-factor)
• B. Gyroscopic precession
• C. Spiraling slipstream
• D. Torque reaction

Answer: (A)

The main concept here is asymmetric propeller loading caused by P-factor. In forward flight, a propeller blade experiences different relative wind on the top half versus the bottom half of the disk. When the aircraft is at a high angle of attack, the downward-moving blade meets the oncoming air at a steeper angle of attack than the upward-moving blade. That steeper inflow increases the lift generated by the downward blade relative to the upward blade, so it produces more thrust. Since thrust is what drives the airplane forward, this uneven loading creates a yaw tendency toward the side of the downward blade.

Gyroscopic precession, spiraling slipstream, and torque reaction all describe other aerodynamic or inertial effects that influence flight dynamics, but they do not explain why the downward blade contributes more thrust than the upward blade at high angles of attack.