Private Pilot Private Exam

Under what condition does P-factor cause the airplane to yaw to the left?

1. When at low altitudes

2. When at cruising speeds

3. When at high angles of attack

4. When at zero airspeed

The correct answer is: When at high angles of attack

P-factor is a phenomenon that occurs in propeller-driven aircraft, primarily when the aircraft is operating at high angles of attack. This effect is caused by the difference in thrust between the ascending and descending blades of the propeller. At high angles of attack, the descending blade on the right side of the propeller generates more lift and thus more thrust than the ascending blade on the left side. This differential thrust results in a yawing motion to the left. When the airplane is at high angles of attack, such as during takeoff or when climbing, the airflow over the wings and propeller changes significantly. The descending blade, which is moving into the airflow, encounters fresher air and creates more thrust compared to the other blade, which is moving away from the oncoming airflow. Therefore, the increased thrust on the right side causes the aircraft to yaw to the left. In other scenarios, such as at cruising speeds or low altitudes, the effects of P-factor are less pronounced, and yaw may not be as significant. Similarly, at zero airspeed, the aircraft is in a stationary condition where the dynamics of flight do not apply, and P-factor would not induce a yaw. Thus, the condition of high angles of attack is critical for understanding