Certified Flight Instructor - Flight Instructor Airplane Practice Exam

A propeller rotating clockwise, as seen from the rear, creates a spiraling slipstream that tends to rotate the aircraft to?

1. The right around the vertical axis, and to the left around the longitudinal axis.

2. The left around the vertical axis, and to the right around the longitudinal axis.

3. The left around the vertical axis, and to the left around the longitudinal axis.

4. The right around both axes.

The correct answer is: The left around the vertical axis, and to the right around the longitudinal axis.

The correct answer describes the effects of a clockwise rotating propeller when viewed from the rear. A propeller's rotation causes the slipstream—the air accelerated by the propeller—to spiral backwards and around the aircraft. For an aircraft with a clockwise rotating propeller, the spiraling slipstream will have a tendency to move around to the left, creating a yawing motion in that direction. This is due to the fact that the left side of the propeller pushes more air downward and creates a higher pressure on that side compared to the right side, leading to a yaw to the left around the vertical axis. Additionally, the propeller's rotation and the resulting induced airflow can also result in a roll to the right around the longitudinal axis. This rolling tendency occurs because the right side of the propeller produces a greater lift as the increased airflow on the left side tends to create a downward force on that side, generating a right roll. Thus, the description of a left rotation around the vertical axis and a right rotation around the longitudinal axis is accurate regarding the effects of this specific propeller rotation and the characteristics exhibited during flight.