FAA Powerplant Written Practice Test

How can aerodynamic imbalance in a propeller be largely eliminated?

1. Increasing engine RPM

2. Correct blade contouring and angle setting

3. Balancing the propeller weight

4. Reinforcing propeller blades

The correct answer is: Correct blade contouring and angle setting

The effective way to largely eliminate aerodynamic imbalance in a propeller is through correct blade contouring and angle setting. This process involves fine-tuning the shape and angle of attack of each blade to ensure that they generate equal lift and thrust. When the blades are properly contoured and set to the correct angle, it helps to minimize variations in aerodynamic forces acting on each blade during rotation. As a result, the propeller operates more smoothly and efficiently, reducing vibrations and enhancing overall performance. Other methods such as changing engine RPM, balancing propeller weight, or reinforcing blades do not address the fundamental issue of aerodynamic forces. While increasing engine RPM can impact performance, it does not directly resolve the imbalances caused by blade design. Similarly, simply balancing the weight of the propeller does not ensure that aerodynamic forces are equal across the blades. Reinforcing propeller blades may improve their structural integrity but will not eliminate aerodynamic imbalance. Therefore, correct blade contouring and angle setting is the most effective approach to achieve aerodynamic balance in a propeller.