Propeller Troubleshooting

Start with the simple and cheap. Here are some that qualify.

• Repair cracks. Under air loads they can cause an aerodynamic imbalance besides sapping power.
• Static balance.
• Make sure the bolts are tightened evenly. If the prop is askew widthwise on its mount (making one blade have a higher angle of attack than the other), an aerodynamic imbalance can cause vibration.

Problem

Possible solution or link.

1. Prop bolts are loose.

2. Center bolt that holds prop hub against drive spline is lose.

3. Something is preventing the prop hub resting on its backing. The prop should mate flat against the back plate. If it doesn't then it will be rocking on the spline which will eventually wear.

4. Reduction drive problem with mount or bearings.

1. Leading edge is rough.

2. A crack or other deformity is causing drag.

.

1. Static imbalance. One blade is heavier than the other.

2. Aerodynamic imbalance. This is where one blade is producing more thrust than the other. Causes may be:

 - Prop is on laterally crooked such that one blade has a higher angle of attack than the other.

 - One blade has is larger than the other.

 - One blade has been sanded down so that it has a higher angle of attack than the other.

 - One blade is warping under air loads. This is more probably with weaker woods or thin (flat) blades.