Tip Archive

1. To measure angles (with TAPE selected for "Weights relative to:") measure from the location of the tape as the 0 or 360 degree index point.
2. To measure angles (with SENSOR selected for "Weights relative to:") move the blade with the tape directly in front of the Phototach, in the position where it triggers the tach event. With the propeller in that position, go to the location of the sensor and use it as the 0 or 360 degree index point.
3. Always measure angles with ascending values in the opposite direction of rotation as viewed from the front of the propeller looking toward the aft. If balancing a "pusher" propeller, the view is from aft looking forward.
4. Make sure you use the same speed, or as close to the same speed as possible, for each run. Major changes in speed from run to run will cause the influence to change and render the solution ineffective.
5. Do not apply solution weights in a cumulative manner. Each new provided solution requires that the previously installed weights be completely removed. You may have a solution at a same angle for consecutive runs, but reduced or increased in weight. In this case, remove the weight completely and adjust as necessary before reapplying to the location.
6. If using a longer screw for adding test weights to the spinner at the retaining screw locations, don’t forget to add the weight difference between the standard screw you removed from that location and the longer screw you are using. Also, remember to adjust for this when installing final weights.
7. If the vibration amplitude increases during the second run, after you added a test weight, don’t stop the procedure. An increase in amplitude is not an indication of a fault or failure of the equipment. This weight is only meant to induce a measurable change to the previously measured condition. The analyzer calculates an influence based on the amount of change induced according to the amount of test weight added and the angle at which it was added. In all cases, the amplitude should be reduced by the solution added following the second run.
8. Never balance in gusty winds or steady winds in excess of 7 to 10 knots. The influence on the propeller will make efficient balancing impossible.
9. If the propeller is successfully balanced but a vibration is still felt in the airframe, conduct a vibration survey to determine if the vibration is being caused by the propeller or other components. The vibration amplitude at the turning speed of the propeller should be approximately the same as the amplitude of the verification run of the balance job (after the final solution is added).
10. If the amplitude is not reduced by the third run, inspect the propeller and engine assembly for:
    -Mechanical faults such as looseness, cracks in blades or hubs.
    -Worn or damaged engine mounts.
    - Damaged, cracked or loose spinner or spinner bulkheads.
    - Incorrect spinner installation. If the spinner was removed to add weights,  was it indexed and reinstalled in the same position?
11. Refer to the FAA-approved ACES SYSTEMS' GUIDE TO PROPELLER BALANCING for FAA-approved methods and hardware installation.

Tip Archive