Propeller Balancing Troubleshooting Guide

By Michele Lorusso and Yasmin Elkalish

Balancing your propulsion system can help your drone achieve optimal performance, efficiency, and service life. The Flight Stand software’s propeller balancing feature simplifies this process by guiding you through the steps to identify where mass should be added or removed.

If you’re having trouble achieving your desired balance quality grade, the troubleshooting steps below can help identify the cause and resolve the most common issues that can prevent a successful balancing session.

Unable to Start the Balancing Session?

If your balancing session does not start after selecting the “Create” button and the software displays this error message: “Rotation speed sensor used for balancing cannot have a divider, it should have only one rotation speed update pulse per rotation”, that means the rotation speed divider is configured incorrectly. 

To resolve this, ensure that the system has one reference point per rotation which is used to determine the rotor's position. To do that:

1. Navigate to the Hardware tab > Built-in Systems > Rotation Speed > Settings button > Divider 

2. Set the Divider to 1

   

Can’t Achieve a Passing Balance Grade?

If after completing the balancing session, the software displays a red X as the balance result or you are unable to achieve the needed balance grade despite multiple corrections, the issue may be related to the test configuration. Check the following potential sources of error to identify and resolve the problem: 

1. Ensure that the Flight Stand is securely mounted to a rigid surface, i.e., bolted in a concrete floor.

It will be challenging to achieve a passing balance if the stand is not properly secured to the ground. Avoid mounting the stand on crates, tables or surfaces that can vibrate.

2. Ensure that the motor, propeller, adapter and fasteners are securely tightened.

   

3. Confirm that the “Rotation speed” and “Vibration” inputs are correctly mapped

Incorrect input mapping prevents the software from using the correct sensors and channels.

For the “Rotation speed” input, select the Optical RPM probe from the drop-down menu. Do not select the fiber-optic sensor for the “Rotation speed” input as it is not associated with the measured vibrations for balancing.

4. Verify the value used in the “Rotor mass” field

Entering a rotor mass that is too low or too high can affect the software's calculation of the correction mass needed to reach the quality grade. Ensure the value entered includes the mass of both the motor’s rotating components and the propeller.

5. Verify the “Operating speed” field

The operating speed typically corresponds to the RPM at which you intend to operate the propulsion system in real-world conditions. However, if balancing at this RPM does not provide consistent results, resolve this by using a higher or lower RPM.

6. Verify the “Correction radius” field

The correction radius entered in the balancing session details corresponds to the location at which the balancing mass will be added. Placing the correction mass too close to the propeller’s hub reduces the correction effect. To resolve this, select a higher correction radius toward the tip of the propeller blade.

Finally, ensure that the radius entered in the software matches the actual position of the added mass.

Final Balance Is Worse After Adding the Correction Mass?

If the final balance grade displayed is higher than the desired value after adding the correction mass recommended by the software, resolve this by following the steps below:

1. Make sure the trial weight has been removed before adding the correction mass.

The trial weight intentionally increases vibration, allowing the system to determine the location and amount of correction mass required. Leaving the trial weight installed can interfere with subsequent measurements and prevent you from achieving the required balance grade.

2. Verify the mass of the correction weight.

Use a calibrated scale to ensure that the mass being added matches the value specified by the balancing software. This is particularly important for small correction masses, where a small measurement error can represent a significant percentage of the required correction.

3. Ensure that you use the same reference marker blade and blade numbering system throughout the entire balancing procedure. 

The reference marker blade establishes a reference point for where the balancing correction mass should be applied. Do not change the reference blade between runs. Doing so can cause the correction mass to be applied to the incorrect blade and worsen the balance.

For propellers with more than three blades, the numbering increases opposite to the direction of rotation, as seen in the diagram below:

Difficulty Balancing Certain Propeller Types

Certain propellers are more challenging to balance, including:

1. Wooden propellers

2. Propellers with a large hub

3. Folding propellers (not supported)

If possible, switch to a fixed propeller with a smaller hub and/ or a different material. This provides a more stable and repeatable setup for balancing.

Folding propellers are not supported for balancing with the Flight Stand software balancing feature.

How to Balance Your Motor?

If your propeller is balanced but your propulsion system is still experiencing excessive vibration, this may be coming from the motor rather than the propeller. Resolve this by following the steps below:

1. Remove the propeller

2. Balance the motor independently 

3. Set the “Number of Blades” to “Disk” before creating a balancing session.

4. Follow the balancing procedure.

5. Once the motor is balanced, reinstall the propeller.

6. Repeat the balancing procedure for the complete propulsion system.

Unable to Export Balancing Data as a CSV File?

After completing a balancing session, you can view the balancing report in the software, but you cannot export the results directly to a CSV file. If you need to record data while performing a balancing test, you will need to use the Flight Stand software API with a Python script.

If you are still experiencing issues with the propeller balancing feature, please contact our support team through our support form.