Possible causes of yaw imbalance

[HeliHenkie]

Hi all,

I need help with the following problem.
My quadcopter has yaw imbalance.
The mot_yaw value is constantly around +50
I think I checked all relevant possible causes:

1. log_mot_pitch and roll are around 0.
2. all motors and props are balanced
3. props are mounted on square tubes and perfectly level.
4. I recalibrated my esc's several times.

In manual the quad is flying very well, alt/pos hold is reasonable and mission flight is also good.
But I'd still like to know the cause of the yaw imbalance.
What options can I explore further?

Best regards,

Jan Willem
The Netherlands

[chschmid]

You could measure your mot RPM's at a given voltage. Maybe one motor has higher/lower RPM. Or one of your square arms is twisted a little. You know, .5° twist is a lot. I made some (flat staight) blades that I mount instead of the props to align the mots nicely.

Cheers
Christof

[Max]

Distance from center to each motor is even? How about a slightly mis-matched prop? I've seen prop sets in which the pitches don't really match between the CW and CCW versions. And yea, verify your motors really are flat (in relation to the FC), using a level, like Christof suggests. If you can't find anything wrong, you could also try deliberately tilting two of the motors a tiny bit to compensate.

-Max

[HeliHenkie]

Christoff, Max,

Thanks for your replies.
Will try tomorrow.

Best regards,

Jan Willem

[LPR]

Jan

If you test the motors RPM I would change the motor mix to "0" for pitch, roll and yaw. Then all motor should have the same RPM if all is equal. Most motors are hand wound and mistakes are made. The magnets can also vary from motor to motor. If the RPMs are different then you still have to determine if the cause is prop, motor or ESC.

Larry