Servo problem

[ChickenBalls]

@Xpress is an Electric guru, lets see what he thinks

 

[Xpress]

What do the ESC's data logs say? Post them up if you can.

Knocking in flight indicates that the ESC might be losing sync for a split second. I tend to veer away from larger Castle ESC's and stick with Jeti.

 

[hbollier]

It isn't so much the knock as the power loss in surges. The longer it runs the worse it gets. At first only wide open throttle, then at any throttle setting. I have the same motor and ESC combination in another plane that works perfectly.

 

[Xpress]

It isn't so much the knock as the power loss in surges. The longer it runs the worse it gets. At first only wide open throttle, then at any throttle setting. I have the same motor and ESC combination in another plane that works perfectly.

Yes, as I said the ESC may be losing sync, and it may be getting more difficult to keep up as the battery voltage lowers. What propeller are you using?

My only other suggestion would be to send both the motor and ESC into their respective manufacturers for inspection.

 

[hbollier]

Xoar 20x10. Shouldn't be a torque issue. The motor should be able to swing a 21x8 no problem.

 

[Xpress]

Would definitely send both in for inspection then.

 

[ChickenBalls]

Xoar 20x10. Shouldn't be a torque issue. The motor should be able to swing a 21x8 no problem.

How much trouble to get to the other ESC that you are using on the one running right? I'd grab it and plug it up and give it a try, eliminate the ESC from being the culprit.

@Xpress when you say losing sync, is that timing? I've heard them click, squeal, make all kinds of noises.

 

[hbollier]

I'm gonna work on that one loose male bullet first. If I cannot adjust it I will replace it. Next I'll turn off logging(suggested on another forumn). Then I'll swap motors. That should tell the tale.

 

[Xpress]

@Xpress when you say losing sync, is that timing? I've heard them click, squeal, make all kinds of noises.

Yes. When an ESC loses sync with the motor, it can make all kinds of noises. The loud knocking noise could be the ESC sending a signal to the motor just a fraction of a second before the motor gets to the right point so it actually forces the motor to slow for a split second.

Double checking all of your connections between the motor and ESC, and the ESC to the battery is one good method- never use bullet connectors on such large power systems. Always solder the wires directly together to eliminate any and all connection problems, as well as decrease the resistance between the connections.

 

[hbollier]

I swapped out the connections on the motor leads to rule out a bad connection. Then I swapped out my receiver to rule that out. The power still cuts out. I called it a surge earlier, but it is more like an engine with a miss. I changed a few ESC settings to make it match the working combination. The logs show a definite problem. With a constant throttle position the power will cut and return but it never comes back all the way.

Firmware 3.27 (gives the best power measured on a watt meter)
End Points: Fixed
Throttle Response: Custom 10
Brake: Disabled
Cutoff: Disabled
Current Limiting: Disabled
Start Power: High
Motor Timing: Low

I will run it with these settings. If no change I will disable logging and try again. If this doesn't work it will be time to swap out ESCs. If that doesn't work then it is time to send the motor in. The only part in the system that I do not know the history on is the ESC which came from the classifieds. The motor has fresh windings from the vendor so it would surprise me if that were the problem.