Hot motors in 5 min hovering on a quadcopter


I am using these motors T-MOTOR MN4014 400KV and I also use these propellers T-MOTOR Carbon Prop - P17x5.8, with these propellers, everything was working fine. I then installed the NS17x5.8 Prop, generator 3 ultra light props and I have hot motors in 5 minutes hovering flight. Do you have any suggestions? I am using pixhawk orange cube for flight controller and I have ardupilot, I have tuned the flight controller good, I have put soft mount on the motors, I checked the logs and I do not have a lot vibrations. I also check the levelling of the motors and they are good. All the motors are hot. I am sending also the log of the flight:
Can you help me?

I see you have completed all the Initial Tuning parameters so that’s good. Vibes are low as you say. It does look like it needs further tuning. The major problem, which we seem to see posted everyday here on the forum, is a mechanical yaw bias. The CCW motors are commanded much higher than the CW motors. I’m not sure if this is the cause of hot motors but it needs to be addressed. Twisted arms, twisted motor mounts, frame distortion or difference in props typically explain this.

So fix this, then configure the Dynamic Notch Filter, then run Auto Tune.


You probably won’t have to look any further than that motor angle issue Dave posted, that’s a pretty big imbalance. But in case it doesn’t fix it, some ESCs have different timing modes that can affect heat. Like the xrotor40a have intermediate and high timings, and this little blurb in the manual.

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Thanks for your advice, I will check these out

Ok I will check the motors mounting, how can I fix this with the esc if this is the problem? I have made the esc calibration from mission planner

What brand/model ESC do you have? The manual might say if it has different modes.

Yes it has 2 modes as I saw on the manual, although it is on the intermediate by default, I will check it also to be sure.

So probably not that.

Looking at your log, the 1 and 2 motors are significantly higher than the other 2. If you’re set up with the std x, that would be your right front and left rear.

The copter will want to spin the opposite way that the motors are turning, so 1 and 2 elevated means the flight controller is using a lot of right (clockwise) yaw to correct for something (the craft naturally wants to turn left apparently). Probably twisted motors. This was something I have spent a fair amout of time on over the last few years (getting the thrust straight up and down). My procedure was to 1. Adjust the motor levelness getting it close as I could with a bubble level. 2. Fly 3. Analyze logs to see which motors were elevated. 4 Determine which way the craft was trying to turn and see if any of the motors are a little off causing that… then repeat until the motors are all about the same (on a calm no wind day). I had to do it a bunch of times so don’t get discouraged, good luck!

Maybe try this to see how thrust is pointed? :nerd_face: :smiley:

Yes I use true x and it is the 1 and 2 motors, I will do that, thanks a lot for your advice.

Hello again, I tried to level the motors as good as I could and I made a test flight for 5 minutes and the motors were still hot. I am sending you again the log to tell me what you think. Should I proceed with the dynamic notch filter or is there another problem?

That link has an access requirement.

I’m sorry, I fixed it

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Good job leveling the motors, OK now. In fact I can’t find anything in the log that would cause hot motors. The tune is good, low vibes. So I’m not sure what the culprit is. Configuring the dynamic notch filter is a good idea but I don’t know if it will help the hot motor problem.

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Ok thanks again, I will try the dynamic notch and I will see if ti helps