CW Motors Overheating While CCW Stay Cool

According to the Mission Planner logs, the outputs of motors 3 and 4 are double that of motors 1 and 2. Consequently, motors 3 and 4 quickly overheat.


I'm trying to get my new multi dialed-in but after only 5 minutes of hover attempts [at about 45% throttle] both of my CW-rotating motors (3 & 4) get so hot you can't touch them, while the CCW motors remain cool. All calibrations have been re re re re re-run. ESCs, radio, accelerometers, compass, and everything appears to be balanced — fore-aft CG, props, etc. — yaw seems stable, I even disassembled the motors, balanced the bells, lubricated the shafts and bearings with EPIC oil for electrics (note that these motors are new and have less than 15 minutes run time on them).

To make matters worse, This is only the third real attempt to get a stable hover but I can't quite get there from here. I still require manual trim input on the Tx of about 5% right roll and 5% up pitch for it to behave as well as it does in the video. I'd love for it to be rock steady but I'm not sure know how to get there and with two overheating motors there's no way I'm going to attempt to fly outdoors.

I have an email in to HK tech support but no reply yet.

If anyone is interested the video is here and sample log files are here:


For safety, the skids are covered in foam pipe insulation and a prop protector stick was added to each arm (the sticks are from 2 carbon fiber arrows -- $3.50 each at Walmart).

And yes, the props are right-side up =)



Frame: Tarot Iron Man 650

Arducopter: 3.1.2

Props: APC 12x4.5

Motors: NTM Prop Drive 28-30S 800KV

ESCs: Turnigy Plush 40A

Battery: Turnigy 40C 5A 4S

Flight controller: APM 2.6 w/uBlox GPS

Receiver: FrSky D8R-II PLUS (modified antennas)

Transmitter: ER9X with FrSky ACCST 8CH module

Weight as shown: 2.4kg


My current PID settings:


2014-03-09 15-26-22.log

2014-03-08 15-17-29

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            • I looked at your motor outputs and they are very different from my own.  Your motors appear to be all working at similar levels but still quite different -- are you able to maintain hover with stick inputs? Or is it constantly fighting you?

              • i manage to maintain hover but as pid are not good for now, it moves a little.

                • If you're only drifting a little and it's not oscillating then I would think you're ready to try Autotune to tighten it up.  

  • Quite a conundrum eh?

    Frame twist could be an issue but, to demand so much more drive? Seems unlikely.

     -- Could the problem be the converse...Motors 1 & 2 not pulling their share forcing 3 & 4 to overwork?

    I can buy one ESC acting up but two, on the same rotational plane?


    -- Is it possible that you have the APM -> ESC wiring crossed up and fixed the direction with motor wiring exchange?


    In other words, you have M1, M3, M2, M4 wiring at M3, M2, M4, M1 and set the rotational direction with the ESC -> Motor wiring?

    When you have eliminated the possible, all that is left is...


    • I re-checked the wiring and the outputs of the APM, 1 2 3 and 4, are correctly connected to their corresponding ESCs/motors.

    • I'm intrigued. My copter is setup as an X and it flies like an X but as you posited, motors 3 and 4 seem to be doing the lion's share of the work. If the above were the case would I still get normal responses to control inputs?  Aside from the weird overheating it reacts to inputs as you would expect.

  • Are your CW props mounted the correct way? This may explain why they need to work harder to achieve the same thrust as your CCW motors which most likely have their props mounted correctly.

    EDIT: Doh! Nevermind. Didn't see your last sentence "And yes, the props are right-side up =)"

    I only mention because the same thing happened to me a few years ago and that was the issue. Nice looking quad btw.

    • Despite the previous post and with apologies I'll still mention props - we've seen so many times how easy it is to have a problem with that. Check again that you actually have left and right rotating props on left and right rotating motors, and that they really are right side up ... I know, I know, it sounds lame...

      • Third set of props. All balanced right down to the hubs, and yes, they are on correctly.

        • 3702750199?profile=originalI think you might be underpowered.  600-700 on throttle just to barely make liftoff seems like too much.

          Try lightening the load.

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