quad motors overheating and ESC calibration

Is there anything (barring motor thrust axes being misaligned) that would cause an opposing pair of motors to overheat?  I'm guessing my quad is fighting yaw because of opposing pair part.  Navigation looks fine so I don't think its a gyro or compass drift or something like that.

Potentially related:

I've done auto APM 2.5 ESC calibration (https://code.google.com/p/arducopter/wiki/AC2_ESC) and the only deviation from the procedure was I had to drop the throttle in order to get the 2 beeps in step 5 (as opposed to waiting for 2 beeps to drop the throttle).  I waited for 2 minutes and they never beeped twice unless I drop the throttle first.  Am I misunderstanding the procedure?

Any ideas?

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  • Any update on this issue? 

    I'm experiencing the same symptoms - diagonal (opposing) motors get really hot (cant touch them after 5 min flight) while other ones are cold as ice. 

    Quad is stable, flies ok (there is some drift but still have to tweak PIDs), but I don't think this overheating is normal. 

    Setup  - H-quad (X config)

    APM 2.5.

    FW 3.0.1

    Thnx for any info!

    • Did you ever find a solution for the overheating?  I'm experience the same symptoms.

  • They're rctimer HP 2212s. They're the front left and rear right ones which are CW from the top. If I remember correctly I believe that would mean it's fighting a CW net yaw..
  • Are the hot motors rotating CW (from top)? And, what type of motors are they? Some motors build a fan into the bell casing which is rotating the wrong direction for the reverse pitch pair, thus those motors do not cool as well as the others. Same goes for coaxial motor pairs in which the bottom motor will run hot.

  • If you enable motor logging and do a hover, do two motors show higher motor inputs?

    That's a good way of diagnosing imbalances in the system, you can see if any motors are working harder than others, eg if CG is way out or you have some twist causing the CW or CCW motors to have to work harder.

    In a normal, balanced copter with calibrated ESCs, all motors should show basically the same MOTOR value in the dataflash logs.
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