Motor spin when armed- not working

APM 2.6 with I believe AC 3.1.2 but I need to double check.

Castle 35a controllers, 6s battery, 380kv motors, JR 9303.

I typically set up all of my aircraft with the motor spin set to 0 for first flights.  This is working fine.

I now want to set the motors to spin slowly.  By changing the parameter, I cannot get the motors to spin.  I have disabled the pre-arm checks, increased the thr_min, re-calibrated the Tx, all to no avail.  The controllers are set to a very soft start, so I was thinking that the very slow option was not enough.  I changed this value around a few times and only once did the motors try to spin when the aircraft armed.  They did not start completely (they dithered around center because of the soft start) so I changed the value to slow instead of very slow.  Now they will not spin when armed.  I can start them with the throttle as if the value was set to do not spin.  I tried changing parameters with USB cable as well as telemetry.

Also played with the HDOP values as well as GPS glitch radius.  Have been trying to arm in stabilize as well as loiter.

Any help is appreciated.

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  • I had the same problem with my recent hexacopter build. My ESCs werent responding to the "very slow" setting, but it works fine on "slow". I haven't bothered to diagnose beyond this, as the slow setting works just fine for me.

    I did get prop bit once, but it was a good lesson.

  • So, guess ill answer my own question.

    It seems the castle speed controls require the "fast" setting in the motor spin before they will do anything.  They still spin slowly at this setting.  I changed to AC 3.1.1 because it was closer to what I have on an X8 that is working well.

    I am guessing if I upgrade back to 3.1.2 ill have to set it the same.  Based on the RPM that the motors on my X8 spin at the very slow and slow settings, the fast setting on this larger setup would have made the aircraft take off due to its power to weight ratio.  Hoping nothing changes unexpectedly.

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