Quad Flip at takeoff

Hi All,

I’m a newbie here, this is my 1st post.
and of course looking for help :slight_smile:

I replaced the original DJI FC in my old F450 with CUAV Pixhack v3.
Setup went well, Accel calibration, GPS and compass are all OK to my (limited) understanding but quad flips over at the second it takes off
I have double checked, triple checked and verified few more times that spin directions of motors are correct and CW/CCW propellers are at right places. ESC are DJI 30A Opto, these cannot be calibrated so I increased MOT_SPIN_ARM to 0.20 as last motor starts at 18%. I also changed MOT_SPIN_MIN to 0.23 as instructed.

I’ve included the log file, hope someone can come up with suggestions how to solve this

2018-01-24 22-58-15.bin (521.9 KB)

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The flight controller is attempting to do the right thing. Here, you can see the drone flip nose-up in the pitch axis. The rear motors (2 and 4) are throttled up and front motors (1 and 3) are throttled down in an attempt to correct this, but the drone flips anyways.

This points to a configuration error of some sort. I have a few basic suggestions before we try to dig deeper:

  • Prop/motor direction. You said you double checked this, but I’ll put it here for completeness.
  • Motor assignment. Make sure you have the ESC’s plugged into the right ports, according to this diagram. It is different than DJI standard!
  • Your board orientation (AHRS_ORIENT) is set to forward. Make sure your FC is not backwards.

Make sure you calibrated the radio correctly with the pitch green bar going down in mission planner as the stick goes forward. Classic problem.

Your motor sequence is not correct,or the propeller is reversed。
As you can see in the pix,when the pitch rate controller want to make the copter nose down,the copter nose up。

This was it, ESC control wires for motors C and D were swapped at FC end.
Its raining cats and dogs so I cannot test outside, but I’m quite confident it will fly now.
If not, I’ll come back again.

Thank you everyone, Anubis especially.

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Great topic! Thank you guys.