Pixhawk flip crash in stabilize mode

Hello all,

I am building a new quad with pixhawk. Flew it 3 times but got 2 flip-crashes.

The 1st flight was good. Flew for 17mins. Did an autoTune and can loiter in the air.

In the 2nd flight I added additional 500g of LiPo battery on it. It got a clip-crash when I was moving the quad side-way during autoTune. One motor should be stopped in mid-air.

The 3rd flight was taking off in stabilize mode, holding it in mid-air for 3~4mins, and suddenly flip-crashed to the ground. This time I touched all ESC after crash and they were all very hot.

I believe I am running into pixhawk+simonK-ESC+low-Kv-motor unsync issue. But I can’t sure even I have my dataflash log in hand. I will change ESC for sure, but worry if the flip-crash is actually due to something else and I will still get flip-crash.

Dataflash logs for the 3 flights are uploaded to google-drive. They are bigger than 2MB so I put them there.

Here is my quad specification

Any help are very much appreciated. And I am a newbie to pixhawk/ApmCopter.

Great thanks!!!

anyone could offer your help on this? thanks~~

btw if this flip is really due to ESC unsync issue, is it possible the pixhawk/apmCopter can have some sort of ESC sync test feature?

like generating some special signal to ESC, and teach us what to expect if the ESC is or is not a good match with pixhawk. it will be nice if this test exists when we are on the ground.

the best advice I can give you, is to just connect ESC’s it to your RX , and do some real fast stickbanging. - then you can be pretty sure.

I also read this mention on youtube.

If I can burn out the ESC by “real fast stickbanging”, surely I will know.

But if I can’t burn it out, I am not sure if the ESC is real safe or it is just me not being “real fast” enough.

I think it would be much better to have a more systemic way to verify this ESC unsync issue.

well, I’d rather fry one ESC and motor anytime testing, to be 100% sure, rather than risk it happening midair.

If you want to test it without burning one, just hook ESC+motor to a powerful laboratory supply, and set the current limiter to current of about 60% throttle - that should allow the problem to be reproduced, in the range 0-50% but ESC should handle it.

  • I do not know the real value of such test, as current limit is usually hit anyway on fast accelerations (reducing them).