I have a quad which I 3d printed using the electronics from a Cheerson CX-20. It flies well however at least 1/3 of the time when I arm the quad and take off, the quad immediately flips over. I generally turn it back over, unplug and replug the battery, rearm it and then it’s fine.
What could be causing it to flip. The flip is always in the same direction.
I am a beginner as well… you will probably get better advice, Might be good to DL and post your log.
If it is truly intermittent then I am not sure what to suggest. A good thing to check would be if you have a vibration problem ( the wiki has good instruction for this). It could be making the accelerometers go crazy.
My crashes have been caused by:
a bad ESC (only intermittently bad though) depending on load after 60 seconds it would stop, and I wasnt bench testing for that long, so only found it in the field.
Wrong type of prop on one motor
-wrong spin direction of one motor.