Faced a weird issue with my quad suddenly going into a clockwise spin while having very high deviations along roll and pitch axes. Even though it seems to have been able to relatively stabilise the descent, the spin made me wonder if one of the motors (number 4) may have stopped working mid-air, leading to high PWM signals to it, corresponding to the low signal to motor 3. I’m working on testing the components to verify that.
Are there any other scenarios which would lead to such a failure mode? If so, how may I test for them?
If not, what are the possible causes for such a failure in the propulsion system?
I may have had a similar issue in an earlier flight but upon testing the system on ground, all motors and ESCs seemed to working fine.
Please help!
In common scenarios I would say that your analysis is correct it seems a motor4 failure. However your copter is a QUAD and normally quads does not descent stabilized with only 3 motors, they tumble down from the sky.
So it is either a perfectly center CG balanced copter which somehow managed to stay more or less level while spinning down. Or motor4 did had a non total failure, for example overheat protection, which only throttle back but does not stops the motor. (Just guessing).
Thanks for the reply @Eosbandi
Since the log does not show any other failure scenarios, is there any way I can maybe test for those things on ground? I was sceptical about the stabilised descent as well, but I have no evidence yet to say that it was not a loss of thrust on motor 4. Are there any other scenarios, apart from overheat protection, that could lead to a partial failure like this?