Pixhawk autotune fail and crush


My quadcopter crashed today while first autotuning attept and I could not find out why exactly dad happened. this was first autotune, it made 4-5 twitch in roll axis and suddenly droped . while uncontrolled desceding i tried to give throttle but nothingh to do.

multirotor spec:
tbs discovery frame
multistar elite 2216 920 kv motor
2 blade 1045 plastic propeler (properly balanced)
5000 mah 4s 30c battery
fvt littlebee blheli_s 30A esc
flysky fs-i6 radio 10 ch firmware upd.
flysky fs-ia10b receiver
pixhawk fc
apm:copter v3.4.4 firmware
autotune aggresiveness: 0,05
i attached the tlog and parameter settings

thanks a lot2017-03-26 11-21-54.bin (2.0 MB)
2017-03-26 11-21-54.log.param (10.2 KB)

Looks like motor failure. Motor one when it went to twitched didn’t and went to full while motor two went to minimum.

I have seen in the past where Auto tune can cause sync issues with the motors. But you don’t have large propellers or slow motors so I don’t think that is the issue. I do see you are using One shot so don’t know enough about that since it is new protocol.


I found I had to change motor timing to high to get blheli escs to work properly with motors under 1000kv. Before changing the throttle response was very poor resulting in a crash the first time I flew.

Change the timing to high and enabling damped lite transformed it from something unflyable to a sharp handling machine.

Also where did you get your little bee 30a escs? There are a lot of fakes coming from China so when you connect to the esc using blheli configuration tool it should say blheli 30a under firmware version. If it says anything else it’s a fake.

dear iseres,
thank you for your inputs for me. i also think the motor-esc desync issue, because of the low torque motors and big propelers , recommended voltage for these motors are 3S lipo use , but iam using with 4s. what is your opinion for this aspect, i am going to try it again with smaller props and share the results.


dear george,

thank you for your consideration.
when i bougth these esc s i look in with bl_heli suit. they were flashed with the before the last firmware. so i flashed them with the latest firmware. while flashing and reading eprom nothing went wrong. this is the link for these esc s


i dont know if they are genuine or fake. but they say genuine :slight_smile:

If it is a motor sync issue you should be able to see it. By quickly raising the throttle the motor should spin up normally. But if there is a sync issue they will stall.

I don’t think the size of the battery makes any difference.


two days ago i made a motor test and front right motor can not run after %60. first i change it with a new motor. tested again. same problem. i chane it with a new esc. and i change the motor timing from middle to low-middle. i test them again and they all work with %100 throtle. today i made a new autotune. it was succesfull. my settings before and after autotune is as shown. thank you guys for all.
happy flying.

regards from safranbolu