Autotune Crash with a big copter

ArduCopter Copter 3.6
1

Hi guys,

Yesterday my copter crashed while doing autotune. I finished the roll axis, and just after the first twitch in pitch, it got uncontrollable and crashed. Here you can see the log:

My copter can fly either with 2 or 4 batteries, and it is funny because this is the second crash I have with 2batteries. The first one was in Loiter with 2 batteries after finishing an Autotune with 4 batteries. Same behaviour, everything was ok, I did an small input with the transmiter, and got uncontrollable again.

I am starting to suspect that the reason lies in the fact that is overpowered, and with two batteries (5 kg less) even more. As you can see, throttle output is around 23%.

After reviewing the log, is it possible that overpower is the culprit in both accicdents with two batteries?

Thanks,

JM

2

Motors, esc, blades, batteries, weight??

3

Hi,

Motors are T-MOTOR MN801, 28 inches props, Tattu 22.000 mAH

With 2 batteries (when the incident happens), it is around 15 kg

4

what Esc?
Batteries 12S?

5

The ESC was FLAME 60 AHV and the batteries yes, 12S 22000 mAH (x2 batteries mode) and 12S 44000mAh (x4 batteries mode).

BTW, here is the post regarding the other crash I am referring, the sudden oscillations after an endurance flight in loiter.