Thanks for all answers!
They were around 1600 before the failure, The machine was not well CG balanced when it happend ( I knew it ) because I was flying with two packs and my gopro wasn't all the way forward. After the failure the overall output has risen to ~1700. I was expecting more will from the arducopter thrust controller to keep it flying.
Sorry for your crash... It looks the same issue... Almost the same values for MOT_THST_HOVER and yaw imax/yaw headroom.
My hex has almost two years and I've made dozens of simulations with ecalc. It says that it should be OK. Thanks
Fpvberlin - I was in a medium speed forward flight before the crash. It almost flipped, but the controller has recovered and managed roll/pitch very well. The batteries are all good, less than 20 flights , two packs of 10ah - 4s. No problems raising all motors to full and drawing ~90A. They were about 80% of charge at time of failure. So I'm almost sure it wasn't a matter of lack of power. I agree with you that if I have more spare power it would be able to recover. For sure. I haven't had any damage on the frame but the propellers. However I'm not confident in flying above water anymore.
But as I haven't seen the four motors left raising the throttle significantly even loosing yaw if it was necessary, I feel that there is still room for tuning/improvement before changing propellers / motors or batteries. I would be very pleased and happy to go down to the bottom of this and figure it out.
Nice tool. My way of measuring is not nice, but accurate. I held the drone with some negative weight ( pulling it up), secure it with a wire attached to a scale - then calibrate the scale to zero and power the motor up. I've measured 1.57 K of thrust. * 4 = ~ 6Kg - enough to lift the drone with 4Kg auw .