Hello fellow UAV/UAS pilots!

Our Matrix is fitted with a 15" T-motor rotors, 6s power system, and a dummy weight at the gimbal's position, with Pixhawk and was running a back to back Auto missions to tune out sluggish AUTO mode.

The aircraft did the first two trials fine, but it was very sluggish, so I decided to pep up the speed a little bit. 

First flight, was a test of existing parameters/setup, went without a hitch, however a bit slow.

Second flight, we increased the WPNAV_ACCEL to 160m/ss to make it accelerate a bit faster from waypoint to waypoint, and we also set the waypoint yaw to 0, to prevent it from facing into the waypoint, thus reducing time in flight. speed was set at 6m/s.

Went great, so we continued to push forward with changing the accel value to 200m/ss, for more snappiness during auto, and third flight indeed was the fastest/snappiest. but when it was facing into the wind, and needed to change its direction to the waypoint back, the pitch up was very extreme, and ended up rolling the copter on its back, doing a back flip. I barely saved it by putting it into stabilized, and full throttling it. 

It was fairly windy today, ~10-15mph winds.

Here are my questions. 

1. I have the max angle set to 30 degrees, why did it exceed this during auto?

2. Why did the accel value change suddenly made the copter flip on its back in the air? 

3. Is there another parameter I should be looking at, to prevent this from happening again?

4. Would changing the WPNAV_LOIT_JERK help with the AUTO to prevent this from happening? I think its too much of a jerk causing the copter to flip.... any input on this?


I realize the 15" props doesn't react as fast as 10" prop on the Iris, but it shouldn't be doing a backflip because of a little bit of wind. 

Any suggestions/advice would be greatly appreciated. Log is attached. 

2015-06-08 10-49-09.log.zip

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