Octaquadplane: power loss / yaw

ArduPlane Plane 3.7
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1

I’m seeing some strange loss of power in VTOL. I think I’m chasing a yaw problem where the vehicle is trying to correct some yaw error but I’d like to have somebody more qualified take a look.

I’ve checked that my motors are aligned and level

2017-06-12-bad-motors.png3046×810 51.2 KB

DF logs: https://drive.google.com/open?id=0B9UhUyOiU9LpcnF0ZHV1VFE0b1U

Any idea what could be causing this?

EDIT: adding yaw graph @peterbarker
(ATT.DesYaw isn’t logged unfortunately, referenced as a bug here)

2017-06-12-yaw.png2664×742 16.2 KB

2

This graph tells an interesting story. First climb at max throttle resulted in avg vertical speed of 3.66m/s. Second attempt 1.5 minutes later to climb at max throttle resulted in avg vertical speed of 0.44m/s.

  • first: 5m to 38m in 9s
  • second: 6m to 10m in 9s

Screen Shot 2017-06-13 at 12.14.56 AM.png2562×750 26 KB

Am I missing something? This has been happening for a while now, even in AUTO (vehicle stops climbing). Battery pack far from being depleted.