Hi Tridge,
logfile: https://www.magentacloud.de/share/ci7vxt6at6
If the plane is lying on the belly, in QSTABILIZE (or QHOVER) full throttle allows the controller only to turn motor PWM (RCOUT.C5/C6) up to maximal 1400.
That is not enough to lift the planes front. In MANUAL (or FBWA) modes the engine power control works well.
As soon as I raise the plane (with the hands without props mounted) nose up, engine power works also well. As soon as the plane is lying on the belly again, motor control is too weak again (red circle in the diagram).
Thanks for the look
Rolf