Quadplane with front tlit rotor

I designed a quadplane with two front tilt rotor.
when I test it on ground It looks very great.
But when I begin to tilt the front rotor for fw mode, if the tilt angle greater than 9 degree,the yaw angle is not
Anyone know why?
And can I tune the pid parameters of yaw to increase the tilt angle?

I was discussing the idea of a quad plane with tilting forward motors with some friends just last week. I’d love to see some photos of your build. Sounds very interesting.

can you post a log (or even just your parameters) ?