contact points assistance please

would anyone want to take a look at my model and aircraft.cfg to try and find what the h*ll the problem is?
no matter what I do, the plane refuses to stay on the ground, it sinks until it touches the props and starts bouncing up and down.
pretty please?
Thanks
H.
no matter what I do, the plane refuses to stay on the ground, it sinks until it touches the props and starts bouncing up and down.
pretty please?
Thanks
H.