I've been trying to do the calculations to graph the changes in the wheel plane for a double wishbone suspension like in the first picture. Here's what I get for an upper wishbone length of 8, lower wishbone length of 13 and hub length of 7
http://www.freewebs.com/likeoldsportscars/Wheel_Plane.mht . The red plane corresponds to when the suspension is not compressed and the green plane corresponds to when the lower wishbone has rotated upwards 30 degrees. The calcuations for the wheel plane is pretty straight forward in this case but when you consider a double wishbone suspension like in the picture below with the wheel hub connected to the arms with a couple of ball joints the math gets more complicated.
