Z,
Your childish attack on Tim's post aside ("MAN UP boy (!!!) ..." really?), can you explain how you could have non-linear pitch springing whilst creating a stable aero platform and having soft twist mode? Given that torsion bars can't have variable rate (?) I'm assuming you'd set up your 'lever arms' at each end such that they are falling/rising rate. Doesn't this mean that you have to travel to the extremes of your lever arm to get sufficient stiffness for pitch (without bottoming out), which would involve significant chassis movement to achieve (and hence non-stable aero platform)?