geoff birds new trike

Blisters and bubbles aren't the ideal aerodynamically - a homogeneous shape is better as there is less parasitic drag, but if you are designing a circuit racer (or road machine), as opposed to a Battle Mountain machine, then it has to be practical for use in a wide range of conditions otherwise that theoretical speed will never, or rarely, be realised.

In terms of side wind stability as opposed to efficiency, a profile that maintains attached flow in a side wind will probably be less stable as it will act like a wing or sail to create a larger side force.

New smoother nose below.

Jeff.

Looks rather good by the way 

I hope I fit in it though, wouldn't mind a spin in it, not literally of course!

A couple of thoughts about it though; with the height and length of the foot/knee bubbles seeing the apex of a bend might be a problem, of course if you take a nice safe line it won't matter, but if you want to running with a tyre on the edge of the grass it might, also i think you might have overestimated the gap between knee bulges. However without seeing scale drawings it's hard to tell, it also depends on the width of your hips and what width BB you are using of course, just sit and stick your legs out and see what width you have between your knees and then allow clearance for the bubbles, believe me knees and bubbles don't go together, and if they do blood will soon flow.