Craig,
Those funny afterplanes you see on some sponsons would have a dual use. To tidy up the airflow at the back of ths sponson for less drag, but as you suggest to control airflow over the top of sponson and stop it from creating lift when the air flows down the back of the sponson.
I dont have a moving ground plane wind tunnel or CFD software to prove it, but at high speed I think most of the lift would come from air being squeezed out from the riding surface. This air cant flow under the sponson (unless it is out of the water) so has to spill out the sides, which would create a high pressure area under the sponsons. I think this airflow is critical for high speed stability, but I have no way of investigating it!! :-
Mike,
I have had an idea for a while for a passive system to control lift. Imagine a rigger with a large angle of attack, say 5 degrees on the front sponsons. But there is no rear sponson tube, the sponsons pivot at teh front sponson boom and a coil-over damper from a car is used to hold the sponson in place. At high speed in calm water the lift gets high and angle of attack goes up, but if it hits a wave the sponson deflects and the angle of attack decreases.
The problem with such a system is weight and stiffness. It would be tricky to set up the sponsons so that they would pivot in the required manner, yet be stiff enough that they wouldn't flex to much in turns. Hmmmm.... :-
Nitrocrazed racing: Too much spare time....
