justpassntime -
I'm not addressing automation, but I keep this idea floating around in my head :
Side View
*If* you had a flat nose on your car, and *if* you had the space for a cylinder, you could have a stepper motor control a pipe that has a cutaway view that looks like the picture above. The stepper motor would rotate the pipe closed or open.
I *think* it would be robust at wind speeds.
Maybe the best way to fight the wind velocity is to have a sliding grill. Maybe a grid of holes that lines up for ventilation and slides (horizontally?) to misalign the holes, closing the vent.
CarloSW2