Flash wrote:
Back in the 70's, the Univ of MD did a real great study of that sort of
thing. They determined that if you could eliminate the gap altogether, you
would have a MUCH better efficiency.

They had a system of complex levers and springs and stuff on moveable panels
that eliminated the gap on top and sides, right down to the road almost.

Try that on your pickiup and your wickiup. - NOT!


It wouldn't be to hard if you were looking to build something.

Find some way to attach 3 rolls of heavy cloth to the truck, one to each side and one to the top. Spring return. A rod
with built in hooks down the pulled end. Put catches on the sides and top of the trailer. Might even add a zipper at
the top corners. A stiff canvas with a fairly stiff return spring should work.