Aerodynamic...but not aircraft

3/4 ton extended cab pickup towing a 24 foot travel trailer. Fuel
mileage is effected much more by wind than weight.

I want to build a camper shell that will be cab high at the front and
direct the airflow smoothly over the trailer.

There is about 4 feet between the front of the trailer and the rear of
the proposed camper. For some reason, I believe the camper should be
higher than the trailer. But how much higher? Should the angle be
constant? Convex? Concave? A different exit angle?

About a foot from the top of the trailer, the front slopes back at a
45 degree angle. All opinions are welcome but educated calculations
will be given more weight.

--Andy Asberry--
------Texas-----