I have a 6x12 enclosed trailer with standard (not ramp) rear door. The front surface is rounded but the junction between sides and top (or front and top or rear and top) is 90 degrees. The top is pretty much flat.
It has really killed the mileage I get with my Ram 1500, Pentastar engine and 8-speed transmission. So I'm thinking of some mods.
On the sides at the top I was thinking of cutting a piece of 4" pvc pipe lengthwise and attaching each half-pipe along the edge (on the sides, so it merges smoothly with the top surface). This would give some radius but I don't know if that is enough to do any good.
On the front, at that edge, I cannot do it so easily as it is curved. So instead I was thinking of putting a lip up there to separate the flow going over the top with that going around the sides, more or less like the ones I've seen pictures of used on air dams. Maybe 6" wide?
At the rear I am thinking either VGs, or a tapered box, or VGs
on a tapered box. I'm thinking acrylic for the box to avoid having to make a cut-out for the tail lights and any reflectors. Extending back maybe 2 feet just to keep it reasonable, which means if it's 12 degrees it will have come in about 5 inches all around (not sure if it's worth doing on the bottom). I should be able to mount on the door hinges so it will swing out of the way when the door is opened. It would have a sharp transition and I wonder about that.
Then I think, "why bother?" I should just drive 5mph slower and avoid all that work.
