by troubleScottie » Mon Oct 15, 2018 9:14 pm
There are several threads in here on this topic. I have not seen anyone suggest or build the rear deflector -- even on a square back design.
The teardrop profile is possibly the optimal shape as it presents good flow over the trailer. A brick shape is the worst. Wedges somewhere in between.
For any object, the biggest issue is the projected cross sectional area. Ideally the towing vehicle (TV) cross section is equal to or greater than the trailer. Due to the space between the TV and the trailer, the trailer often behaves like a separate object. Your trailers height might be less than the TV which is good, depends on your wheel size, axle placement, etc
Your upright front face may be the least than optimal. If you want a panel to rest against, you might consider a bulkhead inside the trailer. Of course given the 8' length, this might be impractical.
Also, the wheels are sources of drag. They might stick out relative to the TV, and present drag
BTW, 36 inch is pretty short. Given a mattress (2-6") and ceiling (1-3"), the usable height is cramped. Think about sitting under your desk. You might consider a taller design. A whole plywood sheet on top of the trailer bed will give you an additional 12 inches.
The other thing is to consider the materials that you are constructing this out of. Foam is the lightest. Plywood, etc can get quite heavy.
Michael Krolewski
Scottish Terrier Fancier