Many guys have proposed some variant of the "fastback" sloping down at various angles. Some seem to work better (in reducing drag) than others but all have the same problem: They restrict vision out the rear window.
Here's another idea.
Currently my truck is running around with a A.R.E. hard tonneau. Big-timeflow separtion but I see out of it nicely.
What I am thinking about is a series of flat plates, stepping down trying to keep the flow attached at a ten degree angle. I should be able to see out OK.
What do you think?
The tonneau
Two plates with no duckbill
Two plates with duckbill
Three plates with duckbill
I'm not too sure my duckbill is doing much for me. It is 18 inches long and drops 3 inches.
Big-time thanks to Carlos for his help with this.