To me they look like Naca Scoops used on aircraft, we used them on helicopters. I'm not an Areo guy but I think a Gurney flap on the trailing edge of an air foil on top of the rear cap might have a greater effect. We used this on the Horizontal stabilizer of the S-76 model. It is hard to compare the higher speeds of an aircraft to an RV traveling at 60 mph but I'm sure it would at least keep the rear window clean. Kind of like ram air/CAI on a MH it adds more HP mostly from cooler air very little from the ram effect unless you go 100 mpg plus but still worth doing.