[hat_man]

I hate to resurrect an old thread but I have a new idea/question about the pressure differential concept of the half tonneau that Aerohead mentioned. Now that I'm mobile again from the broken foot it's time to start some fab work. I'm still going with the simple idea I had from the start and for now no wing. But reading the Aerodynamics of Road Vehicles book while I was off got my mind wandering again and led to new questions.

So, here goes........

I like the look of the Honda Ridgeline with the sail panels and sloped bed rails in the attached picture. I would never do it, but what if you took that section and magically attached it to the top of the bed rails on a Ranger. Something like in the other picture. Does this create a larger volume of air being acted on? And if it does, how does this affect the pressure difference?

I guess a better way to think of it might be a half tonneau on a Honda Ridgeline like in the last picture. If you put the half tonneau at the level of the red line it would create a specific volume of air being acted on and if you put it on the yellow line it creates a larger volume. (I'm probably using the wrong terms here, but I hope you understand what I'm getting at.)

Also, if you put it at the level of the red line does this create an area above the tonneau that helps direct air flow rearward and keeps it from spilling out randomly over the sides? If it does is that beneficial or just a moot point? I can see how putting it at the level of the yellow line might create a downward slope but way below the "template" line.

Just trying to wrap my head around how changing the volume of air trapped below the tonneau could affect the pressure differential at the tailgate. Always trying to learn something new.

Thanks