Quote:
Originally Posted by Midniteoyl
Hey orby.. great job so far! Joined just to follow your work 
Anyways, as I was reading about your tail, the first thing that came to mind for your bottom side detached flow problem was strakes or fences. These help keep the air from 'circling' and force it more into a straight line. If it does spill over, it'll 'trip' over into a vortex. This idea is already in use on autos to help remove the air from under the car (rear diffuser). Cheaper and easier to try than redesigning the tail.
grrr - cannot post links or pics... Just google 'rear diffuser' 
You are correct on needing to have more outlet for air in the belly pan. I believe what you did was trade under carriage drag for increased frontal and cooling drag. Try to think of how to get any air smoothly out..
Good Luck! |
Thanks for the suggestions midnite, the strakes are a great idea. Since I'm going to extend the hitch back far enough to tow things, I decided I'd just do a quick rebuild of the lower area and drop that down about a foot or so. That will improve the air flow hopefully, and enclose some of the bracing I'm going to do for the hitch. After doing that, if the air still swirls to the right as my friends described, the strakes will go on. Good idea.
I totally agree about the pans. The engine cooling was doing unusual things and I'm sure it had to do with the air flow backing up in the frontal area, probably increasing my bow wave considerably, which is why I saw what seemed like to me almost no gain from the pans. It was also only one test run but when you work full time and it's 900 degrees outside and diesel is $4 a gallon, it's hard to do test runs sometimes.
The summer temps are coming down nicely lately, I've just got to find the time to do the changes in the back, vent the pans, build some wheel fairings, finish the diff, and do some more changes to the front. If I can bust 20 mpg I think I can get this beast in an RV magazine or two maybe. I do business with several RV manufacturers and dealers and I'd love to use this vehicle to get them looking seriously at aero mods for RV's and big vehicles. What was it someone said, these babies are 'target rich' for improvements. Uh, yeah.