Quote:
Originally Posted by Diesel_Dave
I'm working on designing an aero-cap for the White Whale. I've been gleaning quite a bit of information from different threads on the do's and don't's. Shortly, I should be able to post some images of my CAD drawings. I should note here that my expertice is more in engine efficiency than it is aerodynamics (I'm learning  )
From what I've gathered, it's important to keep the slope equal to or less than 12 degrees. Right now I'm planning on using 11 degrees (both from the top down and from the sides inward) and then smoothing out the transitions. As far as the construction goes, I'm planning of doing something similiar to what Fubecca did (ribs covered with thin sheeting covered with plastic).
One thing that I've been picking up in the threads is that people make an aero-cap, it works pretty well at boosting mpg's, but then people end up not using it because they can't use their bed very well with it on and it's a hassle to take it on and off all the time. Here's a solution I'm thinking about : make the cap in 3 pieces (front , middle, back). That way it's really easy to take it off by myself--each section would be fairly lightweight and relatively easy to store. Plus, depending on what I'm hauling I can leave 1 or 2 sections on, getting at least some benefit.
What are everyone's thoughts? Is it a good idea? Has anyone tried this?
-Diesel Dave |
Dave, sections make a neat idea that I haven't seen yet. Here is some food for thought. Plastic covering needs ribs for strength. Each section may need it's own ribs to stay together while handling especially by yourself. That could add some weight.
I haven't built an aerocap yet (other priorities). I designed several and feel 1/4" foam coated with fiberglass is a prudent approach balanacing cost, strength and weight. I lean towards a one-piece hinged, removable lid like Bondo and BZP for bed utility as you mentioned. I'd lay it up section-wise to arch the back, match the cab size and slope cleanly over the tailgate. My preference would be to exploit the full potential of flow attachment.
Wedges seem to give wake stuffing benefit at least, and flow reattachment at best, so that does help noticeably. Simpler geometry is easier to make so I "get" the appeal and bang/buck proposition. BZP is doing well with coroplast and simple curvature.
No matter which way you go I look forward to following your progress.
PS: I'm in IL near Peoria. Are you in near or far IN from me?