I finally ordered 10 sheets of coroplast from Home Depot to do some aeromods and seal the bottom of my trailer. (
Only $110 and free shipping to store, not bad)
The canvas:
First project was making wheel skirts for my truck, 2003 GMC 2500HD, 2WD, 6.0L gas, automatic. There's roughly a half inch gap between the fender flares and the actual fender. I cut 2 ~3" slots in the flares at the top of the wheel well for the coroplast to slide into and secure it up top. I folded in the sides and attached them inside the wheel well using the existing holes for attaching the flares to the fender. There should be plenty of clearance for the tire to move into the wheel well as the suspension is loaded and they're quick and easy to remove without any tools.
Now for the bad... They both bow out about an inch and they get flapping a bit at speed (50MPH is the fastest I've gone so far). Is this messing up whatever gains the skirts otherwise might provide? I'm thinking of putting a strip of metal on the outside of the skirt and riveting it to the flare to control the flapping while still making removal easy.
I'm also thinking of adding a belly pan, but probably just partial because of the large exhaust. If I do an aerocap it'll have to be removable and collapsible in order to accommodate towing our fifth wheel, any ideas? I won't be blocking any of the cooling area of the grill because it's mainly used for towing, but I'll see if there's any nonessential aero-ugliness that can be fixed.