Another truck aero cap idea...

[BamZipPow]

Originally Posted by KamperBob

Keep up the good work. Love the incremental updates.

The buckling under way intrigues me. I wonder if it's positive pressure above or negative pressure below. Have you been able to tuft test that area with a chase car for example?

Rock on!

Sorry Bob...no one to help me but me.

This is the piccie of the hatch being pressed down while in some cross winds and an 18 wheeler in front of me...I had 3 sheets of Coroplast on (but not laminated together). I believe I didn't have my ducktail/rain gap cover on at the time so air could've been gitting under the aero cap. Speed was about 65mph.

[KamperBob]

Originally Posted by BamZipPow

Sorry Bob...no one to help me but me.

This is the piccie of the hatch being pressed down while in some cross winds and an 18 wheeler in front of me...I had 3 sheets of Coroplast on (but not laminated together). I believe I didn't have my ducktail/rain gap cover on at the time so air could've been gitting under the aero cap. Speed was about 65mph.

I'd gladly help but you're too far from IL.

I'm not seeing a big problem in that pic though. I originally thought you meant a big section in the middle was pushed down. So it's really asymmetric?

The neat thing about true compound curvature is that once you have it the shell strength is much more. My Scamp trailer is an excellent example. All molded fiberglass and only about1/8 inch thick. Large flat sections without windows or inside cabinets attached are flimsy. Simple curvy areas will give a little but not much. Compound curvy sections are amazingly stiff. Geometry rocks!

[BamZipPow]

The Coroplast wasn't secured to the middle support...you can see air between the support and the Coroplast! The sections between the middle support and the main outer support is where the Coroplast was being pushed down. Kinda hard to shoot the right picture at the right time as it was happening. I heard what sounded like flapping and then bumping sounds...that's when I looked in my rear view mirror and saw my hatch caving in. I backed off the gas pedal pretty quick and safely looked fer a side road to exit to. At the same time, pull out my camera, point it backwards and run off a few shots...

The new grid support seems to have eliminated the flexing now...came across some severe gusts and the Coroplast didn't flex down like it did before...and this is with only 1 sheet of Coroplast on top! I might laminate the top with another sheet using some 3M Super 77 spray adhesive and some screws to keep it in place. Fun will be trying to line it up as it will stick as soon as I stick the sheets together...no sliding around.

Currently hot gluing all the seams down where I had taped it before. Hopefully it will hold up over time...

[Bill in Houston]

Originally Posted by BamZipPow

I might laminate the top with another sheet using some 3M Super 77 spray adhesive and some screws to keep it in place. Fun will be trying to line it up as it will stick as soon as I stick the sheets together...no sliding around.

Have you used Gorilla Glue before? It's good for this kind of task. Easily repositionable, and sticks well to Coroplast. Just have to manage the drippage as it cures.

[BamZipPow]

Originally Posted by Bill in Houston

Have you used Gorilla Glue before? It's good for this kind of task. Easily repositionable, and sticks well to Coroplast. Just have to manage the drippage as it cures.

I had been reading up on polyurethane glues (Gorilla Glue, Sumo Glue, Titebond polyurethane glue, Elmer's Ultimate Bond, ViseTite, etc), it seems that I need to poke holes in the Coroplast so the glue will have something to expand into and grip. Not sure I want to do that fer a 4'x8' sheet...

I'm been playing with 3M Super 77 spray adhesive...not sure how durable it will be in the long run. We'll see...

[Bill in Houston]

Nah, I get good bonding on flat-to-flat surface uses. But, the best tool is the one you know how to use.

[ECONORAM]

BamZipPow, your air dam and belly panels are better than mine! Nice. I just realized tonight I need to replace my enormous factory muffler before I try fastening the back half on the truck. I like the idea of lowering the factory bumper/air dam. Mine isn't constructed the same, so I'll have to do some thinking.
For glueing, I was going to suggest some two tube epoxy. Get the surfaces wet and then put on a layer of toilet paper or paper towel. Make sure the epoxy saturates the paper. Voila! A composite glue job. You could wrap it around the tube, and extend it over an inch or two of the corroplast.

[winkosmosis]

Originally Posted by MetroMPG

The template should be sized (apparently) so your tires share the same ground plane as the aero car in the drawing.

(I'm not sure it's strictly correct for very large vehicles, but that's another discussion.)

That makes no sense. If he lifted his truck 1 ft, would that then mean the whole template has to be scaled?

No, the curve along the top matters for keeping flow attached, it has nothing to do with the ground.

[BamZipPow]

Decided not to go with the hot glue...never know when it's gonna give out if it's the main support.

Put in some support rails that I glued and screwed into the main rails. Installed the 2 PVC pipes and then screwed those to the new rails. Screwed the top Coroplast to the rails. Added in the support ribs to keep the top Coroplast from caving in. This should work fer now...

[BamZipPow]

Just hot glued the leading edge of the duck tail to the cab roof. We'll see how well this method holds up compared to the taped method (gave out due to the summer heat).

I installed some soft pipe insulation on the leading edge of the aero cap so there isn't a major gap between it and the cab. It's the self stick kind so I applied it to the Coroplast edge to make sure it won't fly out on it's own.

No piccies of these "improvement" fer the moment. Need to git more things packed so I can head up North again. Long run to Nebraska cutting through tornado alley...