truck topper modifications

[freebeard]

Thanks for the pictures. So it's not about the skin as much as the framing. 1/4" ply would be heavy, consider luan paneling (cheap) or marine plywood ('spensive). Here's a chart that lists 4 materials available in 1/8" thickness:

Plywood Thickness | ThePlywood.com

You might could use steam to bend the curve. If you wedge the shape, tumblehome will increase from front to back.

[craveman85]

Tumblehome? Lost me there

[freebeard]

Tumblehome - Wikipedia, the free encyclopedia

[craveman85]

Ah. I'm not going to wedge it front to back. I've decided that a complete lid lift is going to take too long and more money than I want to put into it. If I wedge it then I won't really be able to use my rear gate. I need access to the bed very frequently so function over rules maximuaerodynamic benefits for me.

[freebeard]

OK, but then why did you remove the skin?

I like the way they did the Dodge Magnum:

[craveman85]

I had to take it off to do my mods. It also has a 3 dimensional texture to it which I'm sure wouldn't help airflow much. It also has a bunch of dents, dings, and was sagging in spots from heavy snow. My cap will probably be about the same general shape as the magnum.

[freebeard]

Apparently small-scale roughness isn't too much of a problem. People say a clean car isn't better (for aero) than a dirty car, and then there's the controversy over dimples and whether they help. Dents and sagging would be more problematic.

The Magnum is pretty much ideal. That gets back to curved taper vs wedge. The L-shaped hatch would present problems with framing and sealing, to prevent exhaust intruding into the interior.

I'll watch to see how you do.

[craveman85]

I may be able to do more of a curve if I anneal and bend the horizontal bars

[mikeyjd]

I'm watching with interest. I plan to build my own aero cap this summer and have yet to decide how I want to approach it.