t_vago's compound curve foam board pickup aeroshell

[NeilBlanchard]

Here's a 12 degree slope on the bed dimensions of your truck:




If I curve it down at the center, and curve in the sides, the height and area of the transom face can be shrunk some, but this is obviously very different from before.

I'll keep going...

Oh, what is the height of the cab roof at the center of the bed where you want the cap to be level with?

[KamperBob]

The target angle should be maximum and final. Using 12 degrees and 63 inch bed length the trig works out to a 303 inch radius of curvature. That would be level at the cab and 12 degrees directly over the tailgate with a height drop of 6.6 inches.

If the sides curve in the same amount then 6.6 off each side would make the rear base 13.2 inches narrower than the tail of the truck.

[t vago]

Originally Posted by KamperBob

The target angle should be maximum and final. Using 12 degrees and 63 inch bed length the trig works out to a 303 inch radius of curvature. That would be level at the cab and 12 degrees directly over the tailgate with a height drop of 6.6 inches.

If the sides curve in the same amount then 6.6 off each side would make the rear base 13.2 inches narrower than the tail of the truck.

My spreadsheet agrees with you, regarding the measurements using only 12 degrees.

I am planning on 3 degrees between the 1st and 2nd ribs, 6 degrees between the 2nd and 3d ribs, and 12 degrees for the rest of the aerocap. I'm looking at about a 11 inch height and 11 inches narrower from the centerline, at the tail.

[NeilBlanchard]

Okay, here's what I got:







Obviously, it's a different pickup model -- this one was much closer to the right scale. And the dimensions of the base are exactly what your truck bed is.

[BamZipPow]

Starting to look like a upside down boat back there...almost like aerohead's truck.

[NeilBlanchard]

A couple more views:

[MetroMPG]

Cool design, Neil! I have no idea how to do such a compound shape in Sketchup.

One comment: the leading edge of the cap should either be flush with the trailing edges of the cab or have about a 1 inch radius curve on the corners.

But I'm sure everyone knows that.

[NeilBlanchard]

Thanks Darin -- the leading edge would definitely need to seal the gap. Extending the pink "foam" surface forward to the cab would be easy to do.

I've been practicing -- once you get the base model imported from the 3D Warehouse, it is much easier. I drew the centerline profile, the transom profile next, and the slim side panel, and then the front panel at the gap. then I drew the main "valley" arc; followed by all the other longitudinal arcs. The infill triangles are last.

[MetroMPG]

Are the triangles added manually?

[NeilBlanchard]

Yes -- on one half of the model. I make one half into a "component" (which is a sub-file, essentially) and then I insert a copy of it, mirror it, and align it to form a full model. You can edit either component half and it happens on both sides.

If anybody wants a copy of the SketchUp file, I'd be happy to send it to you. Take a look at it, poke and prod and edit, and find out how it works.