t_vago's compound curve foam board pickup aeroshell

[aerohead]

Originally Posted by jamesqf

This reminds me of an idea I had, which is to make some air from the sides flow through the bed. Have a NACA-style inlet forward of the wheel well, and louvers in the tailgate. Any thoughts?

If the cap is properly configured you run the risk that air will actually flow forwards carrying exhaust gas with it.If you had an open slider window you could be exposed to carbon monoxide.

[aerohead]

Originally Posted by KamperBob

I have two different designs.

A) Split with a hinge in front. The top lifts up. The sides are wedges bulged slightly at the front. All convex - no concave.


B) One piece that slides back and tilts forward. The bottom gutter edges would have a couple inch fillet (hard to draw).


Notes:

• Both match cab shape at the front for smooth transition.
• Slopes are all less than 22 degrees from normal.
• Compound curvature using fiberglassed (similar to T's).

Which would you prefer and why?

Bob,you can do both.The boat hull on the T-100 has both and tuft testing demonstrates attached flow over the entire structure.The MPG seems to concur.

[aerohead]

Originally Posted by NeilBlanchard

The shape at the tailgate would seem to be very important, too. The black Italian-designed unit appears to have a *rising* wedge on the sides? The cap I modeled has a downward curve on the sides:

Neil,just thinking out loud,but it seems that the short bed would aggravate separation in a cap with such steep curvature,and by 'raking' the rails upward they effectively reduce the steepness.
The wake is a little larger but zero separation before the gate .

[t vago]

Originally Posted by jamesqf

This reminds me of an idea I had, which is to make some air from the sides flow through the bed. Have a NACA-style inlet forward of the wheel well, and louvers in the tailgate. Any thoughts?

I suppose it could work, though my gut instinct says "No." You'd have to experiment with the idea.

Originally Posted by KamperBob

B) One piece that slides back and tilts forward. The bottom gutter edges would have a couple inch fillet (hard to draw).

Which would you prefer and why?

Choice B) is preferable to me. Side airflow is more adequately addressed than in choice A).

[KamperBob]

I started "virtually" building of my Version A aerocap design. Sketchup is great for working out details in 3D. I tweaked it by flattening the the rear center and pushing the departure angle all the way down to 22 degrees over the tailgate. Starting over with a framework then skinning it was very good exercise. Now I am more confident about the feasibility of the design and fabrication.

[BamZipPow]

I would still put some sort of taper from the front to the rear. I have found out with mine that if I could just pull it in just by a few inches that it would be better in the long run...even if it's just the same width of the tailgate. This will be incorporated in my next version...

[Frank Lee]

Originally Posted by 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.

Nice concepts. Just wanted to point out in case everybody didn't already know, that you don't want the cap to actually touch the back of the cab and literally seal the gap. If you've ever ridden in the box of a pickup when it's going down the road you'd be amazed at how much relative movement there is between cab and box. Of course if one really was concerned about that gap they could try some thick weatherstripping... it might make annoying squeaky noises tho'...

Two summers ago I started a coroplast aerocap for the F150; mine only uses simple curves. I didn't finish because I was out of state for 6 months and I ran out of Coroplast. Maybe this spring...

[KamperBob]

Originally Posted by BamZipPow

I would still put some sort of taper from the front to the rear. I have found out with mine that if I could just pull it in just by a few inches that it would be better in the long run...even if it's just the same width of the tailgate. This will be incorporated in my next version...

Yeah, version A as shown is 3" wider than the tailgate. I'd like to do a virtual build of B next. Then tweak A some more...

[KamperBob]

Originally Posted by Frank Lee

Nice concepts. Just wanted to point out in case everybody didn't already know, that you don't want the cap to actually touch the back of the cab and literally seal the gap. If you've ever ridden in the box of a pickup when it's going down the road you'd be amazed at how much relative movement there is between cab and box. Of course if one really was concerned about that gap they could try some thick weatherstripping... it might make annoying squeaky noises tho'...

Two summers ago I started a coroplast aerocap for the F150; mine only uses simple curves. I didn't finish because I was out of state for 6 months and I ran out of Coroplast. Maybe this spring...

Frank, you really should build something.

[Frank Lee]

It's all under about 5 feet of snow right now, and I'm sicker than a dog.

Hopefully I can accomplish something when it starts getting nicer out...