t_vago's compound curve foam board pickup aeroshell

[Varn]

I would think that you might get interference drag between the curved area behind the cab and the bed cover, might be better to radius those areas with fillets.

[slowmover]

I'll admit to liking the look, alone (as in Post #46).

And on reflection -- with the side taper -- the vehicle side mirrors can handle all rearviews without the need of the interior rearview mirror (when I mentally view the changes from my conventional non-windowed topper to aerolid to this.)

[t vago]

A lot of time and effort was put into making those models, Neil. They look really good.

That being said, I'm not sure that's how the version 2 aerocap will look when all is said and done. The rear side tapers seem to be a bit excessive (certainly more than 12 degrees).

I have an idea that hopefully will enable me to make a quick-release mechanism for the version 2 cap. The basis of the quick-release mechanism will be the mechanism for the AgriCover Access Vanish.

[BamZipPow]

Access® Vanish™ Roll Up Truck Bed Covers - Low Profile Truck Bed Tops and Tonneau Covers

[t vago]

...just don't pay any mind to the Access Vanish estimated fuel savings calculator. It's incorrect. The author of that app took the 7.5% reduction in C(d), and assumed that 100% of that reduction translated into a 7.5% improvement in fuel economy.

[NeilBlanchard]

I had fun doing it -- and I now know how I'm going to build my CarBEN EV prototype shell. The 1/4" polystyrene is a revelation for doing compound curves.

The 12 degree slope in the thesis was for a straight surface, and the slope was only on the top. The 3D cap shows how a curved surface can work better -- and there have been a lot of discussions here on EM with 15d slope being ideal, and even 18d works on cars like the EV1 because of the air flows in from the sides, as well.

I'll look around for the "ideal profile" image and see how it lines up with this cap? And it is no "recurve" like the prototype, so the main descending surface is much longer than previously.

[Edit: Here's the "ideal profile compared to the SU cap model:



So, the cap may be a little steeper than ideal -- I'll try a less steep version.]

The comment about the side mirror sight lines not being blocked by the cap is something I had not thought about.

[Edit 2: On the other hand, here's the EV1 compared to the ideal profile:



As you can see, it deviates as much or more than the cap. And here's the Dolphin:



I think the profile is a fine 2D guide, but is 3D, the air can flow in from the sides so the taper can be steeper *if* the sides are also tapered?

What do you folks think?]

[NeilBlanchard]

My gut sez that this cap would likely be pretty good air flow. I really like the "massing" of it -- I wanted to preserve as much of t_vago's original design as possible, but only real-life tuft testing will tell.

I added the gap infill at the cab / bed junction, and a 1" trailing lip:







I think adding a "Cyclops" brake light in the obvious spot would be a good thing?

[KamperBob]

Neil, as with t_vargo's V1 it looks beautiful. Even if it does not support fully attached flow all the way back, it's still stuffing the wake over a tonneau. My hesitation with this basic approach is utility of the truck bed. How to get stuff in and out of the front of the box, where you want most of your weight to go (ahead of the axle) ideally. Maybe if it slid back then tilted up as well?

[BamZipPow]

If you wanted a working cap, it would have to be split with a sloping cut...so it clears the bed when raising/lowering the cap....something like the piece that's on the Chevy Avalanche. That would almost be perfect to attach a cap to...

[NeilBlanchard]

Hi,

Here's my final version showing (4) windows and a possible hatch outline: