Partial Tonneau cover on pickup (plus cab extension - cab wing)

[botsapper]

I looked in my past studies and I saw this concept almost with the same aero-intent but with a different purpose.

The flying buttress has been a retro cool-look for some time. If there is an aero benefit, the better. This contribution for the forum is for the intermediate-advanced tuner/body modders. The donor, a Chevy Colorado, with its distinctive sculpted sides is a great base for a fun project. The graphic shapes is the inspiration for the additional sail panels/flying buttress. The folding hard tonneau with smooth strakes completes the bed cover. Outrigger mirrors, underside belly panel ending into the smooth rear valance & the ubiquitous lower rocker panels and complimentary spats finish the 'laminar' (could be real?) look.

Pardons, if this takes it above a weekend garage project & $$, but I hope it provides the spark for more ideas. And elevates the aesthetics and acceptance of eco-modding.

[Big Dave]

I'm trying to figure out how to do a lower bed project kinda like the retro aero 'rado but with a cap somewhat like the Nissan. No egg-crate spoiler, though.

[cmroseberry]

I was at Texas Tech during the pick-up research. What I remember is that covering the last third of the bed gave most of the benefit of a full bed cover. I may be repeating myself, but a significant secondary benefit of a partial bed cover is a 40% decrease in lift.

[KamperBob]

Originally Posted by Concrete

If you could post pictures that would be terrific
even more of the original content of the report would help

I have been struggling with this concept since summer
the best I have managed is to breaking even on drag

Picture is worth a thousand words
picture of my second generation cab extension
what am I doing wrong?

the third generation cab extension looks better but still a loser
any inspiration would be appreciated
Thanks

Concrete, it's been a while since you posted about this project. And it sure looks promising. Any chance for an update?

Cheers
KB

[Concrete]

Originally Posted by KamperBob

Concrete, it's been a while since you posted about this project. And it sure looks promising. Any chance for an update?

Cheers
KB

KB,

Life has intervened a bit. moved & trying to avoid being laid off etc.
the good news is my commute is only ~3 miles now
- so my gas usage is down.
but the truck time has suffered. I hope to be back on track by warm weather.

Thanks for the concern
Concrete

[KamperBob]

Originally Posted by Concrete

KB,

Life has intervened a bit. moved & trying to avoid being laid off etc.
the good news is my commute is only ~3 miles now
- so my gas usage is down.
but the truck time has suffered. I hope to be back on track by warm weather.

Thanks for the concern
Concrete

I hear you about pesky life getting in the way of serious fun.

Congrats on the shorter commute. That's gotta help!

BTW, I made a short cap for my Tacoma a few years ago.
Slide Hitch/Short Cap

As you can see it was part of a larger project. Take my MPG claim with a grain of salt. I've tracked every tank of gas in a book (for decades) but my numbers were anecdotal not ABA scientific. And obviously my application was different from yours. Still, I thought you might find it interesting.

Cheers
KB

[talldudenumber5]

nice

[Snax]

One thing I notice about the cab extension in the tuft test video is that there are clearly some vertical axis vortecies produced immediately behind the structure. This can be seen by watching the one tuft on the tonneau spinning. Essentially this strikes me as working to replance one axis of turbulence with another, where the vortex would normally be on axis across the back.

The two things I think need to be changed in this design are:

#1 The open nature of the extension should be closed off with plexi or some other material. This would reduce the amount of area such vorticies can setup in, resulting in smaller vortecies.

#2 Reduce the angle of the sides to nearly on plane with the cab.

The current effect of setting up vertical axis vorticies is at odds with the natural horizontal axis vortex over the broader area behind the cab. The two work against each other. And since it's pretty clear such a design is not going to extinguish such vortecies entirely, it makes more sense to reduce the number of them and clean up what's left as much as possible.

[makindue]

Originally Posted by Concrete

I found bed cover pics - it was Phil Knox with the boat on his truck
sorry about the mix up

would love to see picture of your truck
but let me start with a sketch from Phil's

are we talking about something like the portion I highlighted yellow
but will the same basic curves as Phil's full cap as shown?

Nice bed cover pics. I really love it. I think yes it is the he portion you highlighted yellow.

[kach22i]

Originally Posted by KamperBob

BTW, I made a short cap for my Tacoma a few years ago.
Slide Hitch/Short Cap

I know this is an old thread, but this is really nice.