Box Cavity for a pick-up truck

[kach22i]

Originally Posted by freebeard

^^ That's a cool find, too bad the trail goes cold in the comments section at that link.

This is totally a KISS method, might try it on my own truck. Is it crazy or what?

Modified a random image off the Internet, should work on any pick-up truck.

Cant corrugated plastic in 10-degrees from top and both sides, with tailgate down.

Automobile 2 - Odds And Ends Photos by kach22i | Photobucket


Might have to put a cargo net back there, could be trouble otherwise.

Inspiration was this:
http://www.curbsideclassic.com/autom...-size-matters/

[t vago]

Heh - that might could be the first time ever that a tailgate-down pickup truck would get better gas mileage than a tailgate-up truck!

[JeffD]

California98Civic: Thanks for the link to your thread, seems like we were going down the same path. I'd be curious for a picture of yours. That is where the 100mm number came from.

Xist: thanks for the link, I had found a different presentation by the same person and subsequently lost it.

There is also a Brookhaven report that mentions short box cavities (although I didn't get a whole lot out of that one). The rear end extension panels on commercial vehicles seem to be much deeper (Hucho) which makes the tailgate idea sound better.

I'm thinking I may have missed the point though. Several of the box cavity examples that extend from the trailing surfaces have slanted or curved walls. The ones with straight walls are inset from the side surfaces. I wonder if that inset acts like a slanted surface to the air flow. I think maybe I'd be better off if I moved the half bed cover forward 4" and made a 15 degree sloping extension for the top wall (interferes with the utility since you wouldn't be able to open the tailgate w/o opening the cover though). The side walls having to be inset due to the tail lights could remain straight. Can't do much about the bumper on the bottom...

Sound right?

If this works, might put a box cavity behind the cab too! (although not sure how it'll interact with the half bed cover).

[nathan01xl]

Originally Posted by kach22i

This is totally a KISS method, might try it on my own truck. Is it crazy or what?

Modified a random image off the Internet, should work on any pick-up truck.

Cant corrugated plastic in 10-degrees from top and both sides, with tailgate down.

Automobile 2 - Odds And Ends Photos by kach22i | Photobucket


Might have to put a cargo net back there, could be trouble otherwise.

Inspiration was this:
Automotive Aerodynamics: Drag Area – Size Matters

this looks like it could definitely be worth trying

[California98Civic]

Originally Posted by JeffD

California98Civic: Thanks for the link to your thread, seems like we were going down the same path. I'd be curious for a picture of yours. That is where the 100mm number came from.

Thanks for checking out my test. I have the pics but have been missing the cable. I'll try to find the right cable and post them.

Originally Posted by JeffD

Xist: thanks for the link, I had found a different presentation by the same person and subsequently lost it. ...

If you want the PDFs I have them. PM me if you want them with an email address. I'll email the attachments. You are right that the box cavities that start at the outer body edge angle inward and those that extend from the tail lights and such are straight, expecting the flow to "skip" over the corners. The goal was apparently to raise base pressure a little by reducing turbulence a little. The tests satisfied the designers, eventually--or so they claimed.

Originally Posted by JeffD

... Several of the box cavity examples that extend from the trailing surfaces have slanted or curved walls. The ones with straight walls are inset from the side surfaces. I wonder if that inset acts like a slanted surface to the air flow. I think maybe I'd be better off if I moved the half bed cover forward 4" and made a 15 degree sloping extension for the top wall (interferes with the utility since you wouldn't be able to open the tailgate w/o opening the cover though). The side walls having to be inset due to the tail lights could remain straight. Can't do much about the bumper on the bottom...

Sound right?

Safe bet to assume aerohead has it right when he says that the box cavity will need very clean flow before it will work. (Props to Frank Lee also, who pegs it in one of his posts above.) So your first efforts could be to work on the flow from the front backward. You might start with an air dam and maybe the mirrors. Then the aft portion of the cab. I wouldn't move your half-tonneau, but maybe make it a full tonneau. Wheel well covers. THEN the box cavity.

The studies we are both referring to made it clear that a sedan shape benefited even less than the hatch, and in each case they observed that the state of the flow (especially under the car) mattered a lot for the effectiveness of the box cavity. So you and are are making the same mistake at the same time: we need to do more for the flow that approaches the back end if a smaller measure like this (instead of a long kamm or boat-tail) is going to work.

[kach22i]

Originally Posted by California98Civic

........ we need to do more for the flow that approaches the back end if a smaller measure like this (instead of a long kamm or boat-tail) is going to work.

A roof wing could help, mine seems to work at redirecting the flow to the bed cover.

I think a larger and more consistent gap with a roof wing slope of 10-degrees down would help even more. However I have not yet tested these changes.

[bondo]

Originally Posted by kach22i

This is totally a KISS method, might try it on my own truck. Is it crazy or what?

Modified a random image off the Internet, should work on any pick-up truck.

Cant corrugated plastic in 10-degrees from top and both sides, with tailgate down.

Automobile 2 - Odds And Ends Photos by kach22i | Photobucket


Might have to put a cargo net back there, could be trouble otherwise.

Inspiration was this:
Automotive Aerodynamics: Drag Area – Size Matters

Thinking the same way.

https://www.google.com/patents/US840...ed=0CDQQ6AEwAA

The black Aerolid and boat tail combo has had a best of 28.73 mpg @ 70 miles per hour over many months of road testing.

Bondo

[kach22i]

Originally Posted by bondo

Thinking the same way.

https://www.google.com/patents/US840...ed=0CDQQ6AEwAA

Bondo/Brett, you had the patent filed about 1-1/2 years ago.

The idea must have come to you years before that, plus the lawyer's schedule to put the package together took time.

I won't even ask about funding for a patent, too daunting a task considering my current income level.

What are your current plans for production/marketing of the "Aerodynamic stowable truck bed extender"?

[bondo]

Originally Posted by kach22i

Bondo/Brett, you had the patent filed about 1-1/2 years ago.

The idea must have come to you years before that, plus the lawyer's schedule to put the package together took time.

I won't even ask about funding for a patent, too daunting a task considering my current income level.

What are your current plans for production/marketing of the "Aerodynamic stowable truck bed extender"?

This is my first Pro Se effort (No Attorney). Got lucky I guess. Was granted the patent on the aero bed extender in less than 14 months with only one Office Action from the USPTO. Did it all myself and saved a bunch of money too!

Started pondering on the design some years back. Built three prototypes over the past three years. Ended up with the foldable one which doesn't take up alot of space in the truck bed when stored away.

Since I have tried for 5 long years to get the Aerolid to market, now going to concentrate on the extender. It will be vacuum formed out of ABS and easy to fabricate. Meeting with a plastics manufacturer that came in with a good quote on July 25th to possibly build them.

Like Winston Churchill once said, "Never, never, never give up!".

Bondo

[kach22i]

Originally Posted by bondo

This is my first Pro Se effort (No Attorney). Got lucky I guess.

This is the first time I've heard of something like this - thanks.

Good luck with your new venture. I'm guessing half the sales of the box will be people wanting more storage and nothing to do with fuel savings.