Another truck bed question

[hat_man]

I recently built a cheap bed cover (tonneau) for my Ranger. I had decided on a fulll cover to help keep the weather out. I have read in other posts how a half or 2/3 cover was better for aero, but after seeing a posted picture from a book (It is refrenced here often but I am not sure which one it is...brownish pages) a full cover was better, only slightly, than a half cover by itself. The half cover was much better when paired with a cab spoiler (?). So, here is the question...

For the people looking to keep the weather out or secure their belongings, would a full cover paired with a cab spoiler be as effective as the half cover paired with the cab spoiler?

It seems it would be the best of both worlds for bed coverage and aero if it were effective. I know nothing about aero stuff except what I try and read/understand here. I have learned a few things here and you all are wonderful "teachers". I have to thank you for putting up with my very basic questions.

[hat_man]

OK so it probably is a dumb question. Maybe cab spoiler isn't the right term. I was thinking of a "duck tail" type thing that extends the cab roofline rearward and downward about 4*-7*. Much more and I think the air flow would separate wouldn't it?

The picture I was talking about is the one that has the "baseline" pickup at the top and a bar graph for each subsequent truck. The last one has a full aerocap I think. It doesn't show much difference in the half and full tonneau alone but when paired with a "duck tail" the half cover is much more efficient. I was just wondering if the same held true if you paired a full cover with a "duck tail" as it wasn't shown in the chart. Maybe a smarter guy could draw the conclusion by I can't.

I do know that my cheap cover isn't working out very well. It doesn't like the sun very much and the 10mm coroplast is warping badly. I am going to try and "re-engineer" this idea with some better more rigid (read pricier) material. If there is a big difference in a half cover, rather than a full cover, when paired with a "duck tail" then it would save me some $$$ but I would have to give up a secure bed. If the difference is only minimal then I'll spend the extra $$$ to try and get the best ratio of form and function.

Thanks

[Frank Lee]

Putting up or linking that pic would help.

Re: warpy coroplast: I'd just put more supports under it- wood, aluminum, or whatever- treat it as a skin and not a structural member.

[aerohead]

Originally Posted by hat_man

OK so it probably is a dumb question. Maybe cab spoiler isn't the right term. I was thinking of a "duck tail" type thing that extends the cab roofline rearward and downward about 4*-7*. Much more and I think the air flow would separate wouldn't it?

The picture I was talking about is the one that has the "baseline" pickup at the top and a bar graph for each subsequent truck. The last one has a full aerocap I think. It doesn't show much difference in the half and full tonneau alone but when paired with a "duck tail" the half cover is much more efficient. I was just wondering if the same held true if you paired a full cover with a "duck tail" as it wasn't shown in the chart. Maybe a smarter guy could draw the conclusion by I can't.

I do know that my cheap cover isn't working out very well. It doesn't like the sun very much and the 10mm coroplast is warping badly. I am going to try and "re-engineer" this idea with some better more rigid (read pricier) material. If there is a big difference in a half cover, rather than a full cover, when paired with a "duck tail" then it would save me some $$$ but I would have to give up a secure bed. If the difference is only minimal then I'll spend the extra $$$ to try and get the best ratio of form and function.

Thanks

I went into the Phil Knox's Aerodynamic photos Album,in the graphs/tables section to look at the work from Texas Tech,who'd done the testing.
They don't show results for the configuration you're considering so we can't say anything qualitatively.
My opinion is that you should just go ahead,do the full cover.Experiment with the wing later.Record your results,and we'll all have additional data to network.
I've had tools stolen out of a pickup,and that's my means to make a living,so security and weather protection IS a big deal!
If your just keeping your shares of stock in the Easter Island Lumber Co. back there it won't matter.

[hat_man]

I traded those shares for an ocean front condo in Arizona. I haven't been there yet but they say the view is incredible. Lots of sandy beach stretching all the way to the water.

I have been looking for that pic FrankLee. If I find it again I'll cut/copy/paste it here. I thought the 10mm coroplast felt pretty rigid when I got it but I guess not quite enough. I had build an aluminum frame for it but the material was a little suspect from the start. Down and dirty cheap just isn't going to cut it. I found a material like coroplast sandwiched in between two sheets of metal. I think they called it aluma-lite. It was really pricey but the shop told me about something called alu-panel. It's like the aluma-lite but only painted on one side. Still a bit pricey but it seems as rigid as the aluma-lite and much sturdier than the 1/2" coroplast. The aluma-lite was around $125 for a 4x8 sheet. The alu-panel was around $75. I know I'm getting into that "just buy a cheap vinyl cover" range but, if I change my mind and want to try something else later I'll have material already paid for to try and make some skirts or wheel gap fillers. It'll have some holes in it from the bed cover mounting system (still in the re-engineering stage) but it won't cost me any extra $$$.

Now, off to try and find that pic again.

Thanks

[some_other_dave]

A buddy of mine made a cover for his pickup bed out of plywood. Two sections, a short one at the front of the bed and a longer one covering the rest, with hinges holding them together. He also had a spot for a padlock on the tailgate end. IIRC, he bolted it down to either the tie-down locations or to the edges of the plastic bed-liner.

Been a while since I saw it last, so the details are fuzzy. I don't know how it worked for MPG; he built it for security and keeping stuff out of the weather.

-soD