To Kamm or not to Kamm...that is the question

[mikeyjd]

Originally Posted by freebeard

You get my point. There's a lot you can do before you get down to that fine tuning. The rest of the ¶ shows you have a handle on the issues.



One thread had the poster using a bigger square of paint friendly tape and a smaller square of something to hold the yarn to the first piece. I'd add—that could be hot melt glue before you cut a strip of tape into squares.

...and only half the cap needs to be tufted. A grid is a good start, but if you suspect separation, or worse—backflow, use longer yarns. A reconfigurable boom that gives a top rear view means you don't need a chase vehicle, although you could use one as well.

I'd skin it with Polymetal. Think strong as 5/8 plywood and light as coroplast. I haven't done a whole project with it, but I have tested samples. I could shear and roll it, but to brake an edge, I think you'd have to crush it along the line first. A 4x8' sheet is approx. $100 wholesale and $150 retail.

I'd be nervous about messing up. If you ruin that sheet and there goes 1 years fuel savings on the cap ^

[hat_man]

I already took care of the side mirrors of that's what you mean by rear view mirrors. There gone!

[freebeard]

mikeyjd -- "Nothing worth doing is easy."

Baby steps. Measure twice, cut once.

One nice thing is it's available in 4x8, 4x10 and 5x10 size which might mean fewer seams.

[mikeyjd]

Originally Posted by freebeard

mikeyjd -- "Nothing worth doing is easy."

Baby steps. Measure twice, cut once.

One nice thing is it's available in 4x8, 4x10 and 5x10 size which might mean fewer seams.

I can't say I agree with the saying, but I take your point. "If it's worth doing, it's worth doing right" or something like that. Not that it would be much harder per say than another material. Just thinking out loud I guess. I would love to see more projects done with polymetal, so that I have someone else's expensive experience to learn from

[freebeard]

I read it as "If it's easy, then everyone has, is, and will be doing it; so what's the point."

hat_man -- Gone as in no outside mirrors at all? Video? I like street rodder Peep mirrors, small and close to your eye.

[hat_man]

Yeppers. As is not there any more. With it being a pickup I could always look through the rear window and get a better view of what was behind me and to the sides than the little mirrors. With the new cap i am going for a rear piece of plexi-glass down the back and 2 smaller pieces (16" x 22" approx.) on each side. If that's not enough to see safely then I will have to see about some sort of new mirrors. Illinois says I only need "a mirror" (as in one) that allows me to see clearly 200' to the rear. I agree, but when safety becomes a factor then I will go beyond what they say. I would love to do a small video camera like an RV back-up camera hooked to a small monitor in place of my rear view mirror, but now were talking $$$ and this is just my little ole work truck. It is a '97 after all. Low budget transportation.

[freebeard]

$14.99 at Speedway Motors. Less than a ticket.

[aerohead]

Originally Posted by hat_man

I have started my aerocap and the frame is done. It is changeable at this time and I have another question.

I have seen these Kammbacks on other vehicles. I assume they are to help get a cleaner air separation at the rear. With my cap being vertical and nearly flush with the tailgate (red line), could I benefit from adding something like this (green line) at the tail end of my cap? Or does the cap in general constitute a Kammback and maybe add nothing.

It was just a thought and wouldn't be all that hard to add if I would see any more benefit. Or if the benefit is too small maybe it's not worth doing?

The base pressure of your wake will be determined by the separation line ahead of the green line area,so it can't really increase the pressure,but it can help sculpt the wake a bit and it is occupying volume,so it must be beneficial.

[ECONORAM]

Originally Posted by freebeard

I left off the

Marginal gain. It's at the end of a long smooth curve.

The aerocap is the thing that gives the greatest gain. On a pickup the underbody comes next. Time and effort would be better spent on the rear view mirrors.

All IMHO, of course.

Maybe this would be more apropos:

Gotcha. I'm half-way on a belly panel. I have a topper so the aero cap will have to wait. I'm curious about mirrors though; don't think I'm ready to delete them, but I'm sure they could use some improvement...

[freebeard]

This was posted by kach22i in the Interesting Aerodynamic Cars thread. Notice how close and small and behind the [virtual] A-pillar they are. The law may require a mirror but does it say whether or not you have to turn your head to see in it?