beetle kammback

[tpotts]

Sell IT. As they say in auto sales: there is a rear end for for every seat. HA!

[skyking]

that's not happening. It is more comfortable for my rear end than anything else I have driven. I did a 590 mile run the other day and I was not broken afterward.
My camry would have left me in shambles. only the full size diesel truck is as comfortable for me, and I like the economy of this one.

[tpotts]

The Sell it comment was in reference to ecos comment of making a speaker chair out of his homemade project. Best Tom

[skyking]

Tom, you can see where I was a little lost there

[skyking]

Originally Posted by skyking

This is the basic shape I came up with. I am trying out the look of several different trailing edges.
Call this one the normal rake

Shallow rake

sharky

Bringing this back to the tail of the thread for suggestions/comments.

Looking at sharky, what I have in mind is a nice curve here to go with the rest of the body styling. I don't have the paint skills to draw it. Use your imagination and tell me what you think of that. I was thinking a nice curve from plan view as well, resembling a receding hairline of midlife crisis :P

My beetle is black. I grabbed this profile off the web.
The finish will be gloss carbon fiber style 284

[freebeard]

Does that picture represent the 1/8" divinycell?

Beware usiing The Template in plan and elevation. You don't get the whole story.


Even this is non-canonical, the bottom of The Template should be at ground level. it's height is half it's width. But it shows that relatively flat New Beetle roof needs to transition to the crown of The Template. Matching the height and width only makes it worse. The forward edge should be curved instead of straight across the car. To overcome this you might consider the squircle:


As for the trailing edge, here's Colani:

[skyking]

That looks great but it is not going to happen. From an earlier post in the thread:

I can't lift the template up or move the kammback forward without undergoing serious body rework.
The roof is immediately too steep. Not ideal. I get that and have figured a single piece design that will mount to the hatch and hit the roof a couple of inches aft of that antenna.

So it will be nearly straight across just forward of the window line, and that little slice of template represents my planned profile shape. It was just a handy curve tool for me to use, since I don't have the graphics "chops" to draw up things like that on my computer.

That trailing edge is similar to what I had in mind.

[aerohead]

I don't have the New Beetle with me,but I've got the New,New Beetle here.
The 2011 Beetle has a Length/Height ratio of 2.878 and Cd 0.37?
*1999 Prius-I ------------------------------2.876 and Cd 0.29
*1991 GM HX3 -----------------------------2.856 and Cd 0.258
*2000 Honda Insight-I --------------------- 2.854 and Cd 0.25
*1980 VW 2000 --------------------------- 2.781 and Cd 0.25
*1987 Renault Vesta II ---------------------2.772 and Cd 0.186
*2008 M-B Boxfish ------------------------- 2.560 and Cd 0.19
--------------------------------------------------------------------------
All these cars have 'shorter' fineness ratios than the Beetle,but better rooflines and sides.
Extending what you have along the AST contour as far as you dare will pay the highest dividend.If you went a little further,you could correct the rear fenders as well.
Going as far as the rear bumper,with a pure vertical chop (like Carl Breer did with his 1934 DeSoto Airflow (the world's 1st actual 'Kammback)) would yield the lowest drag with zero added length.
And it can all be open at the back,with 'steps' inside,like Ford did with the Merkur XR4Ti bi-wing spoiler.The flying-buttresses will create a perfect hybrid box-cavity/boat tail,forcing where turbulence can or cannot be.

[skyking]

Thanks Phil.
I can take is as far as my crude overlay, which is right above the top of the fender, without harming my rear view.
It would follow the plan taper and body line of the hatch surround.
You are suggesting building a lower step beyond that, so I can still see through?

The trailer design I touched on will fit into the current plan. I figure I can sacrifice rear view when towing, as that is what I am used to anyway.
I would continue with a solid add-on section to the bumper, and the trailer would tuck up to that. It would clip on with a few fasteners.

I will leave the above as a reminder to thought processes
Now i see your slotted version, and maybe I can keep the top of the trailer low enough to have a decent rear view through the slot

[freebeard]

Here, I was treating the upper and lower body separately. The original Beetle had more distinction between the upper and lower body taper.



The upper section could be truncated different to the lower section, for visibilty. Here's one in the opposite direction.