New bug, .38 CD why?

[bnmorgan]

I've gotten a few basic measurements to begin some design work, and I'll get some simulations done once I have progress enough to actually get something reliable. Does anyone know where I could find a 3d model of the NB? Even a dumb solid would work so long as it's accurate. I'll be working in Solidworks so the formats are pretty flexible. Also, does anyone know or have a good idea as to the effects of the sunroof when in the vent mode?

On to a different subject, and my apology for the following to those interested and actually involved in this thread

Frank, If you are implying that I would falsify empirical test results for my own self-gratification, then you are the jerk you appear to be. If you are implying I am incapable of designing, testing, adjusting, and if needed multiple iterations of an item, you are simply as ignorant as you appear. In either case it seems that you are apparently implying that you think I am dumb, stupid, or both. While this may be true, it's going to take someone a hell of a lot smarter than you to prove it. It's obvious you aren't very mannered as such personal insults lack any sense of honor. If you have nothing constructive, useful, or which otherwise pertains to this thread, just shut up? Nobody cares about your sarcastic cry-baby attitude. If you can do better, do it, but stay out of trying to tear down my intent. You don't matter enough to discourage me. When you have something useful to say, by all means, chime away. Otherwise, butt out?

[Frank Lee]

Have fun, see ya when your spoiler is done

[aerohead]

If you're looking for scale models of the New Beetle,there are very nice die-cast models and also a 'Barbie'-size,rather large plastic car.
Check local thrift stores,flea-markets,and yard sales.
If you're looking for a 3-D CFD program I have no idea,short of M.I.T.,manufacturers' tech centers,or university labs.

[bnmorgan]

I've got the CFD software, and 3d design software, I am wondering if someone has a 3d model of the NB i can use for a base to build on in Solidworks. I have the silhouette that can be used on the Chernyshenko simulator, but that slice is such a limited and "rough estimate" thing, I'd love to do it in full 3d flow simulation before i start building pieces.
I just need the beetle model

[Patrick]

Why not just make a cardboard prototype to see if it works?

[bnmorgan]

Well, I don't think cardboard is gonna stand up for 500 miles, and I don't want to run any less than a full tank for comparison. I was planning on making it from either hot cut HDPE foam or ABS sheet, once I have an idea what shape it needs to be.

[MetroMPG]

Just a note: tank to tank comparisons aren't the best way to judge the effectiveness of mods. For the vast majority of drivers, there's just too much normal variation to be able to say with any certainty if a mod has helped, hurt, or done nothing at all.

See: http://ecomodder.com/forum/showthrea...ery-11445.html

For simplicity's sake, you could tease out a simple "better/worse/no change" result in an hour or so with coast-down, or terminal velocity downhill testing.

[ChazInMT]

I have some ideas I'll post later, I've been messing with the Flow Illustrator and I have to say I'm not encouraged. It seems like the roundness or the roof is pulling down on the air pretty hard, and the roof spoiler isn't big enough to be effective and I have it out to about 10" now. I didn't think a half Kamm back would be needed. And, the big wing located at the base of the wind screen seems to smooth things out, however, there is still the issue of the air dropping too quickly and I believe it is creating a large low pressure area.

BTW: In researching the big wing Idea, I came across that Ernie Rogers guy, he's all over the place on his numbers, look into it, he has like 4-5 things out there and they all say something different, makes me a little worried.

The little ebay prefab roof spoiler would be I think worthless.

I'll put up a bunch of stuff soon.

[XJguy]

Here is something to chew on, scroll down the the part they talk about aerodynamics and handling:

How to Hotrod Volkswagen Engines - Google Books

[aerohead]

Originally Posted by ChazInMT

I have some ideas I'll post later, I've been messing with the Flow Illustrator and I have to say I'm not encouraged. It seems like the roundness or the roof is pulling down on the air pretty hard, and the roof spoiler isn't big enough to be effective and I have it out to about 10" now. I didn't think a half Kamm back would be needed. And, the big wing located at the base of the wind screen seems to smooth things out, however, there is still the issue of the air dropping too quickly and I believe it is creating a large low pressure area.

BTW: In researching the big wing Idea, I came across that Ernie Rogers guy, he's all over the place on his numbers, look into it, he has like 4-5 things out there and they all say something different, makes me a little worried.

The little ebay prefab roof spoiler would be I think worthless.

I'll put up a bunch of stuff soon.

If you'll take a look at the thread for the Chrysler Airflow you'll notice,that by adding no length,but by merely stuffing the wake of the body,to flesh it out more like a truncated K-form,they dropped the Cd by about 11%.
The Beetle would fair about the same,as both cars share the same pseudo-Jaray fastback which is WAY too 'fast'.
Had Breer pushed the Airflow's roofline up higher,closer to the template,the drag would have been even lower.