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Old 08-22-2012, 08:50 AM   #8 (permalink)
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Originally Posted by 2000neon View Post
I am really considering a much more dramatic, full kammback for my Neon. Allowing the sides to taper in as much as possible without interfering with opening the trunk. Also, I am considering making a hinge system on the top, to allow me to fold it back and use the trunk. My issue is with building rounded corners on the top-to-side transition.

I know that rounded corners are preferred aerodynamically speaking, ease of construction is another story. To the best of my understanding, this is because with just a straight, creased edge, the airflow "trips" over the edge, causing vortices which will increase drag and severely limit the drag reduction potential, am I correct?

So how drastic of a rounded corner does it need to be? I assume the more rounded the better, but is there a known minimum amount of curve that is required?

Finally, I know people can compare the amount of roundness by talking about the size of it, for example a 3/4" radius. So does that mean that if the curve was a whole circle, it would be 1.5" in diameter? Is that sufficient for avoiding air tripping over the edge? I am just trying to get my head around what kind of curve I need, to figure out the best way to build it.

Thanks for any input, you guys have already helped me out so much in building my Neon to where it is, and I appreciate it. This site is great!
Edge radii solve a problem. Ideally (perfect design) flow wouldn't need to mix between top and sides. In practice cross winds mean up/down wash can't be avoided. From Hucho

Using a nominal 6' body %5 would be 3.6" radius.
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