Thread: Cd 0.38
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Old 10-26-2015, 06:08 PM   #4 (permalink)
aerohead
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how can

Quote:
Originally Posted by Cd View Post
I just don't understand.
How can the Smart car have the same Cd, yet have such a massive wake ?
The wake of the Z-28 is tiny in comparison.

Are the vortices just more controlled in that design, or what ?
*The car is highly detail optimized,with minimal turbulence before the tail truncation.
*It has extremely good sectional density,displacing the air nicely with it's leading edges for complete flow attachment,and gradual reduction in cross-section allowing separation-free flow to the truncation,with perfect pressure recovery.
*It's fineness ratio is adequate for Cd 0.38.
*While it DOES have a relatively large wake,the base pressure is higher due to the careful contours and pressure recovery upstream.Just like a 2015 Ford Econoline which shares the same Cd.

*It's 'Stromform' nose is of the lowest drag.

*It's the only car with a proper K-form truncation.
*It has zero-induced drag penalty.
*There is essentially zero vorticity.
*The base pressure of the Z-28's wake will be the same as at it's early separation point,way forward on the back slope.Very low pressure! Quite a penalty!
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Last edited by aerohead; 10-26-2015 at 06:09 PM.. Reason: spelling
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