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Old 08-17-2011, 12:14 AM   #21 (permalink)
Patrick
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Quote:
Originally Posted by MetroMPG View Post
As for the headlights, I'd say they're significant. But to me, significant = 2%
I estimate it at about 13%.

If the lights are about 6" X 9" we have 108 square inches, or 0.75 square feet. 0.75 X 1.17 Cd (for a flat plate) = 0.8775 CdA.

Clean Ford Probe = 21 square feet X 0.31 Cd = 6.51 CdA.

0.8775/6.51 = 0.135 or 13.5%.

Or, to put it another way, it's like taking the 0.31 Cd of the clean car up to 0.352.
0.8775 + 6.51 = 7.3875. 7.3875/21 = 0.352 Cd.

42 Cd points is quite a bit.

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