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Old 08-14-2010, 04:32 PM   #11 (permalink)
aerohead
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offset

Quote:
Originally Posted by miket View Post
Im not talking about the Cd as much as the CdA. A longer vehicle will have more internal volume with a smaller cross section. Will the skin friction offset the smaller cross section?
miket,CdA is the ultimate criteria for air drag,so you could definitely play around with dimensions.For example:
The 'Template' would constitute a 40%-Thickness fuselage,Cd 0.04-free-air,Cd0.08-in ground-effect,Cd 0.12-with 'skinny' tires.
An 8.33:1 streamline body would constitute a 12%-thickness fuselage,Cd 0.066-free-air,Cd 0.132-in ground-effect,Cd 0.172-with 'skinny' tires.
So,for instance,a Honda Civic CRX at 18.5 square-foot frontal area and the 'Template's 2.5:1 full tail @ Cd 0.12 would have the same drag as a 8.33:1,12%-thickness fuselage-shaped body @ Cd 0.172 and 12.9 square-feet frontal area ( a 1960s Lotus Elan with the windshield removed ).

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