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Old 01-03-2012, 10:48 PM   #9 (permalink)
3-Wheeler
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Quote:
Originally Posted by aerohead View Post
The lowest drag cars have fully enclosed wheels.AEROCIVIC would be a contemporary example.
Hi Aerohead,

OK, I am going to ask a nit-picky question here....

So a car with wide spaced wheels and thus covered with an appropriately wide body will, for it's resultant frontal area, have a lower Cd.

So far so good.

However, the counter response to this is....

Make an appropriately sized 1) "cigar-shaped-fuselage" and cover the vehicle occupant, and 2) make proper sized airfoils for the appendages hanging outside the main fuselage, such as wishbone suspension members and wheels/tires.

I would think that this second vehicle, while having a higher Cd overall, would also possess a lower frontal area, and thus come away with an overall lower aero drag component than the "one-piece-body" shape.

Now my "discussion" above makes the assumption that this "body shape" is optimized for a single occupant, who is also the driver of the vehicle. I am not talking about the "new" VW 1L that has side-by-side seating and thus forces a wider body shape to the wind.

The width of the cigar body is, let's see, about 27 inches wide.... I had to measure the one that's in the basement right now....

I simply can not imagine how a car with a track width of let's say 60 inches, and a body that also is wide enough to cover this same width, and has a Cd of let's say 0.10 is going to ultimately have a lower overall drag component than a cigar shaped body with width of 27 inches and all external appendages covered with airfoils, with a Cd of let's say 0.15??

It may be that our responses to the main question above need to be qualified a little better to avoid over-simplifying the answer.

Just my opinion.

Jim.

Last edited by 3-Wheeler; 01-03-2012 at 11:05 PM..
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