The drag coefficient is a ratiometric number. To determine the actual
drag force you have to multiply by the effective frontal area of the
vehicle (and the square of the speed, etc.). So the 'vette, with less
than half the frontal area of a SUV, will have half the drag of the SUV,
even if the drag coefficient was the same. Lowering the car reduces the
effective frontal area. This is one reason why lake speedsters are
lowered right down to the salt.
Theo
________________________________
From: CoolVT@aol.com [mailto:CoolVT@aol.com]
Sent: December 20, 2007 8:05 AM
To: Smit, Theo; tigers@autox.team.net
Subject: Re: [Tigers] Gas mileage
In a message dated 12/20/2007 9:51:53 AM Eastern Standard Time,
Theo.Smit@dynastream.com writes:
For a highway test it's not about the horsepower rating of your
engine,
it's how much power you need to get down the road at 55 mph (or
whatever
Is the drag coefficient based on an over-all model and size or is it
just a measurement of the efficiency of the car being tested. In other
words would a large SUV that had a drag coefficient of say -0.50 have
the same efficiency as a Vet that also had a -0.50? Or is the larger
vehicle still going to push more air and therefore require more energy?
M
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