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Re: drag behind a car

To: FastmetalBDF@aol.com
Subject: Re: drag behind a car
From: "Thomas E. Bryant" <saltracer@awwwsome.com>
Date: Wed, 9 Nov 2005 12:01:51 -0800 (PST)
 > Just how effective were those  ducts that had outlets at the base of
the rear window on altered or comp coupes ?
>

Bruce,

My car has the ducts behind the rear window that are used to exhaust air
from the radiator. The air for the radiator is induced through NACA Ducts
just behind the door and in front of the wheel wells. I installed the rear
window ducts when the car was built, before I installed the NACA Ducts. As
was mentioned, the Stude Coupe had a problem they began to lift the rear
at about 180 MPH. After the ducts were installed, Stude Coupes went over
250 MPH without problems.

If memory serves me well, ducts that pass air through the car are not
allowed. Many years ago, Bob Brissiette wanted to do that on his roadster.
and was turned down by the rules committee. Ducts can be used to supply
air for engine intake or cooling system only.

As most of you know, even with the ducts behind the rear window, I had
handling problems with our car at speed. It was breaking traction causing
it to spin. I added weight to the front to correct the problem. (Moved the
center of gravity forward.) It stll spun the wheels, but went straight. We
later added a spoiler and removed the weight and the car handles very well
now at much higher speeds.  I don't know exactly how the spoiler works,
but it evidently modifies the air at the rear of the car. I am sold on it.

Tom, Redding CA - #216 D/FCC




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