[DeTomaso] Pantera aero info

[Charles Engles]

Dear Forum,

 

 

              The latest issue of Grassroots Motorsports (May 2010) has an
excellent article on Aerodynamics, called "Wing It" by Steve Stafford, a
gearhead  aero engineer.    There is a lot of good information in the
article.

 

              I wanted to share one interesting angle that he discusses for
informal amateur aero testing.   I have long understood the purpose of yarn
testing.  I have also thought it was pretty tedious to apply the yarn and
then there is the logistical problem of video recording of the test at
speed.   It is a "simple" test in concept, but problematic in execution.
He may have a better idea.  I quote:

 

         "So, how can you find out how your car is interacting with the air?
The simplest method is to apply a flow visualization fluid and see how it
streaks when the car is at speed.  The trick is using a liquid that won't
dry too quickly and won't run too easily.  It also has to be thin enough to
streak.

 

           The recipe that I use is safe, easy to make and can be mixed for
cars of any color.  The ingredients are water-based powdered paint---you can
find it at any arts and crafts store----plus 3-In-One-Oil and a little bit
of rubbing alcohol.  This mix provides good results, but it's important to
achieve the right consistency: not too thick, not too runny.

 

         The testing process is easy as well.  First, use a small paintbrush
or a syringe to apply the solution to the car's body.  I often make a
syringe to apply the solution to the car's body.  I often make a line of
dots ahead of the area I want to study.  Then I simply go for a drive and
decipher the information upon my return. (My comment: this seems much less
involved than a video camera plus a chase car plus a third person to be the
cameraman...)

 

 

            You want to look at the length and direction of the streaks.
You can even snap some photos to save these "measurements" for later.

 

          Here's what's going on:  The longer the line, the faster the air
is moving over that area of the car.  The direction of the streaks will be
pretty easy to decipher.

 

 

          You should use this information to correctly line up ducts and
also find the high and low pressure areas on the car.  {Long streaks signal
low pressures, while short streaks or no streaking at al signal high
pressure.}

 

          This process than also be used to test new equipment.  Do the
paint test before and after installing a piece of hardware to see what's
going on."

 

 

         I hope that the aero obsessed on the Forum find this tip  and the
"Wing It" article helpful and motivating.

 

 

 

                             Warmest regards, Chuck Engles