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This is the original
1968-1970 Charger 3/8 scale wind tunnel model, which was donated
to the Winged Warriors/NBOA club in the early 1980's. This model
was constructed by Chrysler NASCAR program engineers in 1967.
It was originally built to test the wind characteristics of
the new 1968 Charger. It was modified many times to test the
aerodynamics of the 1969 Charger 500 forward grille area and
fastback rear window; the 1969 Daytona nosecone (they tried
several versions) and different wing ideas, and the 1970 Charger
short track car. The wind tunnel model was tested at wind speeds
of up to 250 mph.
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Aerodynamics tests of bodies have been done since at least
the days of the Chrysler Airflow. Chrysler built similar models
of the 1966-67 Charger, Coronet and Belvedere, 1968-69 Coronet,
RoadRunner, SuperBird and the 1971 RoadRunner and Charger. This
is one of two musclecar era wind tunnel cars to survive. It is
being restored to include all of the various front
ends, wings and details.
Construction of this scale model car began by reducing to
3/8 scale the actual-sized paper drawings of the Charger body.
From these shrinks, a hand-molded body was made, perhaps from
modeling clay. From this was made a reverse mold, into which
the fiberglass body was molded. This model weighs about 250
pounds.
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A cut-down heater core was used
to simulate a cooling radiator. Behind this was mounted a
variable speed electric motor, with an attached fan. Many
tests were run to determine the best designed fan for oval
track racing, but actually the different designs made little
difference in car speed. The above photos are looking into the engine
compartment where you can see the radiator area (where duct
tape is applied) and the bracket that held the electric
motor.
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Aerodynamic engineer Gary Romberg used this model in 1969
and 1970 to test ideas for improving the Charger race body.
If the wind tunnel tests were positive, full sized parts
were handmade, then fitted to a rather crude test "mule"
car. This was the odd-looking #71 car. It was known as the
"mule of all mules". If these race parts worked well, they
were produced by machine, then tested on the #88 car under
the supervision of chief mechanic Larry Knowlton. Finally,
the parts were distributed to Chrysler race teams.
The exhaust extensions were made to test the possible
aerodynamic benefits of very long pipes. On the underside
of the chassis there is a molded-in single exhaust system,
including a muffler. Because of the detail on the K-member
and rear springs, this chassis probably was used on many
different wind tunnel bodies.
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The wind
tunnel model has three types of side windows: the original
molded-in fiberglass, tin plates and wire screens.
Vent-door-quarter windows were originally all molded into
the body and aerodynamic tests were made. The side windows
were later sawed out of the body, and tests were made with
a combination of screened windows and plugged windows. The
tin plates were likely used to support the modeling clay.
Aerodynamic tests were done on side window possibilities
because of various race track requirements and NASCAR rule
changes.
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Look closely at the above photos showing the tubes
around the window openings and
in the roof area. The tiny tubes were cemented on at
dozens of locations on the body. At each point is a hole
in the body. Rubber lines connected each tube to a
monitor, which measured the air pressure at each point
(Velocity Points).
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The 1970 Charger front section was
made slightly too large so modeling clay was used to
make smooth body lines. This car's integral body
ends between the wheels and grille, so different
front end design sections could be fitted, including
standard 1969 Charger, the Charger 500, long and
short Daytona clay noses and the fiberglass versions.
All will be made again as part of the restoration on
this car.
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This is looking into the passenger's
compartment towards the rear of the car.
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This is just one of many wing heights
and designs that were tested.
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