Page 8 - Combined_24_OCR

For ease of use and understanding the specific effects of various changes’to
the optimum, and recommended configuration are compared to the optimum in all
discussions, graphs and figures. The optimum nFn race configuration is also
compared to the current race configurationo

Recommended nFn Race Configuration

The following items are recommended as an optimum race package (does not
include wing and stabilizer recommendation). These items represent additions
or changes to the current race vehicle.

1. l6.£n front end extension (styled version as reflected in templates),
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■2. sq. in. air intake opening located along leading edge of front
end extension.
Lower front fender sheet metal pulled out in front of tire to shield
tire.

Front undernose spoiler located approximately 13” aft of leading
edge of front end extension and extending to minimum ground clearance
at Li.^0 angle to sheet metal - spoiler length to be approximately 5>ln
with corners styled to undernose.

Bubbled fenders reduced as much as possible.

Figure 1 shows the drag reduction gained with the new package. The axial force
coefficient has been reduced by .078,from the previous low of .373• In so doings
the optimum drag condition now exists at a body rake angle of -0.>°---as^-rompared
to -l.£° for the current race car. In terms of increased speed, assuming
handling, tires, and other factors do not deteriorate at higher speeds, the new
package should result in approximately a p to 6 MPH increase in lap speed at
Daytona. If, in fact, the aerodynamic control surfaces at the rear of the
vehicle improve the handling and reduce tire scrubbing and other cornering
losses, the predicted speed increases could be even greater.

Figure 2 illustrates the change in front and rear lift with the proposed package.
Front lift has been reduced by approximately p00 pounds throughout the body
rake angle schedule while rear lift has. been increased by approximately 200
pounds throughout the schedule. With the new package, front and rearllift are
essentially zero at g = -1.0°. However, if the front to rear lift differen­
tial (presently front lift is 700 pounds greater than rear lift) is 'as
critical as thought, the rear wing and vertical stabilizers will be required
for good handling.

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