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However, the vertical stabilizer effectiveness demands a very rearward

location. Coupling the vertical stabilizer requirements with the

practical aspects of mounting the horizontal stabilizer resulted in

the compromise that is on (T he car today,.

Also shown in Figure 11, for comparative purposes, are the aero­

dynamic characteristics of a 1” high, 45° rear deck lip spoiler. The

comparison indicates that the horizontal stabilizer is a much more

effective and efficient aerodynamic system than the rear deck •H a

spoiler. Lift to axial force ratio is a time honored method of measur­

ing aerodynamic efficiency. The lift to axial force ratio of the rear

deck lip spoiler is 7 while the ratio is 19 for the horizontal stabilizer.

Backlight Effects - The modified backlight of the Charger Daytona

is a carry-over from the 1969 Charger race package and is quite different

from the backlight of the basic 1969 Charger. Although the backlight is

not a new feature of the Charger, the effects of the backlight change

are presented because of the significant axial force reduction which

resulted from this modification.

Two dimensional flow theory would predict separated flow over the

backlight area of any conventional car with anything less than a full

fastback treatment. However, on actual vehicles, three dimensional

C D ffects considerably affect separation and allow attached flow over back­
lights with relatively steep angles. Flow visualization studies on

models and full-sized vehicles show significant airflow onto the roof

and backlight areas from the sides of the vehicle. Thus, the airflow

path onto the roof and backlight from the sides of the car will have a

significant effect on the ability of the flow to remain attached as

backlight angles become steeper.

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