Page 22 - Combined_73_OCR

range of positions investigated the axial force change was minimal ;

however, the front axle lift changes dramatically. These data indicate

front undernose spoiler fore and aft position is an effective way to vary

front axle lift with minimum axial force change.

Effect of Vehicle Attitude - Sensitivity of lift and axial force to

vehicle attitude is shown in Figure 10 for both the Daytona and the 1969

race car. As shown, the axial force and front end lift are very sensi­

tive to body attitude and the 1969 race car and the Daytona exhibit

very different axial force characteristics as a function of body angle.

The 1969 race car achieves minimum drag at-1.5° body angle whi the

Daytona minimum drag angl C D is -.5°. The front axl c o lift coefficient,

while reduced by about .2 by the Daytona Package, xhibits a highe d

than the 1969 race car. Rear
O
sensitivity per degree of body rake angl J
axle lift coefficient is relatively insensitive to body attitude. The

sensitivity of both configurations illustrates the importance of body

ttitude and establishes -.5° as the optimum attitude for the Daytona.
C O

Effects of Rear Deck Stabilizers - Figure 11 shows the minor axial

force panalty resulting from the rear deck stabilizers. At a horizontal

stabilizers angle (<Xq) of -10°, the axial force is increased by 7% at

zero yaw angle. Figure 11 also presents the front axle and rear axle

lift coefficients as a function of yaw angle. These data indicate the

wide range of rear axl lift coefficients available with the horizontal

tabilizer (approximately .14 for C O 10° change in **g)• Note that as the

horizontal stabilizer angl D C H* c n increase negatively, the front axl lift

increases slightly. This, of course, is due to the horizontal stabilizer

being positioned behind the rear wheels. A more optimum position for

the horizontal stabilizer would be directly over the rear wheels.

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