Page 9 - Combined_24_OCR

Figures 3j h and p show the changes in lift, drag and side force with varying
yaw angle. The side force curves for front and rear wheels sho^< that the
aerodynamic cross wind or cornering stability is virtually unchanged from
"E" to "F" .race configurations.
Effect of Varying Undernose Spoiler Ground Clearance £i Location

Figures 6 & 11 show the effect of spoiler ground clearance & fore and aft
location. In general, the spoiler ground clearance is much more critical to
drag than is the fore and aft location. By removing the front undernose spoile
completely, better than half of the drag reduction obtained with the recom­
mended package is lost.

Although drag is not greatly affected by fore and aft location, lift is very
much affected by both fore and aft location and ground clearance as illustrated
in figures 7 & 12. Figures 8, 9, 10, 13, lli'and 1> show the effects of
spoilers on vehicle drag,'lift and side force with yaw.

Effect of Air Intake Opening & Location

Tests indicate that the forward facing air intake opening located on the
leading edge of the nose extension is preferable from a drag standpoint to an
equal sized opening in the lower nose surface (Figure l6> Approximately .p
MPH is gained by using the forward opening. In addition, reduction of the
opening area is favorable drag-wise; ie. - reducing intake area from 90 sq. c~
ins. to hp sq. ins. results in approximately a MPH speed increase.
Figures 1?, 18, 19 <1 20 indicate that lift, drag and side force at yaw and
lift vs. rake are unaffected by opening location and size.

Other Effect w

Addition of bubbled front fenders to the race vehicle should be avoj.ded._ ——
Figure 21 shows the appreciable drag penalty associated with such fenders;
approximately a 1 MPH speed penalty would result with the fender modification.

Another of the items considered in the recent test was the effect of moving
the base of the windshield forward 3” so as to reduce ’windshield slope and
improve the flow condition at the "A" post. An increase in speed of only
(Figure 23) 11PH would result from such a major change and thus this item
is not included in the recommended package. ■

Raising or lowering the leading edge of the nose extension without spoilers
has a rather pronounced effect on drag and lift. As the leading edge' of the nose is
"drooped" both front end lift and drag are reduced by approximately 2> pounds
and Ip per degree, respectively. However, when minimum ground clearance spoilers
are added it appears that the "droop" effect is greatly reduced. Further
studies of this effect are. recommended.

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