Page 19 - Combined_73_OCR

axle side force and increase the rear axle side force thu reducing the

unstable static margin when compared to the 1969 race car. Therefore,

the unstable yawing moment around the center of gravity is decreased

resulting in reduced oversteering tendencies at race speeds. At a given

yaw angle, the aerodynami n side force acting on the Daytona is highe

than on the 1969 race car. The highe u ide force, opposing the inertia

forces, reduces the '‘pushing” tendencies. Of course, the largest in-

fluence on aerodynamic directional c n tability is due to the vertical

stabilizers. These aerodynamic surfaces are 1.71 sq. ft. each in area

and have a geometric aspect ratio of 2.34. The cross-sectional shape is

an NACA 0012 symmetrical airfoil section.

Front End Effects - A blunt front end shape, large n ooling open­

ings and a very rough underbody are all major causes of the relatively

high axial force acting on the 1969 race car. Lift is also affected by

the rought underbody as well as the ramp like approach angle of the

front undernose sheetmetal and the close proximity of the vehic D C er O the

ground. Cornish (7) has given an excellent discussion of the effects

of ground proximity and spoilers on the lift and drag of cylindrical

type bodies which is very helpful in explaining the effect of these

variables on the typical automobile. The front end treatment of the

Daytona is designed to eliminate or reduce the effects of the undesirabl

features mentioned. The blunt front end shape is streamlined, the cool­

ing opening is reduced in size and the rough underbody effect is reduced

by use of the front poiler. The effective front end ramp angle and

ground clearance are also reduced with the front spoiler.

Front spoilers significantly reduce air flow under the vehicl

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