Page 8 - Combined_22_OCR

MODEL AND TEST CONDITIONS

MODEL

The model tested simulated the full-scale race vehicle as closely as possible.
The underbody was relatively clean in comparison to a production vehicle (see Figure
5) and sealed with the body at all times. An underbody rake angle (i.e., underbody
orientation relative to body) of~l°42’ prevailed throughout the tests. The area be­
tween the rear of the front under-sheet metal and the yoke section was sealed so that
all engine cooling air flow was directed through the radiator core. Wheel well cut-outs
were standard; however, there were no wheel wells for the front wheels. Simulated
racing wheels were used throughout the tests. The engine compartment was similar
to the race vehicle with the engine itself simulated by an electric motor which was
capable of driving the fan at scale RPM. However, previous tests had shown no sig­
nificant change in aerodynamic parameters with simulated fan RPM, so these tests
were conducted with the fan wind-milling only. For ease of identification, the con­
figurations tested have been coded and are as follows:

Configuration
No.* Description

ER-23 (Race Configuration) modified with a semi-fast-
t-H
back backlight; cooling air intake through standard grille
only.

to ER-23 (Race Configuration) modified by the addition of an
18TT aerodynamic nose fairing (see Figure 3).

Same as Configuration 2 except semi-fastback backlight
c o
added.

Same as Configuration 2 except fastback backlight used.

* The addition of a letter to the configuration number (i.e., Configuration 2A) indicates
the aerodynamic nose fairing has been mounted to the car in a deflected position. The
following code applies:

Letter Deflection

> Fairing mounted with 5.7° down deflection

w Fairing mounted with to .9° down deflection

a Fairing mounted with 2.9° up deflection

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