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scale models and a very limited study of a full scale model. Specific

features of the two tunnels are listed in Table I.

TABLE I - WIND TUNNEL COMPARISON

Wichita State, Lockheed-
Tunnel Feature
University Georgia

Test Section 7’ x 10’ 16’ x 23’

Contraction Ratio 6.0 6.8

Maximum Velocity 200 MPH 370 MPH

Test Section +1.5% (at +0.7% (at
Dynamic Pressure 80 psf) 40 psf)
Variation

Turbulence Factor 1.22 1.05

Flow Angularity -0.4° in pitch -0.3° in pitch
+0.1° in yaw +0.2° in yaw

At both tunne I — * c n six component, aerodynamic force and moment data were

taken for all major modifications at yaw angles up to 15°. The balances

used to obtain the data were of the external truncated pyramid type

mounted below the tunnel floor. Digital readouts of raw data were used

for preliminary evaluation of the effects of various modifications. At

Wichita State University, all data were reduced using an IBM 1130 com­

puter within 4 hours of the test run; this allowed reasonably rapid

evaluation of test results.

MODEL DESCRIPTION - The base model used during the test program was

a 3/8 scale replica o iw a production 1969 Dodge Charger. 3/8 scale re-

presents a satisfactory ’’trade off” between the desire for a large

model to minimize Reynolds Number differences from the full sized car and

a small model to minimize blockage and other wall effects encountered in

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