Page 1 - Combined_110_OCR

INTER COMPANY CORRESPONDENCE

DATE
codeS&M-ASM-110| November 1, 1968
TO - NAME DEPT. DIVISION PLANT/OFFICE
*
DISTRIBUTION
FROM - NAME DEPT. DIVISION PLANT/OFFICE
J. E. Vaughn 4831 Space Huntsville

Wind Tunnel Tests of 3/8- and Full-Scale Automobiles - A Performance
Report Cove ring the Period 7 October through 25 October 1968

Mr. V. Wayne Sparks has devoted full time to preparing different sections
of the report which will present results of the 3/8-scale tests at Wichita
University’s 7 x 10 ft tunnel. Analyses conducted thus far include:
stagnation point study, bouyancy study, and boundary layer evaluation.

The stagnation point study included a break-down of data taken using a
vertical static pressure rake located in front of the vehicle. Wind tunnel
runs were made at dynamic pressures of 6.2, 16.0, and 40 psf. Analysis
of the data revealed that the location of the stagnation point changed very
little with a C fQ iven change in dynamic pressure.

A bouyancy study was made from data obtained using a Pitot-static probe
located at different longitudinal positions along the ground plane. This
evaluation involved determining the change in pressure per unit length
along the ground plane and incorporating this into formula, utilizing the
cross-sectional area of the vehicle at various stations to yield the drag
due to bouyancy.

Data obtained from a boundary layer ’’mouse” located at various positions
along the ground plane were utilized to evaluate the boundary layer. Results
of the evaluation of the data included a velocity profile analysis, boundary
layer transition analysis, and boundary layer thickness analysis for
dynamic pressures of 40 and 80 psf.

Efforts are now being directed toward analyzing data for the effects O c o olid
and wake blockage due to installation of the ground plane and model and also
the installation of an additional vehicle for the drafting s tudies. Other data
to be analyzed include pressure differences ac ross the radiator, effect of
vertical position of the ground plane, and flow angularity. o nee the data
has been analyzed, an investigation will be ma de on the ac curacy of data
with respect to repeatibility.

Tests at Lockheed-Georgia Low Speed Wind Tunnel began on 14 October
1968 with the 3/8-scale Plymouth Road Runner. The primary purpose fo
these 3/8-scale tests at Lockheed were to obtain data on the vehicle in a
wind tunnel where the effects of the wind tunnel walls on the tunnel flow
would not be felt at the car. (i. e. , negligible blockage effects). Preliminary

^.1 84- 1 10-7879 REV. 1-63