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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







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