Page 12 - Combined_137_OCR

SPACE DIVISION CHRYSLER ____
CORPORATION

Prior to shipment to the tunnel for tests, all models will be checked for
dimensional accuracy and proper fit of all parts. Any pressure tubing will be checked
to insure against leaks. Data reduction equations will be verified and constants provided
where necessary.

At the tunnel, calibrations will be made of all instrumentation and checks made
of all data reduction constants. CHO will supervise the model installation into the tunnel and
will supervise all model changes during testing. During the tests, checks will continually be
made of data being recorded to validate its accuracy and insure proper trends. Any abnor -
malities will be immediately investigated. Repeat runs will be made on each configuration
to assure data repeatability and increase accuracy.

References 5 and 7 have shown that a ground board gives adequate test results
when compared to full-scale values. They suggest, however, that closer correlation is
obtained, particular in lift, when the car is separated from the ground plane a distance equal
to the displacement thickness of the boundary layer. Of course, by using suction or blowing
on the ground board the boundary layer could be removed and would offer the optimum test
condition. This possibility will be investigated during initial talks with the tunnel personnel
and,if feasible, will be incorporated in the tests. In any event, boundary layer profile in­
vestigations will be made to ascertain that the best profile will be utilized during tests. Car
height above the board will also be given further investigation.

To allow positive comparison of data taken in different tunnels, a basic con­
figuration will be established and tested. Subsequent tests in other facilities will test this
same configuration which then will afford a common means of data comparison and will
eliminate any wind tunnel irregularity effects from the data. Where different scale model
tests are involved, it will also help identify scale effects, if any. Concerted efforts will be
continually exercised to keep accuracies to the highest order. An accurate run log will be
maintained containing all information for every test run.

All data collected during the tests will be plotted against appropriate param­
eters to illustrate the effects of changing various components of the automobile. Aerody­
namic drag will be the prime parameter of concern, although aerodynamic lift and center
of pressure will exhibit considerable influence on certain body forms and will not be over­
looked. Comparisons of data with other similar configurations and with other scale data,
where available, will be made to substantiate data accuracies. Theoretical comparisons
will also be made where possible. From these plots, conclusions, recommendations, and
opinions can be formed. Internal drag will be determined from pressure readings in the
engine compartment. Flow visualization aides such as tufts, fluorescent oils, dyalite beads,
powder and high speed photography will be utilized to aid in formulating the complete aero­
dynamic picture.

As pointed out earlier in this proposal, the objective of these tests is
to collect data which can be used by styling personnel as guides when styling any par­
ticular configuration. Although much experimental technical information will be in­
cluded in this report, it will be organized and presented in such a manner as to be easily

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