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Old 05-29-2021, 05:00 PM   #7 (permalink)
Join Date: Nov 2017
Location: Australia
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A few observations.

- The rear diffuser will work only if the floor ahead of it is also smooth. ie the airflow pattern ahead of the diffuser is critical.

- Measuring surface pressures will tell you at least as much as tufting.

- Trying to ascertain Cd accurately by road testing is, I think, impossible. Just go on changes to the total power (A * V), averaged over a long distance in two directions. Also, ensure that when you make a deliberate change to drag (eg by having the windows down), that change is clearly measurable. Otherwise, you may be measuring just noise.
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