|
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.
|