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Old 07-06-2008, 09:33 AM   #27 (permalink)
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Originally Posted by cfg83 View Post
.Cd -

This is cool. I was thinking of X-Mas tree tinsel, but that's crinkly. Audio/Video tape is smooth, so I think it is better for staying flush to the car.


Let me add a disclaimer : I tested only a few strips at the base and middle of my winshield and drove for all of a mile and a half. I placed some of the strips directly behind my winshield wiper and noticed severe flutter once I reached anything past ten or so MPH. This is good for indicating that there is drag in this region, but I wonder if the cotton thread would show the direction of the vortexes better.
Sorry - I was keeping my eyes on the road in front of me vs. on the test.

After running prior tuft tests with the car, I saw the direction in which the flow traveled along the windshield.
(As you know, sometimes air will travel in directions that you would never imagine it would. Sometimes it will even reverse itself.)
To test how these strips would handle this kind of situation, I intentionally placed some of the strips perpendiculal to the airflow.
( I placed them vertically where I knew from the previous testing that the airflow was horizonatal.) I found that the strips fold over themselves and accurately show the true direction.

Still, I wanted to add that I did a really quick, sloppy test. The experts ( used to ) use yarn. Apparently there is a reason they dont use the tape.
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