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Old 03-26-2012, 01:31 AM   #33 (permalink)
Otto
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Quote:
Originally Posted by Tesla View Post
So then I assume the Subaru, being much the same is also crude and I should have no fears in attempting an improvement.
What do you think of the serated version on the Merc in this link?
News - Automotive Engineer
It would be easy to do a knockoff of the depicted Mercedes deflector, out of, say, a section of plastic paint pail with crenelated edge.

I wish they'd included all the streamlines in their drawing, especially showing the air at and immediately around the tire and front corner of the car. Some streamlines appear to originate at the tire leading edge, so they should show where that air came from. Is this a variant of the recent BMW air curtain idea, or what?

And, their computerized streamlines vary considerably from actual smoke streamlines as shown in Hucho's wind tunnel work on the Opel Calibra, which is much more acute oblique flow at the nose.

Best way to check, seems to me, is do your undertray, then tape tufts of yarn off it, wet the tufts with tempura paint, drive down the road at 70 mph, then look under the car and see which way the wind was blowing, from the paint deposits on the undertray. Then, orient your wheel fairings accordingly. Based on Hucho's photos, I suspect your streamlines will look more like Hucho's photo than the Mercedes drawings. In any event, the yarn tell tails will tell the tale.
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