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Old 11-11-2020, 11:18 AM   #94 (permalink)
aerohead
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wiper drag

Quote:
Originally Posted by CigaR007 View Post
Oh I see what you mean now. To be honest, I doubt the front wipers cause much drag. They seem to be stowed well enough to avoid any drag.

I intend to tuft-test the entire hood. Perhaps I can look into the wipers.
The angled intersection between the hood ( bonnet ) and windshield ( windscreen ) is usually an intentional design consideration, intended to create a small stagnation bubble from which to harvest ambient static pressure for cabin ventilation, without the need of running the electric fan.
I sealed this area off completely, plus adding a more streamlined windshield to my truck. The aero improvement was Cd 0.005. I can't tell you whether it was all from the new glass, from sealing the cowl area, or a combination of the two.
The stagnation bubble also helps isolate the wipers from lifting at high speed. Fast, high performance cars may hide the wipers inside a depression behind the hood. In the past, some Porsche's with 'exposed' wipers, had downforce wings riveted to the wiper arms to keep them planted at high velocity. Safety!
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