Quote:
Originally Posted by freebeard
Sorry, what kach22i said. It's an external aero duct...
I think the Ferrari is a good example, diverting air sideways before it piles up under the windshield. I don't know if it would do much downstream...
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In my humble opinion, the negative lift benefit is from more than just preventing air flow from piling up on the windshield. The design defeats the usual upward lift airfoil of the car body, by causing more air to flow around the sides instead of over the top.
Normally the car body serves as an airfoil, creating lift. By removing air flow and sending it out the sides a portion of the usual lift is removed. So it's a relative downforce.
By setting up an upside down airfoil along the side (flank), the benefit is increased., if indeed the air follows that pretty path.
I think the re-directing of the air flow creates drag, unless the angles and curves are kept very gentle. But the negative lift benefit probably is real.