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Old 02-15-2018, 02:04 AM   #40 (permalink)
freebeard
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I gave that my best shot at Permalink #24 with the half-bell. Think about a NACA duct. Vortexes generated by the curvature of the duct sides pulls air down into the throat of the duct. This acts like a reverse NACA duct, pulling underbody air in toward the center and up into the bell.

For balance, here's a different approach, from Bonneville:



This is also a bell — the roof has some curve to it. But it progresses from the full width, narrow inlet to an outlet that is ~4-5x the opening. I think this slows the air down and decreases it's static pressure to match the wake. But... I'd want to get aerohead's opinion on whether that's even wrong.

and again:

2nd from the top left is the High Momentum Mudflap. It's boat tail shaped.
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