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Old 09-18-2020, 02:56 PM   #3558 (permalink)
aerohead
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fault

Quote:
Originally Posted by freebeard View Post
Is that a fault of the user, or of the template? How would a template independent of ride height differ?
It's a misapplication of the tool. Like using a 1/4-inch ratchet to torque lug nuts.
The air 'sees' all vehicles in mirror reflection, with an imaginary, upside-down twin below the road surface.
The template contour is based upon this 1:1- scale. Shrinking the scale introduces a contour which no longer satisfies 'streamlined.'
The positive pressure gradient generated will overwhelm the turbulent boundary layer and trigger flow separation, the whole thing we're trying to avoid like the COVID.
As to ride height drag variability, we'd have to test it. Research on the Audi A2 proved that there is no universal absolute relationship between ground clearance and Cd. It remains an unknown quantity.
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Hucho does imply that by lowering a vehicle, one is 'integrating' the wheels further into the body, which he said would be part of a strategy for achieving Cd 0.09
I believe McLAREN, with respect to the SPEEDTAIL, noticed this part of his book.
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