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Old 01-10-2021, 03:33 AM   #3 (permalink)
JulianEdgar
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Quote:
Originally Posted by freebeard View Post
Who is working to four decimal places?

Can you think of things that the modifier should worry about. They're standing there with a handful of test gear, and looking at an arbitrary victim.

It starts with intent obviously, but then what comes next? Rules of thumb, one from column A and one from column B, or parsing a decision tree?

Here's one design pattern: simplify and add lightness.
Aerohead often quotes to this precision of number - to four decimal places, all with his made-up figures! Do a search and you'll see.

If you're after low drag, the easiest thing to aim at is high pressures on the rear surfaces and low pressures on the front.

But that requires actual measurement of aerodynamic pressures on real cars.

So far I have seen, only three people on this forum actually deign to do so. You, Freebeard, have never done so - as far as I know, at least. It requires doing real stuff, not just sitting behind a keyboard and postulating hypotheticals based on drawings.

It all reminds me so much of car modification of 30 years ago, when chassis dynos were rare, and people just made up engine power figures based on what they expected their engine mods to do.

To be blunt: the techniques now to exist to measure real aerodynamic stuff, and the other approaches (eg guessing from drawings) is as weak as it used to be in guessing engine power from valve sizes.
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