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Old 11-17-2022, 11:49 AM   #559 (permalink)
aerohead
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'tail......... configuration............ drag change

Quote:
Originally Posted by Phase View Post
Ioniq looking more aero. No mirrors. Wheel skirts. Also put silver duct tape over the brake cooling holes on the front tires. Full grill is blocked. Mpg still wasn’t going as good as I wanted

Still need to smooth under under the car more and def get that rear diffuser made

Very tempted to do a mini boat tail

I can’t do a full boat tail that eventually pinches at the end

Could anyone give me a break down of different boat tail lengths and reduced wake sizes and how each configuration lowers the cd?

Like how much would my cd be dropped with a 2 foot long boat tail versus a fully extended one?
1) If you can reliably isolate the OEM wake perimeter, and estimate it's wake area by measuring the width, in one-inch slices, from top to bottom, this will provide your Cd 0.24 'baseline.'
2) Since drag varies linearly with wake area, any desired percentage reduction in Cd will simply be that percentage in wake area reduction.
3) If you had AUTO-CAD, different scale renderings of the wake area could be evaluated from the automatic pixel count function, provided to determine the required tail length which would produce that 'size' of wake.
4) It's 'simple, not easy.'
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5) Without CAD, you could fabricate a 'cardboard and duct tape' length of boat-tail capable of supporting attached flow, and by percentage, using either width or height, determine the 'size' of the new rear transom which would generate the desirable wake size.
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