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Old 04-08-2022, 03:56 PM   #81 (permalink)
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Just no idea how I’d do that realistically.
Hence the suggestion to go below the tail lights. Some try transparent side pieces since the tail lights are the impediment.

Do you understand the function of a wickerbill?

A 'Turnpike Cruiser-style fender skirt would extend from the front of the wheel well [or door opening] to a separation edge at the side of the box cavity, keeping the surface as smooth as is possible.

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Old 04-08-2022, 04:21 PM   #82 (permalink)
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Hence the suggestion to go below the tail lights. Some try transparent side pieces since the tail lights are the impediment.

Do you understand the function of a wickerbill?

A 'Turnpike Cruiser-style fender skirt would extend from the front of the wheel well [or door opening] to a separation edge at the side of the box cavity, keeping the surface as smooth as is possible.
A down or up angled wicker bill? Sorry Iím new to all of this. Google images only show them pointing up and I have no idea how that would help the aero
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Old 04-08-2022, 04:23 PM   #83 (permalink)
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Also I agree on the cruiser style fender skirt. It shouldn’t be too hard to do since the Ioniq actually angles back after the rear wheel well already.
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Old 04-08-2022, 07:40 PM   #84 (permalink)
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I have no idea how that would help the aero
Points up on cars, down on airplane wings. It's a localized feature that affects the overall flow. Think of it as a linear vortex generator.
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Old 04-09-2022, 08:38 PM   #85 (permalink)
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Underside of rear. Interesting muffler placement. Any advice on cover it with under body tray? Most other cars apparently just have it over to the side. Mines right in the middle sideways!
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Old 04-09-2022, 10:15 PM   #86 (permalink)
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Improvement is improvement though. I wish I knew how much.
You said you've watched all of Julian's videos. Did you try any of his techniques for testing and measuring things?
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Old 04-10-2022, 12:44 PM   #87 (permalink)
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You said you've watched all of Julian's videos. Did you try any of his techniques for testing and measuring things?
I canít afford all of those sensors to measure pressure. Most I can do is tuft testing but that wonít tell me how much
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Old 04-10-2022, 01:58 PM   #88 (permalink)
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Tuft testing is one of the easiest, most effective, most useful forms of testing; you can trial things like separation edges, mirror changes, fences, vortex generators, air curtains, etc. and see what actually happens to the flow (which is worth an infinite number of guesses). That is a measurement: the tufts show flow direction and, as you learn to read them better, turbulence and speed. Most importantly, the tufts will show you exactly where on the body flow is attached and where it is separated.

An example of useful tuft testing: you asked about your muffler. Tape tufts to it, station a friend on the side of the road down low with a camera and take pictures as you drive by. Is the flow attached or separated? If it's attached, what do you think a plastic panel would "fix" exactly? If it's separated, throw a piece of cardboard on it temporarily and see if it's better, worse, or the same. Use your head rather than throwing up your hands and going, "Well, looks like all I can do is guess." I used to be that way. It's a giant waste of time.

For pressure testing, you can find digital manometers on Amazon for $50 or less; I bought this one, which came with two pitot tubes at the time but you can buy one separately. Disks are easy to make at home with metal bar stock and small brass tubing, which you can find at hardware or hobby stores. Julian's book walks you through the process. He was also nice enough to collect explanations of various test techniques in a single thread here.

This quote--from a 1963 paper on aerodynamics and body design by two GM stylists--is as true today as it was then:

"Technical apathy is often a far greater deterrent to the acquisition and application of vehicle aerodynamic data than any excessive expenditure of time or money" (Kelly, Kent and Harry Holcombe, "Aerodynamics for Body Engineers," SAE 640050).
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Old 04-10-2022, 02:05 PM   #89 (permalink)
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An addendum, on being cheap: I am a proud cheapskate (I slept in my car the last three nights, on my way to the Green Grand Prix and back, rather than waste money on hotel rooms). If it wasn't possible to conduct aerodynamic testing cheaply I wouldn't be doing it. Look at my truck thread to see what I'm using: scrap cardboard, scrap wood, nuts and bolts left over from other projects, scrap paper, etc. Cost shouldn't scare anyone away from testing things for themselves.
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Old 04-10-2022, 02:09 PM   #90 (permalink)
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Consider a bellypan that is level up to the muffler, cut out around it with a bend on each side, and an angled diffuser abaft.

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