Making the Ioniq slippier

[aerohead]

If that's how you characterize low-drag, then the race is run and you have nothing. There's no point in spending one more iota of energy thinking about it.
I'll send a congratulatory note to the duPont family in Delaware. They succeeded in destroying aerodynamics in the crib.

[freebeard]

I'm just trying to make my car more aerodynamic without making it ugly as junk.

What's the overall length ? 12-14ft? The 84" being suggested would add 7ft.

Everything underbody won't be noticeable on the street. Your linked article is interesting, especially the areas called out in the side skirt section.


www.trdparts.jp/english/product/prius/aero.html

No spoiler is capable of the drag reduction you're entertaining. Only box-cavities and boat-tails can do it.

No love for plasma actuators?

[Phase]

Originally Posted by aerohead

No spoiler is capable of the drag reduction you're entertaining. Only box-cavities and boat-tails can do it.
Remember, your design specification is 60mpg @ 80-mph. And Cd 0.12, half that of Prius, Ioniq.
If it was that easy, they'd already be doing it, and you'd have your 60 / 80 ratio.
The car must be reduced to surface friction drag and wheel drag.
Surface friction we can't do anything about, but wheel drag can be cut by 70% according to Goro Tamai of MIT.

hence the box cavity idea. cd of 0.12 probably isn't possible. but even if i could reduce the ioniqs drag down to 20 i would be happy honestly

[Phase]

Originally Posted by aerohead

I looked at it and vote thumbs-down on the rear spoiler.
1) The IONIQ is already on the 'template' contour at its upper separation point.
2) Directing the flow up and over a rear spoiler would only re-accelerate the local flow, destroying the only thing which could provide pressure recovery, a higher base pressure, and lower overall drag.
3) I like the front wheel arch gap-fillers. That's a GO!
4) I like the rear wheel skirts. That's a GO!
5) Any additional paneling you can get away with underneath.
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6) As the Cd comes down you'll need less and less cooling, as with Mercedes' new EQXX.
7) There may be a tiny amount of fruit with more 'Tesla-esque' side mirrors, on very-narrow stalks, at least 80mm away from the body.
8) 'Janky' coroplast wheel covers zip-tied to alloy wheels, or ventilated Dzus-fastened MOONs on steel wheels.
9) I've never seen an IONIQ at rest. If you can tell us where the rear diffuser begins underneath the car, there might be a recommendation for its upsweep angle.
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After all existing OEM features are addressed, you need to consider basjoos' comment about a receiver-hitch-mounted tail.
10) The IONIQ is missing 84-inches of body length.
11) You only have 43% aft-body as it is.
12) Your Length-to-Height ratio is only 3.082:1.
13) In order to approach your target 60-mpg @ 80-mph, you'd actually need a fully-gap-sealed, fully-boat-tailed, tadpole trailer, like BamZipPow's.
14) Any remarkable drag reduction is going to come from elongation. There's no way around it.

whats a good way to help fill in the wheel arches on the front end?

[freebeard]

Air curtains.

[Phase]

Originally Posted by freebeard

Air curtains.

the ioniq already has air curtains build in though?

[Phase]

https://insideevs.com/news/425581/ga...erodynamic-ev/

getting some inspiration from this new car. cd of .14 and it doesnt even have a full boat tail or skirts

[aerohead]

Originally Posted by Phase

hence the box cavity idea. cd of 0.12 probably isn't possible. but even if i could reduce the ioniqs drag down to 20 i would be happy honestly

You should have enough information now, to estimate the IONIQ's mpg @ 80-mph with Cd 0.20, or any Cd for that matter.
You won't have to speculate.
The material from Coventry University's aero mods of the Audi A2 ought to be adequate to get you to Cd 0.20.
Technically, your IONIQ's Cd is already as low as Kamm's lowest K-car that he drove in Germany.
Four wheel skirts would likely be sufficient for Cd 0.20. ( AeroCivic, Ford Probe-V, Ford Probe-IV, Porsche 60K10, Railton Mobil Special, Volkhart V2 Sagitta, MG EX 181, VW-Drop, VW-Flow, VW-Blunt, GM Aero 2000, GM Aero 2002, Solar Team Eindhoven Stella VIE, etc. )

[aerohead]

Originally Posted by Phase

whats a good way to help fill in the wheel arches on the front end?

1) Ballast the car with all the weight you're ever likely to carry in the car.
2) On a flat, level surface, exercise the wheel-flop from lock-to-lock, running the steering through its entire range of motion.
3) As you're articulating the front wheels, tape 'coupons' of cardboard or chipboard ( breakfast cereal boxes ) onto the front fender, all around the wheel arch, allowing whatever clearance you desire from the tire surface.
4) Repeat the movement of wheel until your satisfied that no clearance issue exists.
5) Tape butcher's paper from the meat section of the grocer's over what you've done.
6) After sunset, place an electric light source in the wheel-well to 'back-illuminate' the arch and the ends of all your coupons.
7) Trace the illuminated shape onto the butcher's paper to create a paper pattern.
8) Cut out the pattern and use it to mark and cut your gap-filler material.
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9) Examine the construction of the lip of the wheel arch for possible means of attachment points.
( A NASA rocket scientist from White Sands Missile Range designed the rear skirts on my Toyota pickup, using the existing sheet metal flange created during stamping operations. Heavy-gauge L-brackets were attached flush with the outside of the arch, using Grade-8, hex-head cap screws attached to Nyloc nuts. They're vibration-proof. The brackets are drilled and squared, to receive nylon nuts used to secure license plates.)
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10) If you don't want exposed fasteners, flathead studs can be bonded to the back side of the gap-fillers, the brackets drilled to let the studs pass, and nylocs attached from behind.
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11) The gap-fillers themselves can be plastic, metal, or composite. Whatever you're proficient with or want to develop skills with.
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MetroMPG's ' Cardboard And Duct-tape ( CAD ) system can easily tell you any delta- mpg they may provide.

[aerohead]

Originally Posted by Phase

https://insideevs.com/news/425581/ga...erodynamic-ev/

getting some inspiration from this new car. cd of .14 and it doesnt even have a full boat tail or skirts

Good Choice!
In side elevation, the GAC has a 50.8% aft-body, compared to the IONIQ's 43%. ( Elongation is your friend! )
In plan-view, GAC is the ' extremely boat-tailed' Cd 0.14- 0.16, 1937, Ludwig Prandtl' 'Lange Car' form, from AVA Gottingen, which inspired Dr. Erwin Komenda's Porsche 60K10. You can't see the boat-tailing from the side view ( as with Rolf Buchheim et al.'s, 100% boat-tailed VW-Drop Shape of 1981 )
At Cd 0.146, The GAC ENO. sort of validates the early wind tunnel data.
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Drag-for-drag, the 1983 GM Aero 2002, and subsequent, Aero 2002A, is a more efficient shape than GAC, but the Aero was never intended for production, just a 'halo' car.
The Chinese market may not already be addicted to 'styling' and may come to accept a serious aerodynamic specification production automobile.
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PS, The GAC ENO. 146 is both VW-Flow Body ( long-tail) and AST Template-III. The contours only diverge behind the GAC's trailing edge.
PPS, The 2017 Solar Team Eindhoven's Stella Vie extends the tail out even further, for a sub-Cd 0.137 coefficient. ( they won't tell us the cars actual Cd )