'separation trap'

[aerohead]

I've yet to find anything official, related to this so-called 'separation trap.'
It may be a situation where a journalist has mis-identified an extant device and has attributed it to the IONIQ-6's head of design at Hyundai; who, while mentioning the aerodynamics folks who cheated ten more counts out of 'Prophecy' shape, failed to mention the elusive 'trap' as a component of their bag-of-tricks.
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Any rear spoiler which lofts its tearing edge up to the 'reversal point', is, essentially capturing a separation bubble, which will travel with the car as a dynamic feature.
The dual rear spoilers on the '6' probably aren't as effective as the 'tea-tray' spoiler on the Prophecy concept, but work in that direction.
Maybe the Prophecy was too 911-esque for management's comfort. It certainly suffered the 911's rear shortcomings.

[aerohead]

After reviewing the wind tunnel smoke-flow imaging videos for the Ioniq-6, I recommend NOT attempting to use this device.
The Ioniq-6 has turned out to be a 'silhouette' car, just like the 1968 PORSCHE 911 RS 2.7. It's designed for it's 'look', not aerodynamics.
And Hyundai's 'N' Division ( The AMG of Hyundai ), wishes to campaign the RN22e, Ioniq-6 race variant at the eTouring Car World Cup Race Series.
The Ioniq Hybrid has a 'better' roofline than the '6.'
Had the designer used the 2007 hybrid roofline, the '6' would have lower than Cd 0.21.
Hyundai wants to 'emotionalize' the car... make it 'fun to drive fast'... a 'showoff drift king', leaving consumer logic and reason at the door.

[Phase]

Originally Posted by aerohead

After reviewing the wind tunnel smoke-flow imaging videos for the Ioniq-6, I recommend NOT attempting to use this device.
The Ioniq-6 has turned out to be a 'silhouette' car, just like the 1968 PORSCHE 911 RS 2.7. It's designed for it's 'look', not aerodynamics.
And Hyundai's 'N' Division ( The AMG of Hyundai ), wishes to campaign the RN22e, Ioniq-6 race variant at the eTouring Car World Cup Race Series.
The Ioniq Hybrid has a 'better' roofline than the '6.'
Had the designer used the 2007 hybrid roofline, the '6' would have lower than Cd 0.21.
Hyundai wants to 'emotionalize' the car... make it 'fun to drive fast'... a 'showoff drift king', leaving consumer logic and reason at the door.

So why does the 6 have much longer drag than the hybrid? Smoother under body, smaller wheel arch gaps, larger air curtains? Smaller wake?

[aerohead]

Originally Posted by Phase

So why does the 6 have much longer drag than the hybrid? Smoother under body, smaller wheel arch gaps, larger air curtains? Smaller wake?

Consider that, they've had six years to shave thirty counts off a car, which is now a BEV.
The '6's 'engine is 350% more efficient than yours. Consider what that does to radiator size requirements, grille opening.
Not 'smoother' but 'smoothest' underbody. 1983 technology.
Add my 1991 front gap-fillers like they did.
Their 18-inch aero wheels are the only ones which will fetch 0.21.
'Cameras' or mirrors? They don't say.
You're free to do wheel skirts. Air curtains are a joke in comparison.
It took PORSCHE 25-years to ditch the 26-degree roofline. They won't be going back. PORSCHE's 'failure' can magically become Hyundai's 'success'?
You can clearly see the 'fail' in the smoke flow images. Any additional chance for drag reduction was lost with that lowest streamline quitting the body, long before 'touching' any part of that rear slope.
A 'small' wake is meaningless if the base pressure due to separation-induced vortices and turbulence is lower than that of a 'larger' wake.
Without adding an inch to your car you could be at Cd 0.20. We talked about this when you first started your thread.
Dr. Teddy Woll of Mercedes Group gives you full permission to insulate your entire exhaust system, and hang a perfectly smooth belly pan and diffuser underneath it.
If you have, Modifying the Aerodynamics of Your Road Car, take a look at page-141. The separation edge addition to the 2015 Buick Excelle GT's taillight lens was good for a 0.3% drag reduction. I suspect that this is about what you might expect from a 'separation trap.' You'd never 'see' it, even if it was there.

[Phase]

Originally Posted by aerohead

Consider that, they've had six years to shave thirty counts off a car, which is now a BEV.
The '6's 'engine is 350% more efficient than yours. Consider what that does to radiator size requirements, grille opening.
Not 'smoother' but 'smoothest' underbody. 1983 technology.
Add my 1991 front gap-fillers like they did.
Their 18-inch aero wheels are the only ones which will fetch 0.21.
'Cameras' or mirrors? They don't say.
You're free to do wheel skirts. Air curtains are a joke in comparison.
It took PORSCHE 25-years to ditch the 26-degree roofline. They won't be going back. PORSCHE's 'failure' can magically become Hyundai's 'success'?
You can clearly see the 'fail' in the smoke flow images. Any additional chance for drag reduction was lost with that lowest streamline quitting the body, long before 'touching' any part of that rear slope.
A 'small' wake is meaningless if the base pressure due to separation-induced vortices and turbulence is lower than that of a 'larger' wake.
Without adding an inch to your car you could be at Cd 0.20. We talked about this when you first started your thread.
Dr. Teddy Woll of Mercedes Group gives you full permission to insulate your entire exhaust system, and hang a perfectly smooth belly pan and diffuser underneath it.
If you have, Modifying the Aerodynamics of Your Road Car, take a look at page-141. The separation edge addition to the 2015 Buick Excelle GT's taillight lens was good for a 0.3% drag reduction. I suspect that this is about what you might expect from a 'separation trap.' You'd never 'see' it, even if it was there.

the best things i could do that i havent done without adding an inch just seems to be the snoother under body and a proper rear diffuser

[aerohead]

It would be a game changer!

[Phase]

Originally Posted by aerohead

It would be a game changer!

i also have a hole the size of an engine air filter in the front engine tray from running over a stump. i wonder how much that affects my cd

i want to make something like this for the back of my car versus a super long boat tail

[freebeard]

That's particularized to the box van shape. Better the Mercedes IAA Concept


https://i.imgur.com/W8TA6tA.jpeg

[Phase]

Originally Posted by freebeard

That's particularized to the box van shape. Better the Mercedes IAA Concept


https://i.imgur.com/W8TA6tA.jpeg

well yeah i would follow the natural curves already at the rear of the ioniq

does mercedez mention how much drag is reduced when that rear extends out?

[aerohead]

Originally Posted by Phase

well yeah i would follow the natural curves already at the rear of the ioniq

does mercedez mention how much drag is reduced when that rear extends out?

So far, not a word from them about it.