Hyundais 2024 new ACTIVE AIR SKIRT

[Phase]

Hyundai is going to essentially add deeper and curved front tire deflectors that drop down at higher speeds and reduce drag by 3 percent and increase downforce and stability.

Seems like a lot of moving parts and mechanical costs for something that could always be installed.

https://newatlas.com/automotive/hyun...ive-air-skirt/

I know aerohead hates in Hyundai saying they don’t care about drag, but it seems like Hyundai is doing more low drag innovation than Toyota or Nissan or Honda or any other Asian company out there right now. Especially with the Ioniq 6 and it’s .21 cd

[freebeard]

I wonder what actuators are in use. Probably electric, but it might be possible to use air pressure at the stagnation point.

Imagine a Coanda nozzle in the air curtain and pneumatic actuator.

[Phase]

If there’s a total drag reduction of 0.008 just for front flares, then I wonder how much drag reduction happens when putting them in front of the back wheels too along with boat tailing behind the wheels

[aerohead]

I looked at the article, then the Kia/Hyundai original content, with video and simulated flow.
Some quanta:
1) for the Genesis GV60, we're told that the AAS is good for delta Cd 0.008
2) we're told that this constitutes a 2.8% drag reduction when deployed.
3) dividing 0.008, by 2.8% ( 0.028) = Cd 0.2857 for the un-deployed AAS car
4) subtracting the delta-Cd 0.008 yields Cd 0.2777 ( a smidgeon lower than the McLaren Speedtail )
5) Sun Hyung Cho does not specify whether he is referring to Cd, or CdA.
----------------------------------------------------------------------------------------
6) From observing the GV60 materials we 'know' that the GV60 has 'two' different frontal areas which are unaccounted for.
7) without the Cd/CdA data, we're left with un-actionable information, exactly as Ford Motor Company did a few years ago with their SAE Paper on the F-150 airdam/Cd investigation which Vman455 shared with us.

[Phase]

Originally Posted by aerohead

I looked at the article, then the Kia/Hyundai original content, with video and simulated flow.
Some quanta:
1) for the Genesis GV60, we're told that the AAS is good for delta Cd 0.008
2) we're told that this constitutes a 2.8% drag reduction when deployed.
3) dividing 0.008, by 2.8% ( 0.028) = Cd 0.2857 for the un-deployed AAS car
4) subtracting the delta-Cd 0.008 yields Cd 0.2777 ( a smidgeon lower than the McLaren Speedtail )
5) Sun Hyung Cho does not specify whether he is referring to Cd, or CdA.
----------------------------------------------------------------------------------------
6) From observing the GV60 materials we 'know' that the GV60 has 'two' different frontal areas which are unaccounted for.
7) without the Cd/CdA data, we're left with un-actionable information, exactly as Ford Motor Company did a few years ago with their SAE Paper on the F-150 airdam/Cd investigation which Vman455 shared with us.

They look pretty far ahead of the wheels too and there are already normal deflectors there so the double deflectors looks a bit goofy in my opinion.

[aerohead]

Originally Posted by Phase

They look pretty far ahead of the wheels too and there are already normal deflectors there so the double deflectors looks a bit goofy in my opinion.

Yes, and without the automatic deployment, they'd be knocked off the car, the first time it went up or down a driveway ramp, since they violate the SAE Handbook recommended practice for 'approach angle.'
So someone was thinking, as once you're 'away' from the urban environment, where ground clearance has less impact, they can get away with it, with little liability for a ground strike.
At Cd 0.2857 they need all the tricks they can get away with.

[Phase]

Originally Posted by aerohead

Yes, and without the automatic deployment, they'd be knocked off the car, the first time it went up or down a driveway ramp, since they violate the SAE Handbook recommended practice for 'approach angle.'
So someone was thinking, as once you're 'away' from the urban environment, where ground clearance has less impact, they can get away with it, with little liability for a ground strike.
At Cd 0.2857 they need all the tricks they can get away with.

Give it a few years and we will have automatic full wheel flares for the front and back. A more refined front deflector and then a boat tail that drops down behind the wheel too at highway speeds

[freebeard]

So you have 2" effective clearance and then you hit a bridge with a 1/2" lip at speed and the wheel deflects 2". Ground strike.

[aerohead]

Originally Posted by Phase

Give it a few years and we will have automatic full wheel flares for the front and back. A more refined front deflector and then a boat tail that drops down behind the wheel too at highway speeds

Hope so! It would just be an ensemble of off-the-shelf technology, languishing until whatever committee responsible for green-lighting the additions, thought higher of low drag.

[aerohead]

Originally Posted by freebeard

So you have 2" effective clearance and then you hit a bridge with a 1/2" lip at speed and the wheel deflects 2". Ground strike.

The Interstate Highway System is designed for 100-mph travel. And the thermal expansion-joints in bridge sections are 'sliders,' and are 'flush', to the road surface, with no facility to translate vertically.
And because of a vehicle's own inertia, even if it were to strike some 1/2-inch hazard at speed, the 'body' of the car would essentially remain traveling 'level', while the wheels translated vertically over the rise.