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curv872 05-17-2011 02:16 PM

Air Curtain
 
http://www.bmwblog.com/wp-content/up...ir-Curtain.jpg

"The new Air Curtain is the latest innovation BMW aerodynamics. First introduced in the BMW 1 Series M Coupe, Air Curtain now would be a standard feature on the 128i Convertible. Air curtain increase airflow around the front wheel arches with the benefits of turbulence are significantly reduced."

I would love to see some DIY takes on BMW's latest innovation.

crmears 05-18-2011 12:21 AM

My impression is that it is more of a marketing too. Sorta like hood scoops that are not connected to the intake or most rear located spoilers on sports cars. Just my humble opinion but I am always open to being shown different.

Randy

Frank Lee 05-18-2011 12:27 AM

I have those suspicions too. Ducts generally don't increase aero efficiency, even if these things aren't exactly long ducts. There is a chance they are on to something- they have the wind tunnel after all. We'll see if this strategy becomes commonly implemented...

euromodder 05-18-2011 04:20 AM

Corner scoops / air guides are fitted to just about all European cab-over-engine trucks.
This looks like it's doing the same on a smaller scale, then using the scooped air to blanket the wheel arch like an invisible front skirt.

I don't see why it should be disregarded.
These guys have their own pretty modern windtunnel.

vtec-e 05-18-2011 04:50 AM

Most new cars around here have them. But the scoops are blanked off! lol!!
I expect the drag created on the functional ones will be offset by the drag reduced by the air curtain. Watching this space.

lunarhighway 05-18-2011 06:06 AM

Quote:

Corner scoops / air guides are fitted to just about all European cab-over-engine trucks.
my observation on these is that they are near the sides of the grill only wich makes me think they're there either get more air into the grill or less at speed when you might want the air to go round them. i think the primary goal is cooling however, given the overall lack of attention to aero on these trucks with square corners sticking into the airflow everywhere.

that said i wouldn't just dismiss the bmw setup as just marketing, it's usually little details that cause little changes in drag. in fact the new ford fiesta over at the parking lot at work has two open side scoops that lead into the bumper and i think there's some vents in the front fender too. could be the same thing.

when looking at the bmw efficient dynamics concept there's something interesting too

http://i77.photobucket.com/albums/j5...-car-walls.jpg
the car seems to have some sort of scoops on the front and this picutes shows theres actual clean ducts to the wheel wells and not radiators or whatever
http://i77.photobucket.com/albums/j5...ynamics_15.jpg

seems like the same thing going on there

curv872 05-18-2011 11:32 AM

The air curtain is pretty small but effective in reducing drag at speed (albeit .01%, but every bit helps)

Euromodder is spot on, the scooped air is being used to blanket the wheel arch like an invisible front skirt.

View of the slots on the M Coupe.
http://www.caranddriver.com/var/ezfl...cd_gallery.jpg

Reverse angle.
http://farm6.static.flickr.com/5088/...0c348e70_z.jpg

DonR 05-18-2011 05:07 PM

Quote:

Originally Posted by euromodder (Post 239188)
Corner scoops / air guides are fitted to just about all European cab-over-engine trucks.
This looks like it's doing the same on a smaller scale, then using the scooped air to blanket the wheel arch like an invisible front skirt.

I don't see why it should be disregarded.
These guys have their own pretty modern windtunnel.

Somewhere on internet I have seen these mounted on big rigs. I think the theory is that they turn the air around the corner, preventing separation & the drag associated. The ones I saw were mounted on the front corners & above the windshield.

botsapper 05-18-2011 08:41 PM

The Iveco ECOSTRALIS & Scania hi-box trucks have these corner deflectors that help cut side aero resistance. It is supposedly more important on crosswind aero and yaw dependance drag. The side deflectors work to diffuse the tall vertical bluff-cornered boxes.
Maybe it works like a race car side ducts, 'in front'. Wheel wells traps so much turbulent air from counter tire rotation, engine bay & brake heated air. Opposite a typical corner canard, the front vertical airflow reduce the pressure difference & air stagnation inside the bay.

ECOSRALIS Aerodynamic Kit

aerohead 05-20-2011 06:22 PM

claim
 
Quote:

Originally Posted by curv872 (Post 239013)
http://www.bmwblog.com/wp-content/up...ir-Curtain.jpg

"The new Air Curtain is the latest innovation BMW aerodynamics. First introduced in the BMW 1 Series M Coupe, Air Curtain now would be a standard feature on the 128i Convertible. Air curtain increase airflow around the front wheel arches with the benefits of turbulence are significantly reduced."

I would love to see some DIY takes on BMW's latest innovation.

There might be a specific context in which the full spirit of their claim is captured.
If you're burning,and someone throws gasoline on you,there will be a localized cooling effect,but you're still on fire.

Frank Lee 05-20-2011 06:56 PM

Perhaps the Cd value well tell what value these ducts have.

curv872 05-20-2011 07:00 PM

Stated in post #7, a reduction cd of .01

euromodder 05-20-2011 07:12 PM

Maybe they're underdoing it for esthetic reasons.
Looks like only 1/3rd of the wheel is covered.

How about a scoop that ranges from top of the wheel arch, down to as low as the body is.
Obviously without going much beyond the original width of the car.

curv872 05-20-2011 07:17 PM

"inlets at either side route air in front of the wheel openings creating a boundary layer of air, reducing drag around the wheels and tires. Not that the 1M is slippery with a drag coefficient of 0.37. At least the "air curtains" drop that by about 0.01." - interwebs

botsapper 05-20-2011 08:41 PM

The BMW air curtain is a very subtle corner canard as compared to very extravagant front corner versions from the Japanese racing aftermarket. These external examples are corner box canard/splitters. Note the horizontal winglets are angled flat, collecting front air pressure flow and narrowing it down just before the well opening, probably with similar hopeful results.
http://www.gtrblog.com/wp-content/up...02-540x405.jpg
Other concept cars with these devices.
http://theblogaboutcars.com/wp-conte...citroen-GT.jpg

lunarhighway 05-24-2011 05:31 AM

brand new audi S1 ....air curtains?
http://i77.photobucket.com/albums/j5...bb67lt_800.jpg
http://i77.photobucket.com/albums/j5...abh2lx_800.jpg
http://i77.photobucket.com/albums/j5...absklr_800.jpg
they look like it might be just cosmetic, but on the last picture if you look closely you can see trough the left duct meaning it's really open and might do a little more than just be for looks.

since this is a fast version of the A1 it might be more for stability than economy

Bill in Houston 05-24-2011 10:40 AM

ooo, yeah, look at that... it looks like it is helping the air turn the corner...

Phantom 05-24-2011 01:45 PM

On the way to work today I saw a Subaru sedan but not sure on the year or model but it had something similar to this after the front wheels. It looked like there was a slit inside the wheel well that vented about 2-3 inches back from the wheel, I assume this is to give the air a place to escape reducing the amount of turbulent air shooting out from the wheel.

lunarhighway 05-24-2011 03:12 PM

think it might have been this model you sawhttp://upload.wikimedia.org/wikipedi...X_STI_rear.jpg

seems to have vents in front and behind the wheels

Phantom 05-24-2011 04:34 PM

The one I saw was not a hatch but that is what I was talking about, I did not notice the vent in the front but it could have had one and just blended in since it was dark blue. I wonder if having the vent only after the wheel well if it would reduce cd.

lunarhighway 05-24-2011 05:22 PM

some vents might be to aid cooling. since viewing this thread i'm looking with a little more attention to these areas and only today i noticed on i think a mazda 5 mpv that the "fake" airscoop on one side as actually open and had a little radiator behind it that vented into the wheelwell at the back... i suppose this is for the airco.
but it created an interesting tension between the left "fake" scoop and the right functional one.
this is largely off topic but what i mean to say is that not every vent is an "air curtain" and might be for just styling or cooling, and i think on the subaru it's likely one of those

Arragonis 05-24-2011 05:45 PM

I think with the A1 it is the intercooler in the wheelarch issue like my Fabia. They put the same outlet for the warm air on both sides to make it look the same.

curv872 05-27-2011 02:23 PM

Possible Air Curtain, Pikes Peak Dacia Duster:

http://www.blogcdn.com/www.autoblog....r-no-limit.jpg
http://www.blogcdn.com/www.autoblog....r-no-limit.jpg
http://www.blogcdn.com/www.autoblog....r-no-limit.jpg

curv872 05-31-2011 12:59 AM

2012 Jaguar XKR-S
http://www.otofans.com/wp-content/up...-side-view.jpg

kach22i 09-12-2011 09:44 PM

I saw this in Troy, Michigan last week.

Air curtain?

http://i184.photobucket.com/albums/x...iata-mouth.jpg

mcrews 09-13-2011 01:10 AM

Quote:

Originally Posted by curv872 (Post 241963)

I want!!!!!!!!!:o

mcrews 09-13-2011 03:04 AM

Quote:

Originally Posted by crmears (Post 239148)
My impression is that it is more of a marketing too. Sorta like hood scoops that are not connected to the intake or most rear located spoilers on sports cars. Just my humble opinion but I am always open to being shown different.

Randy

Well......geee....... Think about what you just said........" like hood scoops that are not connected to the intake "........key word *****NOT******

SO........BMW just made up the picture to convience a bunch of ricki racers to buy the 1 series.........

Do you realize the grief that would rain down on BMW if that picture was not 100% factual????


come on.......

mcrews 09-13-2011 03:05 AM

Quote:

Originally Posted by kach22i (Post 260718)
I saw this in Troy, Michigan last week.

Air curtain?

http://i184.photobucket.com/albums/x...iata-mouth.jpg

that hurts my eyes :eek: .....

mcrews 09-13-2011 03:11 AM

just saw this on another site.....

http://i678.photobucket.com/albums/v...how/photo5.jpg

mcrews 09-13-2011 03:14 AM

actually, it is very practical.
Keeps from having to do discs on the rims.
discs cost money. air flow doesnt.
heat build up is now a mute point.
They can still design stylish rims.

botsapper 09-13-2011 02:16 PM

Just a sample of interesting side suckers at Frankfurt Auto Show.

http://cache.gawkerassets.com/assets...9/kia_gt_2.jpg

http://static5.businessinsider.com/i...-forvision.jpg

http://motoren.files.wordpress.com/2...prod-press.jpg

http://www.tuningnews.net/news/11083...ept-car-01.jpg

http://shows.autospies.com/gallery/2...g/L1080064.jpg

kach22i 09-13-2011 05:26 PM

Quote:

Originally Posted by botsapper (Post 260823)
Just a sample of interesting side suckers at Frankfurt Auto Show.

I might have to admit this stuff works, at least in selling cars.;)

I'm cross-linking to another thread (not my work) I've been posting in for a few weeks. You guys might find this project of special interest, and the comment made of some value. You may have to sign-up to see some of the images, sorry about that.


http://thefactoryfiveforum.com/showthread.php?3231-Cfd
http://i184.photobucket.com/albums/x...orvid-CFD1.jpg

euromodder 09-13-2011 07:19 PM

Not every side-mounted airscoop develops into an air curtain.

kach22i 09-13-2011 07:59 PM

Quote:

Originally Posted by euromodder (Post 260881)
Not every side-mounted airscoop develops into an air curtain.

I have to agree, that sample I came up with, well the last two samples just seem to capitalize on the twin/split radiator look of water cooled Porsche's and Ferrari's and have little to do with an air-curtain.

My other hobby is hovercraft, and early hovercraft used an "air curtain" to contain the cushion or bubble of lift air under the hovercraft hull. In that context, I have to ask what's next? A blower fan blowing pressurized air over the wheel wells?:p

That idea is not so crazy, NASA has a few illustrations of helicopter, propeller and fan blades with pressurized air flow. The intent in those examples is to lower the overall sound levels caused by turbulence.

Arragonis 09-14-2011 06:26 AM

Well racers have had blowers before (old posting I know)

http://ashcom.homestead.com/RMH3257W.jpg

http://upload.wikimedia.org/wikipedi...6B_Fan_car.jpg

Slightly OT - what about Ground Effect which was used in F1 for a few years (until banned).

http://upload.wikimedia.org/wikipedi...a_Lotus_78.jpg

You would need variable ride height though, maybe ? Just a though.

autogyro 09-14-2011 09:23 PM

Don't laugh too loudly about fans. Morelli et al realized a 5kW reduction in power required for an expenditure of 240W by putting inward drawing fans in rear wheel covers. (Admittedly with some fancy ductwork too)

euromodder 09-14-2011 09:31 PM

Quote:

Originally Posted by Arragonis (Post 260997)
what about Ground Effect which was used in F1 for a few years (until banned).

On public streets ?

The average pothole is way deeper than the almost non-existant ride height .

HighMPG 09-14-2011 09:43 PM

1 Attachment(s)
I'm a mazda guy and here is Mazdaspeed's 3
Down-force and collecting air at the sides.
http://ecomodder.com/forum/attachmen...1&d=1316047336

HighMPG 09-14-2011 09:46 PM

Quote:

Originally Posted by Arragonis (Post 260997)
Well racers have had blowers before (old posting I know)

http://ashcom.homestead.com/RMH3257W.jpg

I think this was for down force right?
I believe taking air out from under the car creates better down force.

Arragonis 09-15-2011 04:38 AM

Quote:

Originally Posted by euromodder (Post 261103)
On public streets ?

The average pothole is way deeper than the almost non-existant ride height .

Only useful on motorways which tend to be smoother - but then again I buckled my wheel last year on the M8...


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