Mercedes CLA sedan: 0.23 drag coefficient (0.22 for BlueEfficiency model)
 

http://ww4.hdnux.com/photos/17/27/51.../3/628x471.jpg

http://bonjourlife.com/wp-content/up...Benz-CLA-3.jpg

http://www.zercustoms.com/news/image...G-4MATIC-3.jpg

From the MB press release:

Amazing! I guess that explains how the base CLA can crack 130 mph with just 122 hp and 150 with the two liter.

This is one Merc I can't wait to test-drive. After the horribly plasticky B-Class, it's nice that Mercedes is trying to find ways to go mass market (read: FWD) without losing its premium appeal.

And that trunk probably doesn't even hit template. Shows how the details can add up!

Yup: detail optimization can make up for a lot. Tells us how bad the "details" must be on most cars, doesn't it?

The brochure is fascinating reading.
http://www.mercedes-benz.fi/content/...7_0113_021.pdf

Wow - .22 for the high efficiency model, coming later. Editing the post title. :)

From the PDF:

Funny, I have been noticing the Merc sedans lately.
Noticing how low the front edge is to the ground and how low the front hood is to the ground.
also how 'tight' the tires and wheels are to the edges of the wheel well.
Usually a sedan's bumber will clear a curb. Butthe newer merc arent high enough.
As Metro said....'opitmizing the details"!

MB
 

MB proabably lurking here at ecomodder? How bout the belly?

Just as a reminder, Merc was the first to do 0.24 in a production car, just a few years ago:

http://ecomodder.com/forum/showthrea...html#post88383

And they seem to be getting closer to their goal:

Mercedes to Sell Super-Aerodynamic Cars in 5 Years

"...hugging the ground..." has always been good for reducing aerodrag.

...and, matching tyre diameter to wheelwell circumference gives errant 'air' almost no place to create air turbulence (drag).

I'm surprised it has a .23 Cd. That is fantastic! Sigh, my truck is more than 2x that...

That's incredible. I was just thinking earlier today how there needs to be more education to the general public regarding vehicle aerodynamics. I hope Mercedes starts a trend of low drag vehicles.

and yet the wheels... don't look very aero at all.

Back in 1984 the poverty spec W124 (skinny tires, smooth hub caps) pulled a 0.29cd. I would like to bring mine down to that level or maybe improve on it a bit.
http://eblog.mercedes-benz-passion.c...132_84F156.jpg

Possible, spokes could be partially streamlined? Besides, they could've engineered the fenders to divert flow away and reduce drag.

Likely that. And as Old Tele Man says, the fender-to-wheel gap plays an important part, too.

I think that the main difference between 300D and basic model is the front bumper.

Have they released their fuel consumption figures out yet?

I found that Co2 is 118 g/km which gives 4,45 l/100km average fuel consumption.
Mercedes-Benz CLA 180 BlueEFFICIENCY, 2013 C 117 technical specifications & information 304480

Just a thought: MB has been known to put clear aero-covers on it's show cars. IIRC, including a high-zoot FourTwo Brabus.

That said, in any of the pictures I don't see the evidence that such covers are in use: clips/fasteners in either the spokes, the rims, or hub.

Also it's a safe bet the photo doesn't necessarily show the lowest-drag variant.

Thus the disclaimer in nearly every car ad: "model may not be exactly as shown".

The brochure linked by niky in post #6 gives a range of 4.5 - 4.2 l/100km (52 - 56mpg) for the combined (urban & extra-urban) on the CDI with auto transmission... 3.8 - 3.6 l/100km (62 - 65mpg) for extra-urban! Pretty dang good! I'm assuming the (higher) FE numbers in the brochure for the BlueEFFICIENCY (with lower Cd and manual transmission) are estimates... ?

http://photo.netcarshow.com/Mercedes...4_photo_9b.jpg
http://photo.netcarshow.com/Mercedes...4_photo_a0.jpg
http://photo.netcarshow.com/Mercedes...4_photo_9f.jpg
http://photo.netcarshow.com/Mercedes...4_photo_a1.jpg
http://photo.netcarshow.com/Mercedes...4_photo_54.jpg
( Image above is a CG rendering, but might be close to reality )

Some good images here - plenty from inside an actual wind tunnel : http://www.google.com/search?q=Merce...w=1436&bih=786
http://www.autoconception.com/wp-con...ineering-9.jpg

A few weeks ago I went to go take a leak at a highway rest station and during the relieving part a corner of my eye caught a parked semi-truck full of CLA`s.
I love the beauty of this thing, they truly shoved a finger up the behind of all those whiny designers who said you must make compromises between efficiency and aesthetics. It`s a work of art. I hope those soccer moms drop those SUVs and go for this beauty.

Using the latest overlay on the Benz.
Industrial Design - Transportation Photos by kach22i | Photobucket
http://i184.photobucket.com/albums/x...psc99962a2.jpg

Using a green felt tip pen to redesign it for maximum effect.
http://i184.photobucket.com/albums/x...pse7107793.jpg

Very nice sketch - I'd tweak the rear wheels back a bit and narrow the rear track, so the side taper can start a little bit closer to the front.

Do you have SketchUp George? [/Nudge, nudge, wink, wink - say no moah!]

I downloaded it over a year ago but haven't even opened it up.

A friend has offered to walk me though it, but I just have not made the time for it.

I click enough keys for AutoCad 2D drawings and just surfing the Internet, drawing by hand is my relaxation.

Newly posted Video: CLA Aerodynamics
 

Fiddling around on a sleepless night, I found these videos. A couple stills from the first video were posted earlier in this thread, but the video itself seems to have only just appeared on Youtube. Watching the smoke test of several details that make the low Cd possible is interesting: wheel-well curtains, spoiler, tail light fixtures, a-pillar, rear view mirrors, and others:
http://www.youtube.com/watch?v=uNXgYSbEaKg

And here is the "preparation" vid, which is kinda fun. It shows the procedure for putting the car in place and securing it:
http://www.youtube.com/watch?feature...&v=LqeljvJ6j-k

Impressive facility. I wouldn't be surprised if it's a bit of a sought-after privilege to work in it.

It is all very impressive and no doubt that the car is good, but I remained unconvinced on much of these MB Cd numbers. After all, we only have their testing and their word for the results. There are ample areas of doubt such as the open rear wheel arches, the huge wake (shown in the video) and the questionable wheel designs. It would be very interesting to have the Insight and the CLA tested in the same wind tunnel.

really.......:eek:

do you also believe that the oil companies squashed a carb that got 99mpg??????? :rolleyes:

Here is something to think about.
Some other german car maker w/ a big windtunnel (bmw maybe) has some engineer come in and say "mb is blowing smoke on the .23 cd......let's go buy one, run the test and then expose them!!" :thumbup:
2 days later MB is retracting and firing.
Loses MASSIVE credibility in the marketplace.........

just sayin......:cool:

I cant believe we still build cars with outside mirrors.

The proof of the aerodynamics will be in the speed. When they first released the projected performance numbers, I was impressed at the quoted top speed given the quoted power. If it really can hit those numbers, then the aerodynamics claims are more believable.

No, I do not. I'm an engineer and I spend a fair amount of time reading my Hucho. I know the equations. It's all about environment, weight, frontal area, and Cd. It's Cd under discussion.

Read your Hucho. There is enough wiggle room between different wind tunnels that such a test would probably prove nothing. Identical testing in the same wind tunnel would be the only convincing test IMO. But, admittedly I am speculating. I just don't see the stuff on the car that translates to .23 when the Insight is .25. Of course, that has not been independently tested either, far as I know;)

Insight is sandbagging!!!! lol

As I had commented early, I am just 'visually' impressed with the obvious stuff that MB seems to be doing on the aero side.

I know you smart guys see alot more stuff due to your training. :thumbup:

The thing I marvel at and wonder ...Huh?...is the very front. Looks like a bull dozer blade, I'm surprised that's an optimal shape. Something to be learned here fer sure.

http://i43.tinypic.com/2qdznyb.jpg

I also note how there is just one long arc from the base of the front windscreen to the base of the rear window, and only then does it break just slightly for the trunk, something tells me this shape has been refined to the Nth degree.

couple of non-engineer thoughts:
the lip to ground is very low. That thing wont clear a curb much less a parking stop.
Also the angle up the hood starts out pretty dang low compared to any other similar sized car in the market

http://www.autoconception.com/wp-con...ineering-9.jpg

These are the aero wheels. Note how that the wheel is actually flat with a small section cut out for cooling. The 'spokes' are simply the area of the wheel that is not painted black.
Stealth aero.:thumbup:

At 6:47 you can see how the trip strip works on their taillights.