Go Back   EcoModder Forum > EcoModding > Aerodynamics
Register Now
 Register Now
 

Reply  Post New Thread
 
Submit Tools LinkBack Thread Tools
Old 06-03-2014, 05:09 PM   #51 (permalink)
Master EcoModder
 
aerohead's Avatar
 
Join Date: Jan 2008
Location: Sanger,Texas,U.S.A.
Posts: 15,861
Thanks: 23,922
Thanked 7,207 Times in 4,640 Posts
recent M-B tunnels

Quote:
Originally Posted by Vman455 View Post
Looks like Mercedes opened its own aeroacoustic tunnel last year; buried in the press release is a reference to a climate tunnel opening two years before that.

https://www.daimler.com/dccom/0-5-71...0-0-0-0-0.html
Thanks Vman455,this helps a lot.And would explain the photos of ice-covered M-Bs that are out there.
It would be nice if Daimler had published an SAE paper discussing the merits of the spinning wheels.
Ferdinand Porsche would drive 90-mph between Stuttgart and Berlin on the Autobahn in the 60K10,with fully covered wheels.Brake cooling didn't seem to be an issue.
With the climatic tunnel,they could simulate brake loads and evaluate brake cooling performance.
I've driven the Autobahn only once,but on the unlimited speed sections you'll see the large Benz, BMWs,and Porsches blow by at top speed.You wouldn't want brake fade out there in a panic stop situation.The ceramic rotors must be great!

__________________
Photobucket album: http://s1271.photobucket.com/albums/jj622/aerohead2/
  Reply With Quote
Alt Today
Popular topics

Other popular topics in this forum...

   
Old 06-03-2014, 05:13 PM   #52 (permalink)
Master EcoModder
 
aerohead's Avatar
 
Join Date: Jan 2008
Location: Sanger,Texas,U.S.A.
Posts: 15,861
Thanks: 23,922
Thanked 7,207 Times in 4,640 Posts
VW/M-B Cds

Quote:
Originally Posted by oldtamiyaphile View Post
VW quote 0.33 for the T5 Transporter:



I coast down tested my old MB100 and after running the numbers it came out to 0.36, and given the VW's vastly better coasting (basically identical frontal areas), I have no problem believing VW's 0.33 claim. Now given that a brick can be aerodynamic, I see no issue with 0.26 for a GT-R.
The Cds for the vans don't seem out of line a bit.FIAT has had a bus with around Cd 0.28 for a couple of decades.Here's some examples:
__________________
Photobucket album: http://s1271.photobucket.com/albums/jj622/aerohead2/
  Reply With Quote
The Following 3 Users Say Thank You to aerohead For This Useful Post:
NeilBlanchard (06-04-2014), oldtamiyaphile (06-03-2014), sendler (06-06-2014)
Old 06-03-2014, 05:41 PM   #53 (permalink)
Master EcoModder
 
aerohead's Avatar
 
Join Date: Jan 2008
Location: Sanger,Texas,U.S.A.
Posts: 15,861
Thanks: 23,922
Thanked 7,207 Times in 4,640 Posts
wing /diffuser

Quote:
Originally Posted by UltArc View Post
It was clear, now it is not clear lol. Does anyone have resources I could review to expand my knowledge on this? I understand how a wing is going to hit the air and become an issue, but if it's creating less force than the underbody (which has less drag) wouldn't it noticeably increase the rolling resistance? I suppose RR should not be included in Cd lol
We ought to select one vehicle and consider it with different configurations.
I have an SAE paper on Indycar aerodynamics from awhile back which included the wing research.
*The body was around Cd 0.28
*Adding exposed wheels netted around Cd 0.56
*Adding front and rear wings pushed the drag over Cd 1.0
--------------------------------------------------------------------------
*At rest,the car weighed 1,400-lbs
*At race velocity the car weighed 5,500-lbs
-------------------------------------------------------------------------
*You can imagine what the rolling resistance would do,but this downforce allowed the car to carry 235-mph through the curves.
------------------------------------------------------------------------
*The diffuser is a ground proximity device.Depending upon where the diffuser starts on the body,it can be optimized for low drag at shallow angles.
*With steeper angles,the diffuser triggers separation and allows the low base pressure of the wake to migrate under the car's rear,as far forward as the length of the diffuser.The low pressure acting on the underside of the diffuser creates a moment arm( torque) which attempts to pitch the car, rotate it around the rear axle,lifting the nose,creating downforce,which is balanced (hopefully) by the weight bias of the car.
*This 'torque' can be 'tuned' by varying the diffuser angle.
*And I agree that there bis probably a 'sweet-spot' at which you get drag reduction as well as a little downforce.
*If you drive at extra-legal speed and hit a wet spot,this extra downforce might mean the difference between hydroplaning or not.
__________________
Photobucket album: http://s1271.photobucket.com/albums/jj622/aerohead2/
  Reply With Quote
Old 06-03-2014, 05:42 PM   #54 (permalink)
...beats walking...
 
Join Date: Jul 2009
Location: .
Posts: 6,190
Thanks: 179
Thanked 1,525 Times in 1,126 Posts
As Arsenio Hall would say with a British-accent: "...it's all about the BOOTIE..." (wink,wink)

  Reply With Quote
The Following User Says Thank You to gone-ot For This Useful Post:
aerohead (06-03-2014)
Reply  Post New Thread


Thread Tools




Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2024, vBulletin Solutions Inc.
Content Relevant URLs by vBSEO 3.5.2
All content copyright EcoModder.com