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

Reply  Post New Thread
 
Submit Tools LinkBack Thread Tools
Old 03-31-2008, 12:47 PM   #1 (permalink)
EcoModding Apprentice
 
fabrio.'s Avatar
 
Join Date: Feb 2008
Location: Italy, Morbegno (SO)
Posts: 151

tigra AERO - '96 opel tigra
Thanks: 9
Thanked 38 Times in 18 Posts
Wink BMW cooling duct

some pictures of radiator/cooling exhaust of an BMW 320 D

I am sure interests to you.

Sorry for the bad quality, but I used a cellphon!





last photo, from rear car:



note the quality of smooth underbody...very good.

the car it is standard!

__________________
.................................................. ...................

  Reply With Quote
The Following User Says Thank You to fabrio. For This Useful Post:
Piwoslaw (03-25-2010)
Alt Today
Popular topics

Other popular topics in this forum...

   
Old 03-31-2008, 01:09 PM   #2 (permalink)
Banned
 
Join Date: Feb 2008
Location: california
Posts: 1,329
Thanks: 24
Thanked 160 Times in 106 Posts
Cool. Is this an E46 or E92?
  Reply With Quote
Old 03-31-2008, 01:18 PM   #3 (permalink)
MechE
 
Join Date: Dec 2007
Location: Bay Area
Posts: 1,151

The Miata - '01 Mazda MX-5 Miata
Thanks: 0
Thanked 20 Times in 17 Posts
Looks NACA ish Also note the wheel deflectors
__________________
Cars have not created a new problem. They merely made more urgent the necessity to solve existing ones.
  Reply With Quote
Old 03-31-2008, 01:49 PM   #4 (permalink)
EcoModding Apprentice
 
fabrio.'s Avatar
 
Join Date: Feb 2008
Location: Italy, Morbegno (SO)
Posts: 151

tigra AERO - '96 opel tigra
Thanks: 9
Thanked 38 Times in 18 Posts
I think to remember an E46!
__________________
.................................................. ...................

  Reply With Quote
Old 03-31-2008, 11:58 PM   #5 (permalink)
Master EcoModder
 
Join Date: Jan 2008
Location: Victoria , Australia.
Posts: 499
Thanks: 20
Thanked 46 Times in 33 Posts
Fabrio,
Thanks for posting these great photos.
Some great details to study.

Cheers , Pete.
  Reply With Quote
Old 04-01-2008, 01:16 AM   #6 (permalink)
MP$
 
diesel_john's Avatar
 
Join Date: Jan 2008
Location: SW Ohio
Posts: 594
Thanks: 5
Thanked 18 Times in 13 Posts
Send a message via MSN to diesel_john
i am saving that pic
  Reply With Quote
Old 04-01-2008, 10:31 AM   #7 (permalink)
Master EcoModder
 
Join Date: Mar 2008
Location: USA
Posts: 560
Thanks: 1
Thanked 67 Times in 53 Posts
Notice the radiused surface on the aft side of the outlet. NACA did studies of cooling inlets and outlets during WWII for piston aircraft, using the best methods found on both our and German/Japanese aircraft. Outlets are as important as inlets for good aerodynamics. Actually, you need matched inlets, internal ducting, and outlets to get the lowest drag. This BMW has some comparativelygood outlet geometry, but could be better.

Google for "AR-5 aircraft" by Mike Arnold, who studied these methods when building his fine little plane.
  Reply With Quote
Old 04-01-2008, 03:59 PM   #8 (permalink)
EcoModding Apprentice
 
fabrio.'s Avatar
 
Join Date: Feb 2008
Location: Italy, Morbegno (SO)
Posts: 151

tigra AERO - '96 opel tigra
Thanks: 9
Thanked 38 Times in 18 Posts
hi Otto, I have find the mike arnold's site, but I do not "have tried this interesting page.
Could you send me the correct adress please?

from "Race Car Aerodynamic by Joseph Katz":


By fabrio
__________________
.................................................. ...................

  Reply With Quote
Old 04-04-2008, 12:40 PM   #9 (permalink)
Master EcoModder
 
aerohead's Avatar
 
Join Date: Jan 2008
Location: Sanger,Texas,U.S.A.
Posts: 11,216
Thanks: 17,980
Thanked 5,970 Times in 3,628 Posts
BMW cooling duct

The photo exhibits very good design on the part of BMW.This is exactly the sort of technology race teams have used for decades,and what Walter Korff of Lockheed Aircraft was advocating for passenger cars back in the 1960s.Glad to see that Rip van Winkle is waking!
__________________
Photobucket album: http://s1271.photobucket.com/albums/jj622/aerohead2/
  Reply With Quote
Old 04-04-2008, 01:53 PM   #10 (permalink)
Master EcoModder
 
Join Date: Mar 2008
Location: USA
Posts: 560
Thanks: 1
Thanked 67 Times in 53 Posts
I wish I knew how to post scanned images here. If so, I could show you illustrations out of Dr. S. Hoerner's "Fluid-Dynamic Drag" page 9-16, with cites and sources.

The optimum outlet is not as shown in the BMW photo, or anything close. It is more like the bottom drawing D in the above illustration, but with the outlet channel as close to parallel to outside flow as possible, and with the downstream intersection radiused.

Fast flow of the outside air means low pressure, which in turn sucks the outlet discharge into the free stream. If the outlet is as close to parallel with the free stream as possible, and the downstream intersection radiused, the outlet air can merge with the free stream with the least possible turbulence and greatest efficiency. Think of it as an on-ramp to a freeway, where the cars represent air molecules.

BTW, some folks use NACA submerged inlets and turn them around backward as outlets. Ungood. These NACA arrowhead-shaped inlets look sexy and work pretty good as inlets, but are not efficient as outlets.

Bottom line: If outlets and internal ducting are good, the stagnation point inlet at the nose can be quite small.

  Reply With Quote
Reply  Post New Thread


Thread Tools


Similar Threads
Thread Thread Starter Forum Replies Last Post
Duct Tape for Aero Testing? cfg83 Aerodynamics 28 03-31-2011 05:10 PM
BMW vs Prius Sandy General Efficiency Discussion 17 04-08-2008 06:41 PM
Cooling system drag Daox Aerodynamics 7 01-29-2008 09:01 PM
Speed vs. MPG: 1996 BMW 318ti MetroMPG General Efficiency Discussion 0 01-24-2008 10:45 AM



Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2020, vBulletin Solutions Inc.
Content Relevant URLs by vBSEO 3.5.2
All content copyright EcoModder.com