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

Reply  Post New Thread
 
Submit Tools LinkBack Thread Tools
Old 12-21-2008, 01:01 AM   #11 (permalink)
NightKnight
 
NachtRitter's Avatar
 
Join Date: Dec 2008
Location: Placerville, CA
Posts: 1,594

RippinRoo - '05 Subaru Legacy Wagon 2.5 GT
Subaru
90 day: 21.16 mpg (US)

Helga - '00 Volkswagen Jetta TDI
TEAM VW AUDI Group
Diesel
90 day: 53.91 mpg (US)

Olga - '03 Volkswagen Jetta Wagon
90 day: 46.24 mpg (US)
Thanks: 303
Thanked 311 Times in 186 Posts
Quote:
Originally Posted by fanamingo View Post
It was meant as a joke. The CFL is intended to provide light for windtunnel crews studying an otherwise "black art".
Aaaaaaah... I get it!! (duh!)

  Reply With Quote
Alt Today
Popular topics

Other popular topics in this forum...

   
Old 12-21-2008, 02:16 AM   #12 (permalink)
Pokémoderator
 
cfg83's Avatar
 
Join Date: Dec 2007
Location: Southern California
Posts: 5,864

1999 Saturn SW2 - '99 Saturn SW2 Wagon
Team Saturn
90 day: 40.49 mpg (US)
Thanks: 439
Thanked 530 Times in 356 Posts
fanamingo -

Quote:
Originally Posted by fanamingo View Post
It was meant as a joke. The CFL is intended to provide light for windtunnel crews studying an otherwise "black art".
I thought the "joke" was that the light bulb was very close to the shape of a tear-drop and could be used to demonstrate really good aerodynamics.

*shrug*

CarloSW2
__________________

What's your EPA MPG? Go Here and find out!
American Solar Energy Society
  Reply With Quote
Old 12-21-2008, 02:34 AM   #13 (permalink)
NightKnight
 
NachtRitter's Avatar
 
Join Date: Dec 2008
Location: Placerville, CA
Posts: 1,594

RippinRoo - '05 Subaru Legacy Wagon 2.5 GT
Subaru
90 day: 21.16 mpg (US)

Helga - '00 Volkswagen Jetta TDI
TEAM VW AUDI Group
Diesel
90 day: 53.91 mpg (US)

Olga - '03 Volkswagen Jetta Wagon
90 day: 46.24 mpg (US)
Thanks: 303
Thanked 311 Times in 186 Posts
Quote:
Originally Posted by cfg83 View Post
I thought the "joke" was that the light bulb was very close to the shape of a tear-drop and could be used to demonstrate really good aerodynamics.
Ya, that's why I didn't get it originally either... an incandescent is shaped aerodynamically, but a CFL is usually shaped like a coil of glass tubes... which doesn't seem to be all that aero... (granted, there are some CFLs that are bulb shaped, but those are less common)
  Reply With Quote
Old 12-21-2008, 10:10 AM   #14 (permalink)
Master EcoModder
 
basjoos's Avatar
 
Join Date: Dec 2007
Location: Upstate SC
Posts: 1,088

Aerocivic - '92 Honda Civic CX
Last 3: 70.54 mpg (US)

AerocivicLB - '92 Honda Civic CX
Team Honda
90 day: 55.14 mpg (US)

Camryglide - '20 Toyota Camry hybrid LE
90 day: 62.77 mpg (US)
Thanks: 16
Thanked 676 Times in 302 Posts
Quote:
Originally Posted by instarx View Post
The danger of wingtip vorteces from landing aircraft wan't fully realized until the 70's or 80's.
The air force became aware of this in the 50's once they started messing with large, heavily wing loaded jets. (notably the YB-70/F-104 accident). It didn't start becoming important in civilian aviation until the introduction of the Boeing 747 and other "heavies" into the airport environment, where the mix of smaller, lightly wing loaded aircraft and large heavy wing loaded "jumbos" created a safety problem that had to be studied and regulated.

Quote:
Originally Posted by instarx View Post
Why all the resistance to a few new novel ideas being applied to aero in cars. Doesn't every little bit help? Maybe everyone got up on the wrong side of the bed this morning?
I don't have any resistance to these ideas. I was just pointing out that they are merely aerodynamic tricks to try to clean up an otherwise inefficient aerodynamic design (sort of like adding stall fences to an aircraft's wings to correct an aerodynamic deficiency) and that by themselves they won't turn the typical 0.36 Cd car into a 0.22 Cd wonder.
__________________
aerocivic.com
  Reply With Quote
Old 12-21-2008, 01:05 PM   #15 (permalink)
Master EcoModder
 
Join Date: Mar 2008
Location: USA
Posts: 568
Thanks: 1
Thanked 73 Times in 58 Posts
The "area rule" or Coke bottle fuselage was known in the 1940's, and to my understanding was first used in the Grumman F8 Bearcat, a high performance propeller aircraft that was a composite of the best ideas then available, taken from German, Japanese, and Allied aircraft and rolled into one new plane. Unfortunately, the Bearcat came at the end of the war, and propeller designs were dumped as the new jets came in. Area rule showed up in the F-106 et al in the 1950s. See also B-58, T-38, etc..
  Reply With Quote
Old 12-21-2008, 01:55 PM   #16 (permalink)
Master EcoModder
 
Join Date: May 2008
Location: Auburn, NH
Posts: 451

Wicked Wanda - '99 VW Beetle GLS
90 day: 29.59 mpg (US)

Green Monster - '99 Ford Explorer Sport
90 day: 16.73 mpg (US)

Dad's Taxi - '99 Honda Odyssey EX
90 day: 24.23 mpg (US)
Thanks: 0
Thanked 2 Times in 2 Posts
GM has had great aero designs dating back to the '50s! But no, they wouldn't build them. No wonder they are in trouble.




__________________
  Reply With Quote
Old 12-21-2008, 04:02 PM   #17 (permalink)
Dartmouth 2010
 
SVOboy's Avatar
 
Join Date: Nov 2007
Location: Hanover, NH
Posts: 6,447

Vegan Powa! - '91 Honda CRX DX
Team Honda
90 day: 66.52 mpg (US)
Thanks: 92
Thanked 122 Times in 90 Posts
Send a message via AIM to SVOboy Send a message via MSN to SVOboy Send a message via Yahoo to SVOboy
Damn, I wanted to post this! Nice job.
  Reply With Quote
Old 12-21-2008, 04:52 PM   #18 (permalink)
Master EcoModder
 
basjoos's Avatar
 
Join Date: Dec 2007
Location: Upstate SC
Posts: 1,088

Aerocivic - '92 Honda Civic CX
Last 3: 70.54 mpg (US)

AerocivicLB - '92 Honda Civic CX
Team Honda
90 day: 55.14 mpg (US)

Camryglide - '20 Toyota Camry hybrid LE
90 day: 62.77 mpg (US)
Thanks: 16
Thanked 676 Times in 302 Posts
I’m afraid this is just another example of automotive stylists gone wild rather than an honest attempt to create a low Cd car. This was GM’s turbine powered concept car, the 1959 Firebird III, so they were styling it to resemble a jet fighter. Since they were copying a very low Cd subject (a jet aircraft), they couldn’t help but to get some of the aerodynamics right if they were to retain the “look” of a jet fighter. But there are a number of aerodynamic flaws. Most noticeably, the angle of the trailing edge of the canopies is far too sharp to retain attached airflow. The fins are mostly for show. The vertical fins would provide some yaw stabilization, but the 4 horizontal fins are totally useless (no need for roll control on a ground vehicle), unless they are using them to generate downforce. There is also a big ridge along each side of the hood that is drag inducing and is there purely for cosmetics. Also the stagnation point on the nose is too high for a ground vehicle. Its certainly neat and cool looking, but not low drag, except purely by accident.

However the 1980 GM Epcot 2003 is a different story, now that was a concept car designed for low drag. And, of course, the 1988 GM Sunraycer.
__________________
aerocivic.com
  Reply With Quote
Old 12-21-2008, 05:15 PM   #19 (permalink)
Master EcoModder
 
Join Date: Aug 2008
Location: South Dakota
Posts: 460

WonderWagon - '94 Ford Escort LX
Last 3: 51.52 mpg (US)

DaBluOne - '99 Ford Escort SE
90 day: 48.97 mpg (US)

DaRedOne - '99 Ford Escort ZX2 Hot
Thanks: 0
Thanked 15 Times in 4 Posts
Quote:
Originally Posted by basjoos View Post
However the 1980 GM Epcot 2003 is a different story, now that was a concept car designed for low drag. And, of course, the 1988 GM Sunraycer.
1980 GM Epcot 2003

1988 GM Sunraycer
__________________
  Reply With Quote
Old 12-22-2008, 04:18 PM   #20 (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
why

Quote:
Originally Posted by instarx View Post
If aerodynamics has been fully understood since 1800 why all the discussion of dimples, air tabs, ziggy tape, etc in ecomodder? For decades aircraft designers "knew" that there was nothing better than a teardrop shape for a fuselage, but then in the 1980's it was discovered that constricting the fuselage in the wing area was a much more efficient shape. Even the effect of dimples on golf balls wasn't discovered until 1850ish. Winglets on the end of wings to improve economy are a recent discovery. The danger of wingtip vorteces from landing aircraft wan't fully realized until the 70's or 80's. So it seems kind of silly to claim that aerodynamics has been fully understood since 1800.

Why all the resistance to a few new novel ideas being applied to aero in cars. Doesn't every little bit help? Maybe everyone got up on the wrong side of the bed this morning?
instarx,your questions are good ones.My short answer,at least for the United States (and this is an observation and not meant to be a mean-spirited comment),is that there is no public education with respect to the physics of automobiles.( That's why we are attempting to do it here ).------------------

With respect to my comment about 1800,I should have qualified the comment,and limited it to aerodynamics as applied to automobiles,which did not yet exist at the time.------------------------

Your remark about contraction of the fuselage is in the realm of aerospace engineering,and derives from Dr.Whitcombs research in supersonic flight."Whitcomb-waisting" or "Coke-Bottleing" is found to provide for "high sectional- density",with a constant cross-section along the longitudinal axis of the aircraft, where the wings interface with the fuselage, providing for more uniform pressure distributions along that axis.This is not something which really concerns us as aero-modders.------------------------------

The dimpling phenomena does not affect our investigations either,do to Reynolds Number effects,although does solve D'Alemberts Paradox,as at the time of his fluid dynamics research,the concept of viscosity and shear did not exist.That would have to wait for Prandtl.--------------------------

Wing-tip vortices also have no bearing on ground vehicle aerodynamics,and today,as no doubt tip-vortices are addressed for economy among aircraft,their primary function is to compress landing intervals between arriving planes.--------------------------------

So,in order to keep the pot stirring,I'm going to hold to my claim that the year 1800 probably signaled the date for a general understanding of fluids as applied to automobiles,and todays University' 7,000-mpg vehicles,are direct descendents of Sir George Cayley's trout.----------------------

Any corporate spokesperson who genuinely believes that aerodynamics is a "black art" has never looked at the sky or seen things swimming below the water.

__________________
Photobucket album: http://s1271.photobucket.com/albums/jj622/aerohead2/
  Reply With Quote
Reply  Post New Thread


Thread Tools


Similar Threads
Thread Thread Starter Forum Replies Last Post
Sources of Aerodynamic Drag in Automobiles and Possible Solutions SVOboy Aerodynamics 12 02-17-2010 02:09 PM
Another Autospeed aero article: methods for measuring aero drag Daox Aerodynamics 4 02-14-2008 12:34 AM



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