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

Reply  Post New Thread
 
Submit Tools LinkBack Thread Tools
Old 05-22-2014, 02:04 PM   #21 (permalink)
EcoModding Lurker
 
Join Date: Apr 2014
Location: Central OK
Posts: 24

Slow Silver - '09 Chevy Cobalt XFE Coupe
90 day: 37.56 mpg (US)

GMC pickup - '86 GMC C1500

Hephaestus - '09 Kawasaki Vulcan 900 Custom
90 day: 47.13 mpg (US)
Thanks: 1
Thanked 2 Times in 2 Posts
Quote:
Originally Posted by aerohead View Post
* Also,it would lower the stagnation point which is very good for low drag and lift.Ideally,the nose would be vertical,or slightly canted backwards with the air dam integrated right into it.Just like NASCAR.You'd need to watch your approach angle clearance (16-degrees) so it doesn't scrub or worse.
*The rear backlight area is where the money is.The current 2nd-gen Insight has a fine contour to mimic.If you get the roofline up to 'Kamm' specs,then she's a candidate for tail,which should get you into 50-mpg territory.Easy.
For the nose bit, how do you mean vertical or canted backwards? I am picturing the opening at the lowest point being perpendicular or slightly negative angle respective of the horizontal. I mean with the upper and lower protrusions either equal or with the lower lip being a shorter length than the upper. I think I get that the stagnation point would be both lower to the road surface as well as have a smaller surface area, with most of the stagnation pressure being directed through the cooling system. especially with a proper air dam and/or splitter.
As for the rear glass (*backlight?) I found my old protractor and tried to remember how to use it. From a square side-view image of my model car it looks like the peak of roofline to the tail edge of the trunk is about 10*. What I am picturing is a curved sheet of clear what-have-you over the existing rear glass and extending to the tail edge of the low rise wind. Like the Insight.
*Would an extended fast back @10* and approximately 10" longer than my stock configuration give me enough benefit alone to justify it? Or would that only be worth it as prep for extending the overall tail Kamm?

I think the basic shape is a really good starting point as the front has fairly smooth transitions and the rear is raked noticeably.
Still think the most economical option is the undercarriage streamline. I just gotta use RACEcar principles without it looking like RICEcar handiwork!

  Reply With Quote
Alt Today
Popular topics

Other popular topics in this forum...

   
Old 05-22-2014, 03:15 PM   #22 (permalink)
Master EcoModder
 
freebeard's Avatar
 
Join Date: Aug 2012
Location: northwest of normal
Posts: 27,619
Thanks: 7,758
Thanked 8,572 Times in 7,058 Posts
Quote:
For the nose bit, how do you mean vertical or canted backwards?
Take a look here:
Chevrolet Cobalt Body Kits at Andy's Auto Sport

They have 10 different options from conservative to full race. The former have an 'underbite' and the latter have an 'overbite'.



Notice the approach angle part. Ground clearance only applies to level ground. It always seems to be the gas stations with the high curbs to get over.

Last edited by freebeard; 05-22-2014 at 03:21 PM..
  Reply With Quote
The Following User Says Thank You to freebeard For This Useful Post:
aerohead (05-23-2014)
Old 05-22-2014, 05:24 PM   #23 (permalink)
EcoModding Lurker
 
Join Date: Apr 2014
Location: Central OK
Posts: 24

Slow Silver - '09 Chevy Cobalt XFE Coupe
90 day: 37.56 mpg (US)

GMC pickup - '86 GMC C1500

Hephaestus - '09 Kawasaki Vulcan 900 Custom
90 day: 47.13 mpg (US)
Thanks: 1
Thanked 2 Times in 2 Posts
That is actually the EXACT body kit I've been wanting. I know those are not the stock 15" wheels, and I'm pretty sure the car has been lowered. It looks good to me, problem is its 900$ plus shipping and install. gotta save for that.
  Reply With Quote
Old 05-23-2014, 01:19 AM   #24 (permalink)
Master EcoModder
 
freebeard's Avatar
 
Join Date: Aug 2012
Location: northwest of normal
Posts: 27,619
Thanks: 7,758
Thanked 8,572 Times in 7,058 Posts
We have good taste.

If the full kit is $900, the front air dam should be some fraction of that. Still spendy, though.
  Reply With Quote
Old 05-23-2014, 06:14 PM   #25 (permalink)
Master EcoModder
 
aerohead's Avatar
 
Join Date: Jan 2008
Location: Sanger,Texas,U.S.A.
Posts: 15,879
Thanks: 23,955
Thanked 7,219 Times in 4,646 Posts
nose

Quote:
Originally Posted by OKXXFE View Post
For the nose bit, how do you mean vertical or canted backwards? I am picturing the opening at the lowest point being perpendicular or slightly negative angle respective of the horizontal. I mean with the upper and lower protrusions either equal or with the lower lip being a shorter length than the upper. I think I get that the stagnation point would be both lower to the road surface as well as have a smaller surface area, with most of the stagnation pressure being directed through the cooling system. especially with a proper air dam and/or splitter.
As for the rear glass (*backlight?) I found my old protractor and tried to remember how to use it. From a square side-view image of my model car it looks like the peak of roofline to the tail edge of the trunk is about 10*. What I am picturing is a curved sheet of clear what-have-you over the existing rear glass and extending to the tail edge of the low rise wind. Like the Insight.
*Would an extended fast back @10* and approximately 10" longer than my stock configuration give me enough benefit alone to justify it? Or would that only be worth it as prep for extending the overall tail Kamm?

I think the basic shape is a really good starting point as the front has fairly smooth transitions and the rear is raked noticeably.
Still think the most economical option is the undercarriage streamline. I just gotta use RACEcar principles without it looking like RICEcar handiwork!
When your standing in front of the car,the 'face' should either be perpendicular to the ground,or leaning slightly away from you at the top.Either setup will have the same Cd according to FIAT research.
The actual hole for the cooling inlet IS your stagnation point,everything else will have curvature,steering the air around or over the nose.
If you run into interference (literally!),raise the nose to clear,then add a flexible wrap-around air dam to close off that flow from under the car.
--------------------------------------------------------------------------
As to the rear glass (backlight) it's not certain how hard GM fought for low drag there.I like to think that it's optimized.Don't know.
We know that the K-form roof is superior as far as drag is concerned.I suspect that if you do the Kamm addition,that it will reward you at the pump.
As far as the 'angle' goes,you want to think in terms of curvature with 'local' tangent angles as with the Aerodynamic Streamlining Template tool at the top of the Aero Forum.

__________________
Photobucket album: http://s1271.photobucket.com/albums/jj622/aerohead2/
  Reply With Quote
The Following User Says Thank You to aerohead For This Useful Post:
OKXXFE (05-23-2014)
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