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

Reply  Post New Thread
 
Submit Tools LinkBack Thread Tools
Old 04-28-2015, 03:11 PM   #1 (permalink)
EcoModding Lurker
 
Join Date: Mar 2015
Location: Texas
Posts: 29
Thanks: 15
Thanked 11 Times in 11 Posts
"Bottom Kammback" shape

What kind of shapes are ideal for the bottom end of a kammback (sloping up from the bottom of a/the bumper)?

What is the angle relative to the top (e.g. is it simply an inversion of the shape of the usual top-end Kammback, or can/should it be a more dramatic curve/angle)?

  Reply With Quote
Alt Today
Popular topics

Other popular topics in this forum...

   
Old 04-28-2015, 06:57 PM   #2 (permalink)
Master EcoModder
 
aerohead's Avatar
 
Join Date: Jan 2008
Location: Sanger,Texas,U.S.A.
Posts: 12,358
Thanks: 19,873
Thanked 6,200 Times in 3,825 Posts
bottom

If you have a complete and well executed belly on the car,the region aft of the rear axle can be made to form a diffuser of 2.5-degrees,to 4-degrees up-slope,depending on where the origin of the diffuser begins.
2.5-degrees is preferred for low drag.But you need to honor ramp and departure angles which can create a ground strike on driveway ramps,etc..
__________________
Photobucket album: http://s1271.photobucket.com/albums/jj622/aerohead2/
  Reply With Quote
The Following User Says Thank You to aerohead For This Useful Post:
whatmaycome14 (04-29-2015)
Old 04-29-2015, 02:08 PM   #3 (permalink)
Master EcoModder
 
Sven7's Avatar
 
Join Date: Aug 2011
Location: Warren, MI
Posts: 2,456

Boo Radley - '65 Ford F100
90 day: 13.28 mpg (US)
Thanks: 782
Thanked 665 Times in 408 Posts
Angles for several body types, compared to drag values.

__________________
He gave me a dollar. A blood-soaked dollar.
I cannot get the spot out but it's okay; It still works in the store
  Reply With Quote
The Following User Says Thank You to Sven7 For This Useful Post:
aerohead (04-29-2015)
Old 05-23-2015, 03:18 PM   #4 (permalink)
Experienced UAW Mechanic
 
Join Date: Sep 2014
Location: Bear Lake
Posts: 363
Thanks: 7
Thanked 73 Times in 63 Posts
This all started with one race car, for loading / unloading. The driver discovered the downforce, his competitors saw his advantage, and the very next race the entire field had done it. Better to copy than to whine. I guess it was worth the loss if a win to learn the lesson. Shame today's racers are all such losers.
  Reply With Quote
Old 05-23-2015, 06:45 PM   #5 (permalink)
Master EcoModder
 
freebeard's Avatar
 
Join Date: Aug 2012
Location: northwest of normal
Posts: 18,796
Thanks: 5,225
Thanked 6,199 Times in 4,967 Posts
Quote:
What is the angle relative to the top (e.g. is it simply an inversion of the shape of the usual top-end Kammback, or can/should it be a more dramatic curve/angle)?
Less dramatic, as aerohead says. The free air over the top of the car and the air in the tunnel between the belly and the road are different situations. But the side view angle is only part of the story, it's three-dimensional.



An overall rake is helpful.

  Reply With Quote
The Following User Says Thank You to freebeard For This Useful Post:
BamZipPow (05-23-2015)
Reply  Post New Thread


Thread Tools




Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2021, vBulletin Solutions Inc.
Content Relevant URLs by vBSEO 3.5.2
All content copyright EcoModder.com