View Single Post
Old 08-26-2024, 11:53 AM   #146 (permalink)
aerohead
Master EcoModder
 
aerohead's Avatar
 
Join Date: Jan 2008
Location: Sanger,Texas,U.S.A.
Posts: 16,251
Thanks: 24,380
Thanked 7,358 Times in 4,758 Posts
' VGs 'hurting '

Quote:
Originally Posted by JohnForde View Post
UPDATE: The structure is done to 4' behind the rear bumper. Top and sides are all 11-12 degrees. Floor is foam and close to air tight.

I plan on adding tail lights and going 2 more feet in the next couple of days. Yesterday was too windy to test. I am heading out in an hour for a 60 mile test.

JSH suggested the VGs may be hurting. I removed one easily. I may remove them all.

I still need to improve the upper corners. Then add the 24" of twin wall polycarbonate to the tail. Should happen in the next 2 days.
1) Pressure drag reduction is what's in the cross-hairs.
2) It depends on base pressure.
3) The base pressure is dependent upon the static pressure which exists at the separation line.
-------------------------------------------------------------------------------------
4) VGs 'lower pressure'.
5) Without the whale tail, the VGs would essentially be 'right at' the separation line. And lowering pressure 'there' would be antithetical to drag reduction.
--------------------------------------------------------------------------------------
6) With the VGs in place, they might act as an 'insurance policy' as far as flow attachment 'down' the whale tail is concerned. Since they're already in place, you might consider leaving them, at least until you make at least one test run, giving you 'data' for future comparison.
--------------------------------------------------------------------------------------
7) If the 24-inch extension causes the 'floor' to end right where the side panel's lower 'angled' intersection is, that would be great, taking maximum advantage of available pressure recovery.
Travel safe. Have fun!
__________________
Photobucket album: http://s1271.photobucket.com/albums/jj622/aerohead2/
  Reply With Quote