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XyZspineZyX
08-05-2003, 05:14 PM
Having played Il2 for some time I really should know thishttp://ubbxforums.ubi.com/infopop/emoticons/icon_smile.gif

Question: When on the edge of a stall what are the white contrails coming of the wing tips? Disrupted air?

I understand vapor at high alt but I am stumped on this one.

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XyZspineZyX
08-05-2003, 05:14 PM
Having played Il2 for some time I really should know thishttp://ubbxforums.ubi.com/infopop/emoticons/icon_smile.gif

Question: When on the edge of a stall what are the white contrails coming of the wing tips? Disrupted air?

I understand vapor at high alt but I am stumped on this one.

"Do unto others before they do unto you"

XyZspineZyX
08-05-2003, 05:25 PM
Check out this link..it might help:


http://www.eng.vt.edu/fluids/msc/gallery/vortex/bhsu27.htm

XyZspineZyX
08-05-2003, 05:26 PM
Check this site out.

http://www.faatest.com/books/FLT/Chapter17/WingtipVortices.htm

Basically, it's just air whipping around the wingtip from the area of high pressure (below the wing) to an area of low pressure (above the wing). This leaves a whriling motion left behind as the aircraft travels forward. Ever wonder why some planes have those wingtips that bend upward at the end. Well, it's to stop this turbulence.

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Message Edited on 08/05/0312:36PM by EvilBen

XyZspineZyX
08-05-2003, 05:37 PM
Thanks guys.

I wasn't far off the mark.

Am I right in thinking the vortices in FBs are the disrupted air type and not the condensation type?

If it was condensation wouldn't it hang around in the air?

"Do unto others before they do unto you"

XyZspineZyX
08-05-2003, 05:41 PM
Lift generated condensation will dissappear almost immediately.

XyZspineZyX
08-05-2003, 05:57 PM
Thanks again!

I have been stumped on that for a while.

"Do unto others before they do unto you"

XyZspineZyX
08-05-2003, 10:43 PM
It does not stop it ben, simply reduces it as tip voticies increase drag which results in less efficency and a higher fuel burn, and as to the original post, its not a dumb question, a lot of posts in here are not dumb just the answers. /i/smilies/16x16_smiley-wink.gif

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XyZspineZyX
08-05-2003, 11:13 PM
Uberduper, the vortices are always there. In level flight however, they usually aren't strong enough to condense the water vapor out of the air. As the aircraft gets slower, or pulls more g, the pressure gradient between the top and bottom of the wing becomes sharper, the vortex becomes stronger, and the pressure in the center of the vortex becomes lower. That's why the tip vortices only become visible at high g, slow speed flight in the sim (and usually in real life, too.) The air isn't disrupted (as in a stall), it's just accelerated and redirected. In humid air, the low pressure on the upper surface of the wing can condense water vapor under the same high g, low speed conditions too. Zysbot's link has a good shot of an F-16 with this condensation. We referred to the phenomena as "pulling ectoplasm" or "turning into a golf ball" (technical terms, I know.)

Blotto

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