Contrails

Hi all, i have noticed that quite a lot of you get contrails from the wings in your shots, and i was wondering how you do it? Because i never seem to see them in my sim 

Flight Simulator and other chat
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https://forums.simviation.com/phpBB3/viewtopic.php?f=43&t=153827
What would the .cfg entry look like....
something like this perhaps...
[SMOKESYSTEM]
smoke.0=0.00, -0.70, 1.40, fx_smoke_w
Ive had a try at this, and does anybody know how to get the smoke thinner
eno....
i don't have any ifdg aircraft, could you give me a glimpse at the .cfg