posted on Apr, 7 2011 @ 11:09 PM
Originally posted by JBTECH71
reply to post by Aloysius the Gaul
So now contrails are not the result of hot exhaust gasses from the engines, but of aerodynamic lift from the wings???
they can result from both.
"Aerodynamic contrails are independent of exhaust contrail formation. Whereas exhaust contrails need cold conditions to form, aerodynamic
contrails probably form under warmer conditions (i.e. lower altitudes) and may be complimentary forms of contrails.
dunno where you got that from, but it is only a partial explaination.
Usually one observes them under humid conditions near the ground where they are short–lived phenomena. Aerodynamic contrails appear also in
cruise levels where they may persist when the ambient atmosphere is ice–supersaturated. In the present paper we present a theoretical investigation
of aerodynamic contrails
in the upper troposphere.
- from the American Meterorological Society journal online
You probably did some high-school physics, so hopefully this will make sense - in a nutshell the air flowing over the top of the wing is at lower
pressure than that underneath. As the air on top drops in pressure its temperature drops - this is the gas law that used to be taught in Form 6/year
12. It is also one of the fundamentals that lets air conditioning and refrigeration work.
As the temperature drops, the air cannot hold as much moisture as it did at its previous higher temperature.. If there is too much moisture at it's
"new" temperature, the excess will condense out.
THAT is what causes aerodynamic contrails.
Looking at the altitude of the video, would you guess the temperature to be warm? No, VERY cold at that altitude.
Looking at your comments you probably didn't really understand much about aerodynamic contrails, but now you do, so you don't have to worry about
this particular non-existant evil any more - happy to have helped