Quote:
Originally posted by Machine
I also really liked how the hovering craft that appears to use means other than propellors or jets, suddenly leaves a trail that is only left by an internal combustion engine. lol
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That's a good point, but I'm not sure it's accurate.
Now I'm not 100% sure of this, but I believe that while normal vapour trails are left by the mixing of warm air from the exhuast of combustion engines with the cold air outside, vapour trails can also be left by any object that moves at great speed. It's caused by the condensation of water in the air due to the friction between the air and the solid object that high velocity causes.
If you have a look at photos of jets as they break the sound barrier (and other times actually), they condense a large plume of vapour in front and over the wings.
In this case, it's due to the sound waves overlapping and causing an area of high pressure.. if the air is humid enough, this will be enough to condense it an leave a vapour trail.
Jason.