What are those white clouds that follow planes called?

Question

I am talking the potnetially dangerous ones! They have a name. not crop dusters, but those clouds of smoke that follow like jets and stuff!

Answer 1

Contrails or vapor trails are condensation trails and artificial cirrus clouds made by the exhaust of aircraft engines or wingtip vortices.

Answer 2

They aren't dangerous, it's condensing water vapor from the exhaust; contrails.

Well, they are dangerous if one is trying not to be seen from 20_ miles away...

Answer 3

CONTRAILS - they can be caused by the exhaust or by air condensing as it compresses while passing over the aircraft.

Answer 4

they are called vapor trails..

Answer 5

its called a plane passing gas.

Answer 6

Contrails

Answer 7

First, they're called contrails.  Second, they're not by any means dangerous.  Contrails are formed when the superheated exhaust from the turbine engines meets the supercooled air of the upper atmosphere.  When the several-hundred degree exhaust hits the negative temperatures of the air, it immediately condenses into this "cloud" that can be seen in the jet's path.  Just like other clouds, contrails are made of water vapor.

To address what may be causing you to believe they are dangerous: Larger aircraft (jets, namely) produce what are called wingtip vortices.  These vortices are produced by the air pressure differential above and below the wing.  Above the wing is a low pressure system, whereas a high pressure system exists below the wing.  Each vortex is formed as the wing moves forward, leaving remnants of this pressure differential behind.  The air in the high pressure system wants to flow into the area of low pressure.  This happens immediately after the wing leaves a given space, thus the air must flow up and around the wingtip.  When this effect is repeated, you get a helical-shaped airflow behind each wingtip.  With large, heavy aircraft, these vortices can be very strong and can adversely affect smaller aircraft flying in the vicinity of them.  The danger with these vortices is really only present at lower altitudes, on approach paths to airports, for example.  There have been numerous occasions where smaller aircraft can actually be flipped or rolled in midair if caught in a strong vortex of a passing aircraft.

Answer 8

Hey guys--contrails are not vapor.  The water you see has condensed; it isn't vapor.  It is liquid or solid water droplets.