Why do some jets leave contrails and others don't?

Question

I'm sure moisture & speed must be involved - maybe when they kick in their afterburners, but anyone have any details?

Answer 1

contrails are the moisture residual in the exhaust that freezes and suspends in the atmosphere. The staying power of a contrail is dependent on the amount of moisture in the air, the temperature at altitude, and the amount of wind present to disperse the ice particles. Typically, the larger contrails are created by the larger airplanes. A 747, with four large engines, is going to make more of a contrail than a 737 with two smaller ones, but with the right conditions, either will leave one. Or not, if the air is drier.
Speed is not a factor, nor is use of afterburners, as no commercial aircraft have them, nor do military transports or tankers. Given the right conditions, turboprops and the older radial engines will leave a contrail. Piston engines can leave a contrail, but you won't see it unless you're close, as it would be fairly small, and the turbulence caused by the airflow around the fuselage will disrupt it.

Answer 2

in case you're responsive to contrail formation and length, you will see that they might right this moment burn up or unfold horizontally into an huge skinny cirrus layer. How long a contrail remains intact, relies upon on the humidity shape and winds of the better troposphere. If the ambience is close to saturation, the contrail might exist for sometime. on the different hand, if the ambience is dry then because of the fact the contrail mixes with the atmosphere it dissipates. So could be those jets are flying at distinctive heights...and subsequently the formation & non-formation of contrails in each and each case... I advise you pass to the positioning under, for greater info....

Answer 3

Contrails are the cloud like streamers which are generated behind aircraft flying in cold, clear, humid air. There are 2 types: Exhaust contrails and aerodynamic contrails.
Exhaust contrails form when the exhaust adds enough moisture to the atmosphere to saturate it. It then freezes and leaves the distinct trails that can last a long time. Aerodynamic contrails are formed by reduction of air pressure passing by airfoils, engine nacelles, and propellers and cooling the air. They are not as dense as exhaust contrails, but under certain atmospheric conditions, an aerodynamic contrail may trigger the formation and spreading of a deck of cirrus clouds.

Answer 4

the reason that some jets have contrails and others dont is due to altitude above a certain height all jets leave contrals due to the fact that the cold air and moisture mixes with the hot jet stream coming from the engines surprisingly it has nothing to do with jets afterburners and as quoted by the first answerer it does not matter at all whether it is a military jet or not i hoped that your answer was answered or not

Answer 5

It's more due to atmospheric conditions at the moment than anything else. Any jet can leave a contrail if the conditions are right.

When the relative humidity is high the water vapor in the exhaust cannot evaporate and condenses into a cloud. You're seeing that cloud, that's all.

Answer 6

It's all on the heat signature of the engine. Some engines run hotter than others. The hotter the engine runs the more air it condenses in the sky. Hope this helps.

Answer 7

contrails forming are dependant on the humidity/temperature of the air the jet is flying in, not in design differences in different aircraft

Answer 8

Depends on how much moisture is in the air

Answer 9

depends on air temperature and humidity of the air, plus the magic of the flight.

WW ll b-17's didn't have afterburners

Answer 10

You haven't heard? It's the high flying planes dropping chemicals over our populated cities. Or that's the latest nonsense conspiracy theory coming through the web these days.

Thank Art Bell for it.