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Author Topic: Airplane Vapour Trails  (Read 2121 times)

Offline neilep

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Airplane Vapour Trails
« on: 31/08/2007 19:13:37 »
I've never seen so many vapour trails in my little corner of sky before (this is all within 15 minutes or so)



















See this last one ?...you can barely see it but why is there a break in this vapour trail ?

How do airomobiles make vapour trails ?...do they become bona fide clouds ?
Do you think it was the weather condition that made them ?

« Last Edit: 31/08/2007 20:24:39 by neilep »


 

Offline daveshorts

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Airplane Vapour Trails
« Reply #1 on: 31/08/2007 23:11:27 »
The vapour trails which you can see from the ground are mostly because plane engines burn hydrocarbons for fuel, when the hydrogen in these burns it makes water vapour, as this cools down it will eventually condense into water droplets again, unless the air is so warm and dry that the added moisture can be absorbed directly by the air. the reason they take a while to form behind the plane is that it takes the gasses a while to cool down enough for ht water to condene.

The one with a gap in it is probably because in the gap there is some warmer drier air, so either the trail never formed or possibly more likely it has evaporated more quickly than in other areas.

The  other possibility is that the trail is in the dhadow of a real cloud. It only shows up well because it is reflecting lots of sunlight, if it is in shadow it would be very hard to see.
 

Offline ukmicky

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Airplane Vapour Trails
« Reply #2 on: 01/09/2007 15:10:09 »

I thought vapour trails were created by the engine however whilst i was flying to the Caribbean i noticed one being created from the 757 i was flying in and it looked like it was being created by the metal work surrounding the front of the engine due to it cutting through the air, it was cool as it was flowing in a tight stream over the wing like a scene from a wind tunnel.
 

paul.fr

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Airplane Vapour Trails
« Reply #3 on: 01/09/2007 15:23:58 »
Another way to look at this is the exhaust pipe from your car during the winter, you see a visible plume of water vapor as the exhaust from the car cools.  You will also see this happening in the exhaust from a power plant chimney. The principle is the same as what you see with the airplane contrails (vapor trails)

Just to add to what Dave sad: The temperature of the air is more important than the altitude or the speed of the plane. The fuel contains water, which is vaporized by the heat of the engine.  This is expelled into the air behind the plane and mixes with the colder air.  As the jet contrail cools to the dew point the water vapor turns into water droplets forming the contrail.
 

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Airplane Vapour Trails
« Reply #3 on: 01/09/2007 15:23:58 »

 

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