Contrails (not chemtrails)

[Everskyward]

I like watching contrails and I though this was an interesting one so I took a picture of it. What do you think is causing this? It's not the normal rotation you see from wingtip vortices. The only explanation I was able to find was on this site, contrail instability waves, and I still don't really understand what's causing it. So can anyone help me out?

 

[Pilawt]

From different angles:

http://www1.airliners.net/open.file/0392881/L/
http://myaviation.net/?pid=209072

In the second photo you can see that the vortices are still intact as the contrail is being tossed about.

I would just think it's the product of turbulent air at altitude. Whatever, it's interesting to look at.

-- Pilawt

 

[cwyckham]

From different angles:

http://www1.airliners.net/open.file/0392881/L/
http://myaviation.net/?pid=209072

In the second photo you can see that the vortices are still intact as the contrail is being tossed about.

I would just think it's the product of turbulent air at altitude. Whatever, it's interesting to look at.

-- Pilawt

Those two photos and the later part of the first photo look like the contrail being caught up in the wingtip vortices. Note the mirror symmetry of the two contrails due to the counter-rotating vortices. The contrail comes from the water in the engine exhaust, so it's actually to one side of the wingtip votex. When it gets pulled down and around the vortex it'll look a bit like the smoke from Diana doing a barrel roll.

Note that the idea that there's a single wingtip vortex is a bit simplistic. There's actually a shear layer coming off the wing that interacts in a realtively complex way (you can thing of it as lots of little vortices of varying strength side by side as you move along the wing in a spanwise direction). A bit downwind of the aircraft, they will all coalesce into two wing tip vortices. This may be why the contrail in the first photo looks messy at first and then later in the picture things get nice and symmetrical as one would expect from the simple model of two perfect vortices coming from the wingtips.

Chris

 

[jesse]

Contrails are the government trying to spray the entire country to protect us from holes in the ozone layer.

 

[JasonCT]

I thought it was the govts way to immunize all its citizens?!

 

[Cap'n Jack]

It's them newfangled steamjet engines the guvmint is testing for its new secret spyplane to replace the SR-71