Vapor trails?

[DB605]

Originally Posted by Strike

The aircraft contrails caused by the aircraft engines are a result of the combution of fuel. The main bi-products of fuel combustion are CO2 and Water. Contrails appear when water is released into the atmosphere at normally an altitude of ca 8,000m or above and at temperatures below -40C. When all the water molecules enter the atmosphere they quickly saturate the air with water, causing the water to condensate and form tiny droplets of water. When combined with temperatures below -40 the water becomes supercooled and will turn into ice particles instantly if "triggered" by a disturbance. This disturbance is provided by the exhaust particles from the engines and therefore the particles freeze instantly, causing these nice frozen clouds in the sky.

Mind you wingtip vortices are more common during some atmospheric conditions than others, mainly dependant on air humidity. I do, however, think they forgot to include the effect in the initial release. It would add for some realistic dogfighting visuals. But even during very rainy days, one can see the vortices on takeoff/landing from say, the tip of the deployed flap, because there is a huge difference in air pressure between the flap and the rest of the wing.

Vortices are generated at wingtips because of a higher pressure under the wing, than above the wing. At the very tip of the wing, the higher pressure manages to "escape" around the wingtip to the upper surface, thus inducing a spin. Seen from the rear; the left wingtip will have a clockwise spin, and the right wingtip a counter-clockwise spin. The speed of which the air travels in this vortex has a resulting pressure and temperature drop. If this temperature drops below the local dew-point, the water will condensate and turn into visible droplets cotained within the vortex. In some weather conditions, if you're flying at enough speed, you'll see the vortices all the time, whilst in "normal" conditions, you'll see it during high AoA manouvers. This is because during these high AoA manouvers the difference in pressure between lower and upper surface of the wing is so great that the speed induced in the vortex lowers the pressure and temperature sufficiently to provide condensation in the local atmosphere.

Just thought I'd share that ;p

Thank you for great explanation. My english is not good enough to write something like that, even i was aware most of the things I just recalled
contrails form after 7,000 meters, i stand corrected.

[Vengeanze]

Vortices would be nice!

[Blackdog_kt]

Originally Posted by Strike

The aircraft contrails caused by the aircraft engines are a result of the combution of fuel. The main bi-products of fuel combustion are CO2 and Water. Contrails appear when water is released into the atmosphere at normally an altitude of ca 8,000m or above and at temperatures below -40C. When all the water molecules enter the atmosphere they quickly saturate the air with water, causing the water to condensate and form tiny droplets of water. When combined with temperatures below -40 the water becomes supercooled and will turn into ice particles instantly if "triggered" by a disturbance. This disturbance is provided by the exhaust particles from the engines and therefore the particles freeze instantly, causing these nice frozen clouds in the sky.

Mind you wingtip vortices are more common during some atmospheric conditions than others, mainly dependant on air humidity. I do, however, think they forgot to include the effect in the initial release. It would add for some realistic dogfighting visuals. But even during very rainy days, one can see the vortices on takeoff/landing from say, the tip of the deployed flap, because there is a huge difference in air pressure between the flap and the rest of the wing.

Vortices are generated at wingtips because of a higher pressure under the wing, than above the wing. At the very tip of the wing, the higher pressure manages to "escape" around the wingtip to the upper surface, thus inducing a spin. Seen from the rear; the left wingtip will have a clockwise spin, and the right wingtip a counter-clockwise spin. The speed of which the air travels in this vortex has a resulting pressure and temperature drop. If this temperature drops below the local dew-point, the water will condensate and turn into visible droplets cotained within the vortex. In some weather conditions, if you're flying at enough speed, you'll see the vortices all the time, whilst in "normal" conditions, you'll see it during high AoA manouvers. This is because during these high AoA manouvers the difference in pressure between lower and upper surface of the wing is so great that the speed induced in the vortex lowers the pressure and temperature sufficiently to provide condensation in the local atmosphere.

Just thought I'd share that ;p

Excellent explanation and probably the reason why a lot don't see them yet: they are not hard-coded at 7km of altitude like in IL2:1946, but dependent on weather conditions.

[Strike]

Originally Posted by DB605

Thank you for great explanation. I just recalled
contrails form after 7,000 meters, i stand corrected.

Hey, you're welcome for the explanation, but you are in no means at all wrong by saying 7,000 meters. That is just circa what it was in IL-2 1946 because the atmosphere was always the same. You'd get contrails in IL-2 because of the height you were flying at, not because of the surrounding air. So you could very well get contrails at 7000 meters, if it's cold enough


For the interested, here's showing that not only wingtips create vortices

Flap during typical humid day:

http://www.youtube.com/watch?v=TXDPCINTFKA

And this is why you need carburettor heaters

http://www.youtube.com/watch?v=TFYzHfjTGtk

That stuff would ice up really fast if it wasn't heated

Typical propellers also create vortices

http://www.youtube.com/watch?v=_g1SInGmRv0

[unreasonable]

Nice posts, thank you.