You can also see this happen with prop driven aircraft as well,
both around the propellers and over the wing and is quite dependent
on the amount of moisture in the air. You can see it in a corkscrew
shape as it forms behind the tips of the propellors.
When you compress a parcel of air it will heat up and when it expands
it cools and if it cools sufficiently then the water vapour can condense
out to form mist/fog/cloud
cheers, Graham
At 06:00 AM 6/4/00 -0700, you wrote:
>> both produce a vapor cloud, and the sports illustrated
>> blurb suggested that this occurs just as the plane
>> goes super-sonic. i doubt that the fly-by in the mpeg
>> was even near super-sonic that close to the ground and
>> crew.
>>
>
>I haven't seen the picture, but if the vapor cloud has a straight leading
>edge
>that trails off at 45 deg. angles, IT IS THE SOUND BARRIER!!!!
>
>
>lately i've begun noticing vapor clouds
>> forming behind the wings in certain spots in the air.
>> yesterday, i saw this for sure, as a plane flew directly
>> overhead and relatively low. i could see a vapor trail,
>> maybe 10% of the wing chord behind the wing. obviously,
>> i can't see if it forms above the wing.
>>
>> what is this, and what is its cause?
>
>The low pressure area precipitates the available moisture into a cloud.
>You can also see this on the top surface of most fighter jet wings when they
>perform high G maneuvers and from the wing tips of many jets.
>The effects are dependent on the available moisture in the air.
>We don't see it much in AZ.
>
> Mark Mech
>[EMAIL PROTECTED]
> www.aerofoam.com
>
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