Contrails

Is there a certain speed an aircraft must be going for contrails to form? I
have never seen a 172 with contrails but as a kid I used to go to Road
America with my dad and watch the (then CART Indycars) and in the morning
you could see the contrails off the rear wings, so that tells me it has
something to do with speed/humidity nothing to do with altitude.

BTW, if you never seen an Indycar run at Road America in WI in person I
highly recommend it!

--------------------------------------
DW

Darkwing theducksmail"AT"yahoo.com wrote:
Is there a certain speed an aircraft must be going for contrails to form? I
have never seen a 172 with contrails but as a kid I used to go to Road
America with my dad and watch the (then CART Indycars) and in the morning
you could see the contrails off the rear wings, so that tells me it has
something to do with speed/humidity nothing to do with altitude.

BTW, if you never seen an Indycar run at Road America in WI in person I
highly recommend it!

--------------------------------------
DW

Highly simplified explanation:

Technically, contrails are formed at altitude from exhaust water
vapor and what you see at low altitudes are vortices usually from
wing tips.

As things like wings move through the air they cause a pressure
drop around them which in turn decreases the air temperature.

If the temperature drop is enough to get below the dew point, the
water vapor condenses any you get visible "fog" for lack of a better
term.

For a more detailed explanation:

http://en.wikipedia.org/wiki/Contrail

--
Jim Pennino

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In article ,
wrote:

Highly simplified explanation:

Technically, contrails are formed at altitude from exhaust water
vapor and what you see at low altitudes are vortices usually from
wing tips.

As things like wings move through the air they cause a pressure
drop around them which in turn decreases the air temperature.

If the temperature drop is enough to get below the dew point, the
water vapor condenses any you get visible "fog" for lack of a better
term.

You can also watch them form off the prop tip under humid conditions.
Several posters have put up some photos of C130's, Corsairs, etc over on
the binaries group. I have been in a C170 in central Florida and watched
it happen.

"john smith" wrote in message


You can also watch them form off the prop tip under humid conditions.
Several posters have put up some photos of C130's, Corsairs, etc over
on the binaries group. I have been in a C170 in central Florida and
watched it happen.

I've seen it a few times in my C182, as well.

--
John T
http://sage1solutions.com/blogs/TknoFlyer
Reduce spam. Use Sender Policy Framework: http://openspf.org
____________________

"Darkwing" theducksmail"AT"yahoo.com writes:

Is there a certain speed an aircraft must be going for contrails to form?

No. They depend mostly on atmospheric conditions.

I have never seen a 172 with contrails but as a kid I used to go to Road
America with my dad and watch the (then CART Indycars) and in the morning
you could see the contrails off the rear wings, so that tells me it has
something to do with speed/humidity nothing to do with altitude.

It has to do with all of these. Any combination of conditions that encourages
water to condense out of the air (including water in engine exhaust).

--
Transpose mxsmanic and gmail to reach me by e-mail.

Mxsmanic wrote in
:

"Darkwing" theducksmail"AT"yahoo.com writes:

Is there a certain speed an aircraft must be going for contrails to
form?

No. They depend mostly on atmospheric conditions.

I have never seen a 172 with contrails but as a kid I used to go to
Road America with my dad and watch the (then CART Indycars) and in
the morning you could see the contrails off the rear wings, so that
tells me it has something to do with speed/humidity nothing to do
with altitude.

It has to do with all of these. Any combination of conditions that
encourages water to condense out of the air (including water in engine
exhaust).


new site for ya!


http://****ingdickhead.com/

On Mar 20, 9:54 am, "Darkwing" theducksmail"AT"yahoo.com wrote:
Is there a certain speed an aircraft must be going for contrails to form? I
have never seen a 172 with contrails but as a kid I used to go to Road
America with my dad and watch the (then CART Indycars) and in the morning
you could see the contrails off the rear wings, so that tells me it has
something to do with speed/humidity nothing to do with altitude.

BTW, if you never seen an Indycar run at Road America in WI in person I
highly recommend it!

--------------------------------------
DW

Its a secret chemical called Dihydrogen Monoxide or DHMO that the
military is releasing.

-Robert

"Robert M. Gary" wrote in message
ups.com...
On Mar 20, 9:54 am, "Darkwing" theducksmail"AT"yahoo.com wrote:
Is there a certain speed an aircraft must be going for contrails to form?
I
have never seen a 172 with contrails but as a kid I used to go to Road
America with my dad and watch the (then CART Indycars) and in the morning
you could see the contrails off the rear wings, so that tells me it has
something to do with speed/humidity nothing to do with altitude.

BTW, if you never seen an Indycar run at Road America in WI in person I
highly recommend it!

--------------------------------------
DW

Its a secret chemical called Dihydrogen Monoxide or DHMO that the
military is releasing.

-Robert


I just drank a big glass full of that stuff today, now I feel bloated and my
bladder is in pain, not sure what to do, better call poison control!

----------------------------------------------
DW

In article ,
"Darkwing" theducksmail"AT"yahoo.com wrote:

Its a secret chemical called Dihydrogen Monoxide or DHMO that the
military is releasing.

I just drank a big glass full of that stuff today, now I feel bloated and my
bladder is in pain, not sure what to do, better call poison control!

Better check into a hospital quick!
I heard a news report a couple months ago about a woman competing in a
radio station contest died after drinking too much of that stuff.

john smith writes:

Better check into a hospital quick!
I heard a news report a couple months ago about a woman competing in a
radio station contest died after drinking too much of that stuff.

It takes a couple of litres minimum over a short period to produce the
hyponatremia from which she died.

--
Transpose mxsmanic and gmail to reach me by e-mail.