Why do jets leave a white trail behind them.

"george" wrote in
oups.com:

Snipola
I kept asking the 'chemtrail' kooks where I had to look on the aircraft
I fly to find the 'chem tank and the spray nozzles'
ROTFL

Some of them say it's a chemical put in the fuel, hence why some
plane's leave such long and permanent trails.

Well, they must have been doing this since at least WWII, if not
sooner, as I regularly see footage of WWII bombers making trails
over Europe on various cable/sat documentary channels.

Brian
--
http://www.skywise711.com - Lasers, Seismology, Astronomy, Skepticism
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Sed quis custodiet ipsos Custodes?

"AliR" wrote in message
. ..
Oh it's called Contrails, I didn't know that. I found lot's of info on it
on the web. Thanks.

Which is short for "condensation trails."

The water produced from burning lots of gallons of Jet A fuel, producing
water, in vapor form, (lots of it) then exhausting it into very cold air
(20, 30, 40 degrees F, below zero) causes nearly all of that moisture
condense into visible water vapor, pretty quickly.

If you notice, sometimes, you see a space behind the jet where there is no
visible vapor, then it finally cools enough to become visible.

This same thing even happens behind piston engines. They are still burning
fuel, producing water, and having it cool greatly. It is most often seen
behind the high level, heavy bombers of WWII.

I remember the Jimmy Stewart flick, where he was called back into service
after WWII, in the Strategic Air Command. I think that was the name of the
movie, also. Anyway, if you don't get anything else out of the movie, the
flying scenes are "to die for." There are many minutes of seeing the B-36's
flying at very high altitude, with the contrails appearing a few hundred
yards behind the planes.

Kinda neat.

Of course, these planes had jet engines, and gasoline engines, and a lot of
them. Aluminum airplanes, and iron men! Make a point of seeing that movie.
It is worth it.

Extra points, for trivia. What kind/s of fuel did the B-36 carry?
--
Jim in NC

Thomas Borchert wrote:

AliR,


Is either one of us right?



Your friend, partly. There are atmospheric conditions when the pressure
change over the wing or at a wing tip is enough to make the water in
the air visible. But they are rare and don't make long contrails. The
long contrails from jets you see are because the exhaust contains small
particles (soot and other stuff) which cause the water vapor in the air
to condense on them where it wouldn't condense without them.


And the combustion of hydrocarbons produces a lot of water...

Matt

"Morgans" wrote
Extra points, for trivia. What kind/s of fuel did the B-36
carry?

Probably 115/145 AVGAS Purple Stuff

Bob Moore

"Morgans" wrote in message
...

"AliR" wrote in message
. ..
Oh it's called Contrails, I didn't know that. I found lot's of info on
it
on the web. Thanks.

Which is short for "condensation trails."

The water produced from burning lots of gallons of Jet A fuel, producing
water, in vapor form, (lots of it) then exhausting it into very cold air
(20, 30, 40 degrees F, below zero) causes nearly all of that moisture
condense into visible water vapor, pretty quickly.

If you notice, sometimes, you see a space behind the jet where there is no
visible vapor, then it finally cools enough to become visible.

This same thing even happens behind piston engines. They are still
burning fuel, producing water, and having it cool greatly. It is most
often seen behind the high level, heavy bombers of WWII.

I remember the Jimmy Stewart flick, where he was called back into service
after WWII, in the Strategic Air Command. I think that was the name of
the movie, also. Anyway, if you don't get anything else out of the movie,
the flying scenes are "to die for." There are many minutes of seeing the
B-36's flying at very high altitude, with the contrails appearing a few
hundred yards behind the planes.

Kinda neat.

Of course, these planes had jet engines, and gasoline engines, and a lot
of them. Aluminum airplanes, and iron men! Make a point of seeing that
movie. It is worth it.

Extra points, for trivia. What kind/s of fuel did the B-36 carry?
--
Jim in NC



Since it had "six turnin' and four burnin'" did it have to carry AvGas and
JP?

It also carried a nuclear reactor aloft at one point:

http://www.cowtown.net/proweb/nb36h_jde.htm

Jay B

Jet fuel also contains a lot (relatively) of water, which
condenses soon after leaving the exhaust. That is why they
are called CONTRAILS condensation trails. They were first
seen behind the bombers during WWII and so-named.


"Thomas Borchert" wrote in
message ...
| AliR,
|
| Is either one of us right?
|
|
| Your friend, partly. There are atmospheric conditions when
the pressure
| change over the wing or at a wing tip is enough to make
the water in
| the air visible. But they are rare and don't make long
contrails. The
| long contrails from jets you see are because the exhaust
contains small
| particles (soot and other stuff) which cause the water
vapor in the air
| to condense on them where it wouldn't condense without
them.
|
| --
| Thomas Borchert (EDDH)
|

Purple 115/145 avgas, burns just fine in the jet and was
required by the big P&W radials.


"Jay Beckman" wrote in message
news:EcUzf.9831$jR.3049@fed1read01...
| "Morgans" wrote in message
| ...
|
| "AliR" wrote in message
| . ..
| Oh it's called Contrails, I didn't know that. I found
lot's of info on
| it
| on the web. Thanks.
|
| Which is short for "condensation trails."
|
| The water produced from burning lots of gallons of Jet A
fuel, producing
| water, in vapor form, (lots of it) then exhausting it
into very cold air
| (20, 30, 40 degrees F, below zero) causes nearly all of
that moisture
| condense into visible water vapor, pretty quickly.
|
| If you notice, sometimes, you see a space behind the jet
where there is no
| visible vapor, then it finally cools enough to become
visible.
|
| This same thing even happens behind piston engines.
They are still
| burning fuel, producing water, and having it cool
greatly. It is most
| often seen behind the high level, heavy bombers of WWII.
|
| I remember the Jimmy Stewart flick, where he was called
back into service
| after WWII, in the Strategic Air Command. I think that
was the name of
| the movie, also. Anyway, if you don't get anything else
out of the movie,
| the flying scenes are "to die for." There are many
minutes of seeing the
| B-36's flying at very high altitude, with the contrails
appearing a few
| hundred yards behind the planes.
|
| Kinda neat.
|
| Of course, these planes had jet engines, and gasoline
engines, and a lot
| of them. Aluminum airplanes, and iron men! Make a
point of seeing that
| movie. It is worth it.
|
| Extra points, for trivia. What kind/s of fuel did the
B-36 carry?
| --
| Jim in NC
|
|
|
| Since it had "six turnin' and four burnin'" did it have to
carry AvGas and
| JP?
|
| It also carried a nuclear reactor aloft at one point:
|
| http://www.cowtown.net/proweb/nb36h_jde.htm
|
| Jay B
|
|

"Jim Macklin" wrote in message
news:LMUzf.66027$QW2.60514@dukeread08...
Purple 115/145 avgas, burns just fine in the jet and was
required by the big P&W radials.

Yep. As I recall, the jet engines did also not run continuously, but were
turned off, after takeoff and climb. Correct?
--
Jim in NC

Jim Macklin wrote:

Jet fuel also contains a lot (relatively) of water, which
condenses soon after leaving the exhaust. That is why they
are called CONTRAILS condensation trails. They were first
seen behind the bombers during WWII and so-named.

If jet fuel is full of water, how do you get it to burn? When I took
chemistry, hydrocarbon fuels contained .... drum roll please ... carbon
and hydrogen. No water of any level of significance.

Matt

In article , Paul Tomblin wrote:
In a previous article, "AliR" said:
Oh it's called Contrails, I didn't know that. I found lot's of info on it
on the web. Thanks.

Just beware of the paranoid lunatics who talk about "chemtrails".

Well, you know... it is, after all, a *very* dangerous chemical:

Dihydrogen Monoxide (DHMO) -- someone has posted a MSDS (material safety
data sheet) on it:

http://www.dhmo.org/msdsdhmo.html

So...



Best part was the time where city hall in a town in the U.S. actually
passed a law banning DHMO. It stood in force for a day before the very
red-faced city council repealed that ban.

I do, however, have great respect for DHMO in its various forms since it
can cause real problems for GA pilots. :-)

-Dan

(Alternative theory: contrails were invented to give the chemtrail kooks
something to do in their copious spare time. /tongue-in-cheek)

Note to AliR: I'm just kidding in this post. Not poking fun at your
serious inquiry, which has gotten a number of great responses. I'm just
poking fun in passing at the chemtrail kooks.