rendezvous
Posts: 531
Joined: Sun May 20, 2001 9:14 pm

Contrails

Mon Dec 24, 2001 12:31 pm

I just wondered what conditions are needed for contrails to appear behind the jet engines?
 
dragogoalie
Posts: 1172
Joined: Sun Oct 14, 2001 3:58 pm

RE: Contrails

Mon Dec 24, 2001 7:32 pm

"Many people are familiar with the long streaks of white clouds produced by jets flying at high altitudes. The clouds which are made up of condensed vapor called condensation trails, or contrails, are generally produced by jets flying between 25,000 and 40,000 feet in moist air. If the relative humidity is low, contrails may evaporate rather quickly, however, in high relative humidity conditions, contrails may remain visible for several hours. This indication of moisture content may point to other clouds and, possibly, precipitation moving into the area within the next day or two" (Jeppesen Private Pilot Manual p 6-26)

here you go, hope that helps. They also have a diagram showing that most of the contrail (if not all of it) is actualy made up of ice crystals, not water vapor.

--dragogoalie-#88--
Formerly known as Jap. Srsly. AUSTRALIA: 2 days!
 
POSITIVE RATE
Posts: 2121
Joined: Sun Sep 16, 2001 11:31 am

RE: Contrails

Mon Dec 24, 2001 8:30 pm

On some really moist days the contrails are really long and defined and they can remain for up to 30 mins if the conditions are right. Sometimes a contrail will even dissipate and form a Cirrus cloud- quite amazing really!
 
donder10
Posts: 6945
Joined: Sun Oct 21, 2001 5:29 am

RE: Contrails

Mon Dec 24, 2001 9:39 pm

Contrails are rather interesting. I like spotting planes at high altitude so I see alot of them. If you use the search feature you will find several posts about this subject.
Thanks,Alex
 
rendezvous
Posts: 531
Joined: Sun May 20, 2001 9:14 pm

RE: Contrails

Tue Dec 25, 2001 2:18 pm

THanks
 
Twotterwrench
Posts: 1087
Joined: Tue Jan 16, 2001 5:57 pm

RE: Contrails

Tue Dec 25, 2001 3:10 pm

Of course, there is the "new" explanation for contrails precipitated by Art Bell and his crowd of "they're coming to take me away" and "the internet is used for government mind control" people who say contrails are actually "chemtrails" sprayed by the US govt for every conceivable purpose including weather control and mind control. Put that in your pipe and smoke it.
 
donder10
Posts: 6945
Joined: Sun Oct 21, 2001 5:29 am

RE: Contrails

Thu Dec 27, 2001 3:55 am

Twotterwrench,
there is actually a yahoo club or group about chemtrails LOL!Needless to say there about 5 members.
Alex
 
Av8trxx
Posts: 632
Joined: Sun Nov 11, 2001 7:08 am

RE: Contrails

Thu Dec 27, 2001 8:10 am


Click for large version
Click here for full size photo!

Photo © Mark Garfinkel



A contrail forms because one of the components of jet engine exhaust is water. Jet fuel is made of carbon and hydrogen. When jet fuel burns with oxygen, most of the exhaust consists of CO2 (carbon dioxide) and H2O (water). The water is generally an invisible vapor. When you exhale, your breath contains a great deal of invisible water vapor as well. You may have noticed that on certain days in the winter your breath will form a cloud of condensation when you exhale. In the summer, however, you don't see your breath. In the winter the moisture in your breath hits the cold air and condenses into visible water vapor. Cold air can hold a lot less moisture than warm air, so the moisure form a visible cloud when you exhale.

The same thing happens when a jet engine "exhales". If the temperature, winds and humidity in the upper atmosphere are right, long white contrails form when the moisture in the exhaust condenses forming those long white contrails.

 
Continental
Posts: 5223
Joined: Sun Jun 25, 2000 3:46 am

RE: Contrails

Fri Dec 28, 2001 2:00 am

Actually, after a while, it appears that the contrail that was left hours ago, may appear to be a Cirrus cloud!

Continental
 
CloudNine
Posts: 65
Joined: Tue Apr 17, 2001 12:23 pm

RE: Contrails

Mon Dec 31, 2001 4:56 am

I'm gonna go the the Art Bell view. I kinda get this "fuzzy/goofy" feeling a few hours after standing under 3 or 4 of those contrails. The government is up to something ?....!!!....? I just know it!.....Peace On Earth OOops,gotta go! just saw another flying sauc.......
 
Darius
Posts: 139
Joined: Thu Jul 19, 2001 7:21 pm

RE: Contrails

Mon Dec 31, 2001 10:16 am

As stated above, the relative humidity must be high for contrails, but the winds have to be calm too, in order to preserve the contrail's shape.

How serious is this chemtrail story? It can't be more than just a joke that people really believe it, can it??
 Confused
 
POSITIVE RATE
Posts: 2121
Joined: Sun Sep 16, 2001 11:31 am

RE: Contrails

Mon Dec 31, 2001 12:27 pm

I've seen many contrails form into Cirrus clouds. I live under a major flightpath and on clear and calm days the contrails form cirrus clouds and last for hours and hours.
 
Twotterwrench
Posts: 1087
Joined: Tue Jan 16, 2001 5:57 pm

RE: Contrails

Mon Dec 31, 2001 12:50 pm

Darius - Be afraid.. be very afraid....

http://www.chemtrailcentral.com

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