IAH744
Topic Author
Posts: 127
Joined: Sun Dec 04, 2005 11:09 am

Contrail Question

Sat Dec 10, 2005 8:14 am

1. how powerful does a jet engine have to be to produce a contrail?


2. would a learjet 60 produce one?


3. about how high do they start forming?
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grimey
Posts: 309
Joined: Tue Jun 07, 2005 2:48 am

RE: Contrail Question

Sat Dec 10, 2005 8:27 am

Quoting IAH744 (Thread starter):
1. how powerful does a jet engine have to be to produce a contrail?

See my answer to number 3.

Quoting IAH744 (Thread starter):
2. would a learjet 60 produce one?

Maybe it could, depending on the conditions (see below)

Quoting IAH744 (Thread starter):
3. about how high do they start forming?

Depends on tempreture, humidity and air pressure at the time, I think usually around 20,000 feet.

Correct me if I'm wrong on anything.

Grimey
 
c680
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RE: Contrail Question

Sat Dec 10, 2005 8:29 am

1) It has nothing to do with a jet engine. Look at all of the pictures of WWII radial prop bombers leaving contrails for an example. It is the rapid cooling of water vapor that produces the condensation trail or "Contrail."

2) Yes, a Lear 60 could produce one, given the correct atmospheric conditions. I've seen a King Air make them.

3) They can form at ground level on up - again, it all depends on the atmospheric conditions. It is a factor of temperature and humidity, not altitude. But, to give you the answer your looking for - mid 20's and higher.
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IAH744
Topic Author
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RE: Contrail Question

Sat Dec 10, 2005 8:40 am

4. at supersonic speeds would aircrafts contrails be scattered?

like not in a straigh line
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mjzair
Posts: 355
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RE: Contrail Question

Sat Dec 10, 2005 8:45 am

Interesting but useless trivia...

The level at which contrails will start to occur is called the Mintra Level.
 
SlamClick
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RE: Contrail Question

Sat Dec 10, 2005 9:43 am

Quoting C680 (Reply 2):
They can form at ground level on up

I read a long time ago that a Twin Otter operator way up in northern Canada would have that problem. Because it was so cold (Resolute Bay?) the first takeoff in the morning would lay an ice crystal contrail down the runway. After that everyone was making zero-zero intrument takeoffs.

We have two major kinds today, the "chemtrail" that goes from one horizon to the other and eventually begins to spread out into a cirrostratus layer. The other is maybe only half a mile long - forms and dissipates in a few seconds. A friend of mine calls these "comets."

When I was a kid I never recall seeing the second kind, only the ones that went from horizon to horizon. I think I know why. The planes that were laying down "vapor trails" back then were B-29, Boeing 307, Connies and the like. Their radial engine exhaust was really oily and smoky. So lots more particulate matter = lots more contrail. That is just my best guess.

In answer to #2 yes, just as readily as an Airbus. I see corporate jets pulling cons all the time up there.
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DLKAPA
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RE: Contrail Question

Sat Dec 10, 2005 9:48 am

I've heard stories from my friends up at UND that on cold mornings when the piper warriors take off they leave contrails. Oh yeah and the contrails are actually chemicals created by the CIA to reduce brain function, make our physiology more susceptible to drugs, and keep Lindsay Lohan from gaining weight  duck 
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IAH744
Topic Author
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RE: Contrail Question

Sat Dec 10, 2005 12:35 pm

Quoting DLKAPA (Reply 6):
Oh yeah and the contrails are actually chemicals created by the CIA to reduce brain function, make our physiology more susceptible to drugs, and keep Lindsay Lohan from gaining weight

you never said that, you will deny any knowledge that that statement ever existed

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jetmatt777
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RE: Contrail Question

Sat Dec 10, 2005 12:44 pm

Quoting C680 (Reply 2):
3) They can form at ground level on up

Yes, I agree 100% with that.  biggrin 

During my brothers football game I saw a CRJ-200 on base for OKC 's RWY 17L and it was at about 3,000 - 5,000 feet AGL(Above Ground Level). I didn't know they could form that low but now I do.

Cheers,
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