i just saw two "planes" fly over me...

one made a contrail and the other did not...

why???

do you know if they were flying at the same altitudes?
if trails are weather related....like some would like me to believe...then perhaps the difference in altitudes and temperatures would explain why.

if they were flying at the same altitude and I don't know how we can ever be sure of this stuff..then perhaps it was a military craft that made the trail?

Hey there,

It's all based on altitude. Anything lower than about 28.000 FT will not make contrails, anything above that will, due to condensation in the atmosphere at that level mixing with the vapors from the jet's exhaust. Hope this answers ya!

Many reasons possible. Could be different altitudes. Just like the days we get fog it depends on the dewpoint (the temperature that the air must reach for the air to hold the maximum amount of moisture it can). Pressure & temperature. Some engines burn cleaner, some cooler etc.

If you watch them being created you'll notice some times it comes off the wing surfaces and other times off the jet exhaust.

[Edited on 29-3-2004 by outsider]

Living near a major airport, I see all sorts of contrails. Its based on weather conditions and the type of engines. On some days virtualy every jet has contrails, and on other days only certain engines give on contrails.

AlnilamOmega--- youre welcome for the pic

the contrail was expanding as it was leaving the "plane" and it looked REALLY like a commercial "plane" but it could be military...

never can be too shure these days...

Altitude and acceleration of air about the lifting surfaces.

That's the reasons.

thanks for the pick rock and i understand this subject a liitle more now...

Originally posted by hhensley84
Hey there,

It's all based on altitude. Anything lower than about 28.000 FT will not make contrails, anything above that will, due to condensation in the atmosphere at that level mixing with the vapors from the jet's exhaust. Hope this answers ya!

Are you sure about this? Ever watch a plane on final approach or look out the window of that plane? The wings will make what I would call a quasi-contrail. Now, those may not be considered contrails but then what are they?

Closed as there is alread plenty of threads on this topic.

they see ALL this tendency to start threads without even bothering to look around for yourself is irritating.