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Post by ronturner on Aug 7, 2019 17:55:34 GMT 1
Looking up at the clear blue sky from my home in Western France, today I see an abundance of contrails in every direction, and even a few curved ones. In the same clear blue sky over recent weeks, I cannot remember seeing so many, and yet, I guess the same types/airlines/ routes are plying along, more or less every day.
Why is it that on this day I see so many more and so clear, and not other days.?
Is it a function of airline routing, or is it a function of upper air temperatures?
I bet somebody out there knows the answer
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Post by davecalveley on Aug 7, 2019 21:05:45 GMT 1
Sometimes works the other way Ron often I can hear a jet and despite it being a clear blue sky nothing can be seen ..........
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Post by viscount on Aug 7, 2019 23:15:32 GMT 1
An interesting subject on which I have seen very little sensible written. Vast amounts of rubbish from the Chem Trails conspiracy brigade though.
Certainly the propensity to form a white vapour condensation-trail (contrail) depends on the height of the aircraft, temperature, upper level winds, air pressure and very likely other factors too. Some days trails will stay and slowly spread over a period of an hour more; other days criss-cross the sky staying as tight white lines for considerable time; other days very short trails that last barely a minute while on other days none at all, yet the tadpoles still wiggle their way across the FR24 screen at cruising height.
I'm also fascinated in the way there are so many accounts of WWII air battles being followed by the public on the ground as the con-trails wound their patterns in the sky - yet most WWII air battles were at a much lower level than today's cruising level airliners. Indeed I can remember seeing Constellations and DC-7s very occasionally during winter trailing over Liverpool on the slow climb out from Manchester, much lower than the jets of today on climb-out, yet I cannot ever recall watching a Manchester jet departure trail over Liverpool. Only exceedingly rarely, and then only in winter, can I recall seeing a modern piston or turbo-prop trail.
Yes, an interesting topic, formation of trails must have been researched from interaction with the atmosphere but also by jet engine manufacturers and the military (a contrailing stealth fighter is an absolute contradiction of terms), but knowledge is certainly not widely in the public domain ie never the topic of a proper scientifically based tv Horizon style programme, nor aviation magazine articles (well not in the mags I see).
I bet someone does likely know the answer to Ron's question - but it is not me!
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Post by woody66 on Aug 8, 2019 11:08:17 GMT 1
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Post by ronturner on Aug 9, 2019 9:07:03 GMT 1
As you say. Woody66, very heavy reading. The conclusions are very interesting and in some way answer my original question, although time has moved on, so some of the efficiency criteria might now have changed. I don't pretend to have read and understood every formula in this argument, although I am particularly taken by final paragraph from the research paper, immediately before the conclusions. I like the idea of a 707 and a 340 flying information with a Falcon as an observation platform.
If there is anybody out there with a budget to fund a new study with aircraft of 2019 vintage, I am volunteering to be on the camera ship.
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