Pre 1995 Persistent Contrail Archive

[Jazzy]

Not sure if these are "persistent enough", but there are some quite substantial contrails off the canards of the XB-70 at 2.05 and 2.20 - just for a second or 2 each. I wonder if they are actually smoke for airflow indication?

No.

The forewings of a canard aircraft suffer a higher wing loading than the rear wings so that near the stall the nose of the aircraft automatically lowers. That wing loading (when exploited sufficiently) will cause a sufficient pressure (and therefore temperature) drop at the tip vortices to form a temporary trail in certain atmospheric conditions.

When the XB70 was lost (by one of its tailfins colliding with a Starfighter chaseplane) it went into a flat spin and a complete cloud formed above the whole aircraft as it fell.

[Mick]

Five minutes looking. 1977.

http://www.flickr.com/photos/30159472@N04/5715276757/



http://www.flickr.com/photos/3015947...n/photostream/

[FreiZeitGeist]

A Schoolar Poster about Contrails made by "Deutsche Zentrum für Luft- und Raumfahrt e. V. " (DLR) from the year 1989.

(Dont´ be confused about the sligthly changed name behind "DLR", they had changed their name a little bit)



I´ve searched a readable version for a long time , now i found it again...

http://www.abload.de/img/chn8oa3.jpg

[Mick]

Discussion of Scott Stevens' take on these photos moved to:
http://metabunk.org/threads/957-How-...s-of-Contrails

[Mick]

I was browsing in a second hand bookstore today and found this:

Life Magazine, Nov. 29, 1943, pp 69-83.


Looked it up when I got back. It was an air-force book, partially reprinted in Life.

Target Germany.pdf

Also has this small image:

And mentions of vapor trails:



There's also a video with the same name that seems to have some close-up shots of a contrail from above, as well as some conventional contrails video.
http://www.youtube.com/watch?v=5hp0x80fqOU

[Tim TheToolman Coles]

Very Nice catch Mick.

[FreiZeitGeist]

This seems to be from the TV-Series "Daniel Boone" produced in the 60s
http://en.wikipedia.org/wiki/Daniel_...28TV_series%29

[MikeC]

Target Germany.pdf



There's also a video with the same name that seems to have some close-up shots of a contrail from above, as well as some conventional contrails video.
http://www.youtube.com/watch?v=5hp0x80fqOU

I am not sure that this particular one is a contrail - for the few seconds it is in the video it sems to get smaller, which makes me think it might be a smoke marker.

the following text explains how they were used:

Content from external source:

When the lead bombardier's Norden bombsight released his bombs, two smoke bomb were released from below the chin turret. When the rest of the squadron bombardiers or toggleers saw the smoke bombs released we then hit the SALVO switch and released our bombs also. Of course, milli-seconds later we would have seen the actual explosive bombs falling from the bomb-bay but in an attempt to group the bombs on target we needed to release them ALMOST at the same time the lead bombardier released his bombs.

From here - http://goodsky.homestead.com/files/deception5.html

Earlier in the video you can see smoke trails ending in bombed areas - these are very distince single trails, as opposed to smoke screens from the ground.

[FreiZeitGeist]

These are two great ones...

Number one: From the german Nazi-Propaganda Magazine "Der Adler", Year 1941, Number 6



The title means "Skywriting at war" and the article discripes, how contrails are formed and that they could be used to find the Airplanes of the enemy.

Number Two: Script of a Scientific Lession for "german Academy for Aviation-Science (1940)".

The Article´s name is "Die Entstehung von Eisnebeln aus den Auspuffgasen von Flugmotoren"
(The formation of icy-clouds due to Evapurations of Airplane-Engines)

This is a more scientific analysis how contrails are made and under what conditions they stay permanemt. Compareable to the "Color of Clouds"-Book from 1972. Take a look to this graph, showing under wich conditions contrails are persistant;



"Wolkenschweife" means "contrails".
X-Axis is temperatur in celsius. Y-Axis is relative humidity.
Black squares are Flligths without any contrail.
Circles are Fligths with a short contrail under 300 meter
"+"-Sings are Contrails between 300 and 1000 meters
black circles are contrails longer than 1000 meters

Some other captures from this early WW2-Paper:






You can donwload the PDFs to both articles here:

First Article:
Der Adler, 1941 Heft 6, Über die Entstehung von Kondensstreifen
http://chemtrail-fragen.de/der_adler...nsstreifen.pdf

Second article:
Die Entstehung von Eisnebel aus den Auspuffgasen von Flugmotoren
Ernst Schmidt, 1940, Deutsche Akademie der Luftfahrtforschung
http://chemtrail-fragen.de/ernst_sch...tforschung.pdf

Somebody who has better english-skills than me should translate these documents from World-war-2.

[Cairenn]

It would imply that if enemy planes were being able to follow the contrails back to their source, that they were Persistent and long lasting.

[Ross Marsden]

FreiZeitGeist, did you notice that the two photos on "page 21" of your Number Two have been cropped out of the top right photo on "page 160", your Number One?

[JFDee]

I assume the article in the "Adler" magazine is based on the paper by Ernst Schmidt.

Here is my shot at translating the interesting part in that paper (pg. 19 and 20). For references to "DFS", see Wikipedia

The problem of sublimation and condensation in supersaturated layers low on nuclei could be solved only to a small degree. It seems however that supersaturated conditions without condensation and sublimation are not as frequent as A. Wegener has assumed. Some of the phenomenons observed by Wegener are likely to have been caused by influx of water vapor. On their high-level flights, the DFS is conducting experiments with injection of hydroscopic and non-hydroscopic nuclei in the upper troposphere. No unambigious results have been found yet. The experiments are suffering from the impossibility to measure water vapor saturation properly at low temperatures.

Based on the experiences about cloud trail formation behind airplanes to date, the DFS has issued a leaflet for the battlefront. Slow planes are more likely to create cloud trails than fast planes. With short cloud trails, alternating between full and reduced throttle affords a certain level of protection. If long and persistent cloud trails are forming, climbing and gliding flight has to be employed in turns.

The problem in question has further relevance with regard to conditions for ice accretion. Jaumotte has pointed out an interesting case which is associated with the phenomenons described here. Above a rain and hail cloud at around 5000 m altitude, a 6 to 10 cm layer of ice formed on a plane in an area that was entirely clear. The reported thickness of the ice seems exaggerated, however the incident implies that above the cumulus cloud there must have been a clear layer with high supersaturation which was made unstable by the airplane, causing rapid icing.

This case closely resembles the accident of three Italian planes near Lucca. In 1939, on December 6th three planes of the Italian air force crashed due to ice accretion. The planes were part of a larger squadron flying at 3000 m altitude above the clouds, within sight of each other. The planes flying in the middle of the group were creating veritable snow clouds, more accurately ice cloud trails, when they passed between two towering clouds. The following planes crashed when they passed that area, quite obviously due to icing. It is likely that the cause has been heavy supersaturation prevailing between those two high-reaching clouds which was amplified and "triggered" by the preceding planes, so that the trailing planes suffered sudden and rapid ice accretion.

These cases are showing how scant our knowledge is about the supersaturated layers which exist in the atmosphere, and how significant the experiments conducted to research the meteorologic conditions of the upper troposphere are with respect to the safety of aviation. However, major progress can only be expected once the problem of exact humidity determination at low temperatures is solved, by methods that can be handled easily.

[Tim TheToolman Coles]

I took some time this afternoon to translate the first one so that it was a bit easier to understand it. A bit rough but I gave it my best.

[Cairenn]

Is this site listed here?

http://goodsky.homestead.com/files/gallery.html

[Mick]

Is this site listed here?

http://goodsky.homestead.com/files/gallery.html

I think it's been referenced a few times. That's Jay's site.

[Cairenn]

Ah, nice site Jay

http://www.flickr.com/photos/phil_p/4317237037/

Lots of contrails there

not sure how to post the picture, sorry

[Mick]

http://www.flickr.com/photos/canadagood/3068353370/


http://www.flickr.com/photos/65309933@N02/8299502295/


http://www.flickr.com/photos/sftrajan/8553565634/

[MsVickie]

​These are chemtrails, [...]

[Mick]

​These are chemtrails, [...]

Perhaps you'd like to explain why, and we can discuss it in a new thread?

Maybe pick one photo and explain why you think it's a chemtrail.

[Mick]

Disneyland, 1980:

http://www.flickr.com/photos/kappach...n/photostream/

As a response to this 2013 photo:
https://www.facebook.com/photo.php?f...0517689&type=1

[Cairenn]

Some of the nice diffused ones in that second photo

[Unregistered]

Here is some US diplomatic cables from 1973 onwards that are clearly talking about weather modification involving spraying from aircraft.

https://www.wikileaks.org/plusd/cabl...E149164_b.html

https://www.wikileaks.org/plusd/cabl...E059146_b.html

https://www.wikileaks.org/plusd/cabl...E296420_b.html

https://www.wikileaks.org/plusd/cabl...E058920_b.html

[Mick]

Here is some US diplomatic cables from 1973 onwards that are clearly talking about weather modification involving spraying from aircraft.

https://www.wikileaks.org/plusd/cabl...E149164_b.html

https://www.wikileaks.org/plusd/cabl...E059146_b.html

https://www.wikileaks.org/plusd/cabl...E296420_b.html

https://www.wikileaks.org/plusd/cabl...E058920_b.html

Weather modification is not secret. It's been done quite openly since the 1950s. See these small ads from the 1960s
http://metabunk.org/threads/306-Debu...ification-quot

[solrey]

Here is some US diplomatic cables from 1973 onwards that are clearly talking about weather modification involving spraying from aircraft.

All of those cables are clearly talking about cloud seeding, for which silver iodide flares are the most common method of dispersal from aircraft, which isn't really "spraying". In fact, the proposal in Florida never happened due to "adequate natural rains". The second cable talks about NOAA's position that seeding orographic clouds offers some promise in alleviating water shortages, however NOAA is less confident about the effectiveness of seeding of cumulus clouds. In the third cable it was decided to NOT approve a proposed cloud seeding operation in Jordan. The fourth cable talks about a careful policy review concerning funding for a proposed cloud seeding project in Turkey. All of those cable's original security classification was "unclassified". So what are those cables supposed to be evidence for again? The government wants to alleviate water shortages?

[Critical Thinker]

https://www.facebook.com/photo.php?f...type=1&theater




Even when there are images of persistent contrails, these people resort to their usual M.O. and claim that the image was doctored.

[Mick]

https://www.facebook.com/photo.php?f...type=1&theater

Even when there are images of persistent contrails, these people resort to their usual M.O. and claim that the image was doctored.

The original image:

Captioned:

Content from external source:

Bahia Mission Bay San Diego 1961
Scanned from Ford Times magazine.

Approximate location of the image:
https://maps.google.com/maps?q=Bahia...,35.2,,0,-4.81

[frenat]

1942 report on contrails that also talks about persistence.
http://naca.central.cranfield.ac.uk/...a-wr-l-474.pdf

Also, I don't have a screen grab but I do know that in the original "Italian Job" from 1969 at the end where the bus is hanging off the cliff there is a persistent contrail above them.

[hemi]

1942 report on contrails that also talks about persistence.
http://naca.central.cranfield.ac.uk/...a-wr-l-474.pdf

Also, I don't have a screen grab but I do know that in the original "Italian Job" from 1969 at the end where the bus is hanging off the cliff there is a persistent contrail above them.

[CbIncus]

An example of a persistent spreading contrail from the book "Aeronautical Meteorology" by Matveev and Smirnov, 1955 (Part 1). The book can be downloaded here: http://u8239182.letitbit.net/downloa...92923.rar.html.



The translation of contrail chapter:

Content from external source:

Condensation and sublimation of water vapor in the atmosphere lead to the formation of so-called contrails after a flying plane.
Observations show that contrails are formed in the troposphere at temperatures lower than -30...-40 degrees.
Contrails are formed due to sublimation of water vapor, which is the result of combustion of aircraft fuel (gasoline, kerosene) getting into the atmosphere. The effect of pressure drop under an airplane's wing due to faster air motion (Bernulli's law) contributes considerably to contrail formation. The decrease of pressure leads to decrease of temperature (the process is adiabatic). If the air at the flight's height is close to saturation, the additional temperature drop under a wing will cause condensation and contrail formation. Extra condensation nuclei originated from non-combusted particles of fuel contribute to the process. Observations show that contrails form in regions which are close to saturation over ice. This fact along with additional water vapor and condensation nuclei from an airplane produce a persisting contrail.
Another fact is that persisting contrails form in the regions with cirrus clouds or light haze (which may not be visible from the ground) in the upper troposphere. When air is unsaturated (over ice), contrails will rapidly dissolve because of turbulence. The trails usually form after each engine. Later they merge into a single one. Contrails may also be formed after an aircraft's wing due to flow underpressure and jet disruption.

[justanairlinepilot]

An example of a persistent spreading contrail from the book "Aeronautical Meteorology" by Matveev and Smirnov, 1955 (Part 1). The book can be downloaded here: http://u8239182.letitbit.net/downloa...92923.rar.html.



The translation of contrail chapter:

Content from external source:

Condensation and sublimation of water vapor in the atmosphere lead to the formation of so-called contrails after a flying plane.
Observations show that contrails are formed in the troposphere at temperatures lower than -30...-40 degrees.
Contrails are formed due to sublimation of water vapor, which is the result of combustion of aircraft fuel (gasoline, kerosene) getting into the atmosphere. The effect of pressure drop under an airplane's wing due to faster air motion (Bernulli's law) contributes considerably to contrail formation. The decrease of pressure leads to decrease of temperature (the process is adiabatic). If the air at the flight's height is close to saturation, the additional temperature drop under a wing will cause condensation and contrail formation. Extra condensation nuclei originated from non-combusted particles of fuel contribute to the process. Observations show that contrails form in regions which are close to saturation over ice. This fact along with additional water vapor and condensation nuclei from an airplane produce a persisting contrail.
Another fact is that persisting contrails form in the regions with cirrus clouds or light haze (which may not be visible from the ground) in the upper troposphere. When air is unsaturated (over ice), contrails will rapidly dissolve because of turbulence. The trails usually form after each engine. Later they merge into a single one. Contrails may also be formed after an aircraft's wing due to flow underpressure and jet disruption.

The pressure drop is over the top of the wing. Must be a typo or an error with the translation.
High pressure moves to low pressure giving way to lift.

[CbIncus]

Thank you justanairlinepilot for pointing out this detail. I've checked the original source in Russian and there is told about the drop of pressure and temperature under the wing (I think the authors speak about engines). The drop above the wing is higher and this is the cause of airplane's lift.

[magnus]

me too D:
http://www.youtube.com/watch?v=DcZxX...50BDB1556D113E

[Mattnik]

me too D:
http://www.youtube.com/watch?v=DcZxX...50BDB1556D113E

Hi Magnus, a welcome to Metabunk. Could you identify some key points in that video and possibly start a new thread for it? At 1hr 40mins it's rather too long to have any meaningful discussion about. Thank you.

[Woody]

There are 365 days in the year, out of these days what would you say is the average amount of days during a given year, estimated, when these lingering trails of an hour or longer can exist in the sky?

[Jazzy]

There are 365 days in the year, out of these days what would you say is the average amount of days during a given year, estimated, when these lingering trails of an hour or longer can exist in the sky?

365 days and nights.

[Pete]

There are 365 days in the year, out of these days what would you say is the average amount of days during a given year, estimated, when these lingering trails of an hour or longer can exist in the sky?

Woody, you must qualify your question with either; one location, any particular location, or the entire world. I believe Jazzy has answered for the entire world, as on any day, somewhere will have a contrail lasting an hour or more.

The atmosphere is different everywhere, depending on the time of year, weather systems e.t.c.

[Woody]

Woody, you must qualify your question with either; one location, any particular location, or the entire world. I believe Jazzy has answered for the entire world, as on any day, somewhere will have a contrail lasting an hour or more.

The atmosphere is different everywhere, depending on the time of year, weather systems e.t.c.

Lets take Kansas City in the center of the nation.

[Pete]

Lets take Kansas City in the center of the nation.

So the number of days (24 hour periods) it could happen would be based the total number of days above Kansas City when air at whatever the cruising altitude of aircraft fly at over Kansas city is at the correct temperature and humidity for contrails to form and persist. I reckon wind speed would need to be factored in, as the faster it is the quicker the contrail would disperse or move. You also need to account for changes in jet engine design over the last however many years you want to compare it to, as newer engines are more contrail productive. So a contrail from a newer aircraft will last longer.

But seeing as I'm not proposing chemtrails exist, or indeed that the number of days above Kansas City where contrails could persist has gone up/down due to anything other than issues (natural or not) outside of the chemtrail argument, the onus is on you to collate the information. To be blunt, its an awful lot of weather records to collate, and it ain't my job, its the believer's!

[Woody]

So the number of days (24 hour periods) it could happen would be based the total number of days above Kansas City when air at whatever the cruising altitude of aircraft fly at over Kansas city is at the correct temperature and humidity for contrails to form and persist. I reckon wind speed would need to be factored in, as the faster it is the quicker the contrail would disperse or move. You also need to account for changes in jet engine design over the last however many years you want to compare it to, as newer engines are more contrail productive. So a contrail from a newer aircraft will last longer.

But seeing as I'm not proposing chemtrails exist, or indeed that the number of days above Kansas City where contrails could persist has gone up/down due to anything other than issues (natural or not) outside of the chemtrail argument, the onus is on you to collate the information. To be blunt, its an awful lot of weather records to collate, and it ain't my job, its the believer's!

When I was kid I would see these long persistent trails on rare occasions. My neighbor, Bernie, was an aircraft mechanic for Northwest Airlines so his kid and I went and asked him about this. He told us back then that the weather up there was much different than down here and that these days are rare and require both a stable and calm environment for them to exist. What was once occasional is now daily, and I could agree with a change in fuel, alterations in the atmosphere, etc, but the changes would also appear across the board, meaning they would all display the same effect, bringing it back to the aircraft and not atmosphere.

[GregMc]

I think from a number of papers I've perused, that for any location , conditions of supersaturation with respect to ice will occur about 20% to 45% of the time. That means, not just persisting, but contrails spreading out to form overcast haze. By a rough extrapolation that's around at least 62 days in a year. The rest of the time outside that sixty days, ie, in addition to that sixty days, a single contrail may not necessarily grow larger and spread into overcast but multiple contrails may still persist for hours.
http://journals.ametsoc.org/doi/full/10.1175/JCLI3955.1

http://onlinelibrary.wiley.com/doi/1...00526/abstract

In addition to those extra days, there will be warmer drier conditions when the contrails will be short lived, lasting 10 minutes or so.
On rare occasions no contrails at all may form, but as we have seen in Australia, even on one of the hottest days on record at 40C or 104F over the sub-tropical city of Brisbane, persistent contrails will form because the air at high altitudes is still more than 50 degrees below freezing.
http://www.abc.net.au/local/stories/...05/3648013.htm

I suspect your "rare" occurrences of the past are equally likely to refer to the numbers of aircraft flying at high enough altitudes to form persistent contrails. ie, High altitude airliners were rarer.
There is a vastly greater number of airliners flying now-days than in the past http://contrailscience.com/30-years-of-airline-travel/