posted on Mar, 1 2013 @ 09:11 AM
Originally posted by Galadriel
Unless I was at an airshow, I never saw contrails/chemtrails - whatever -- except for a very tiny, short line behind a jet flying so high I could
barely see it. It never left long trails in the sky, and the trail never latest for more than a few minutes and then was gone. This was true my entire
life until more recently, when the skies changed.
Nothing has changed apart from the increase in air traffic with High-bypass engines. I grew up in Scotland under a very well used transatlantic flight
path. As a kid in the 1970s caught with the aviation bug I was fascinated by the aircraft and the contrails produced by the regular air traffic. I
was an avid aircraft enthusiast through the 1970s and into the mid 1980s before I joined the military (since retired). The contrails I observed were
no different from what is produced today albeit that there is more of them. Yes long, long trails that sometimes persisted. This myth of persistent
contrails only appearing from the late 1990s is just that a myth.
Correspondence from aircraft enthusiasts during the 1940s in the UK in regards to aircraft trails.
Note letter from David H. Darbishire in relation to spreading trails.
This is, naturally, a rather rare condition and is the intermediate between the two commoner phenomena of (a) the air is unsaturated and no vapour
trail is formed, and (b) the air is supersaturated to the extent that the vapour trails formed persist, and, under favourable circumstances, may even
Can you explain why people in the 1940s were observing persistent contrails?
Even test-pilots at the time were adding to the correspondence.
Geoffrey de Havilland, Jr, test pilot, wrote in Flight Magazine in June 1942
VAPOUR TRAILS Views of Well-known Test Pilot I WISH to correct the various erroneous statements that have appeared in the correspondence columns
of Flight concerning the origin of aircraft vapour trails. The trails referred to are, without doubt, due to the condensation of the water vapour
content of the engine exhaust gases; this condensation will always occur under favourable conditions of humidity and temperature at high altitudes. I
have myself frequently observed these trails from the cockpit of a high-flying aircraft in the very act of formation at the exit of the exhaust pipes.
The formation of a short trail, or, as Mr. Dixon has expressed if, a trail "like the wake of a boat," is merely the prelude to the formation of the
familiar "permanent" condensation trail which will occur when the aircraft in question runs into more favourable atmospheric conditions. Another type
of trail which may be induced by the passage of an aircraft through air of high relative humidity may well be termed an " adiabatic trail," since it
has its derivation in the adiabatic cooling of the air concerned to below its dew point
Recount from RAF Pilots in the 1950s on persistent contrails.
Image of RAF Canberra bombers producing contrails.
The other was to get the first-ever photographs from above of a formation making contrails at 40,000ft. Fortunately, very persistent trails were
forming at the prescribed height—so much so that in flying a local circuit—via the Firth of Forth and Chelmsford ! —our own trails were still
apparent on the return journey.
Possibilities Investigated by the Aircraft Recognition Society in the 1950s. Note the persistent contrail references and none of this non-sense that
contrails only lasted a few minutes.
Another consideration is the length of the contrail: it may persist, and stretch from horizon to horizon; or it may be quickly re-absorbed, giving
the effect simply of a short plume.
Measurements of the Growth of the Ice Budget in a Persisting COntrail - R. G. Knollenberg
Multiple Contrail Streamers Observed by Radar - Thomas G. Konrad and John C. Howard.
Images and study of persistent contrails
Full timeline at following posts. Includes a video of a chap that can't 'get' a book referencing persistent contrails during the 1940s.
edit on 1/3/2013 by tommyjo because: Malformed link corrected