originally posted by: BennyHavensOh
a reply to: waynos
There is no explanation that anyone has ever offered anywhere that I have seen that explains or "proves" why, all of a sudden over the course of the
last few years these "magic trails" have just started appearing when they have never existed in the past.
Do you mind if i have a go?
Firstly i need to address the belief that these trails didn't exist in the past. Contrails, of all kinds, have existed almost as long as powered
flight with several reports of them before 1920 as aviators tried to figure out why they were appearing. They first really came to public prominence
in the Battle of Britain in 1940 as RAF and Luftwaffe aircraft whirled around in the skies over southern England. This spectacle inspire a famous work
of art, while photographers also captured images as seen below;
Later in the war, as the USAAF bombed Germany from high altitude in daylight, the contrails of bomber streams became a more common sight;
So the notion that such trails did not exist can be seen to be patently false.
It's true that these contrails are far more prevalent now than at any time in the past and its this prevalence that causes suspicion and helps promote
the mistaken belief in chemtrails. There are several factors however that, when taken together, perfectly well explain how there are more and bigger
trails than ever before. Feel free to research any or all of the following in greater depth if you wish;
1 - Aircraft numbers. Since 1945, when commercial aviation once again became a major focus of aircraft manufacturers, the worlds commercial fleets
have grown year on year to previously unimaginable levels. Here I provide the World Airliner Census. The first going only as far back as 1980, where
is will be seen that quite a few ww2 vintage transports were still actively operated, the second to the most recent census from 2014;
World Airliner Census 1980
World Airliner Census 2014
One salient point that stands out from these is that while, in 1980, the worlds best selling airliner was the Boeing 727 with 1,800+ orders from
1962-80, in the 2014 edition Airbus has sold almost that many A320neo's before the first one has even entered service. This illustrates that vast
growth in fleet numbers pretty well, without looking at the totals.
2. Engine type - A further look at these censuses will also reveal that in 1980, only the very largest transports like the 747 and DC-10 were powered
by High-Bypass Ratio (HBPR) turbofans, and in relatively few numbers, whilst in 2014 they power aircraft in every class from the 550 seat A380 down to
the 36 passenger Dornier 328JET.
The significance of this is that these aircraft typically cruise at higher altitudes than many of the old piston and turbojet powered aircraft they
replace, in colder air where trails are more likely to form.
In addition to this a HBPR engine is more likely to produce a contrail than a turbojet in identical conditions anyway. This was explored by nasa when
flying an old tech 707 alongside a modern A340 to measure the difference.
This is because of the nature of the engine. Older turbojets worked purely on the 'suck-bang-blow' principle where air is drawn in the intake,
compressed and mixed with fuel, ignited and ejected out the back. In the High Bypass engine, it is only the central core of the engine that works this
way, while a huge fan is attached to the front of the engine and up to 90% of the air drawn in to produce thrust is merely compressed and ejected by
this fan, without any ignition at all. See pic below;
This results in a much lower fuel burn and greater efficiency than if modern engines were still 'pure jet' giving less pollution and, more importantly
for the airlines, lower fuel bills. It also results in a cooler exhaust, which freezes more readily, and the sudden depressurisation of the air behind
the fan causes the moisture contained within this bypass air to be released, in the same way you can see a wisp of moisture on a pressurised pop can
when you open it. This, plus the water content of the exhaust, aided by any atmospheric dust and soot particles in the exhaust is why you get more
3 - Aircraft size. This is not a reason that trails exist, but is is a factor in them being more visible. The RR RB211 of the first generation Boeing
747's in 1970 produced about 20,000lbs of thrust . The engines that power todays A380's and 777-300's, the trent and GE90, are in the
90,0000-100,000lb thrust class, up to five times bigger!
Remember the Battle of Britain contrails i mentioned that wowed the population in 1940? Well look at the difference in size of a Spitfire and a Boeing
Don't you think it would be suspiciously odd if there WEREN'T more and bigger contrails today than in the past?
Here is a photo of an older and smaller type with HBPR engines, its a 1982 A310, pictured last Sunday. You can clearly see the jet thrust from its CF6
engines and yet some people claim 'chemtrails' are in the fuel? How ridiculous would that be, given that no evidence has ever been found of anything,
but look at this. Spraying out all over the place and every five minutes as the next plane goes and the next. But still there is nothing to be found
after 20 years of supposed spraying? Someone is going to have to come with a theory they have actually thought through before i fall for it.
edit on 12-6-2015 by waynos because: added my own photograph