reply to post by rickymouse
Originally posted by rickymouse
Like I said to someone else, explain to me why such a higher percentage of jets have persistent contrails. I'm putting you into a position to tell
me why something I see with my own eyes is not true. My IQ was tested at 165 so it better be be a reasonable explanation.
It's interesting that you demand such high expectations of proof from others, yet you're quite willing to promote false information as fact. I
would expect better from someone with such immense intelligence as yourself
First off, we have to examine what you've claimed here. Saying that "such a higher percentage of jets have persistent contrails" is different from
saying 'there are more persistent contrails' which is a common observation. To explain the latter, it is quite simple. There are far, far more
planes flying now than there were 50 years ago. They fly further, and to far more locations, meaning more contrails in places that may not have got
them. That is just common sense.
Regarding the proposed significant increased percentage, this is a lot more difficult to ascertain from simply observing the sky. Unless you watch
the sky all day with a good pair of binoculars, you certainly aren't going to notice every
plane that flies in the sky. It is very difficult
to spot an airliner at 35,000 feet when they're not leaving an obvious trail. This leads to the logical conclusion that you would notice far more
planes in the sky on days when conditions support contrail formation, even if the exact same number of planes are flying. This means that there might
not be as high an increase in the percentage of jets leaving persistent trails as it seems from simple observations.
But indeed, there is a reason to explain an increase in the percentage of jets leaving persistent trails. And the answer lies in the type of engines
being used (this has been mentioned already, but I will expand on that here). Originally jet aircraft used
engines for propulsion. Later, these were replaced by low-bypass
engines which divert some air around the combustion core of the engine. This made them more
efficient, and engines are becoming increasingly more efficient with higher bypass ratios. High-bypass ratio jet engines allow for more contrails to
form over a wider range of atmospheric conditions.
Bypass ratios of turbofan aircraft engines have increased over the past 20 years. This has icreased fuel efficiency and reduced engine noise.
Increasing the bypass ratio of turbofan engines also has the effect of increasing the propulsive efficiency of the aircraft.
Higher bypass ratios have led to cooler exhaust temperatures, which in turn lowers the threshold temperatures for contrail formation. The overall
effect of this is that contrails form at higher ambient temperatures for more efficient engines because a smaller fraction of the combustion heat is
released into the plume and causes higher relative
Experiments have proven this to be true. This study set out to determine the "contrail factor", which is the ratio of water vapor to enthalpy added
by combustion to the exhaust plume from an aircraft engine. It is the key parameter determining the highest temperature at which contrails will form
behind a particular engine on a particular aircraft. This was shown by both calculations, and observations.
The computed contrail factors range from 0.030 to 0.053 g¢ kg¡ 1±C¡ 1 for the low-bypass engine and from 0.038 to 0.090 g¢ kg¡ 1±C¡ 1 for
the high-bypass engine
Contrail Formation and Propulsion Efficiency (large pdf)
Recent observations using two aircraft, one with older, low-bypass engines and the other with newer, high-bypass
engines12 show that engine/aircraft systems operating at higher overall propulsion effciency indeed have higher contrail factors and higher threshold
temperatures for contrail
There is far more information out there to explain a perceived increase in contrails, and they don't require 'chemtrails' to prove it. With the
increasing use of the ever increasing bypass ratios on engines such as those on the B787, B737-MAX, A350 and A320-NEO, we will probably see an
increase in contrail formation in the future.
Hopefully I have sufficiently satisfied your IQ in this explanation of why this doesn't in any way prove that there are chemtrails.