Contrail / Chemtrail. The debate ends here.

Figured I'd toss my head in at this point and start trying to ask some of the right questions about the matter. Not really interested in chemtrails, but mostly the oddly-shaped contrail evidence that the 'Trailer boys keep pointing to.

Important point: These are real questions that, if you have good information on, I'd like real answers to. None of that rhetorical-question-to-make-a-point garbage here.
Also important: I have done very little special research on chemtrails. Frankly I don't think that the evidence points to this as a viable or actively used transmission vector for chemical or biological substances. Obviously there are those that disagree, but as a result I haven't seen much of the stuff outside this forum. IE don't assume I've seen whatever evidence from whatever site already.

And now for the musings.

I thumbed through the more recent posts in this thread just to see what was going on. I was shocked to find out that people were disagreeing on what evidence meant. Absolutely shocked. I did notice, though, that there were a lot of posts from our regular Aircraft Projects forum crawlers on contrails as a weather phenomenon. I personally believe this is the most reasonable explanation for the effect, but, being unnecessarily inquisitive, I had wondered if there were other factors in such an irregular phenomenon. Even in my admittedly short engineering experience I've found that the stuff we consider weird or irregular is usually so because there are a bunch of things that have to go into the situation to make the unusual results pop out. So I focused on the other half of what makes con/chem/candytrails: engines and aircraft features.

It occurred to me that the contrail of an aircraft is probably affected significantly by factors of the engine, airframe, and their immediate operating states. Lee has already pointed out the differences between the flap fairings between those on the DC-10 and those on Boeing and Airbus aircraft, but I wanted to expand on that some more onto other parts of the aircraft with a few questions just to get some good info out there from any that happen to know it.

There's a lot of hubbub around the "doughnuts on a rope" implying usage of chemicals. So:

-In creating these trails, how responsible are the weather conditions versus airflow over the aircraft?
-Within the fraction that the aircraft is responsible for, how much depends on aircraft shape? Size? Engine layout? Engine power setting? Airspeed? Vertical speed? Attitude?
-Would they be affected by different trim settings on the aircraft causing non-centered control surface position?
-What role do wingtip vortices play in creating these contrail forms? Would they change from the presence of a winglet? Wing fence? Sharklet? Raked wingtip?
-Within the fraction that is caused by the weather conditions, how much depends on local characteristics (Temperature, pressure, humidity, windspeed & direction) versus global characteristics (changes in weather conditions over the area that the aircraft traverses)?
-Are there any locations which show a higher occurrence rate of these trails than others?
-Are there any aircraft types/makes/models that show a higher occurrence rate than others?
-Are there any aircraft operators or airlines that show a higher occurrence rate than others?

Now some questions about the administration for forming chemtrails, probably more suited to our brethren from another forum:

-Who, in particular, is responsible for directing chemtrail use?
-Who, in particular, is responsible for carrying out chemtrail placement?
-Who, in particular, is responsible for designing, manufacturing, and maintaining chemtrail equipment?
-Who, in particular, is responsible for supplying the chemtrail chemicals? What varieties are there?
-What is the purpose for forming these trails (may vary by who is responsible for each case)? What is the motivation behind that purpose?
-Where are the inspection, maintenance, and repair operations done on these aircraft?
-Where are these aircraft refilled with chemicals? How often do they have to be refilled?

And some questions on the technical nature of the chemtrail system:

-Are the chemicals expelled by spraying into air, or are they put through the engines with the fuel?
-If sprayed, where are the nozzles located on the aircraft?
-Where are the chemicals housed during the flight?
-Where are the chemicals housed at facilities?
-Which personnel fill the aircraft? Are they aware they are doing it?
-What concentrations are required to be effective at ground level?
-Are these components inspected by Flight Regulation Boards?
-Of the organizations who take part in this practice, which administration personnel know of it? Which do not?
-What varieties of chemical exist? Can one system handle multiple types?
-Are the chemical residues in the air visible without a contrail?

And I'm out of letters. Play with these questions for the time being if you can.

Pr0

reply to post by mastersmurfie


The US military uses outside contractors because we don't have NEARLY enough tankers to do the mission. US Air Force tankers double as airlifters, to support C-5s, C-17s, and C-130s. They don't just operate as tankers. I have seen first hand where we have had fighters on ferry flights break, and then sit there for weeks after being fixed, because it takes that long to find an open tanker flight that can take them the rest of the way.

A KC-10, and KC-135R can both "drag" up to 6 fighters (unless we're talking AV-8Bs and then it's like two). It's not efficient to take a tanker out of rotation just to drag two fighters somewhere, so they generally wait until there is a mission going the same way. As busy as the tankers are, that can take a long time.

If you look at just numbers, there are a LOT of tankers in service with the military (over 700 KC-135s I think it is, and 29 KC-10s), but when you start looking at how many of those are in PDM at an given time, or down for inspections at a local level, or even some that are on the books as flyable, that just aren't, you start to see just how FEW we have, for the missions we fly. Then you have to start taking out numbers that are in the Middle East supporting the birds over Iraq and Afghanistan, and that gets cut down further. The only option is to have an outside contractor. Omega doesn't JUST support the US military though. They can be contracted by any other military in the world for operations. Most other countries are heavy on the fighter and patrol type planes, and very light on tankers, because they don't do many long range ops. So when they do, they can hire Omega. Good example is Italy. The Italian Air Force had leased a number of F-16s from the US. They just returned the last of them recently, and all the ferry flights were covered by an Italian C-130, and refueled by a USAF KC-135 the whole way home.

reply to post by Darkpr0

-In creating these trails, how responsible are the weather conditions versus airflow over the aircraft?
-Within the fraction that the aircraft is responsible for, how much depends on aircraft shape? Size? Engine layout? Engine power setting? Airspeed? Vertical speed? Attitude?...........

-Within the fraction that is caused by the weather conditions, how much depends on local characteristics (Temperature, pressure, humidity, windspeed & direction) versus global characteristics (changes in weather conditions over the area that the aircraft traverses)?

The primary factor is relative humidity, RH needs to be at 100% with regard to ice in order for trails to persist, below this they can form, but will quickly dissipate. RH can vary quite a lot in quite small areas, in regard to trails it may cause a contrail to have a stop-start character, at its most basic its why clouds have edges It may also be worth pointing out that contrails are not vapour, they are tiny crystals of ice and this is why they are visible (sorry if you knew that).

The next factor is temperature. Contrails generally form above 25,000ft, where the temp is always below freezing, you can get contrails forming lower down when it is extremely cold and aircraft have been pictured forming contrails at ground level in the Arctic.

The size, speed and form of the aircraft play very little part in any of this (if any at all), however, the cooler and vastly greater volume of jet exhausts from modern high bypass turbofan engines, by comparison with older engine types, does lead to contrails forming earlier and lasting longer than was generally observed. This much was demonstrated by a NASA flight where a modern Airbus A340 began leaving contrails in lower, warmer air than a 707 that was flying alongside it.

-Would they be affected by different trim settings on the aircraft causing non-centered control surface position?
-What role do wingtip vortices play in creating these contrail forms? Would they change from the presence of a winglet? Wing fence? Sharklet? Raked wingtip?

This is a different type of contrail, aerodynamic contrails would not ordinarily be visible from the ground and never persist. This is because the trail is caused by moisture that is already present in the air condensing due to sudden pressure differential (ie the airflow over a flying surface) and it quickly sublimates back whence it came, usually in seconds.

The contrail left by the engine exhaust plume however will certainly be affected by the airflow or wake of the aircraft, the swirling vortex from the wings of an aircraft like the 747 is what causes the donuts on a rope effect as the contrail is carried in a spiralling loop.

So, in a nutshell, its all down to relative humidity and temperature, and is affected by engine type