So an airplane at great heights leaves behind it, stretching for endless miles, a visible "wake" composed of ice particles so tiny that they do not fall as snow but remain suspended in the air.
The spreading out of jet contrails into extensive cirrus sheets is a familiar sight. Often, when persistent conditions exist from 25,000 to 40,000ft, several long contrails increase in number and gradually merge into an almost solid interlaced sheet.
..are underwing fences on the plane designed to reduce air buffeting
Originally posted by Genesis322
reply to post by arcnaver
So then the one guy who seemed to have a bit of paranoia in his voice was just acting to make the film "legit"?
Why would he say "oh god don't video right now"?
"Don't do any evidence"?
That was my point. it peeked my curiosity....
Why did that guy say that in either case of the following aircraft authorized or not.
Originally posted by Now_Then
reply to post by Come Clean
Well this paragraph from wiki seems pretty appropriate in that I assumed it to be a fuel dump.
Many movies and TV news stories mistakenly assume that all aircraft can dump fuel, when in fact most cannot. In certain atmospheric conditions where the moisture content of the air is high, 737s (and other aircraft) flying at low altitudes sometimes leave a moisture trail that can come off the top of the wing, wingtips, or trailing edge flaps. Moisture trails coming off the trailing edge flaps can appear especially odd, since the moisture is being "spun" by aerodynamic forces. It is possible that some people observe these moisture trails and may think this is fuel being dumped; however, this is just water vapor, not fuel.
The purpose of these modifications is to create vortices in a controlled and predictable manner. Vortices are often undesirable because they produce drag, but the vortices these devices create are beneficial since they delay wing stall. Stall occurs when a wing reaches a high enough angle of attack that the airflow separates from its surface. This flow separation results in a rapid loss of lift, and the aircraft may become uncontrollable.
The advantage of wing devices that create vortices is that a vortex adds energy to the airflow and increases its forward momentum. This momentum encourages the airflow to remain attached to the surface of the wing at higher angles of attack than it would otherwise. As a result, the wing is able to continue generating lift in conditions where it would have stalled.
A vortilon serves the same purpose on the lower surface of a wing, and this device is often referred to as an underwing fence for that reason. Like the traditional boundary layer fence, the vortilon can also be used to create a vortex on the underside of the wing at low angle of attack. The vortilon is far more useful at high angles, however, when a second vortex travels around the leading edge and over the upper surface of the wing. This vortex helps delay separation over the upper surface like those created by the other surfaces we have explored.