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Posted: 10/11/2007 5:21:31 PM EDT
[#1]
Compressibility. The plane is near sonic speed and the humidity in the air condenses because of change in pressure/temperature.
You see, water vapor is a gas. Despite what a certain person here might claim. But when the water vapor in the air becomes saturated, the condensing water particles are visible. |
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Posted: 10/11/2007 5:23:54 PM EDT
[#2]
Yes!! They are now equipped with a Trans-Dimensional switch. 
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Posted: 10/11/2007 5:24:52 PM EDT
[#3]
Thanks,I kinda get it.
Basically the plane is going so fast it changes the atmospheric pressure encircling the plane condensing the air into water vapors ? Why did it happen only when the plane was banking,does it happen when the plane is flying level as well ? |
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Posted: 10/11/2007 5:26:03 PM EDT
[#4]
It is a shock wave...basically, the "sound" cannot get out of the way of the plane so the plane pushes it, causing drastic changes in pressure. |
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Posted: 10/11/2007 5:27:23 PM EDT
[#5]
Perfect explanation,in a way a dummy like myself can understand it  ..Thanks again Keith.
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Posted: 10/11/2007 5:28:09 PM EDT
[#6]
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Posted: 10/11/2007 5:30:13 PM EDT
[#7]
If it is a sonic shock wave, why isn't there a sonic boom? I just assumed it was from the higher air pressure. |
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Posted: 10/11/2007 5:32:01 PM EDT
[#8]
Yep, its not so much temperature though. It's just the pressure concentrates it until it is saturated, like you stated. Its LCL, or Lift Condensation Level is met. Similar to dew point. |
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Posted: 10/11/2007 5:35:22 PM EDT
[#9]
Banking is when it happens (normally). Its like trying to collect dust in a dust-pan. It must be at the "correct" angle. |
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Posted: 10/11/2007 5:45:10 PM EDT
[#10]
The plane is NEAR the speed of sound. If the shock wave is just touching the leading edge root filets/empennage, then the plane is transonic. On review of the video, the reason the cone disappears/reappears is due to non-uniform concentrations of water vapor in the air. |
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Posted: 10/11/2007 5:47:42 PM EDT
[#11]
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Posted: 10/11/2007 5:48:13 PM EDT
[#12]
No, it is pressure AND temperature. Ever use a psychrometric chart? All the data is there... |
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Posted: 10/11/2007 5:58:55 PM EDT
[#13]
No I have not. But my undersanding is that temperature is not directly conducive to the condensation of water vapor. I'm a meteorology major, but this is my first semester of major oriented classes. If it's anything like Z tables and parametric statistics I dread it. 
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Posted: 10/11/2007 6:37:16 PM EDT
[#14]
RH and Temp go hand in hand.
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Posted: 10/11/2007 6:41:13 PM EDT
[#15]
Ah, fuck. Being drunk sure as hell doesn't help. But you're right, relative humidiy isn't accurate here. Thinking about it more, you are correct. Things being compressed tend to increase in temperature. Hello physics 101!!!  But in reality, its all due to the pressure, and the temperature is more of a side effect, in the same way that the condensation is a side effect.
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Posted: 10/12/2007 5:56:52 AM EDT
[#16]
NAW, You got it all wrong. The definition of relative humidity is when the sweat off your balls runs down the crack of your sisiter in law's ass. |
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Posted: 10/12/2007 11:08:32 AM EDT
[#17]
I'm going to tomorrows matinee show with the family. My kids are gonna love the Thunderbirds.
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Posted: 10/12/2007 11:13:32 AM EDT
[#18]
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Posted: 10/12/2007 11:16:35 AM EDT
[#19]
Who says that water vapor is not a gas? |
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Posted: 10/12/2007 11:23:23 AM EDT
[#20]
Prototype cloaking device.
Chemtrail generator. All of this nonsense about "water vapor" is what They want you to believe. |
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Posted: 10/12/2007 11:26:03 AM EDT
[#21]
HoodyHoo21 Although he now claims you cannot say a vapor is a gas or that water vapor is not a gas...or something equally false. |
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Posted: 10/12/2007 1:13:34 PM EDT
[#22]
This can happen far below transonic velocities. It has to do with temperature, air pressure, and humidity.
Just over the wing, and in this case, the entire fuselage is acting as a lifting body, the airspeed is higher and air pressure lower. It can no longer hold the moisture as a vapor and it condenses as small droplets. In certain conditions a pilot can see the vapor over the wings and in fact, turn it on and off by slightly manipulating the elevator, thus changing the angle of attack (greater angle of attack, greater vacuum over the wing) and leave a series of cloudy dashes across the sky. |
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Posted: 10/12/2007 1:20:03 PM EDT
[#23]
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Posted: 10/12/2007 1:24:51 PM EDT
[#24]
Oh wow. |
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Posted: 10/12/2007 1:29:17 PM EDT
[#25]
That wasnt a supersonic wave cone. He was pulling a high G turn and the resulting pressure differential caused water vapor in the air to condense on the top of the wing. The underside would have been just as clear as the rest of the sky... The F18 flyby is a true mach cone.
Had the F22 been transonic or super sonic the camera would have not had any sound from the jet until it was passing or had already passed in the form of a sonic boom. It had neither.. |
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Posted: 10/12/2007 1:33:06 PM EDT
[#26]
I don't see what the speed of sound has to do with it. Would the same condensation not appear if a plane were traveling slower and was able to create the same low pressure? (honest question) |
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Posted: 10/12/2007 2:00:04 PM EDT
[#27]
Exactly. It's not a supersonic "shockwave". It's simply water vapor in the air condensing into visible droplets because of the extreme low pressure created around certain portions of the aircraft. The aircraft in the first video clip is banking very hard to the right. This creates an area of very low pressure above the wings and fuselage. The low pressure causes the air to cool rapidly. The right combination of low pressure, cooler air, and relative humidity results in a visible cloud. It's basically fog. Man made fog. For only a brief moment. |
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Posted: 10/12/2007 2:03:10 PM EDT
[#28]
Yes, it can happen at speeds well below mach 1. If the air is very humid and you pull a high G maneuver, you can create low pressure areas which rapidly cool the air and cause condensation to form briefly. I've seen it happen in very humid conditions when a plane is just rotating off the runway. I promise you it was not anywhere near supersonic speed. |
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Posted: 10/12/2007 2:05:39 PM EDT
[#29]
For that matter, I've seen "angel fuzz" form off the wingtips of a Piper Archer when a student nearly overstressed the poor thing in a tight turn. An Archer doesn't go anywhere near mach 1. |
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Posted: 10/12/2007 2:13:05 PM EDT
[#30]
Back in the mid-1980s, commonly known as the Turbo Era of Formula One auto racing, the cars were very light and had tremendous horsepower. Four and six-cylinder, 1.5-liter engines made 1,500 horsepower. In order to have even the slightest prayer of transferring any of that power to the ground, the cars were fitted with massive wings. At the more humid venues, it was not uncommon to see the water literally being squeezed out of the air by the cars at anything above 150mph.
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Posted: 10/12/2007 2:27:45 PM EDT
[#31]
Yes, you CAN get condensation far below Mach 1. But it has to be quite humid. Note in the posted video, there are portions of the flight where the cone disappears.
But the SHAPE of the cone is most perfect at near transonic velocities. |
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