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The Speed of Sound

PUTZ

Grizzled Veteran
Nov 21, 2005
4,561
634
Baltimore, MD, USA
Kewl, no? :cool::eek::D

1601_1.jpeg


http://www.sportsshooter.com/news/1601
 
[CoFR]BooBoo said:
Compression (shock) wave created as the plane passed mach 1. Very common effect, dependent only on the humidity in the air.

Aye, what you are seeing there is the shockwave of breaking the sound barrier pounding the air into vapour, or rather, the humidity in the air, happens every time a plane breaks the sound barrier in medium to high air humidity.
It only lasts a split second though, you barely notice it, but a high-speed camera can capture it.

Thats also why you see white lines trailing from the wingtips when a plane turns sharply, the wingtips (and any other sharp angle on the plane, like air intakes) are pounding the air so hard its turning into visible vapour trailing off the plane, looks very cool.
 
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Somewhat related, on a day of high humidity I saw a large commercial jet coming in for a landing suddenly produce huge "contrails" enveloping the entire wing!

It was very dramatic (sunset light helped), and I'm not sure, but I thought I saw the plane pull out of the landing.

It happened so suddenly, and with the red sunset light, it almost looked like the wings burst into flame. Scared the hell out of my girlfriend.

Man I wish I had my camera... and had ESP to know that would happen so I could set up the shot...and wasn't busy driving on the 405 freeway at the time.
 
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Technically the plane does not need to break the sound barrier. THis is the reason most people in the USA are able to see it as going supersonic in residential areas is normally a no no.

Air travels at different speeds over the airframe. Wile the plane may be going .95 mach there may be areas, notably the wings, where the air is moving significantly faster.

From the front it is even cooler. It looks like a white ring with the center black and the aircraft climbing out of it. Most impressive one I ever saw was a B1B Lancer in Florida. Perfectly silent as it approached since it was going almost the same speed as the sound but when it got over you ROARRRRRRR!!!! Just about every car in the parkinglot with an alarm went off.
 
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Back in the '60's and '70's the Air Force used to routinely rattle the windows here in rural La.
Between England AFB in Alexandria and Barksdale in Shreveport we'd often get quite a show.

Watching a crop duster get buzzed and rocked at near ground level by an F15 shortly after 911 was pretty cool sight. (The crop duster was within the 10 mile no-fly zone of Grand Gulf nuclear power plant.) :eek:

But what really scared the crap outta me was a pair of a10 Wart Hogs. I was driving a tractor on the back 40 when a pair came skimming over the tops of the trees and right over the top of me. One then peeled off and did another flyby. Apparently to take me out. I figured they were hedge hopping and using tractors instead of tanks for practice.
 
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When I was working in a vineyard a year or so ago I saw quite a few fighters, the place was on a penninsula across the bay from Avalon airfield in VIC, which is where they have the big air shows down here. While working during the air show days we were treated to seeing all manner of fighter jets, from F-111's to F-14's and such, zipping around here and there. Even some big heavies like B-52's.

On one of the weekends I was walking my dog at the beach and a bloody pair of what looked to be F-15's (I wasn't too sure they were gone so fast) screamed by at very low altitude, didn't even hear them till they were passing over. My dog was freaked so bad she basically took off into the bush.

Another day, months and months later when the air show was long gone, we were hearing a little rumbling as we worked. Then out of nowhere an F/A-18 went screaming by at tree-top level!

It's an awesome sight to see these things in action.
 
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When I was 11 or 12 (way back in '74), we spent 8 months in Kuwait. When we were returning home we did a tour of Egypt, Iraq, Syria, and, best of all Lebanon.

You really had to see Beirut back then to appreciate what a complete shame the last 20 years have been for that country. The nearest I can compare it to is Sarajevo during the balkans war. But much worse.

Anyway, we hired a cabby for the day who took us on a great tour of his country. At the time I didn't realize it but we toured all around the Bekka Valley. We got reasonably close to the Golan. Close enough to see burnt out Syrian tanks from the last war.

Later we were wandering around a street in Beirut when we heard this very loud bang and rumble, like thunder but not. We were kind of puzzled. Our cabby friend explained it was the Israelis. Apparently, they frequently buzzed the country busting mach to remind the Syrians (and Lebanese) who was boss.
 
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I was in my old house one day, and all of a sudden, a large boom rattled the entire building; It felt as if someone crashed into the side of the building, but after running outside, I noticed no plane or vehicle. I later found out that the plane was 20-some miles away, and had broken the sound barrier on accident.


I also saw some UFOs from this location... a large glowing object lit up in the east, and then two more lit up, forming a pyramid. I pointed at them and asked an aquantaince what the objects were, and after they looked, they immediately vanished. A few days later I heard that several other people had spotted the objects out at a local park. Crazy stuff...
 
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