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Near-record winds over the Northeast push passenger planes to speeds over 800 mph (wamu.org)

submitted 9 months ago by [email protected] to c/[email protected]

37 comments fedilink hide all child comments

Strong high-altitude winds over the Mid-Atlantic sped up sky traffic on Saturday night, getting passengers on at least two commercial planes to their destinations early, after both aircraft hit supersonic speeds topping 800 mph.

Winds at cruising altitude peaked at about 265 mph, according to the Washington, D.C., area National Weather Service office — the second-highest wind speed logged in the region since recordings began in 1948. The highest-ever wind speed recorded in the area at a similar altitude was 267 mph on Dec. 6, 2002.

“For those flying eastbound in this jet, there will be quite a tail wind,” the NWS warned in a tweet.

Sure enough, that tailwind helped cut down the flight time for passengers on a Virgin Atlantic flight from D.C. to London by 45 minutes, according to the tracker FlightAware.

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[–] [email protected] 24 points 9 months ago* (last edited 9 months ago) (3 children)

The supersonic claim reeks of bullshit. Humans had a hell of a time engineering a plane that could withstand that speed, and I'd guess passenger jets would tear apart.

“Although its ground speed — a measure that combines the plane’s actual speed and the additional push from the wind — was greater than the speed of sound, it was still moving through the surrounding air at its ordinary cruise speed. It just so happened that the surrounding air was moving unusually fast,” the Post reported.

Oh! Never knew what "ground speed" meant. So no, those planes were not leaving a sonic boom. Not even close to supersonic at typical altitudes.

(Apologies, don't know how to format a table on here.)


Sea level	15 °C (59 °F)	761

11,000 m−20,000 m (Cruising altitude of commercial jets, and first supersonic flight )	−57 °C (−70 °F)	660

29,000 m (Flight of X-43A )	−48 °C (−53 °F)	673

[–] [email protected] 10 points 9 months ago* (last edited 9 months ago) (1 children)

So you are right they were not going supersonic speeds, not even close. Yes their ground speed exceeded the speed of sound, but ground speed is only meaningful with how fast the plane is going to get to its destination. The plane only cares about air speed.

So it is all about the frame of reference. For a plane in flight the air is in a different frame of reference than the ground. To be supersonic the plane needs to be moving supersonic speeds in relation to the air not the ground.

Also just to make life more fun supersonic is not a transition that happens at a set speed. It is actually pressure dependent. At standard pressure and temperature it is 786mph, but it will go up and down with changes to pressure and temperature.

The true definition of supersonic is when the air the plane is pushing is no longer able to flow around the plane and instead is compressed in front of it. But that definition is hard to put on an air speed indicator so they just use 786mph better known as Mach 1.0.

Thanks for coming to my TED talk.

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[–] Sculptor9157 1 points 9 months ago (1 children)

Yes, we know this, but can you expound upon how the penguins factor in?

[–] 9488fcea02a9 3 points 9 months ago (1 children)

The in flight entertainment system runs linux

[–] [email protected] 2 points 9 months ago* (last edited 9 months ago)

I all ready covered that 😋

https://lemmy.world/post/11881718

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[–] [email protected] 8 points 9 months ago (1 children)

Ah so that's how aliens fly supersonic without breaking the sound barrier. Just move the air around the craft in the direction they're going! Problem solved.

[–] [email protected] 2 points 9 months ago (1 children)

The aliens just move spacetime (with the air included) next to their ships around with their warp drives around. Don't you watch any Star Trek?

[–] [email protected] 1 points 9 months ago* (last edited 9 months ago)

Fuck I'm such an idiot!

[–] [email protected] 0 points 9 months ago

I’d guess passenger jets would tear apart.

Not initially. Supersonic flows disrupt the airflow around the wings, control surfaces and the fuselage in general, so the plane just gets out of control. Since gravity exists, that means the plane will begin to drop, accelerating even more. At some point, the airflow will tear the fuselage apart, but if not, the collision with the ground surely will.

Look up the coffin corner for some interesting explanations of the problems around there.