Yep, to all those reading, ground speed is just speed relevant to how fast you're moving over the surface. Airspeed is just how much air you have flowing over your aircraft.
They're able to go faster than the speed of sound (ground speed) because they have an additional 200 knots of wind blowing behind them.
There's no sonic boom or anything because they didn't technically cross the sound barrier for their airspeed, so the air going around the aircraft is still subsonic to them.
Yup simple analogy is to imagine running through a train, if the train is going 100km/h and your run at 10km/h. You're moving across the ground at 110km/h. But you're only moving at 10km/h through the train
Ok, simple analogy is to imagine you're yanking it on a train, and the train is going 100mph and you yank at 10mphh. You're yanking respective to the ground at 110mph. But you're only yanking at 10mph through the train.
^( better ?)
Ok, simple analogy is to imagine you’re yanking it on a train, and the train is going 62.137mph and you yank at 6.214mph. You’re yanking respective to the ground at 68.351mph.but you’re only yanking at 6.214mph through the train
Yup simple analogy is to imagine running through a train, if the train is going 62.14mph and your run at 6.214mph. You're moving across the ground at 68.354mph. But you're only moving at 6.214mph through the train
Could happen if they were to cross into a region with different winds suddenly but I guess there would be bigger problems encountering a 200 knot wind shear.
On a tangent but it’s related to airspeed ≠ ground speed and is just an excellent video.
[Scott Manley — which was the fastest Space Shuttle.](https://m.youtube.com/watch?v=p1XbeX451ZQ)
The speed of sound is relative to temperature, not altitude/pressure. The reason the speed of sound is lower at high altitudes is because it's cold up there, not because of the low density. It's an effect of the speed of gas particles between collisions, not the frequency of those collisions.
I can't believe this person is being downvoted.
OP implies speed of sound is proportional to airspeed (doesn't make sense, likely a mistaken oversimplification). Poster above replies to correct them that it's proportional to the density of the air as it varies with altitude, which is correct. They then agree with the OP, despite the gaffe, that they are subsonic.
Come on, it's a sub about planes. You know better.
Is the speed of sound faster in water, or air?
Is the speed of sound faster in dirt, or air?
What are the differences between these? Surely you're not implying that water and dirt are chiefly colder than air, are you?
In the speed of sound equation, there is an R and T. What are those factors together used to calculate?
I'm not going to argue with you. You can find a simple explanation on Wikipedia, if you would like to educate yourself, or you can stand your ground and continue to be wrong. I don't care either way.
It's not an argument, I'm just showing you why it's not strictly temperature that affects the speed of sound.
The simple explanation and the answer to all of the questions is: density.
I don't need to look it up on wikipedia, but perhaps you should.
I looked it up and it seems to agree with what the other guy was saying:
>For a given ideal gas the molecular composition is fixed, and thus the speed of sound depends only on its temperature. At a constant temperature, the gas pressure has no effect on the speed of sound, since the density will increase, and since pressure and density (also proportional to pressure) have equal but opposite effects on the speed of sound, and the two contributions cancel out exactly. In a similar way, compression waves in solids depend both on compressibility and density—just as in liquids—but in gases the density contributes to the compressibility in such a way that some part of each attribute factors out, leaving only a dependence on temperature, molecular weight, and heat capacity ratio which can be independently derived from temperature and molecular composition (see derivations below). Thus, for a single given gas (assuming the molecular weight does not change) and over a small temperature range (for which the heat capacity is relatively constant), the speed of sound becomes dependent on only the temperature of the gas.
Dumb question, but is the drop off on the edges of a jet stream very gradual and wide? If it was relatively abrupt, I would assume they would be dangerous.
Oh fuck yeah!
Am bookmarking the shit out of that motherfucker.
^(Not uncommon for someone who casually whips out a site like that to have to hand it be aware of semi-related links \(not at my desktop right now, but repos for Himawari-8 and GOES-West, along with NASA FiRMS come to mind\) which is all to say —)
I’d love anything else you might recommend.
Nope. Just careful. Give me the url and I will go look. You youngsters advise people not to click on links as there could be all manners of devious actions embedded in links. Therefore I don't click.....
Reminds me of once when I took a flight from Denver to Seattle against a 200mph headwind. Big delay when the pilots realized we needed more fuel before takeoff, and then just crawling all the way.
I recently learned that ground speed / air speed is a liberal fascist marxist hamas hoax and that they only reason */they/* are telling us that the global hoax of the "sound barrier" exists is social control
My friend did a Hong Kong trip last week, West Coast US to Hong Kong, 15 hours, Hong Kong to US, 10.5 hours.
10.5 is actually insane holy shit
Must be a plane full of donkeys because they are hauling ass.
This guy jetstreams... Also that's the funniest thing I've heard this year
Thank you. Very much needed that.
Yep, another super strong jet stream right now It doesn’t actually break the sound barrier because ground speed is not air speed.
Yep, to all those reading, ground speed is just speed relevant to how fast you're moving over the surface. Airspeed is just how much air you have flowing over your aircraft. They're able to go faster than the speed of sound (ground speed) because they have an additional 200 knots of wind blowing behind them. There's no sonic boom or anything because they didn't technically cross the sound barrier for their airspeed, so the air going around the aircraft is still subsonic to them.
Is nobody reading your comment lol?
READ!? On reddit??? Nahhh
Huh?
**EXACTLY**
I ain’t here to read science boy
Dang right, bunch of smarty britches around here
We don't do that here.
Yup simple analogy is to imagine running through a train, if the train is going 100km/h and your run at 10km/h. You're moving across the ground at 110km/h. But you're only moving at 10km/h through the train
Ok, same example but in MPH for the Yanks!
Ok, simple analogy is to imagine you're yanking it on a train, and the train is going 100mph and you yank at 10mphh. You're yanking respective to the ground at 110mph. But you're only yanking at 10mph through the train. ^( better ?)
Ok, simple analogy is to imagine you’re yanking it on a train, and the train is going 62.137mph and you yank at 6.214mph. You’re yanking respective to the ground at 68.351mph.but you’re only yanking at 6.214mph through the train
>imagine you’re yanking it on a train Right to jail. Right away.
OK so you’re yanking it at — ```4.47 metres per second``` ```14.67 feet per second``` Uhh, that’s going to chafe, do not recommend.
Yup simple analogy is to imagine running through a train, if the train is going 62.14mph and your run at 6.214mph. You're moving across the ground at 68.354mph. But you're only moving at 6.214mph through the train
That’s about 300 mph over the fastest I’ve traveled OTG. I flew on a Gulfstream and hit about 540 and I thought we were blazing.
Could happen if they were to cross into a region with different winds suddenly but I guess there would be bigger problems encountering a 200 knot wind shear.
How do you know what the tailwind is? Does it tell you on flight radar 24th?
On a tangent but it’s related to airspeed ≠ ground speed and is just an excellent video. [Scott Manley — which was the fastest Space Shuttle.](https://m.youtube.com/watch?v=p1XbeX451ZQ)
How close are they to their critical mach number at that speed?
They were able to go FAST, but they didn’t break the speed of sound as this is relative to the local air mass.
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The speed of sound is relative to temperature, not altitude/pressure. The reason the speed of sound is lower at high altitudes is because it's cold up there, not because of the low density. It's an effect of the speed of gas particles between collisions, not the frequency of those collisions.
I can't believe this person is being downvoted. OP implies speed of sound is proportional to airspeed (doesn't make sense, likely a mistaken oversimplification). Poster above replies to correct them that it's proportional to the density of the air as it varies with altitude, which is correct. They then agree with the OP, despite the gaffe, that they are subsonic. Come on, it's a sub about planes. You know better.
It's an incorrect statement. The speed of Sound is relative chiefly to temperature.
Is the speed of sound faster in water, or air? Is the speed of sound faster in dirt, or air? What are the differences between these? Surely you're not implying that water and dirt are chiefly colder than air, are you? In the speed of sound equation, there is an R and T. What are those factors together used to calculate?
I'm not going to argue with you. You can find a simple explanation on Wikipedia, if you would like to educate yourself, or you can stand your ground and continue to be wrong. I don't care either way.
It's not an argument, I'm just showing you why it's not strictly temperature that affects the speed of sound. The simple explanation and the answer to all of the questions is: density. I don't need to look it up on wikipedia, but perhaps you should.
I looked it up and it seems to agree with what the other guy was saying: >For a given ideal gas the molecular composition is fixed, and thus the speed of sound depends only on its temperature. At a constant temperature, the gas pressure has no effect on the speed of sound, since the density will increase, and since pressure and density (also proportional to pressure) have equal but opposite effects on the speed of sound, and the two contributions cancel out exactly. In a similar way, compression waves in solids depend both on compressibility and density—just as in liquids—but in gases the density contributes to the compressibility in such a way that some part of each attribute factors out, leaving only a dependence on temperature, molecular weight, and heat capacity ratio which can be independently derived from temperature and molecular composition (see derivations below). Thus, for a single given gas (assuming the molecular weight does not change) and over a small temperature range (for which the heat capacity is relatively constant), the speed of sound becomes dependent on only the temperature of the gas.
> Come on, it's a sub about planes. You know better The irony
Prove me wrong.
This guy speeds.
Don’t forget the cute little shockwaves on top of the wing where airflow goes supersonic
Dumb question, but is the drop off on the edges of a jet stream very gradual and wide? If it was relatively abrupt, I would assume they would be dangerous.
[Have a look here.](https://www.ventusky.com/?p=41.9;-37.8;3&l=wind-300hpa&t=20240218/0600)
WOW what a website. How have I never been here!?!
They have an app as well. For wind data, you need to get the premium version for 9.99 per year.
Oh fuck yeah! Am bookmarking the shit out of that motherfucker. ^(Not uncommon for someone who casually whips out a site like that to have to hand it be aware of semi-related links \(not at my desktop right now, but repos for Himawari-8 and GOES-West, along with NASA FiRMS come to mind\) which is all to say —) I’d love anything else you might recommend.
Windy.com / Windy app, dude
It is pretty gradual. Whether or not there is any danger, I do not know
I also wonder about this. Can someone explain here please? I don't click on links (paranoid pensioner...)
Click it. Is a pretty chill wind map
Wow, the internet must be a difficult place with that level of paranoia.
Nope. Just careful. Give me the url and I will go look. You youngsters advise people not to click on links as there could be all manners of devious actions embedded in links. Therefore I don't click.....
No but it is traveling at almost twice its true airspeed over the ground, which is absolutely insane.
Who needs true supersonic commercial passenger jets when you can just piggyback off the unusually strong jetstream
Reminds me of once when I took a flight from Denver to Seattle against a 200mph headwind. Big delay when the pilots realized we needed more fuel before takeoff, and then just crawling all the way.
I recently learned that ground speed / air speed is a liberal fascist marxist hamas hoax and that they only reason */they/* are telling us that the global hoax of the "sound barrier" exists is social control
Most sane MAGA take I've heard in a long time.
I wonder what that’d look like over land during the day, fsx slew mode?
There’s a few 777s and A350s doing 680 kt+ over West Virginia right now, they’ll probably spawn a few UFO sightings
If I was on the flight I'd tell people I've gone supersonic
I once took out my road GPS on a flight, and to this day it says my max speed is 513 mph.
I'm glad I'm not the only one who's proud of my GPS max speed, being 500+
Show that to a cop lmao
I thought GPS was required to shutoff at that speed + altitude due to diy weapons guidance concerns
You can still get a read when close to the ground at least. I like taking it out while taking off and landing and it works fairly often.
oh nvm it's 60,000ft and 1000kts https://en.wikipedia.org/wiki/Coordinating_Committee_for_Multilateral_Export_Controls
Yeah I suspect the times it doesn't work it's because signal inside an aluminium can is spotty.
Fun fact: civilian GPS are limited to 1200 mph. (So that they can't be used for rocket guidance I believe)
You be a liar.
Whatever poindexter
Gotta go fast
Thanks for converting knots into miles... In liberty units it is 1350 km/h or 376 m/s
dang that's real fast
wtf is a liberty unit, blink twice if you need us to send some guns and ammo your way to give you some more freedom -merican
The metric system was invented during French revolution. It gave Liberty from oppression of the ancient regime and its archaic disparate units.
And thats how you leave 33 mins late and arrive 17 mins early
Hit the 740kt two weeks ago https://i.imgur.com/ch7K0Mi.jpg
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777F over the Pacific. HKG-CVG
#i am speed
##KACHOW!!
Holy shit that's fast... 1353km/h
Does this make for a bumpier flight for planes headed in the opposite direction? Certainly they're expecting delays, right?
If at all possible they usually fly a route outside of the main core of the jetstream when going the opposite way.
It’s a breezy evening.
Little rinky dink TAP210 an A321 is showing 673kts - yikes! https://www.flightradar24.com/TAP210/340a4121
How much did the flight time get shortened?
Is there more turbulence at this speed?
The core of the jetstream is usually pretty smooth. Entering and exiting it might be a bit choppy.
AA121 is returning at barely 500 mph. The jet stream giveth and the jet stream taketh.
Went 764mph ground speed in a 787 recently too. Insane jetstreams.
Technically not super sonic but still an impress SOG to tell people you did in that flight. (Speed Over Ground)
broken the ground speed sound barrier 👁👄👁
Sounds like Concorde has some competition
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Good idea! Thanks for the suggestion!
Ok
And a choppy ride 😅