NY - London flight hits supersonic speeds due to Jetstream

Speed over the surface of the earth (groundspeed) is not the same as speed through the air mass in which you are flying.

Further, this statement makes no sense.

 

Their airspeed was never supersonic, just the speed over the ground. Same thing as a boat traveling upstream vs downstream.

 

Is there a treadmill to be mentioned here?

 

I was once on a BA 747 flight like that - the jet stream was reputedly 180 MPH, and it made our ground speed near-sonic, with the result that we arrived over London one hour early. But then we had to hold for around 40 minutes, because they weren't ready for us yet at Heathrow.

 

Great, great post.

 

No stress on the airframe from large tailwinds. The plane has no idea about ground speed, it only knows how fast it is flying through the air.

I am surprised they made such a big deal about that ground speed. Attached is a photo of a flight I made a year ago from Vegas to Akron in a Beechcraft Premier (small jet). As you can see from the pic, I had a 204 knot tailwind, which gave me a 652 knot ground speed. 652 knots = 750mph. Since 777's are at least 25 knots faster than I am, 800 mph would have been more newsworthy.
Image Unavailable, Please Login

 

The exact same thing happened to us when flying back from London to Seattle but it wasn't due to tail winds. We were on a hotrod 747SP that the captain said that would make up for an hour delayed departure at Heathrow. He did it but we were delayed at Seattle because of traffic.

 

Here's my first "700" this year. 703 kts is 808 mph.

Fastest I've seen is 752 kts, which is 865 mph.

Not sure if I'll ever beat 752!

Had to push it to .875 to get the 700. The 747-8 won't let you fly in the top yellow arc whereas the 400 will.
Image Unavailable, Please Login

 

As soon as I say how fast I have been, some SR-71 jock will step in and beat me by a mach number. Then an astronaut will step in with 25,000 fps/14,800 knots. Cannot win.

 

It might take a while for someone to come along and top whatever number you could throw out. I know a guy who used to drive F-111's before he retired and started flying heavies in the reserve. He said they would fly low levels at 300 feet and 540 ground- but the plane could do a lot more. You could melt the paint he said. In am absolute scale 540 g is normal, but down low thats also about 540 indicated, which is impressive.

 

All in good time, my pretty. Alllll iin gooood tiiiime.


Sent from my iPhone using Tapatalk

 

Sound barrier is only broken when flying through the AIR at 758 MPH.

If the air is pushing you (wind) 100 MPH then you add that to what the plane is doing with it's engine. So if you're going 658 MPH and the wind is pushing you 100 MPH then you are moving 758 MPH over the ground but still only 658 MPH though the AIR.

 

Now that is much more newsworthy! Not sure if I will ever be in the 700 knot club.

 

Except during a downwind turn then the laws of aerodynamics go out the window.

 

http://www.ferrarichat.com/forum/aviatorchat-com/435231-aircraft-physics-question.html

http://www.ferrarichat.com/forum/other-off-topic-forum/84930-airplane-physics-question.html

 

There's always someone with more money or better looks. Cannot win.

-F

 

The speed of sound is a function of temperature, which is a function of altitude. At sea level, with standard atmosphere, it is 1117 ft/s, or 762 mph. Between 40,000 msl and 100,000 msl, it is 971 ft/s, or 662 mph. Source: "Foundations of Aerodynamics," A. M. Kuethe and J. D. Schetzer.

 

Of course, you've probably all seen this before, but with all this discussion about "ground speed", this seems to be a good place to repeat Brian Shul's piece from his book "Sled Driver":

"We listened as the shaky voice of a lone Cessna pilot asked (Los Angeles) Center for a readout of his ground speed. Center replied: 'November Charlie 175, I'm showing you at ninety knots on the ground.'

Now the thing to understand about Center controllers, was that whether they were talking to a rookie pilot in a Cessna, or to Air Force One, they always spoke in the exact same, calm, deep, professional, tone that made one feel important. I referred to it as the 'Houston Center voice.' I have always felt that after years of seeing documentaries on this country's space program and listening to the calm and distinct voice of the Houston controllers, that all other controllers since then wanted to sound like that, and that they basically did. And it didn't matter what sector of the country we would be flying in, it always seemed like the same guy was talking. Over the years that tone of voice had become somewhat of a comforting sound to pilots everywhere. Conversely, over the years, pilots always wanted to ensure that, when transmitting, they sounded like Chuck Yeager, or at least like John Wayne. Better to die than sound bad on the radios.

Just moments after the Cessna's inquiry, a Twin Beech piped up on frequency, in a rather superior tone, asking for his ground speed. 'I have you at one hundred and twenty-five knots of ground speed.' Boy, I thought, the Beechcraft really must think he is dazzling his Cessna brethren. Then out of the blue, a navy F-18 pilot out of NAS Lemoore came up on frequency. You knew right away it was a Navy jock because he sounded very cool on the radios. 'Center, Dusty 52 ground speed check'. Before Center could reply, I'm thinking to myself, hey, Dusty 52 has a ground speed indicator in that million-dollar cockpit, so why is he asking Center for a readout? Then I got it, ol' Dusty here is making sure that every bug smasher from Mount Whitney to the Mojave knows what true speed is. He's the fastest dude in the valley today, and he just wants everyone to know how much fun he is having in his new Hornet. And the reply, always with that same, calm, voice, with more distinct alliteration than emotion: 'Dusty 52, Center, we have you at 620 on the ground.'

And I thought to myself, is this a ripe situation, or what? As my hand instinctively reached for the mic button, I had to remind myself that Walt was in control of the radios. Still, I thought, it must be done - in mere seconds we'll be out of the sector and the opportunity will be lost. That Hornet must die, and die now. I thought about all of our Sim training and how important it was that we developed well as a crew and knew that to jump in on the radios now would destroy the integrity of all that we had worked toward becoming. I was torn.

Somewhere, 13 miles above Arizona, there was a pilot screaming inside his space helmet. Then, I heard it. The click of the mic button from the back seat. That was the very moment that I knew Walter and I had become a crew. Very professionally, and with no emotion, Walter spoke: 'Los Angeles Center, Aspen 20, can you give us a ground speed check?' There was no hesitation, and the reply came as if was an everyday request. 'Aspen 20, I show you at one thousand eight hundred and forty-two knots, across the ground.'

I think it was the forty-two knots that I liked the best, so accurate and proud was Center to deliver that information without hesitation, and you just knew he was smiling. But the precise point at which I knew that Walt and I were going to be really good friends for a long time was when he keyed the mic once again to say, in his most fighter-pilot-like voice: 'Ah, Center, much thanks, we're showing closer to nineteen hundred on the money.'

For a moment Walter was a god. And we finally heard a little crack in the armor of the Houston Center voice, when L.A. came back with, 'Roger that, Aspen, your equipment is probably more accurate than ours. You boys have a good one.'"

 

do tell,and whats the highest alt you been too?