Aces High Bulletin Board

General Forums => The O' Club => Topic started by: Skuzzy on February 20, 2019, 09:44:57 AM

Title: Cruising at 800MPH
Post by: Skuzzy on February 20, 2019, 09:44:57 AM
Thought some of might get a kick out of this.

https://www.latimes.com/science/la-sci-sn-jet-stream-flight-20190219-story.html

What a tail wind!
Title: Re: Cruising at 800MPH
Post by: Puma44 on February 20, 2019, 10:54:39 AM
Going the other direction would be like the slow boat to China.
Title: Re: Cruising at 800MPH
Post by: Shuffler on February 20, 2019, 11:35:15 AM
I had read that this morning. Quite a cruise speed.
Title: Re: Cruising at 800MPH
Post by: Drano on February 20, 2019, 12:00:02 PM
Had a chopper fly by fast and low over the house last night. Didn't sound like one of the usual suspects so I brought up flightradar24 to see what it was. Turned out to be a medevac heading towards Baltimore. Saw a large airliner icon passing north of me so I checked it out. Was an A380 going from LAX to Paris at 37k....and 700 or so mph. So I kinda figured that was what was going on! Don't imagine any of the passengers get a fuel discount on that?hehe


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Title: Re: Cruising at 800MPH
Post by: Skuzzy on February 20, 2019, 12:15:42 PM
Going the other direction would be like the slow boat to China.

I would hope the flight plan would route the plane away from the jet stream, in that case.  Hehe,..but it would be funny to watch.
Title: Re: Cruising at 800MPH
Post by: Wiley on February 20, 2019, 12:43:36 PM
So it was supersonic.  Would it create a sonic boom?  Or is a sonic boom dependent on air speed not ground speed?

Wiley.
Title: Re: Cruising at 800MPH
Post by: Shuffler on February 20, 2019, 01:01:01 PM
So it was supersonic.  Would it create a sonic boom?  Or is a sonic boom dependent on air speed not ground speed?

Wiley.

The plane was not supersonic airspeed. It had a very strong tail wind. The high speed given was ground speed, roughly plane airspeed plus tail wind speed.The airliner in question is not capable of supersonic flight.
Title: Re: Cruising at 800MPH
Post by: Wiley on February 20, 2019, 01:03:55 PM
The plane was not supersonic airspeed. It had a very strong tail wind. The high speed given was ground speed, roughly plane airspeed plus tail wind speed.The airliner in question is not capable of supersonic flight.

So it's dependent on airspeed then.  Ok.

Wiley.
Title: Re: Cruising at 800MPH
Post by: Drano on February 20, 2019, 01:57:33 PM
Yeah I think of that thing went supersonic there'd be a boom! Just another kind of boom!

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Title: Re: Cruising at 800MPH
Post by: Puma44 on February 20, 2019, 02:08:05 PM
I would hope the flight plan would route the plane away from the jet stream, in that case.  Hehe,..but it would be funny to watch.

Sometimes, that isn’t feasible but, the dispatchers do try and work around it.  Many times, Mother Nature is in a bad mood and not very cooperative.
Title: Re: Cruising at 800MPH
Post by: Skuzzy on February 20, 2019, 02:22:29 PM
That's true.  Momma nature can be a biotch at times.

That jolt, when they entered the stream had to be a bit harrowing.
Title: Re: Cruising at 800MPH
Post by: Puma44 on February 20, 2019, 02:33:52 PM
Sometimes there’s a jolt of turbulence.  Other times, the ground speed indicator just starts increasing to abnormally high speed and it’s nice and smooth.
Title: Re: Cruising at 800MPH
Post by: Skuzzy on February 20, 2019, 02:48:04 PM
Any chance of losing lift when entering a tail wind stream moving at that velocity?  Or is the approach to it such that the tail wind increases slow enough to allow the plane time to accelerate into it?
Title: Re: Cruising at 800MPH
Post by: Shuffler on February 20, 2019, 03:41:15 PM
Any chance of losing lift when entering a tail wind stream moving at that velocity?  Or is the approach to it such that the tail wind increases slow enough to allow the plane time to accelerate into it?

At that alt I imagine the craft is moving at cruise. That speed minus the tail wind would have to be below stall.
Title: Re: Cruising at 800MPH
Post by: Oldman731 on February 20, 2019, 03:50:16 PM
Any chance of losing lift when entering a tail wind stream moving at that velocity?  Or is the approach to it such that the tail wind increases slow enough to allow the plane time to accelerate into it?


Never heard of wind shear in the flight levels.

Suppose it's possible.

- oldman
Title: Re: Cruising at 800MPH
Post by: davidpt40 on February 20, 2019, 05:18:09 PM

Never heard of wind shear in the flight levels.

Suppose it's possible.

- oldman

No he means loss of relative airspeed due to the tail wind.  Shear literally means transverse, as in a vertical wind.
Title: Re: Cruising at 800MPH
Post by: Oldman731 on February 20, 2019, 05:58:03 PM
No he means loss of relative airspeed due to the tail wind.  Shear literally means transverse, as in a vertical wind.


https://www.aopa.org/news-and-media/all-news/2002/july/flight-training-magazine/wind-shear-max-power

You shouldn't lose air speed (not ground speed) by moving into a different air mass, absent wind shear.

- oldman
Title: Re: Cruising at 800MPH
Post by: Busher on February 20, 2019, 08:32:20 PM
Any chance of losing lift when entering a tail wind stream moving at that velocity?  Or is the approach to it such that the tail wind increases slow enough to allow the plane time to accelerate into it?

No Skuzzy. The wind change is never rapid enough or dramatic enough to affect the airplane in that way. But, as Puma mentioned, sometimes transitioning to the core of the Jetstream is smooth as glass and other times, the turbulence can be "biblical".
You guys should know that when airline pilots see a "cool" groundspeed number like that, they smile but it isn't really all that exciting. Everyone of them just wants to do their 80 to 85 hours for the month and go home. And when you're on the last leg home, no speed is fast enough.
Title: Re: Cruising at 800MPH
Post by: Vraciu on February 20, 2019, 09:10:31 PM

https://www.aopa.org/news-and-media/all-news/2002/july/flight-training-magazine/wind-shear-max-power

You shouldn't lose air speed (not ground speed) by moving into a different air mass, absent wind shear.

- oldman

It depends on the rate of change.   You most definitely CAN lose airspeed when transitioning from one air mass to another. 
Title: Re: Cruising at 800MPH
Post by: Vraciu on February 20, 2019, 09:11:55 PM
No Skuzzy. The wind change is never rapid enough or dramatic enough to affect the airplane in that way. But, as Puma mentioned, sometimes transitioning to the core of the Jetstream is smooth as glass and other times, the turbulence can be "biblical".
You guys should know that when airline pilots see a "cool" groundspeed number like that, they smile but it isn't really all that exciting. Everyone of them just wants to do their 80 to 85 hours for the month and go home. And when you're on the last leg home, no speed is fast enough.

But the one thing we can’t stand is seeing that wind on the nose...   Makes me want to reach for a pen and stab myself in the eye.    :bhead
Title: Re: Cruising at 800MPH
Post by: Puma44 on February 20, 2019, 10:52:45 PM
One thing for sure, supersonic level ground speed is beyond way cool! :aok
Title: Re: Cruising at 800MPH
Post by: Vraciu on February 20, 2019, 11:20:06 PM
One thing for sure, supersonic level ground speed is beyond way cool! :aok

 :cheers:

I topped 750 once.  That was a bookmark moment. 
Title: Re: Cruising at 800MPH
Post by: Puma44 on February 21, 2019, 10:03:55 AM
No Skuzzy. The wind change is never rapid enough or dramatic enough to affect the airplane in that way. But, as Puma mentioned, sometimes transitioning to the core of the Jetstream is smooth as glass and other times, the turbulence can be "biblical".
You guys should know that when airline pilots see a "cool" groundspeed number like that, they smile but it isn't really all that exciting. Everyone of them just wants to do their 80 to 85 hours for the month and go home. And when you're on the last leg home, no speed is fast enough.
Any chance of losing lift when entering a tail wind stream moving at that velocity?  Or is the approach to it such that the tail wind increases slow enough to allow the plane time to accelerate into it?

As Busher said, it’s typically smooth or Biblical. Gain or loss of speed is pretty much an insignificant concern in the big scheme of things.  Now, that last leg home, like he said, is the most important one of the trip.  “Direct” and “Best forward speed” are the two most sought out favorite calls from ATC on that last leg.
Title: Re: Cruising at 800MPH
Post by: Vulcan on February 21, 2019, 01:25:32 PM
We have a jet stream that flows from Australia to NZ and is very consistent. It will frequently drop a 4 hour flight down to 3 hours.
Title: Re: Cruising at 800MPH
Post by: Vulcan on February 21, 2019, 04:10:56 PM
LOL strayans....

(https://uploads.tapatalk-cdn.com/20190221/2072f37ae95d014c004572c162364288.jpg)
Title: Re: Cruising at 800MPH
Post by: icemaw on February 24, 2019, 01:16:44 PM
   You used to be able to simulate these effects in game. We used to use it in KOTH for our alt cap. Very interesting first time you fly into one.