PPRuNe Forums

PPRuNe Forums (https://www.pprune.org/)
-   Rumours & News (https://www.pprune.org/rumours-news-13/)
-   -   Virgin Atlantic Boeing 787-9 Hits 801 mph Ground Speed Due to Jet Stream (https://www.pprune.org/rumours-news/618578-virgin-atlantic-boeing-787-9-hits-801-mph-ground-speed-due-jet-stream.html)

Private jet 22nd Feb 2019 14:02

Fastest I've ever done was "only" 604 kt G/S, (145 kt T/W comp) , but I was flying a CL604 at the time so I thought that was very appropriate! Also was an Atlantic eastbound, Bangor Maine - Luton I think the airbourne time was around 5h 30 (can't remember) I only have the sector time in my book. Quite good for a Chally I think. Good routing close to the great circle, on the jetstream, no delays on arrival. Perfect apart from the fact it was bump bump bump for hours. Trying to eat or drink anything was just aim and hope haha.

5LY 22nd Feb 2019 14:30

To answer NWA SLF, In my days flying out of Seoul we had a daily schedule to Hawaii on the 777. Between Japan and Hawaii we would get very strong jet streams. I several times broke 700 knots ground speed (just over 800 mph).

GordonR_Cape 22nd Feb 2019 17:50

Dumb question (not a pilot): What was the approximate indicated airspeed (IAS) on these flights? Was the ground speed (sum of true airspeed plus wind vector) more than twice the IAS? If so, is that interesting in any way, or just a numerical coincidence?

RodH 22nd Feb 2019 19:08

Back in the 70's I was a F/O on a B727-100 Flying from Perth in Western Australia to Melbourne in Victoria.
At one stage over the great Australian bight we had +225kts tail wind at FL310 and a G/S of 750kts for about 30 minutes. We did wind the old girl up to M.89 just for while.
The dear old B727-100 could really get a move on if needed.
Lovely to fly as well.

eckhard 22nd Feb 2019 20:14


Originally Posted by GordonR_Cape (Post 10397752)
Dumb question (not a pilot): What was the approximate indicated airspeed (IAS) on these flights? Was the ground speed (sum of true airspeed plus wind vector) more than twice the IAS? If so, is that interesting in any way, or just a numerical coincidence?

Around 250-280kts, depending on altitude.

DaveReidUK 22nd Feb 2019 20:25


Originally Posted by GordonR_Cape (Post 10397752)
Dumb question (not a pilot): What was the approximate indicated airspeed (IAS) on these flights? Was the ground speed (sum of true airspeed plus wind vector) more than twice the IAS? If so, is that interesting in any way, or just a numerical coincidence?

The relationship between IAS and TAS isn't really affected by whether there's a tailwind or headwind.

I'm looking at an overflying EK B77W that's reporting (via Mode S) a TAS of 476 kts and IAS of 289 kts, which is pretty typical. Given those 200 kts+ tailwind components that we're discussing, that would give a GS that's well over double the IAS, but I wouldn't attach any particular significance to that.

Private jet 22nd Feb 2019 20:51


Originally Posted by GordonR_Cape (Post 10397752)
Dumb question (not a pilot): What was the approximate indicated airspeed (IAS) on these flights? Was the ground speed (sum of true airspeed plus wind vector) more than twice the IAS? If so, is that interesting in any way, or just a numerical coincidence?

The cruise speed controlling parameter is Mach number. (In fact the later part of the climb too but lets not complicate things) The TAS equivalent of that is dependant on the temperature outside at that location and flight level. TAS is IAS corrected for non ISA sea level air density which is a factor of the flight level & the temperature at that level. Yes I know clear as mud, but like many things once it "clicks" and see it all in action it's obvious. But to give you a "ballpark" set of numbers ; FL360 Temp ISA (-56) M 0.80 TAS 460 IAS 265 The groundspeed is the TAS plus or minus tailwind/headwind component.

Bellerophon 22nd Feb 2019 22:20

togsdragracing

...is this stuff measured wheels off to wheels down, or gate to gate?...

As DaveReidUK has said, no such thing as a dumb question in aviation. Dumb statements are another matter!!

This time was measured from wheels off to wheels on - as is usually the case - but I've been told the flight wasn't very much over 3 hours gate to gate!


RomeoTangoFoxtrotMike

He was the First Officer - so a good guess - but not a correct one! :)

Private jet 22nd Feb 2019 23:06


Originally Posted by Bellerophon (Post 10397972)
togsdragracing

...is this stuff measured wheels off to wheels down, or gate to gate?...

As DaveReidUK has said, no such thing as a dumb question in aviation. Dumb statements are another matter!!

This time was measured from wheels off to wheels on - as is usually the case - but I've been told the flight wasn't very much over 3 hours gate to gate!


RomeoTangoFoxtrotMike


He was the First Officer - so a good guess - but not a correct one! :)

So why was that one faster than normal? AFAIK the Concordes flew on fixed tracks and were above the jetstream winds for the cruise portion.

rjtjrt 23rd Feb 2019 00:11


Originally Posted by RodH (Post 10397807)
Back in the 70's I was a F/O on a B727-100 Flying from Perth in Western Australia to Melbourne in Victoria.
At one stage over the great Australian bight we had +225kts tail wind at FL310 and a G/S of 750kts for about 30 minutes. We did wind the old girl up to M.89 just for while.
The dear old B727-100 could really get a move on if needed.
Lovely to fly as well.

Rod, pretty impressive.
How did you measure the GS?
I assume out of range for DME in the Bight. Pre GPS of course.
I can’t recall if TAA or Ansett 727-100’s had inertial, but doubt it.

bia botal 23rd Feb 2019 07:44


FE Hoppy 23rd Feb 2019 14:13

If only i'd known this was a thing I would have been having kittens every time we flew eastbound across the pond.


All times are GMT. The time now is 23:42.


Copyright © 2024 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.