200 mile an hour tailwind!

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200 mile an hour tailwind!

#1 Post by Cacophonix » Tue Feb 19, 2019 8:47 pm

Who needs the Concorde, anyway? On Monday, somewhere over norther Pennsylvania, a Virgin Atlantic-flown Boeing 787 Dreamliner traveling from Los Angeles to London managed to go where few commercial planes have gone before: to a speed of 801 miles per hour.

As The Washington Post brought to light, pilots and aviation nerds were a-twitter about the Boeing's speed last night, taking to journalism's favorite social medium to broadcast their delight at seeing the giant numbers appear.

There is, of course, a catch: that 801-mph Vmax was the plane's ground speed, or the rate at which it was passing over the chilly landscape of PA below. As far as the 787 was concerned, however, it was still well within the performance envelope it was designed for, zipping along close to its established cruising speed of around 560 miles per hour.

How? It's a matter of airspeed versus groundspeed, of course.

Groundspeed, as it sounds like, is how fast a plane appears to be traveling from the vantage point of an observer on the solid, unmoving ground below. If you were the Flash and wanted to keep pace with the 787 above you yesterday, you'd have to be running along at 801 miles per hour to match it. Airspeed, on the other hand, is how fast a plane is traveling compared to the air around it—for example, how fast it might look to a balloon floating along in the same air. In the case of yesterday's speeding Dreamliner, that wind was a jet stream current flowing from west to east at faster-than-normal speeds; as The Washington Post pointed out, a weather balloon lofted from central Long Island's Upton, New York clocked the jet stream yesterday at a record 231 miles per hour. With wind that strong at the aircraft's back, even a 225-ton 787-9 can pick up a nice speed boost—in this case, enough to push it to speeds never before seen for its type, at least from the ground.
http://www.thedrive.com/news/26559/virg ... m-tailwind

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Re: 200 mile an hour tailwind!

#2 Post by G-CPTN » Tue Feb 19, 2019 9:15 pm

Whereas aircraft flying in the opposite direction would have struggled to achieve their schedules.

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Re: 200 mile an hour tailwind!

#3 Post by Stoneboat » Tue Feb 19, 2019 9:25 pm

I once saw 412 kt groundspeed with a G159. We were eastbound, and because it was cold and we were light we climbed to FL270. I had filed 295kt TAS which was what we were doing, so the tailwind was 120 kt. The boss came up front at the top of descent, and marveled at the speed. Made the remark that "If we only had to fly eastbound, we wouldn't need the Hawker." :D

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Re: 200 mile an hour tailwind!

#4 Post by Pontius Navigator » Tue Feb 19, 2019 9:52 pm

I recall in about '65 or '66 a Vulcan out of Goose Bay bound for Waddington experienced a strong tailwind.

Sensing the opportunity they went for a high mach run and did the 5 hour flight in 3.45 catching everyone at base on the hop as it was a Saturday and ATC and engineers were on minimal manning. Even more flat footed was the customs officer who was well late.

Their Doppler and nav displays were all maxed at 750 knots around 860 mph.

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Re: 200 mile an hour tailwind!

#5 Post by llondel » Wed Feb 20, 2019 3:21 am

It was a few years back, might have been October 2008 or Jan 2009, I was on a Virgin 747 crossing the Atlantic and the flight deck told us we'd joined that select group of people who'd achieved 800mph ground speed due to the impressive tailwind that night. We certainly turned up at Heathrow very early.

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Re: 200 mile an hour tailwind!

#6 Post by Alisoncc » Wed Feb 20, 2019 3:29 am

So if an aircraft were to exceed mach 1 by virtue of a strong tailwind would it still generate a sonic boom? I suspect not, but you never know.

Concord could have flown over land with no problems if followed by an aircraft with a big fan up front. =))

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Re: 200 mile an hour tailwind!

#7 Post by llondel » Wed Feb 20, 2019 4:33 am

No, because airspeed is still below the speed of sound.

I was once in a Dornier 328 when the captain told us we were doing about 450mph groundspeed. Our flight that would normally take an hour took a mere 45 minutes that day.

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Re: 200 mile an hour tailwind!

#8 Post by Ex-Ascot » Wed Feb 20, 2019 4:56 am

G-CPTN wrote:
Tue Feb 19, 2019 9:15 pm
Whereas aircraft flying in the opposite direction would have struggled to achieve their schedules.
They would be on different tracks.

We always proudly announced when we hit 1,000 km/hr. 800 mph is of course much faster.

I wonder what the turbulence was like around that jet stream.
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Re: 200 mile an hour tailwind!

#9 Post by Slasher » Wed Feb 20, 2019 8:32 am

I've seen 709kt by INS over the Pacific TYO-LAX over a NORPAC route yonks ago in an SQ 747 that lasted I think about 2 hours. High alt pressure pattern flying at its best.

IIRC that equated to a 195kt direct TW shoved up our arses. Smooth as a baby's bum cheek too.

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Re: 200 mile an hour tailwind!

#10 Post by Boac » Wed Feb 20, 2019 9:23 am

Pah! 200 mph is gnat's-widdle. I have seen an upper wind of 218 kts in my time.

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Re: 200 mile an hour tailwind!

#11 Post by Cacophonix » Wed Feb 20, 2019 9:30 am

Boac wrote:
Wed Feb 20, 2019 9:23 am
Pah! 200 mph is gnat's-widdle. I have seen an upper wind of 218 kts in my time.
I bet you laid off the baked beans after that Boac. =))

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Re: 200 mile an hour tailwind!

#12 Post by Boac » Wed Feb 20, 2019 10:19 am

No - I asked the c/crew for some curried beans and tried for 250kts but other chap objected :((

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Re: 200 mile an hour tailwind!

#13 Post by PHXPhlyer » Wed Feb 20, 2019 2:51 pm

IMAG0168.jpg
New Year's Day 2013

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Re: 200 mile an hour tailwind!

#14 Post by Cacophonix » Wed Feb 20, 2019 4:12 pm

PHXPhlyer wrote:
Wed Feb 20, 2019 2:51 pm
New Year's Day 2013
Great Lakes area bound on a winter's night with 200 knots up the yazoo! Mach .73 giving you an apparent +-Mach .94 when viewed from the ground. It is magic I tell you.
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Re: 200 mile an hour tailwind!

#15 Post by Ex-Ascot » Wed Feb 20, 2019 4:57 pm

PHXPhlyer wrote:
Wed Feb 20, 2019 2:51 pm
IMAG0168.jpg
New Year's Day 2013
So you forgot to give the rostering girls a box of chocolates for Christmas then. Bad move. [-X
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Re: 200 mile an hour tailwind!

#16 Post by PHXPhlyer » Wed Feb 20, 2019 8:26 pm

Ex-Ascot wrote:
Wed Feb 20, 2019 4:57 pm
PHXPhlyer wrote:
Wed Feb 20, 2019 2:51 pm
IMAG0168.jpg
New Year's Day 2013
So you forgot to give the rostering girls a box of chocolates for Christmas then. Bad move. [-X
No chocolates needed. If I was working New Year's, I was probally working Christmas, too.

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Re: 200 mile an hour tailwind!

#17 Post by Boac » Wed Feb 20, 2019 8:28 pm

Caco wrote:It is magic I tell you.
- and then you fly the return sector............. :YMPARTY:

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Re: 200 mile an hour tailwind!

#18 Post by llondel » Wed Feb 20, 2019 9:56 pm

Boac wrote:
Wed Feb 20, 2019 8:28 pm
- and then you fly the return sector............. :YMPARTY:
Surprisingly, the day of my Do328 experience, the weather system shifted and we had a 50mph tailwind on the way home too. Of course, the flight crew had to do a couple of round trips between my morning and evening flights.

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Re: 200 mile an hour tailwind!

#19 Post by Boac » Wed Feb 20, 2019 10:21 pm

Reminds me of the 'Texas Tailwind' which is so strong it can blow your flaps fully down on finals.

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Re: 200 mile an hour tailwind!

#20 Post by Slasher » Thu Feb 21, 2019 4:15 am

PHXPhlyer wrote:
Wed Feb 20, 2019 2:51 pm
IMAG0168.jpg
New Year's Day 2013
Why were you stooging around at .73 in Selected Mr Phlyer? What was wrong with Managed? The guy ahead was 40 miles passing your level. Was the boss too scared the wind would suddenly drop off? I would've beefed it up to a selected .81 and gone for the personal record! :))

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