The Jet Stream

On the way from Tampa to Boston last night the pilot announced that the jet
stream was blowing at 219 mph ( I guess he meant knots ?) we were at 39,000
feet, apparently he had to point the plane 24 degrees left of the direction
we wanted to go, and our ground speed reached 592 mph.

I guess the transatlantic flights will land early in Europe in the morning.

A quick google seems to say that 100 mph jetstream speed is more normal.

re: jetstream impact on flight time.

One also has to consider if a plane originates from the east of the west.

A flight from London to New York will arrive very late, and with a quick turn
around, they can depart late, but arrive on time back in London.

But a flight that originates in New York will depart on time, arrive very
early in London and will have to wait for its scheduled departure time and
then arrive late back in New York.

nobody schrieb:
>
> re: jetstream impact on flight time.
>
> One also has to consider if a plane originates from the east of the west.
>
> A flight from London to New York will arrive very late,

They will soon run out of fuel against 400 mph. That's why they try to
choose a different altitude and/or routing.

> and with a quick turn
> around, they can depart late, but arrive on time back in London.

Regards, ULF

"Miss L. Toe" wrote

>On the way from Tampa to Boston last night the pilot announced that the jet
>stream was blowing at 219 mph ( I guess he meant knots ?) we were at 39,000
>feet, apparently he had to point the plane 24 degrees left of the direction
>we wanted to go, and our ground speed reached 592 mph.
>I guess the transatlantic flights will land early in Europe in the morning.
>A quick google seems to say that 100 mph jetstream speed is more normal.

Three/four years ago I was on a United flight between IAD and LHR
which was benefitting from a 200 mph tailwind.
Picking words carefully I suppose I could say our we were covering
the ground faster than the speed of sound.

"DALing" wrote
>what you mean is that
>"your over-the-groud speed was faster than that of sound in still air"
>(but not supersonic - that means exceeding the speed of
>sound in the air itself.)

>semiretired had written
>>Three/four years ago I was on a United flight between IAD and LHR
>>which was benefitting from a 200 mph tailwind.
>>Picking words carefully I suppose I could say our we were covering
>>the ground faster than the speed of sound.

"Travelling faster than the speed of sound" sounds good no matter how
many other words you have to hedge it with. Proper supersonic travel is
beyond my budget, and more than a winter transatlantic fare on United!

On 13 Feb 2004 16:55:21 -0800, semiretired@my-deja.com
(semiretired@my-deja.com) wrote:

>"Miss L. Toe" wrote
>
>>On the way from Tampa to Boston last night the pilot announced that the jet
>>stream was blowing at 219 mph ( I guess he meant knots ?) we were at 39,000
>>feet, apparently he had to point the plane 24 degrees left of the direction
>>we wanted to go, and our ground speed reached 592 mph.
>>I guess the transatlantic flights will land early in Europe in the morning.
>>A quick google seems to say that 100 mph jetstream speed is more normal.
>
>Three/four years ago I was on a United flight between IAD and LHR
>which was benefitting from a 200 mph tailwind.
>Picking words carefully I suppose I could say our we were covering
>the ground faster than the speed of sound.

.... at standard temperature and pressure! The speed of sound in, say,
water is somewhat higher <g>

Malc.

In message <b0j330h8aan65ok5t8kp5cqtc90egb3sii@>, Malcolm Weir
<malc@gelt.org> writes
>>Three/four years ago I was on a United flight between IAD and LHR
>>which was benefitting from a 200 mph tailwind.
>>Picking words carefully I suppose I could say our we were covering
>>the ground faster than the speed of sound.
>
>... at standard temperature and pressure! The speed of sound in, say,
>water is somewhat higher <g>

Perhaps that explains why most attempts by aircraft to break the
underwater sound barrier have failed ;-)
--
Roland Perry

In article <38fn30hm2cc9dqmk2lpcko350tfdpae6ul@>, malc@gelt.org
says...
> Consider: Suppose you are heading due north on the prime meridian at
> 50kts with a westerly cross wind of 30kts. After one hour, you will
> not be 50nm north of your origin (you will be 40nm north, thanks to
> Mr. Pythagoras)... but you will be 30nm east of it.

No. You will be both 50nm north and 30nm east. Your ground speed will
have been around 58kts with a trak of about 031.

Had you compensated for the wind, then you would be 40nm north, but not
an inch east or west.

rgds

David

David J Rainey wrote:

> In article <38fn30hm2cc9dqmk2lpcko350tfdpae6ul@>, malc@gelt.org
> says...
>
>>Consider: Suppose you are heading due north on the prime meridian at
>>50kts with a westerly cross wind of 30kts. After one hour, you will
>>not be 50nm north of your origin (you will be 40nm north, thanks to
>>Mr. Pythagoras)... but you will be 30nm east of it.
>
>
> No. You will be both 50nm north and 30nm east. Your ground speed will
> have been around 58kts with a trak of about 031.
>
> Had you compensated for the wind, then you would be 40nm north, but not
> an inch east or west.
>

Thanks, I was wondering how the 30 kts wind was 100 percent successful
in pushing him 30 nm east, but the 50 kts from his power source was only
sending him 40 nm further north.

Now, if you are on the aircraft carrier Lexington doing 000 at 18 knots,
and the windspeed is out from 000 at 12 knots, what course and speed
should you be at in order to have a 30kt head wind for flight ops.
(Yeah, I was chastised for this by the officer on watch in CIC at the
time for not using the manuevering board paper to calculate this)

On Tue, 24 Feb 2004 22:31:39 -0000, David J Rainey
<myfirstnamehere@davidrainey.com> wrote:

>In article <38fn30hm2cc9dqmk2lpcko350tfdpae6ul@>, malc@gelt.org
>says...
>> Consider: Suppose you are heading due north on the prime meridian at
>> 50kts with a westerly cross wind of 30kts. After one hour, you will
>> not be 50nm north of your origin (you will be 40nm north, thanks to
>> Mr. Pythagoras)... but you will be 30nm east of it.
>
>No. You will be both 50nm north and 30nm east. Your ground speed will
>have been around 58kts with a trak of about 031.
>
>Had you compensated for the wind, then you would be 40nm north, but not
>an inch east or west.

Dammit, you're right, of course!

I managed to mix up several scenarios, and ended up with a total mess.

Sorry!

>David

Malc.