astral travel gets you there on time....

"The situation for the plane and a submarine traveling is identical, it is just the medium through which the two travels which is different. Nobody is surprised that the sub doesn't get any benefit from the earths rotation on the return trip, are they?"

I understand that the Gulf Stream runs like a conveyor belt. So to travel from Mexico to England, the sub should travel near the surface, and on the return trip it should travel near the bottom.

All I know is this is probably the worst title of a thread, EVER.

It should read, "OT why I love flying".

Thank you,

This reminds me of a quote by Physicist Pauli: "This isn't right. This isn't even wrong."

The quote in terms of what it actually meant doesn't exactly apply here. But the video still reminded me of it.

A fun thread, thanks. (and awesome animation!)

To confuse people further; there are no less than three speeds to consider when flying in a plane.

1. Indicated airspeed. This is the pressure of air molecules impacting on the sensor at the back end of the little tube thingy that sticks out the front. Higher altitude => less air pressure => fewer air molecules => lower IAS. Aircraft generally operate at an IAS of around 250 knots - if the plane can "feel" 250 knots of breeze under the wings it performs really well. (Indicated airspeed in space will be zero)

2. True airspeed. This is how fast you are really going through the air mass. Clever computers work this out. True airspeed gets up to 500 or so knots.

3. Groundspeed. How fast you are travelling over the ground. The earth is moving (rotating east); the atmosphere is also moving. More important by far is wind - the jetstream as alluded to. If you are rowing a boat upstream (against the current) your final speed will be a combination of how fast you can row, minus how fast the current is dragging you downstream. It's easier to row downstream!! Exactly the same in an aircraft - jetstream winds generally blow west to east, and can be pretty strong (100 knots not unusual). Eastbound routs are usually shorter in time, because although the indicated and true airspeeds are the same, the groundspeeds are quite different.

So there :)

Careful , you'll fall off the edge !

geoff

"Bob what you are failing to explain is the 1670 kmp earth rotation plus 693 kmp speed of the jet is reduced to only 693 kmp when flying west because the wind blows stronger."

Um no.
Firstly a plane flies in the air and the air is moving at much the same speed as the earth. Secondly 1670 kph is faster than the speed of sound, it is simply impossible for wind to move that fast relative to the earth's surface. Thank goodness for that too or we'd all be blown off it :)

Here's a simpler mind game.

Your in a train travelling at 60 kmp, you walk to the back of the carriage, turn around and walk back to the front of the carriage at the same speed of 10 kpm. The time it takes you to walk from the front to the back and the back to the front is the same because your speed relative to the carriage is the same, the motion of the carriage is irrelevant.

To an outside stationary observer though when you walk to the back your speed is 60 - 10 = 50 and as you walk forward your speed is 60 + 10 = 70. However to the outside observer the distance you travel is much greater than the length of the carriage. When you walk to the back of the carriage the distance is shorter than when you walk to the front of the carriage.

"We are talking about distance = 18 000 km is 18 000 km no matter how hard the wind blows."

No, not at all. If you want to include the earth's rotation then when you travel east to west compared to west to east to an outside observer the distance you have travelled is considerably different.

Your whole problem seems to me to be you're mixing up frames of reference.
Everything on the surface of the Earth or the Moon or Neptune moves at the same speed as the surface of what they rest on. If you jump up on the Moon and you can jump pretty high on the Moon the Moon doesn't move under you becuase you were travelling along with it before you jumped and nothing is stopping that motion. When you finally get pulled back to the surface by the Moon's weak gravity you land back on the same spot.

Bob.

I think the problem is I am not drinking enough on the plane.

We may be well trained at school and university but not well educated I guess that’s because you have to educate yourself.
I would really like to to move on to the real heavy stuff like Vegas levels but unfortunately battling with the basics.

rory, your definition of 'basics' puts many of us to shame ;-)

"We may be well trained at school and university but not well educated I guess that’s because you have to educate yourself."

Amen to that. I think it was Mark Twain who said something like "I never let my schooling interfere with my education.".

Bob.

Yea Rory's right. The level of the plane is important. If you're in the stratosphere level then you have to fly faster than if your on the ground level, right?

Also your level of education will help you understand things rather than being brainwashed.

Now where were we? Oooooh you mean Veeegaas levels. Right, I kneeew thaaat.

"If you're in the stratosphere level then you have to fly faster than if your on the ground level, right?"

No. Planes fly faster there because the air pressure / density is lower therefore it is more economic. It's also more dangerous as the effect of the control surfaces is reduced and a stall or spin is more likely.

Bob.

I guess I haven't had enough coffee this morning. What was the YouTube video trying to say?

I harken back to my classes in school, which pointed out that what you observe has everything to do with where you're doing the observing from (sorry, my grammar teacher wouldn't have liked me ending with a preposition). This topic can get really interesting and ties into Einstein's ideas about Special Relativity and such--you know, you zip away to a nearby star and come back hardly aged but everyone you see is much older.

On a practical, flying matter, there WERE accidents with pilots making turns in a traffic pattern around the runway and getting into a stall-spin (always fatal at low altitude). It's because they were basing their turn on ground reference even though they and the airplane were really anchored in a medium (air) that was moving in relation to the ground. So they were if effect confusing the airplane with their control inputs.

Another example is two guys sitting on a merry-go-round in a playground, on opposite ends. One throws a tennis ball at the other and is shocked to see it arc severely away from the intended target. Of course, the ball is going in a straight line (as viewed from a fixed reference) but to an observer on the merry-go-round it arcs like crazy.

Here are a couple...

If you have a 50kt wind in your face, fly from point A to B, and back, that round trip takes longer than if you have no wind on the round trip. You spend a longer amount of time in the headwind, which more than offsets the speed savings in the tailwind. So, if I'm flying an out and back, I typically speed up a bit in the headwind, throttle back in the tailwind.

Another one, if you are flying along at 50kts (very slow plane) or throw a rock at 50kts, and suddenly the plane or the rock encounters a 50kt headwind, they will not immediately stop their "over the ground" movement, intertia with respect to the earth. However, a plane flying at 100kts as it encounters a 100kt headwind will eventually not move over the ground. Bounced these ideas around in flight school.

Bob, you must have some aviation in your background, you touched on the coffin corner concept at high altitudes, which is not even an issue except in high performance jet aircraft.

Finally a topic with which I have some expertise, although nothing to do with why I read this forum, and I still hate the name of this thread.

All of the above issues are why I want someone to please make the Star Trek transporter a reality :)

Mike

Apparently a working tractor beam was created and demonstrated last month. It only works over microscopic sizes and distances, but it's a start.

I do recall reading that a fly was successfully transported across a room in a vacuum some time ago, but since the process required a vacuum at both ends, the process killed the fly.

"Bob, you must have some aviation in your background, you touched on the coffin corner concept at high altitudes, which is not even an issue except in high performance jet aircraft."

Yes, it's been a while, too long really, but I used to fly gliders (sailplanes) and have a lot of interest in aeronautical engineering and aerodynamics.

Within my first couple of flights in a glider I learned first hand how it is possible to be flying forward in the air and yet be going backwards relative to the ground. At the very opposite corner of the envelope I recently watched a very long video about the development of the Russian SU-27 which has now evolved into the SU-37. The aerodynamics involved in how that plane can pull off the "Cobra" are amazing.

Bob.

That is an interesting animation and twist of thought. But, like Bob said, the reference frames are different or untrue for this example.

Case in point, if you are standing still at the equator you are actually going about 1000 mph; not including all the other planetary, solar system, galactic rotation, universe expansion...

I won't even get into the whole time-is-fiction debate - well, maybe a little. :)

Actually, no you're not. The motion of the rotation of the earth is *TINY* compared to the earth's revolution around the sun (about 10,609mph), and also less than the sun's revolution around the galactic center (about 1705mph). So really, we're moving through the galaxy at somewhere between 7,900 and 13,000mph in ... thataway ---> direction, whichever it happens to be at the moment.

We don't even have a clue what the galaxy's movement through the universe is, but we're moving about the speed of light away from the farthest other galaxies we can see. Compared to that, wind speed, ground speed, and air speed are so slow that to 7 significant digits they might as well be a dead stop.

Ah, the Coffin Corner.

Kelly Johnson's famous U2 was notoriously difficult to fly. One reason was because it was designed to cruise at 70,000 feet, and at that altitude the wing would stall at an airspeed only about 5-10 knots below the maximum speed, which was the speed where several effects such as the formation of shockwaves would also cause a loss of lift. So the pilot had to keep the airspeed right in the middle of that window.

Still, it must have been an amazing aircraft to master. Designed long before computers were used in the design or operation of the machine. Nowadays the pilot moves a joystick or yoke and the computers figure out what he wants and how to move the control surfaces to get it, all the while making sure he can't do something to hurt the plane.

What I did pick up on my animation is “text wrap without kerning is as good as a chicken wrap”
Half of 24 is 12 not 13 so I need to kern the double No.s to get 12 half way.
But as the illustration is working off Vegas fx timecode it did not affect the timing/distance at all.

>>>I do recall reading that a fly was successfully transported across a room in a vacuum some time ago<<<

Yeah, Jeff Goldblum did it.