Question re. flying against Earth's rotation

[KhalBrogo]

What would happen if an aircraft was fast enough to match the speed of the rotation of the Earth and it decided to fly against it matching that exact speed (earth's rotation)?

I would imagine it would look like Earth was speeding up but would there be any other physical effects on the aircraft? The passengers?

 

[drvrm]

What would happen if an aircraft was fast enough to match the speed of the rotation of the Earth and it decided to fly against it matching that exact speed (earth's rotation)?

what do you think or expect to happen ?
The geostationary satellites actually match the speed of Earth's rotation and the astronaut's experiences are well documented...weightless ness etc.

 

[Simon Bridge]

The aircraft traveling over the surface of the Earth at speed v just means that the scenery looks like it is going past at speed v.
It does not matter what that speed is (as long at it is well below the speed of light) or what direction you travel in.
Since the motion is circular, you do get pseudogravity effects and stresses on the airframe that depend on speed.
Maintaining the motion at a constant distance from the surface means the aircraft is not in freefall.

Note: the speed of the ground about the rotation axis depends on latitude, it can be quite slow.
You could go to someplace close to the north or south (rotation) pole and fly a model aircraft about and see what happens.
But it is quite easy to imagine.

 

[Delta Kilo]

The Sun will not move in the sky and you arrive at the same local time as you depart.
I believe Concorde used to do that regularly on LHR-JFK route.

 

[A.T.]

Maintaining the motion at a constant distance from the surface means the aircraft is not in freefall.

That is not the criterion of being in freefall, although the conclusion happens to be right in this case.

 

[Simon Bridge]

Yes - I was not using that as the criterion but as an important detail, along with all the others, that can be used to inform an investigation.
To be pedantic: the question implies an aircraft flying as is usual for aircraft.
At the kinds of altitudes aircraft usually fly, the indicated speed does not suggest an orbit, yet the altitude is implied constant - therefore, gravity is not the only force on the aircraft vis: not free fall. Better?

Since this is circular motion we can expect centrifugal effects to be present ... but would we expect "weightlessness"?

 

[russ_watters]

What would happen if an aircraft was fast enough to match the speed of the rotation of the Earth and it decided to fly against it matching that exact speed (earth's rotation)?

I would imagine it would look like Earth was speeding up but would there be any other physical effects on the aircraft? The passengers?

No physical effects. Note: airplanes can do this. The rotation speed of Earth is about 1,000 mph at the equator and gets slower as you go further north/south. The Concorde went faster than that and military fighters do too.

 

[mrspeedybob]

Since this is circular motion we can expect centrifugal effects to be present ... but would we expect "weightlessness"?

Wouldn't this rather be a lack of circular motion? Traveling with the Earth's surface would be circular motion, and i'd expect some centrifugal force to partially cancel out gravity, that's why the Earth bulges at the equator. A plane flying against the rotation of the Earth would not experience this force, so I'd expect the plane and passengers to weigh a bit more then they would at rest with respect to the surface.

 

[micromass]

What would happen if an aircraft was fast enough to match the speed of the rotation of the Earth and it decided to fly against it matching that exact speed (earth's rotation)?

I would imagine it would look like Earth was speeding up but would there be any other physical effects on the aircraft? The passengers?

Go to the north or south pole and run in circles around it.

 

[A.T.]

No physical effects.

There is a small effect on fuel consumption, but it's negligible compared to air currents etc.

 

[nasu]

It is not clear what situation you have in mind because you don't mention in what reference frame is the speed of the airplane considered.
But if you think about a situation where the airplane is stationary above a point on the Earth's surface there may be a problem.
As the atmosphere moves pretty much with the Earth, the airplane will be stationary in respect to the air so there will be not much lift to support the airplane.
Unless there is a strong wind blowing in the right direction.

 

[A.T.]

I would imagine it would look like Earth was speeding up

if you think about a situation where the airplane is stationary above a point on the Earth's surface

Pretty sure not what he means.

 

[mfb]

Traveling with the Earth's surface would be circular motion, and i'd expect some centrifugal force to partially cancel out gravity, that's why the Earth bulges at the equator. A plane flying against the rotation of the Earth would not experience this force, so I'd expect the plane and passengers to weigh a bit more then they would at rest with respect to the surface.

0.3%. A good scale can measure this, but it is still a small effect. Go to the pole if you want to increase your weight even more (because you are also closer to the center of Earth there).

 

[Filip Larsen]

No physical effects.

The centrifugal component of the normal gravity changes (slightly) when traveling east or west, so everything else being equal there should be an effect, even if very minor. For instance, flying west on the equator with enough speed that the centrifugal term is zero should mean around 0.3% less weight and therefore less drag and less fuel consumption, again everything being equal.

 

[A.T.]

The centrifugal component of the normal gravity changes (slightly) when traveling east or west, so everything else being equal there should be an effect, even if very minor. For instance, flying west on the equator with enough speed that the centrifugal term is zero should mean around 0.3% less weight and therefore less drag and less fuel consumption, again everything being equal.

See also:
http://naca.central.cranfield.ac.uk/reports/arc/rm/3680.pdf

 

[lychette]

The Sun will not move in the sky and you arrive at the same local time as you depart.
I believe Concorde used to do that regularly on LHR-JFK route.

agree...concorde answers this question

 

[hsdrop]

Brian Cox hosts a show called: Forces of Nature
and in the 2 episode :Somewhere in Space-time he does just what you asked by getting into a jet and follows the sun till it comes back up throw the horizon its a really good watch if you can find it on the web

 

[sophiecentaur]

Since this is circular motion we can expect centrifugal effects to be present ... but would we expect "weightlessness"?

You would need to be at the same height as a geostationary satellite for weightlessness with that particular angular velocity. (360° per 24 hours). Which is why the satellite is put at that particular height.

 

[Andrew Mason]

What would happen if an aircraft was fast enough to match the speed of the rotation of the Earth and it decided to fly against it matching that exact speed (earth's rotation)?

I would imagine it would look like Earth was speeding up but would there be any other physical effects on the aircraft? The passengers?

As pointed out, there would be no centrifugal effect offsetting gravity so it be a bit heavier. If it was a rocket ship, it would also take a bit more fuel to get into orbit flying against the Earth's rotation. I expect this is why rockets are launched west to east in low latitudes and why, for example, the Virgin Galactic plane flies west to east near the equator when launching its orbital vehicle into space.

AM

 

[Drakkith]

The geostationary satellites actually match the speed of Earth's rotation

They match the angular velocity of the Earth, but not the tangential velocity at the surface.