Life Pick 5 posters you'd like to have dinner with.

**Buck** · 08-25-2009, 03:56 PM

Quote:

Originally Posted by Jenson71

I hate you. I hate my life. I'm leaving forever.

****.

I do have to admit, you personally created the thread that caused me to "miss" out on the most work ever, during the work week.

I'm afraid if you and I ate dinner together we'd argue over whether or not a plane with its wheels spinning on a treadmill could take off.

Jenson71 · 08-25-2009, 03:58 PM

Quote:

Originally Posted by BuckinKaeding

****.

I do have to admit, you personally created the thread that caused me to "miss" out on the most work ever, during the work week.

I'm afraid if you and I ate dinner together we'd argue over whether or not a plane with its wheels spinning on a treadmill could take off.

My face was like this:

reading that thread. I had no idea what was going on.

**Donger** · 08-25-2009, 04:02 PM

Quote:

Originally Posted by BuckinKaeding

I'm afraid if you and I ate dinner together we'd argue over whether or not a plane with its wheels spinning on a treadmill could take off.

Of course it wouldn't.

stevieray · 08-25-2009, 04:05 PM

Quote:

Originally Posted by Donger

Of course it wouldn't.

mythbusters disagree.

**Donger** · 08-25-2009, 04:08 PM

Quote:

Originally Posted by stevieray

mythbusters disagree.

Then they did not use the same criteria described above.

If the planes wheels are spinning, then the aircraft has no relative ground speed. If if has no relative ground speed, no air is flowing over the aircraft's wings. If no air is flowing over the wings, there is no lift. If there is no lift, the plane will not fly.

stevieray · 08-25-2009, 04:11 PM

Quote:

Originally Posted by Donger

Then they did not use the same criteria described above.

If the planes wheels are spinning, then the aircraft has no relative ground speed. If if has no relative ground speed, no air is flowing over the aircraft's wings. If no air is flowing over the wings, there is no lift. If there is no lift, the plane will not fly.

they proved it could be done.

**Donger** · 08-25-2009, 04:15 PM

Quote:

Originally Posted by stevieray

they proved it could be done.

If the wheels were locked (not spinning), and the treadmill was accelerated to the speed required for flight, then yes, it would take off. If the wheels were free to spin, the plane would not move forward relative to the ground and would therefore have no lift.

**Buck** · 08-25-2009, 04:16 PM

Quote:

Originally Posted by Donger

If the wheels were locked (not spinning), and the treadmill was accelerated to the speed required for flight, then yes, it would take off. If the wheels were free to spin, the plane would not move forward relative to the ground and would therefore have no lift.

See my propeller question

Jenson71 · 08-25-2009, 04:16 PM

Quote:

Originally Posted by Donger

If the wheels were locked (not spinning), and the treadmill was accelerated to the speed required for flight, then yes, it would take off. If the wheels were free to spin, the plane would not move forward relative to the ground and would therefore have no lift.

I always thought the treadmill would be going the opposite way of the plane's forward motion (or attempt at motion).

**Buck** · 08-25-2009, 04:13 PM

Quote:

Originally Posted by Donger

Then they did not use the same criteria described above.

If the planes wheels are spinning, then the aircraft has no relative ground speed. If if has no relative ground speed, no air is flowing over the aircraft's wings. If no air is flowing over the wings, there is no lift. If there is no lift, the plane will not fly.

But what if the plane uses a propeller to push the wind? Or does the propeller not do that?

**Donger** · 08-25-2009, 04:19 PM

Quote:

Originally Posted by BuckinKaeding

But what if the plane uses a propeller to push the wind? Or does the propeller not do that?

A plane uses a propeller to provide thrust, yes.

**Buck** · 08-25-2009, 04:21 PM

Quote:

Originally Posted by Donger

A plane uses a propeller to provide thrust, yes.

So ignoring friction, if the planes wheels were just spinning, and the plane remained still relative to the ground, and then the propellers turned on and spun fast enough (theoretically), that would not create enough lift for the plane to take off?

**DaFace** · 08-25-2009, 04:25 PM

Quote:

Originally Posted by Donger

Then they did not use the same criteria described above.

If the planes wheels are spinning, then the aircraft has no relative ground speed. If if has no relative ground speed, no air is flowing over the aircraft's wings. If no air is flowing over the wings, there is no lift. If there is no lift, the plane will not fly.

That would only make sense if the plane were being propelled by its wheels. And even then, you could still take off (in theory) if the wheels are moving more quickly than the treadmill.

**Donger** · 08-25-2009, 04:31 PM

Quote:

Originally Posted by DaFace

That would only make sense if the plane were being propelled by its wheels.

No, it wouldn't.

Quote:

Originally Posted by DaFace

And even then, you could still take off (in theory) if the wheels are moving more quickly than the treadmill.

If the wheels were moving more quickly than the treadmill, then there is some other motive force being applied (say a propeller). The simple fact is that without sufficient airflow over the wings, teh wings aren't going to produce lift.

Of course, a plane's wing can produce sufficient lift for take-off if a gust of wind flows over it at the velocity for take-off.

**Buck** · 08-25-2009, 04:06 PM

Quote:

Originally Posted by Donger

Of course it wouldn't.

Exactly....or wait, did I think it would? I don't remember.