Can the plane take off?

RBB said:
air speed across wing gives lift, since on a conveyor belt makes plane stationary I do not see lift off happening. Surely I am missing something here.
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jmauld said:
There’s no connection between the force that is pushing the plane forward and the conveyor belt. The belt can be moving as fas as it wants and the only force it will place on the plane is the frictional force found in the wheel bearings. Once the engines overpower that force the plane will move forward.

The wheels spin freely. They could spin as fast as they want and it doesn’t stop the ability of the engine to move the plane forward.

this video is only 3 minutes. Please Watch it.
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I suspect you are going to have to give up on this one. They simply can't get their head around the physical mechanics of it all.... We are all "wired" differently.
 
Blueone said:
Where is @Great Lakes …. He started this gong show… he should be held accountable …. It’s always the guys with one head that cause all the shit
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I’m here watching the back and forth. I can’t believe it made it this far. Lol

One day when I’m your age I’ll have two heads. Older fellas need two… :D:D
 
Ok, I'm taking a swing at another way to explain this...

Lets say the conveyor is moving a thousand feet per second backwards (against the direction the plane is pointed) and there is no thrust from the engines:
In a theoretical world where there is no friction in the wheel bearings of the plane - nothing happens, wheels spin like crazy - plane does not move.

In the real world where there is friction in the bearings, the plane will very slowly be accelerated backwards and eventually fall off the conveyor tail first.
This is Newtons 3rd law in action - equal and opposite forces.
The amount of force that the conveyor can apply to the plane is tiny due to the wheel bearings doing their job.

Ok fire up the engines! Now you have thousands of pounds of thrust from the planes engines pushing against the air - the same thing they do when you are starting to roll down the tarmac. The minimal force that the conveyor can apply to the plane through the wheel bearing is nothing compared to the thrust against the air.

Plane goes forward, falls of end of conveyor, breaks in two failing to achieve enough airspeed to create the lift required for flight.

In short, the force the engines can put out against air is huge compared to what the conveyor can put against the plane
 
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bajturner said:
No. That is the misunderstanding you have, and it a profound one. No power is transferred to the wheels.

How does power get to the wheels?
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I agree there are some profound misunderstandings going on.

Back to the plane at the end of the runway, brakes on, and at full power. Why doesn't the plane take off? Because the brakes are on and not allowing any forward movement from the thrust. Can we agree on that?

For a plane to take off, the brakes would be released, the plane would roll down the runway, gaining speed, from 0 MPH until there was enough air speed to create lift. All of the thrust produced at this point is acting directly on the wheels. Removing the brakes doesn't instantly mean the plane is flying due to the thrust from the engines. Can we agree on this?

The original problem stated the conveyor would match the wheel speed in the opposite direction. That means the wheels can't turn faster than the conveyor is moving, which by definition means the plane isn't going to cover any ground. Airspeed and lift never enters the equation because the plane remains stationary.
 
LTD.330 said:
I

The original problem stated the conveyor would match the wheel speed in the opposite direction. That means the wheels can't turn faster than the conveyor is moving, which by definition means the plane isn't going to cover any ground. Airspeed and lift never enters the equation because the plane remains stationary.
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You didn’t watch the video, did you.

Do you have access to a treadmill and a kids wagon?

I’ll say it again. The wheel speed means nothing, it’s just a distraction.
 
jmauld said:
You didn’t watch the video, did you.

Do you have access to a treadmill and a kids wagon?

I’ll say it again. The wheel speed means nothing, it’s just a distraction.
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Hence the question that if it were ski's and the treadmill was made of ice, would forward thrust from the jets push the plane forward? Of course it would. Exact same concept, but people get mixed up with the wheels.
 
We just got rid of our treadmill ….. only thing it was good for was hanging underwear on it….. wife said it was a distraction or disgusting …. I can’t remember which… it’s hard to remember everything she yells at me for. :)
 
If the wheels move one foot forward then the plane moves one foot forward, correct? What if the wheels can’t move one foot forward because the treadmill won’t allow them to. Regardless of the thrust of the plane or the friction of the bearings, etc. The question states it matches the speed. Then the plane can’t move one foot forward either which means no lift.

Now..I think both sides can be correct because the way the question is written.

The no take off crowd reads the question as is. Does not take into account any other factors.

The take off crowd looks past the question and applies knowledge and most likely real world physics.
 
Great Lakes said:
If the wheels move one foot forward then the plane moves one foot forward, correct? What if the wheels can’t move one foot forward because the treadmill won’t allow them to. Regardless of the thrust of the plane or the friction of the bearings, etc. The question states it matches the speed. Then the plane can’t move one foot forward either which means no lift.

Now..I think both sides can be correct because the way the question is written.

The no take off crowd reads the question as is. Does not take into account any other factors.

The take off crowd looks past the question and applies knowledge and most likely real world physics.
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You're suggesting wheel rotation and forward motion are one in the same? If you anchored the plane with a 5,000ft cable tied to a tree just forward of the conveyor, then turned the conveyor on going 200mph in reverse, would the plane move? No. Would the wheels rotate? Yes. Is forward motion and wheel rotation the same thing? No.
 
jmauld said:
No it doesn’t. It moves forward. You have to remember that there is nothing but a free spinning bearing between the plane and the moving conveyor. If you hit the wheel brakes in the air, does the plane stop going forward?
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Well let's see....
Nope, but then again what does it have to do with the wheels in question, they're stuck on a conveyor?
 
Woody said:
Well let's see....
Nope, but then again what does it have to do with the wheels in question, they're stuck on a conveyor?
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How far would he have gone if he had 10 drinks ?
 
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Woody said:
Well let's see....
Nope, but then again what does it have to do with the wheels in question, they're stuck on a conveyor?
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that looks like a helluva on ramp to me. haven't seen anything like it since Dukes Of Hazard.
 
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Great Lakes said:
If the wheels move one foot forward then the plane moves one foot forward, correct? What if the wheels can’t move one foot forward because the treadmill won’t allow them to. Regardless of the thrust of the plane or the friction of the bearings, etc. The question states it matches the speed. Then the plane can’t move one foot forward either which means no lift.

Now..I think both sides can be correct because the way the question is written.

The no take off crowd reads the question as is. Does not take into account any other factors.

The take off crowd looks past the question and applies knowledge and most likely real world physics.
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There is only one answer to the question. It’s in the real life video that I posted.
 
Woody said:
Well let's see....
Nope, but then again what does it have to do with the wheels in question, they're stuck on a conveyor?
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Because the wheels on the conveyor have just as much to do with the plane taking off as trying to use them to stop while in the air.

let’s try a different approach. When the plane lands, the wheels are not moving at touch-down. Why doesn’t the plane come to an immediate stop?
 
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