interesting argument.. (for the self proclaimed geniuses of IA)

[tony]

Saw this on Supraforums and it was a pretty interesting read.

A plane (747 passenger jet) is sitting on a runway that can move (some sort of band conveyor). The plane moves in one direction, while the conveyor moves in the opposite direction. This conveyor has a control system that tracks the planes speed and tunes the speed of the conveyor to be exactly the same (but in the opposite direction).

The question is:

Will the plane (747 passenger jet) take off or not?

[Ruiner]

Yes. The wheels on the plane will only offer a limited amount of drag via the conveyor belt. Once the drag is eliminated via forward thrust, the plane will begin to move forward and will eventually take off (if given enough thrust). The conveyor will hardly play a part.

[/thread]

[Spyder]

Yes. The wheels on the plane will only offer a limited amount of drag via the conveyor belt. Once the drag is eliminated via forward thrust, the plane will begin to move forward and will eventually take off (if given enough thrust). The conveyor will hardly play a part.

[/thread]

This has been discussed before, and several people had different awnsers. The real question that came up in another thread was, how can a plane "take off" with no air under its wings?

[Ruiner]

This has been discussed before, and several people had different awnsers. The real question that came up in another thread was, how can a plane "take off" with no air under its wings?

I said that it had to "move forward" with an appropriate thrust. Read my answer again. Air has to be moving over/under the wings. What I am saying is that NO conveyor belt will hold a plane in one position once the plane's thrust overtakes the drag on the wheels. [/thread]

[Spyder]

I said that it had to "move forward" with an appropriate thrust. Read my answer again. Air has to be moving over/under the wings. What I am saying is that NO conveyor belt will hold a plane in one position once the plane's thrust overtakes the drag on the wheels. [/thread]

The reason this is being argued is because in the described scenero the belt accelerates at EXACTLY the same speed as the plane, there for the plane in essence stays still.

EDIT: I read exactly what you wrote, the problem with it is , it doesnt have anything to do with the question.

[man]

The plane would lift off as normal.

/thread... again

[Ruiner]

The reason this is being argued is because in the described scenero the belt accelerates at EXACTLY the same speed as the plane, there for the plane in essence stays still.

EDIT: I read exactly what you wrote, the problem with it is , it doesnt have anything to do with the question.

I don't care if the belt is running at 1 million miles per hour. It will only put a certain amount of drag on the wheels, bearings, etc. A plane's engine thrust can easily overcome that drag and move forward.

Hold a match-box car on a treadmill. Put the treadmill on slow, medium, and fast speeds. Push the car forward while the treadmill is at each speed. 100 to 1 you will use the same force each time to push the car foward. That force is enough to overcome the drag on the wheels. If the treadmill is moving at 200 mph in reverse, you would still only need a certain amount of force to push it forward.

The plane would take off...

[chrisdavis]

This has been discussed before, and several people had different awnsers. The real question that came up in another thread was, how can a plane "take off" with no air under its wings?

LOL I was just thinking that as I was reading it.

[man]

I don't care if the belt is running at 1 million miles per hour. It will only put a certain amount of drag on the wheels, bearings, etc. A plane's engine thrust can easily overcome that drag and move forward.

Hold a match-box car on a treadmill. Put the treadmill on slow, medium, and fast speeds. Push the car forward while the treadmill is at each speed. 100 to 1 you will use the same force each time to push the car foward. That force is enough to overcome the drag on the wheels. If the treadmill is moving at 200 mph in reverse, you would still only need a certain amount of force to push it forward.

The plane would take off...

Edzachary, the plane would not move if it was propelled by its wheels, also, you have to remember if the plane isn't physically moving, it's speedo will read 0 because it is measured by airspeed, so the belt wouldn't move either.

[chrisdavis]

I don't care if the belt is running at 1 million miles per hour. It will only put a certain amount of drag on the wheels, bearings, etc. A plane's engine thrust can easily overcome that drag and move forward.

Hold a match-box car on a treadmill. Put the treadmill on slow, medium, and fast speeds. Push the car forward while the treadmill is at each speed. 100 to 1 you will use the same force each time to push the car foward. That force is enough to overcome the drag on the wheels. If the treadmill is moving at 200 mph in reverse, you would still only need a certain amount of force to push it forward.

The plane would take off...

I think that in essence the question is could you make the plane take off at a stand still. Which is no, you even stated the plane has to move forward.

[man]

I think that in essence the question is could you make the plane take off at a stand still. Which is no, you even stated the plane has to move forward.

I don't think it is though, seems too easy.

[Spyder]

I don't care if the belt is running at 1 million miles per hour. It will only put a certain amount of drag on the wheels, bearings, etc. A plane's engine thrust can easily overcome that drag and move forward.

Hold a match-box car on a treadmill. Put the treadmill on slow, medium, and fast speeds. Push the car forward while the treadmill is at each speed. 100 to 1 you will use the same force each time to push the car foward. That force is enough to overcome the drag on the wheels. If the treadmill is moving at 200 mph in reverse, you would still only need a certain amount of force to push it forward.

The plane would take off...

but, with the example you gave you are causing the match box car to accelerate at a greater rate then the tread mill is turning... the tread mill would accelerate at exactly the same speed as the car was being pushed, hence effectively keeping the car still. the faster you push the faster the tread mill moves in reverse.

[Spyder]

I think that in essence the question is could you make the plane take off at a stand still. Which is no, you even stated the plane has to move forward.

exactly.

if 2 forces are equal and opposite they cancel each other out.

[man]

exactly.

if 2 forces are equal and opposite they cancel each other out.

but the forces arent equal

[Speedm0(\)key]

dude.. i've been here thinking this thru for 10 minutes... and i came to following conclusion:




lets find tony and beat him senseless

[Spyder]

but the forces arent equal

explain how and i will agree, that is the only basis for my argument.

[man]

dude.. i've been here thinking this thru for 10 minutes... and i came to following conclusion:




lets find tony and beat him senseless

Good Idea!!!

P.S. Mine and Ruiners conclusions are correct.

[Spyder]

dude.. i've been here thinking this thru for 10 minutes... and i came to following conclusion:




lets find tony and beat him senseless

Actually i take back what i said, this is the correct awnser.

[Tiff-O-Bitties]

but the wheels do not push the plane.. they simply guide it.. I think it would still take off but then again.. I'm really no genius..

[man]

explain how and i will agree, that is the only basis for my argument.

There are many more factors here than just the speed of the belt compared to the speed of the wheels on the plane: friction, thrust, weight. They all factor in. Also planes measure speed by how fast the air is moving, so the plane would have to physically move in order for the belt to start moving. Once the plane is moving, the friction on the tires is close to nothing compared to the thrust from the jet engine. The matchbox car example is a perfect example, the wheels on the plane will always be able to match that of the belt, and, in the matchbox situation, the hand pushes the car forward, much like a jet engine.

but the wheels do not push the plane.. they simply guide it.. I think it would still take off but then again.. I'm really no genius..

Exactly!!!

[Speedm0(\)key]

but the wheels do not push the plane.. they simply guide it.. I think it would still take off but then again.. I'm really no genius..

i think all women shouldnt be allowed to answer or even attempt to answer tony's question.

[Spyder]

Good Idea!!!

P.S. Mine and Ruiners conclusions are correct.

Prove it, i have always wondered.

[Speedm0(\)key]

Actually i take back what i said, this is the correct awnser.

[man]

i think all women shouldnt be allowed to answer or even attempt to answer tony's question.

Actually she is correct to an extent.

[Speedm0(\)key]

Actually she is correct to an extent.

dude... thanks for fucking that up.

let me introduce myself: im speedmonkey .. im an asshole wether you're right or wrong.

[Kevykev]

Ok if the the conveyor belt is moving directionally against the plane AT THE SAME SPEED, THE PLANE WILL BE STILL.

[Speedm0(\)key]

ok now seriously, the plane needs AIR to travel against it to take off... like this: (wind)---><----(plane) with out this IT CAN NOT TAKE OFF

[Kevykev]

Let's call those guys at "myth busters."

[Calvin200sx]

The plane will never take off. If the conveyor is moving in the opposite direction as the forward motion of the plane, the plane is essentially standing still. If there is no air movement over the wings, there is no lift. A plane will not lift off without airflow. The jets only act to push the plane forward fast enough through the air to generate enough lift to get the plane off the ground. Prop planes opperate under the same guidelines only the prop pushes/pulls the plane through the air to generate lift on the wings. So no airflow (forward motion) no flying.

[tony]

Just to throw a monkey wrench in this, for the plane to take off it requires thrust correct? If the belt compensates for the speed of the PLANE and not the WHEELS (this is all hypothetical) then how is the plane able to take off and where is the thrust coming from? I'm not saying you guys are right or wrong but the answer isnt as simple as "yes it will take off" or "the wheels arent driving the plane" we know that.. the belt speeds up with the speed of the plane so in essence the plane is going nowhere.

[Speedm0(\)key]

The plane will never take off. If the conveyor is moving in the opposite direction as the forward motion of the plane, the plane is essentially standing still. If there is no air movement over the wings, there is no lift. A plane will not lift off without airflow. The jets only act to push the plane forward fast enough through the air to generate enough lift to get the plane off the ground. Prop planes opperate under the same guidelines only the prop pushes/pulls the plane through the air to generate lift on the wings. So no airflow (forward motion) no flying.

i already said this. but +1

[Speedm0(\)key]

Just to throw a monkey wrench in this, for the plane to take off it requires thrust correct? If the belt compensates for the speed of the PLANE and not the WHEELS (this is all hypothetical) then how is the plane able to take off and where is the thrust coming from? I'm not saying you guys are right or wrong but the answer isnt as simple as "yes it will take off" or "the wheels arent driving the plane" we know that.. the belt speeds up with the speed of the plane so in essence the plane is going nowhere.

you're gonna get jumped for asking that gay question tony, my head hurts

[man]

ahhh.... I guess you guys should start designing planes now, apparently all of my aerospace engineering professors have been teaching me the wrong stuff!!!

Oh and I have a REAL solution:
Sell the 747, buy a Harrier

[Speedm0(\)key]

ahhh.... I guess you guys should start designing planes now, apparently all of my aerospace engineering professors have been teaching my the wrong stuff!!!

Oh and I have a REAL solution:
Sell the 747, buy a Harrier

plus +0.5 <-- would give you a 1, but.. im gonna start being a jew with points because.. well there really isnt a reason

[man]

thanks, lol

[chrisdavis]

ahhh.... I guess you guys should start designing planes now, apparently all of my aerospace engineering professors have been teaching my the wrong stuff!!!

I understand what you and Ruiner are saying. In a real world environment the plane would take off. But the question posed is "Can a 747 take off without leaving its stationary position?" which by both of your accounts is no. The plane must move forward. The question confuses by placing emphasis on the wheels to the conveyor as if the wheels are the driving mechanism.

[B16a2 Civic]

the biggest question is....does the plane have gas?

[tony]

ahhh.... I guess you guys should start designing planes now, apparently all of my aerospace engineering professors have been teaching me the wrong stuff!!!

Oh and I have a REAL solution:
Sell the 747, buy a Harrier

your signature alone makes you right.. lol Actually you and ruiner are right from what I've seen, I just wanted a big 10 page argument about why it couldn't take off.

[man]

the question posed is "Can a 747 take off without leaving its stationary position?" which by both of your accounts is no. The plane must move forward. The question confuses by placing emphasis on the wheels to the conveyor as if the wheels are the driving mechanism.

But it never states that, I think the answer depends on the way you interpret it. Which is its goal, to create argument by interpretation.

[Tiff-O-Bitties]

the biggest question is....does the plane have gas?

bwahaha