Formula88:
If the conveyor speed is opposite the plane speed, how can there be forward motion? Without forward motion, how can there be lift?

Blacktree:
Forget about the wheels! It's the plane's speed in question, not how it gets it. The plane can't move forward because of the control system, not the conveyor.

page 4! Wheeeeee! this is fun!!!!!!!!!!

[This message has been edited by Gokart Mozart (edited 12-24-2007).]

The only way the belt could give a backward force to the plane (to stop forward motion) is if there is
enough rolling resistance (between tires and belt) or bearing friction to give resistance, right?
The conveyor needs a resistance to "push" against to counter the prop thrust.
No resistance, no force, plane flies. Conveyor could run supersonic,
but to counter the force generated by the prop, you'd need opposing force.
Only thing available is friction/resistance of tires/bearings, it is not?

[This message has been edited by TennT (edited 12-24-2007).]

the control system

quote Originally posted by Gokart Mozart:Blacktree: Forget about the wheels! It's the plane's speed in question, not how it gets it. The plane can't move forward because of the control system, not the conveyor.

But...what is *stopping* the plane's forward motion? What control system?

quote Originally posted by Gokart Mozart: the control system

Explanation, por favor

[This message has been edited by TennT (edited 12-24-2007).]

A plane is standing on a runway that can move (some sort of band conveyer). The plane moves in one direction, while the conveyer moves in the opposite direction. This conveyer has a control system that tracks the plane speed and tunes the speed of the conveyer to be exactly the same (but in the opposite direction).
The question is:

Will the plane take off or not?

[This message has been edited by Gokart Mozart (edited 12-24-2007).]

quote Originally posted by Gokart Mozart: A plane is standing on a runway that can move (some sort of band conveyer). The plane moves in one direction, while the conveyer moves in the opposite direction. This conveyer has a control system that tracks the plane speed and tunes the speed of the conveyer to be exactly the same (but in the opposite direction). The question is: Will the plane take off or not?

May it be assumed that for the control system to match the plane speed in the opposite direction that the plane must be developing some kind of movement as an indicator of that speed?

------------------
Ron

It's the Soldier, not the reporter
Who has given us the freedom of the press.
It's the Soldier, not the poet,
Who has given us the freedom of speech.
It's the Soldier, not the politicians
That ensures our right to Life, Liberty and the Pursuit of Happiness.
It's the Soldier who salutes the flag,
Who serves beneath the flag,
And whose coffin is draped by the flag.

quote Originally posted by Gokart Mozart: A plane is standing on a runway that can move (some sort of band conveyer). The plane moves in one direction, while the conveyer moves in the opposite direction. This conveyer has a control system that tracks the plane speed and tunes the speed of the conveyer to be exactly the same (but in the opposite direction). The question is: Will the plane take off or not?

Again - what would PREVENT the airplane from moving. Hint - an airplane's wheels spin freely.

Almost 5 pages of what the hell!!

Forget about it. The plane took off and left.

------------------

Though I am branded a devil in priests clothing I cast not the raiment I wear for I am not beholden to any flock with which any color has been given to me.

quote Originally posted by pokeyfiero: Almost 5 pages of what the hell!! Forget about it. The plane took off and left.

Damn, we missed our plane.

Wait, that means it must have flown off.

------------------
Ron

It's the Soldier, not the reporter
Who has given us the freedom of the press.
It's the Soldier, not the poet,
Who has given us the freedom of speech.
It's the Soldier, not the politicians
That ensures our right to Life, Liberty and the Pursuit of Happiness.
It's the Soldier who salutes the flag,
Who serves beneath the flag,
And whose coffin is draped by the flag.

quote Originally posted by blackrams: Damn, we missed our plane. Wait, that means it must have flown off.

...and everyone but the pilot was left on the treadmill.

quote Originally posted by Gokart Mozart: It's the plane's speed in question, not how it gets it.

This is why you fail to understand the concept. You're ignoring the very reason why it happens the way we've all described. And you're confusing yourself with incorrect assumptions.

Once again, you need to learn about Newton's second law of motion. It is the key to this puzzle.

On a side note, now we can understand why it took so long for people to understand that the Earth isn't flat.

I've been reading and I agree with him... Different forum... same PROBLEM!!

Jason Coleman says:
I don't think this is a really tough question, but as Kottke points out, having some beginning physics helps. Imagine the plane is on a completely frictionless surface (oil so slick, friction between the tires and the ground is absolutely zero). A car on that surface couldn't budge. A plane, however, will move, since the force that propels it is independent of the ground. As a matter of fact, the wheels on the plane are acting just like a frictionless surface, allowing the planes propulsion (prop, jet, rubber bands, etc.) to create forward force.

Same principle applies with the belt that equals the speed of the plane. The belt moves faster as the plane speeds up, resulting in the wheels spinning twice as fast. Since the forward force (thrust, push, pull... it doesn't matter in a force diagram) is independent of the ground, the plane takes off.

» by Jason Coleman on Feb 09, 2006 at 12:58 AM

[This message has been edited by BLK 86 FSTBAK GT (edited 12-24-2007).]

quote Originally posted by BLK 86 FSTBAK GT: I've been reading and I agree with him... Different forum... same PROBLEM!! Jason Coleman says: I don't think this is a really tough question, but as Kottke points out, having some beginning physics helps. Imagine the plane is on a completely frictionless surface (oil so slick, friction between the tires and the ground is absolutely zero). A car on that surface couldn't budge. A plane, however, will move, since the force that propels it is independent of the ground. As a matter of fact, the wheels on the plane are acting just like a frictionless surface, allowing the planes propulsion (prop, jet, rubber bands, etc.) to create forward force. Same principle applies with the belt that equals the speed of the plane. The belt moves faster as the plane speeds up, resulting in the wheels spinning twice as fast. Since the forward force (thrust, push, pull... it doesn't matter in a force diagram) is independent of the ground, the plane takes off. » by Jason Coleman on Feb 09, 2006 at 12:58 AM

Ding! Ding! Ding!!!!!!

We have a WINNER!!!!!!!!!!!

------------------
Ron

It's the Soldier, not the reporter
Who has given us the freedom of the press.
It's the Soldier, not the poet,
Who has given us the freedom of speech.
It's the Soldier, not the politicians
That ensures our right to Life, Liberty and the Pursuit of Happiness.
It's the Soldier who salutes the flag,
Who serves beneath the flag,
And whose coffin is draped by the flag.

Wrong again!

It's not a frictionless surface. The 'ground' is not stationary. The forward force is being countered by an unknown force, being the control system.

Don't think of thrust or friction or wheels. Just the plane. If the plane's speed is being countered, how can the plane move? It can't.

The plane's speed is NOT being countered!! The wheels of the plane absorb any countering force, by revolving!!! AAAAAGH!!!
Nick

quote Originally posted by Gokart Mozart: Wrong again!

I now understand why you're Hiding like Rushdie.

------------------
Ron

It's the Soldier, not the reporter
Who has given us the freedom of the press.
It's the Soldier, not the poet,
Who has given us the freedom of speech.
It's the Soldier, not the politicians
That ensures our right to Life, Liberty and the Pursuit of Happiness.
It's the Soldier who salutes the flag,
Who serves beneath the flag,
And whose coffin is draped by the flag.

You can lead a horse to the water....

I think now I'll just sit back and laugh.

quote Originally posted by Blacktree: You can lead a horse to the water....

...but you can't make him run backwards on a treadmill?

Let's see, *where* is that head-banging animation...?

[This message has been edited by fierobear (edited 12-24-2007).]

Let's just try one more example..but in reverse!! A plane is going to land on an aircraft carrier, out at sea. The carrier is moving TOWARDS the plane, at the same speed as the plane is approaching it. How will it land safely? It can´t, because the landing speed will be double that of a normal landing...the plane is approaching the carrier at normal landing speed, but the carrier is moving towards it at the same speed, so therefore doubling the actual landing speed of the plane..although the landing speed of the plane relative to the motionless SEA is correct, the fact that the carrier is approaching the plane at the same speed (IMPOSSIBLE, I know, but for the sake of the argument ) as the plane is approaching the carrier, the landing speed at touchdown would be double that required for a safe landing...so the deck would need to be double the normal length to make it safe ......in your scenario, the friction of the wheels landing on the deck would be enough to stop the plane safely...but it won´t, BECAUSE THE RUNWAY HAS VIRTUALLY NO INFLUENCE ON THE SPEED OF THE PLANE AS IT LANDS!! OR___TAKES OFF!! ..the wheels turn twice as fast upon contact...and therefore have virtually no effect on the speed of the Plane
Eureka!!
Nick

[This message has been edited by fierofetish (edited 12-24-2007).]

quote Originally posted by fierobear: Uh, gokart...you've got that exactly opposite. Folks who think the plane won't move, let's try this one more time. The airplane's wheels DO NOT DRIVE the airplane. They spin freely. It is the PROPELLER that moves the airplane forward. That's why the call it a *propeller*, because it...drumroll please...propells. The airplanes wheels couldn't care less what is happening below them, as long as they can rotate freely. If you duct tape the wheels to the treadmill, the plane will go in the direction of the treadmill. If the engine is off (propeller not turning), the plane will probably move in the direction of the treadmill. Start the engine, rev to takeoff power, and the plane is *outta there*. As for the Fiero, Cliff said that the FRONT wheels are on a treadmill (rollers). If you start the Fiero engine, put it in gear and gun it, the car will *scream* off that treadmill. Same thing with a plane. Why? Because the treadmill is acting on wheels that DO NOT control the motion of the car. Same as the plane.

That's what I thought. The plane taking of is depended on wind speed. and has nothing to do with the ground underneath.

Hence my idea with a really big fan in front of the plane would make it take off sooner. Or the reverse example: A catapult on an aircraft carrier, that moves the plane faster into the wind to reduce time and tarmac required for the plane to take off.

quote Originally posted by Austrian Import: That's what I thought. The plane taking of is depended on wind speed. and has nothing to do with the ground underneath.

I've been saying that all along.

quote Originally posted by Gokart Mozart: Wrong again! It's not a frictionless surface. The 'ground' is not stationary. The forward force is being countered by an unknown force, being the control system. Don't think of thrust or friction or wheels. Just the plane. If the plane's speed is being countered, how can the plane move? It can't.

Who says the plane's speed is being countered?

Again, that's your assumption - and it's wrong. The question doesn't say the plane's speed is being countered - only that the conveyor is moving backwards. How does that stop the plane?

Here's a scenario for you. The plane is flying at 100 mph, just a foot above the conveyor. The conveyor's control system is working, so the conveyor is going backwards at 100 mph. Since the plane is flying - we can agree it's moving, correct?

What happens when the plane touches down? There's 2 possibilities:
1. The speed of the conveyor instantly stops the plane.
2. The plane continues to move forward at 100 mph, but the wheels on the landing gear are now spinning at 200 mph due to the conveyor's going backwards.

If you say the plane stops - why does the conveyor stop the plane and not just make the wheels spin faster? The only thing the conveyor can touch is the wheels. Any effect it has on the plane must happen through the wheels.

You're sitting in the plane. You move the throttle forward. The RPMs start to climb. You look out the window and see the ground move under the plane but the grass next to the runway isn't moving.

quote Originally posted by Gokart Mozart: The control system counters the planes speed. The wheels are irrelevant.

Those two statements could not be more wrong.

The control system does NOTHING to the plane's speed BECAUSE of the wheels.

quote Originally posted by Gokart Mozart: You're sitting in the plane. You move the throttle forward. The RPMs start to climb. You look out the window and see the ground move under the plane but the grass next to the runway isn't moving.

AAAAAAAAGGGGHHH!!! PLEASE!!!! The throttle controls the engines. The engines control the thrust of the propellers/turbines. The thrust is against a static force...AIR!! The thrust against the air causes a vacuum in front of the propellers/turbines, which pulls them, and therefore the plane too, forward!!! Faster and faster....UNTIL IT TAKES OFF!!!!Nick

They should use rollers like a dyno has . And no it will not fly .

Haaa, it would take all night!! So, I'll set the questions and then answer them myself..and you can tell me where you think I am going wrong
The answer would be initially, TO OVERCOME THE INERTIA, around 750 ft/lbs, dropping to around 500 constant. (FOR ARGUMENT'S SAKE )

So now, the conveyor belt is moving at half take-off speed, and the amount of drag on the rope is 500 ft/lbs. Wind the speed of the conveyor up to take-off speed, and what would the force exerted on the rope then be? It wouldn´t be 1000 ft/lbs(200%)..it would be probably about 550.(10% more)So, to enable the plane to reach take-off speed, AGAINST the speed/drag of the conveyor belt, would then be 600 ftlbs (double the difference of 10%=20%) The thrust of an efficient plane engine is capable of a LOT more than 600 ft/lbs..so the rope is absorbing 600 ft/lbs to keep the plane stationary on the belt. The plane engine then takes over, when it produces said 600 ft/lbs to do the job the rope was doing..keeping it stationary on the belt. Them the pilot opens the throttle full out, which generates say 2000 ft/lbs, which is more than enough to propel the plane against the drag, and increase its speed to take-off speed..and it will fly away!!
WHAT A LOAD OF WAFFLE...BUT THE TRUTH IS ENCAPSULATED WITHIN :
Nick

.
About a year and a half ago in the original thread, Maryjane posted the following Here (with a very slight modification added by me). Too funny...

quote Originally posted by maryjane: Forget the wheels. What are the wings doing? What is the fuselage doing? See the little faces in the little windows? See their little hands waving? They are waving bye bye as the plane moves on down the conveyor to takeoff. Wave bye to the "no fly" people everyone - they're standing there wondering how the plane took off without them.

The "no fly" people appear to have some sort of a mental block. Maybe Santa will bring them some new insight later this evening.

Ho ho ho!

[This message has been edited by Patrick (edited 12-24-2007).]

How about if you leave the conveyor off, and let the plane take off - then turn the conveyor on. The plane will fall out of the sky!!!111LOLWTFBBQ!!

quote Originally posted by Formula88: The plane will fall out of the sky!!!

And the world will change from being round to something flat like a... a... hockey puck !!!

quote Originally posted by Patrick: And the world will change from being round to something flat like a... a... hockey puck !!!

I thought hockey pucks were round?

------------------
Ron

It's the Soldier, not the reporter
Who has given us the freedom of the press.
It's the Soldier, not the poet,
Who has given us the freedom of speech.
It's the Soldier, not the politicians
That ensures our right to Life, Liberty and the Pursuit of Happiness.
It's the Soldier who salutes the flag,
Who serves beneath the flag,
And whose coffin is draped by the flag.

[This message has been edited by blackrams (edited 12-24-2007).]

Yeah!! Like the Earth was flat...but round too, depending upon the view angle!! AAAGH!! Here we go AGAIN!!!
Nick

[This message has been edited by fierofetish (edited 12-24-2007).]

quote Originally posted by blackrams: I thought hockey pucks were round?

Hockey pucks are round AND flat, on two sides no less... and they will fly!

Ok then, how about this one. Imagine an iceboat on a huge piece of floating ice. Somewhere in front of the iceboat, but next to the piece of ice a buoy floats in the water. The wind blows from behind the iceboat. On one side of the ice are a whole bunch of very smart penguins that can somehow track the forward speed of the iceboat and will instantly push the chunk of ice with the same speed in the opposite direction.

Will the iceboat get any nearer to the buoy?



(I'm restoring a backup - I'm bored)

quote Originally posted by Patrick: Hockey pucks are round AND flat, on two sides no less... and they will fly!

Even if the ice is traveling at an equal but opposite direction?

------------------
Ron

It's the Soldier, not the reporter
Who has given us the freedom of the press.
It's the Soldier, not the poet,
Who has given us the freedom of speech.
It's the Soldier, not the politicians
That ensures our right to Life, Liberty and the Pursuit of Happiness.
It's the Soldier who salutes the flag,
Who serves beneath the flag,
And whose coffin is draped by the flag.

quote Originally posted by Cliff Pennock: Will the iceboat get any nearer to the buoy?

Depends on which way it swings. Might be more inclined to get closer to a gurl.

quote Originally posted by Cliff Pennock: Ok then, how about this one. Imagine an iceboat on a huge piece of floating ice. Somewhere in front of the iceboat, but next to the piece of ice a buoy floats in the water. The wind blows from behind the iceboat. On one side of the ice are a whole bunch of very smart penguins that can somehow track the forward speed of the iceboat and will instantly push the chunk of ice with the same speed in the opposite direction. Will the iceboat get any nearer to the buoy? (I'm restoring a backup - I'm bored)

Wow, I'm impressed. You've put some real thought into how to convince some folks the plane will fly. I've come to the conclusion that they're just pushing our buttons. Nice drawing though.

------------------
Ron

It's the Soldier, not the reporter
Who has given us the freedom of the press.
It's the Soldier, not the poet,
Who has given us the freedom of speech.
It's the Soldier, not the politicians
That ensures our right to Life, Liberty and the Pursuit of Happiness.
It's the Soldier who salutes the flag,
Who serves beneath the flag,
And whose coffin is draped by the flag.