The plane will NOT take off on a moving conveyor belt unless the ENGINE THRUST is strong enough to bring the plane up to the forward speed needed for the plane to generate lift.

quote Originally posted by leppy_89:

For those who say it won't fly, if you think about it, the cart will still move, no matter what...

So just imagine the block has wings, and is aerodynamic enough to fly

quote Originally posted by leppy_89: I made a picture. Crude, but I think it works.

The cart will not fly!

quote Originally posted by Cliff Pennock: The cart will not fly!

Ahh... but perhaps it could float?

quote Originally posted by Cliff Pennock: The cart will not fly!

Yeah I know, I used a cart *shrugs*.

I didn't have the time, nor MSPaint skills to draw a plane that wouldn't be laughed at haha.

quote Originally posted by Synthesis: The plane will NOT take off on a moving conveyor belt unless the ENGINE THRUST is strong enough to bring the plane up to the forward speed needed for the plane to generate lift.

That statement is true whether the plane is on a conveyor or on a solid runway. It's all about lift generated on the wings.

------------------
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.

Just to state it more simply....NO....it will not fly until there is a wind generated over the wing at the planes V1 speed. Doesnt matter how fast the conveyor goes, it can be moving 5000 mph and it will stay right on the conveyor with the wheels spinning like mad Now if you pull the plane or lauch it with a catapult, you WILL move the air over the wing surface and it WILL fly.

Ok now we know the airplane will fly..............but can it stop before the "end" of the conveyor runway when it lands?????

runs and hides.....

quote Originally posted by SCCAFiero: Ok now we know the airplane will fly..............but can it stop before the "end" of the conveyor runway when it lands????? runs and hides.....

It depends on if the conveyor is moving in the same direction, I doubt it will stop, or the opposite direction, it probably will stop and then carry the plane to the other end IF the engine(s) are not running or running at a high enough speed to move the plane.

quote Originally posted by Marvin McInnis: Now for something completely different ... Here's a fun (and cheap) experiment that you can all do for yourselves and for the amusement of your friends. You might even be able to win a few bar bets with it: Get an ordinary helium-filled balloon and tie it in your car so that it is free to move in all directions. Close the car windows and turn the heater fan down to low so that air movement doesn't affect the balloon. Now drive around, accelerating, braking, and turning aggressively. What happens to the balloon? Why? Is it what you expected?

the balloon will move forward in the car. it would be more accurate to say that it moves around the drivers head (never passengers) and blocks your vision. the ballon is most prone to do this when 1) coming to a stop light or intersection, 2) when you are trying to change lanes or 3) a cop is behind you.

since there is an equal and opposite reaction to the balloon moving forward this will result in 1)your kid yelling in your ear or 2) your kid kicking your seat.

quote Originally posted by Patrick's Dad: Marvin, the balloon will move to the front of the cabin on acceleration and backward during braking. It will move away from the center of a hard turn.

We have a winner!

The balloon moves exactly the opposite of how a hanging pendulum would move. Anybody want to explain why?

quote Originally posted by Synthesis: The plane will NOT take off on a moving conveyor belt unless the ENGINE THRUST is strong enough to bring the plane up to the forward speed needed for the plane to generate lift.

The plane will also NOT take off from a moving conveyor belt NO MATTER WHAT THE FORWARD SPEED OF THE PLANE IS if the whole dang experiment is performed in a vacuum.

quote Originally posted by Patrick: The plane will also NOT take off from a moving conveyor belt NO MATTER WHAT THE FORWARD SPEED OF THE PLANE IS if the whole dang experiment is performed in a vacuum.

true but then it would be called an airless plane.

yuk, yuk..

quote Originally posted by Marvin McInnis: We have a winner! The balloon moves exactly the opposite of how a hanging pendulum would move. Anybody want to explain why?

The balloon is buoyant relative to the air. When the car accelerates, the air inside the car moves to the rear. Since the air is more dense than the balloon, it pushes towards the back faster than the balloon can. In effect, the air moving rearward pushes the balloon forward.

[This message has been edited by GT86 (edited 12-14-2007).]

Hey!!!!!!! I flew F4s and they fly great. Nothing gives a rush like going 1,000 mph 50 feet over treetops. Now they do make a lot of noise and smoke though, lol. Ive seen people with radio control models of everything from a doghouse to a lawn mower. If its got a wing that can support it and enough power, yes just about anything can fly under control. Thats not the same as just anything can 'fly'. ie/ baseball, rock, tree, house etc.

As I wrote in reply to a similar thread on another forum I frequent:

The singular point that everybody is arguing about is this:

The 'straw man' that the original equation sets up is that the conveyor belt will induce sufficient drag to the aircraft (via the landing gear) to impede forward motion regardless of how much forward thrust is generated, whether or not such a factor is realistically feasable or not.

The realistic look is that there is no way a treadmill could induce enough drag via the wheels to impede forward movement of the airplane. Given that parameter, if there is forward motion allowed, if enough forward motion and speed are generated, the plane will take off. However, this circumvents the question posed by the original equation. It does not answer the equation as stated.

Since the equation itself presents a realistic impossibility, it can only be answered with an if/then statement, not an absolute black-and-white, yes-or-no answer. That being, 'IF the treadmill can provide enough drag to truly prevent forward motion of the aircraft, THEN no lift would be generated and the plane would not fly.'

THAT is the answer to the equation. There is no simple 'Yes' or 'No', because the way the question is pondered depends on whether the reader is willing to suspend reality in order to answer the question as stated, or if the reader is determined to apply natural laws to a realistic impossibility.

------------------
Patrick W. Heinske -- LZeitgeist@aol.com
1988 Red Fiero Formula Convertible
*Desktop Photo Here* (click either link for pics)

quote Originally posted by LZeitgeist: As I wrote in reply to a similar thread on another forum I frequent: The singular point that everybody is arguing about is this: The 'straw man' that the original equation sets up is that the conveyor belt will induce sufficient drag to the aircraft (via the landing gear) to impede forward motion regardless of how much forward thrust is generated, whether or not such a factor is realistically feasable or not. The realistic look is that there is no way a treadmill could induce enough drag via the wheels to impede forward movement of the airplane. Given that parameter, if there is forward motion allowed, if enough forward motion and speed are generated, the plane will take off. However, this circumvents the question posed by the original equation. It does not answer the equation as stated. Since the equation itself presents a realistic impossibility, it can only be answered with an if/then statement, not an absolute black-and-white, yes-or-no answer. That being, 'IF the treadmill can provide enough drag to truly prevent forward motion of the aircraft, THEN no lift would be generated and the plane would not fly.' THAT is the answer to the equation. There is no simple 'Yes' or 'No', because the way the question is pondered depends on whether the reader is willing to suspend reality in order to answer the question as stated, or if the reader is determined to apply natural laws to a realistic impossibility.

I really like your car, but, you talk funny.

------------------
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: I really like your car, but, you talk funny.

LOL!

------------------
Patrick W. Heinske -- LZeitgeist@aol.com
1988 Red Fiero Formula Convertible
*Desktop Photo Here* (click either link for pics)

I'll leave my original post as a penalty for not reading, but let me preface this by saying, I was refering back to a diffrent thread a long time ago where the proposed airplane was stationary on a treadmill, at any rate, I got the question straight (see below posts) and yes the plane will absolutely take off. I'll leave this post for my own humility.

I CANNOT beileve people are still talking about this. I understand some people might not get the concept, but if you dont know what you're talking about, stop arguing! And if you do know what you are talking about, you would be rolling your eyes everytime this came up.


Flight requires lift, so we need only prove if lift is involved.

Go get a flat sheet of cardboard, 24x24 would be nice, but anything sizeable will work.

Go outside, hold it at a ~45* angle in the direction you are facing. Now run. Do you feel it tug up? No? Then your holding it wrong dumb a**, put the edge away from you up, now try again. Okay, feel that tug? Thats lift.

No go back inside (or to your local YMCA). Crank the treadmill to high and hold the same cardboard the same way, jump on and start running. Feel the tug?.... turn off the fan stupid... now feel a tug? No, thats because theres no air moving over the surface, which means there is no lift, which means a plane would not take off.


Was that simple enough? All that matters is the plane moving through the air. The answer is no. If you're asking if its possible to take off on a treadmill, yes, if its long enough the plane can get up to speed. The only way it couldnt would be if the reverse movement of the treadmill was so much that the rolling resistance of the wheel bearings exceeded the power the engine could make, or the bearings overheated and melted. The only question is, is the plane moving through the air.

[This message has been edited by 86GT3.4DOHC (edited 12-14-2007).]

quote Originally posted by Cliff Pennock: They did another one of those "internet myths" in the show that aired here last week: If you have a truck full of pigeons sitting on the floor (or anything else) of the truck, and all pigeons suddenly start flying inside the truck, will the truck become lighter?

Western pigeons, or European pigeons?

What 84 Gt said above.
Read the original premise. The conveyor senses the speed of the forward motion of plane and adjusts the conveyor speed to match it in the opposite direction.
Thus the plane is NOT moving forward in relationship to the rest of its surroundings, ie the trees, grass, you watching this debacle, and more importantly, the AIR. The wheels can spin themselves off of their axles, but there will be NO forward movement.
NO AIR MOVING OVER THE WING, NO LIFT, NO FLY.

quote Originally posted by v6richie: What 84 Gt said above. Read the original premise. The conveyor senses the speed of the forward motion of plane and adjusts the conveyor speed to match it in the opposite direction. Thus the plane is NOT moving forward in relationship to the rest of its surroundings, ie the trees, grass, you watching this debacle, and more importantly, the AIR. The wheels can spin themselves off of their axles, but there will be NO forward movement. NO AIR MOVING OVER THE WING, NO LIFT, NO FLY.

I can't believe people still don't get it.

Why is the plane not moving forward?

If the engine is putting out enough thrust to push the plane forward at 50 mph, and the conveyor is going 50 mph backwards, does that mean the plane is sitting still? Um, no.

It means the plane is moving forward at 50 mph, the conveyor is going backwards at 50 mph, and the wheels on the plane are turning at 100 mph.

quote Originally posted by 86GT3.4DOHC: I CANNOT beileve people are still talking about this. I understand some people might not get the concept, but if you dont know what you're talking about, stop arguing! And if you do know what you are talking about, you would be rolling your eyes everytime this came up. Flight requires lift, so we need only prove if lift is involved. Go get a flat sheet of cardboard, 24x24 would be nice, but anything sizeable will work. Go outside, hold it at a ~45* angle in the direction you are facing. Now run. Do you feel it tug up? No? Then your holding it wrong dumb a**, put the edge away from you up, now try again. Okay, feel that tug? Thats lift. No go back inside (or to your local YMCA). Crank the treadmill to high and hold the same cardboard the same way, jump on and start running. Feel the tug?.... turn off the fan stupid... now feel a tug? No, thats because theres no air moving over the surface, which means there is no lift, which means a plane would not take off. Was that simple enough? All that matters is the plane moving through the air. The answer is no. If you're asking if its possible to take off on a treadmill, yes, if its long enough the plane can get up to speed. The only way it couldnt would be if the reverse movement of the treadmill was so much that the rolling resistance of the wheel bearings exceeded the power the engine could make, or the bearings overheated and melted. The only question is, is the plane moving through the air.

you are missing the key point: the planes engines have NOTHING to do with the treadmill. airplanes are NOT powered thru the wheels. the treadmill is irrelevant. the airplane WILL power itself forward.

If you were talking about a CAR, then yes it would remain stationary. The car's engine turns the wheels at 50 mph forward, and the conveyor goes 50 mph backwards and the 2 cancel out.

BUT on an aircraft the engine doesn't turn the wheels - it pushes against the air. The speed of the conveyor doesn't affect the air. The plane's engine can push the plane forward through the air regardless of what speed the conveyor is moving.

quote Originally posted by v6richie: What 84 Gt said above. Read the original premise. The conveyor senses the speed of the forward motion of plane and adjusts the conveyor speed to match it in the opposite direction. Thus the plane is NOT moving forward in relationship to the rest of its surroundings, ie the trees, grass, you watching this debacle, and more importantly, the AIR. The wheels can spin themselves off of their axles, but there will be NO forward movement. NO AIR MOVING OVER THE WING, NO LIFT, NO FLY.

Uh, sorry, the wheels have nothing to do with it. This is air thrust power, the ground is not a factor at all. I design and build air prop powered craft.

I just can't see what is so tough about this. This is like going to the asylum and debating blue.

quote Originally posted by Pyrthian: you are missing the key point: the planes engines have NOTHING to do with the treadmill. airplanes are NOT powered thru the wheels. the treadmill is irrelevant. the airplane WILL power itself forward.

Are you saying it will or wont take off? Because it wont. Ignore the engines, ignore the wheels ignore the treadmill, the only thing that matters is this : Is there air moving over the wings. If its sitting on a treadmill then the answer is no. Thats all that matters.

THINK ABOUT IT. If this were true, there wouldnt be big expansive airports wasting highly valuable realestate, every airport would just have a landing strip and a hanger size treadmill. Aircraft carriers would be the size of a cruiser with treadmill launchers and short landing strips.

quote Originally posted by 86GT3.4DOHC: Are you saying it will or wont take off? Because it wont. Ignore the engines, ignore the wheels ignore the treadmill, the only thing that matters is this : Is there air moving over the wings. If its sitting on a treadmill then the answer is no. Thats all that matters. THINK ABOUT IT. If this were true, there wouldnt be big expansive airports wasting highly valuable realestate, every airport would just have a landing strip and a hanger size treadmill. Aircraft carriers would be the size of a cruiser with treadmill launchers and short landing strips.

lol - it will take off. just fine. as if nothing was different.
the planes engines do not turn the wheels. the treadmill is misdirection. it changes nothing. the plane will still fire up its jets, which it push it forward, build up speed & take off.

quote Originally posted by Pyrthian: lol - it will take off. just fine. as if nothing was different. the planes engines do not turn the wheels. the treadmill is misdirection. it changes nothing. the plane will still fire up its jets, which it push it forward, build up speed & take off.

But the question is NOT whether the plane can MOVE foward and take off. The question is will the plane take off from a stationary posistion on the treadmill given the treadmill is moving at x MPH backwards, and the planes engines are used to keep it stationary in space. Exactly like my human on treadmill scenario.

Or did someone change the question to a magical mile long treadmill \ runway. In that case, yes absolutely the plane will take off, as long as you dont have an effective wheel speed in excess of the limits of the wheel bearings, the plane will absolutely take off.

Its a matter of ground speed VS air speed. Ground speed is irrelevant, barring physical limitations, you could have a ground speed of 1000 MPH with a tail wind of 1000MPH, and an effective airspeed of 0 MPH and the plane would be like a rock.

[This message has been edited by 86GT3.4DOHC (edited 12-14-2007).]

Where people get hung up on this is thinking the treadmill will keep the plane from moving.

The other thing is when I first read this dumb question on the other thread I think what "they" were asking the question whether the plane would take off while the treadmill kept the plane remaining stationary as far as ground speed relation.

Which is more idiotic?.

quote Originally posted by 86GT3.4DOHC: Are you saying it will or wont take off? Because it wont. Ignore the engines, ignore the wheels ignore the treadmill, the only thing that matters is this : Is there air moving over the wings. If its sitting on a treadmill then the answer is no. Thats all that matters. THINK ABOUT IT. If this were true, there wouldnt be big expansive airports wasting highly valuable realestate, every airport would just have a landing strip and a hanger size treadmill. Aircraft carriers would be the size of a cruiser with treadmill launchers and short landing strips.

You are right in part. If there is air moving over the wings, the plane will fly. The plane has to move through the air to generate lift.
Do we agree on this much?

The question then becomes is the plane moving? You're saying if the plane is on a treadmill it won't move - therefore there's no lift and it won't fly. I'm saying the plane WILL move, even on a treadmill, and generate lift and will fly.

How does the treadmill slow down the plane?

Try this. Take a matchbox car and put it on a treadmill. Put your finger behind the car and push it forward with the treadmill off. No problem, right?

Ok, now turn the treadmill on and keep your finger behind the car to hold it still. There's a little pressure on your finger, but you're just sitting there with the car stationary and the wheels turning, right? If you speed up or slow down the treadmill, the car stays right there on your finger, right? Now, try to push the car forward. It moves - even though the treadmill is going backwards. Why? Because your HAND is moving the car forward and your hand is not connected to the treadmill.

The airplane's engine pushes against the AIR - not the treadmill. Just like your matchbox car, the plane moves forward normally, but the wheels just spin faster on the treadmill.

Since the plane moves forward, it generates lift and will take off.

quote Originally posted by 86GT3.4DOHC: Its a matter of ground speed VS air speed. Ground speed is irrelevant, barring physical limitations, you could have a ground speed of 1000 MPH with a tail wind of 1000MPH, and an effective airspeed of 0 MPH and the plane would be like a rock.

Ground speed is not the relevant factor for flight.

Ahh dammit, wrong discussion. I went and read the linked thread in the first post. There was a post a while back where the theoretical airplane was on a stationary treadmill, IE did not move in space. It was a retarded question. This is a diffrent question.

This is a retarded question in and of itself as well, I was just answering the wrong question.

So yes, in the context of this question, the plane will absolutely take off. Sorry, I'll read rather than assume next time. Perhaps that is the cause of all the controversy, misunderstanding of the context, as surely this should be fairly obvious.

The thread linked in the first post is the same question.

quote Originally posted by Formula88: The thread linked in the first post is the same question.

Yea I get it now, I was thinking of a diffrent question wherein the plane remained stationary on a treadmill the size of the plane. This question refers to a treadmill the size of a runway.

My explanations refer to an airplane that uses its engines to maintain its location on a treadmill, thus remaining stationary in space. THIS IS NOT THE PREMISE OF THIS THREAD. I'll see if I can find the thread that I read this alternate question on.

[This message has been edited by 86GT3.4DOHC (edited 12-14-2007).]

quote Originally posted by v6richie: Read the original premise. The conveyor senses the speed of the forward motion of plane and adjusts the conveyor speed to match it in the opposite direction. Thus the plane is NOT moving forward in relationship to the rest of its surroundings, ie the trees, grass, you watching this debacle, and more importantly, the AIR. The wheels can spin themselves off of their axles, but there will be NO forward movement. NO AIR MOVING OVER THE WING, NO LIFT, NO FLY.

If at any point "the plane is NOT moving forward in relationship to the rest of its surroundings", then why would the conveyor belt be moving at all?

Sorry, but you need to read the original premise.

quote 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 Patrick (edited 12-14-2007).]

LOL

Good post SA. Without imagery it's easy to misunderstand the question even though everyone understands the physics behind it all perfectly well.

quote Originally posted by timwdegner: even though everyone understands the physics behind it all perfectly well.

The airplane and the treadmill has probably been debated on every forum known to man. I know I've seen it on at least 7 different forums, usually with 20+ pages. I've seen some intelligent posts, and some downright idiotic posts, with everything in between.

I would dispute the idea that everyone understands the physics

[This message has been edited by GT86 (edited 12-14-2007).]