Airplane on a treadmill question

I'm almost tempted to call the treadmill-and-wheels part of the ENTIRE argument a red herring.

Do whatever the fuck you want to the wheels with the treadmill. Forward. Backward. Faster. Slower. Whatever.

None of that will affect the airframe and the force of thrust being enacted upon the airframe.

Exactly. The tires spinning do not effect the motion of the plane.

Not "about" as long as a typically runway. EXACTLY as long as a typical runway. Take off distance of the plane will be the exact same as if it was a solid, non-moving surface underneath it. Again, the rotation of the tires do not effect the motion of the plane. There is no connection between the tires and the airframe, except a pin that allows the tires to rotate freely around it.

If the treadmill moves as fast as the plane it wont take off.

If the plane moves faster than the treadmill and builds up enough speed, yes it will.

Depends on how the question is worded.

So what if the treadmill is moving as fast as the plane? Does the movent of the treadmill restric the flow of air under the wings thus not lifting the plane?

For the plane to take off, there are two forces required: thrust and lift. The speed of runway or whether it's moving forwards or backwards has NO effect on those forces whatsoever.

well if the treadmill is moving just as fast as the plane, there is no wind to move over the wings to provide lift.....

Now you're just fucking with us, right? Right?

don't the wings need air resistance to lift the plane?

If you are running on a treadmill holding a hangglider, and you jump forward, will you fly?
no, there is no air resistance....

READ THIS THREAD.....

Link to plane on treadmill thread...

That thread contains everything you wanted to know about a plane on a treadmill... but were afraid to ask.

well, thats not really a treadmill now, is it?

look up the definition of treadmill. There is a key part to the definition, the object on the belt remains stationary. You got the plane moving a 1/4 mile or more = not stationary, ipso facto, your plane is not on a treadmill.

Okay.

Stop focusing on the treadmill.
The wheels are free-rolling. The movement of the wheels and the treadmill DON'T MATTER.

The engines light up, start generating thrust, and propel the plane FORWARD. During this movement, the wheels are spinning a trillion miles an hour in whatever direction you like -- IT'S IMMATERIAL!

As the thrust pushes the airframe forward atop those little spinning wheels WE DON'T CARE ABOUT, the air is moving across the wings faster and faster, until enough lift is generated, and the plane takes off -- at approximately the exact same distance down the treadmill-runway as it would on a concrete-runway.

That means that the plane is moving faster than the treadmill, "propels forward".
I dont care about the wheels either. If it moves faster than the treadmill yes it will take off. But the treadmill is supposed to be moving as fast as the plane....

If you are running on a treadmill holding a hangglider, and you jump forward, will you fly?
no, there is no air resistance....

If I put a fucking Weslo-Cadence ButtFucker 2000 in my home gym and walk in place on it, it's a treadmill.

If my cat jumps on the fucking thing and starts running forward, backwards and throwing up hairballs on it, has it suddenly become a towel-rack?

I get what the definition is. Alternating its use for ten minutes does not turn it into a big bowl of spaghetti or a luscious pair of tits.

It's still a treadmill.

If Mine has been sitting in the same place for 14 months collecting old condoms is it still a treadmill?

Chia, come shoot me in the head so I can get out of this fucking thread, will you please?

You guys have all lost your focus.
The orginal question, as posed on XOC, specified a Conveyer Belt, not a treadmill.
Any discussion of "treadmills" is therefore off topic and all such posts should be deleted out of respect for the original poster.

is earth just a giant treadmill? I mean its rotating, i guess when i'm jogging I'm really on a treadmill?

The cat still remains relatively stationary. The longer you make the walking surface, the more it becomes a walkway. Not a towel rack.

the condoms are stationary, aren't they

we're not in that thread, we're in this one, and it says treadmill.

You are RUNNING down the tread mill by using feet to push off the treadmill. You misconception is here. A jet plane does NOT USE WHEELS to push off the tread mill, thus the speed of the given shitty fuckin' tread mill does not matter.

I wish someone had done this for me:

"Walk away, man. It's not worth it. It's not WORTH it!"

ok, if the conveyer belt is moving as fast as plane, as stated in the original question.
Where does the air resistance come from to lift the plane?

Alright. Picture this, Chumpman.

You've seen a car on a dyno machine before. So, no matter how fast the car goes, the rollers of the dyno will keep the car in place, because they spin at the same speed as the tires.

Now, imagine a jet plane on a dyno. You put all of it's wheels on the rollers, fire the engines and the rollers would not spin, the plane will propel itself forward going over the rollers because the power does not come through the wheels. Thus, the speed of the treadmill is irrelevant.

What's going to end up happening, is that the wheels of the plane taking off will spin at twice the speed they normally would, given any speed the plane reaches during take off (since the treadmill mathes the speed of the plane, but in the other direction).

Plane lifts off with the wheels spinning twice the speed they normally would, that's all.

A treadmill moving in the opposite direction of the plane, does provide enough force to counteract the thurst of the plane.

If it did apply enough force going in the opposite direction of the plane to stop it from lifting off, then it's logical to think that if it treadmill was standing still, it would provide HALF of that force? According to your logic it is so, however it's not. Think about it.

it isnt asking if the engines power the wheels.
I know that they dont.
Your saying that a plane is on a set of rollers that dont move in the opposite direction...

"This conveyor has a control system that tracks the plane's
speed and tunes the speed of the conveyor to be exactly the same (but
in the opposite direction)."

If you are saying that the wheels are moving twice as fast, then the conveyer is not matching the planes speed. the plane is going faster.

Doesnt matter what pushes the plane, if it can not get the air resistnace ( due to the Conveyer belt moving AT THE SAME speed in the opposite direction) under the wings It will not take off.

No.

The SPEED of the wheels will be the exact same as the aircraft. They're fixed to the plane in the horizontal & vertical axis. However, they're not fixed in the Z axis, which means:

The ROTATIONAL VELOCITY (the only thing the treadmill can actually effect on the plane) will be faster than the treadmill is moving.

But we don't really give a damn about the ROTATIONAL VELOCITY of the wheels, do we? We care about the SPEED of the aircraft. Which, while the treadmill accelerates in the opposite direction as the plane accelerates, they do not have any shared forces whatsoever. The treadmill causes ROTATIONAL VELOCITY/ACCELERATION of the tires, only. The plane causes DIRECTIONAL velocity/acceleration of the tires via the pin that holds them in place (the axle shaft).

There are 3 dimensions of movement, here, and you're not realizing the Plane effects 2 of them (moving forward (x-axis) & upward (y-axis)). The treadmill effects the 3rd (causing rotation of the tires about the Z axis). ANY force about the Z-AXIS does NOT counteract ANY force about the X or Y axis.

You're still confusing rotational veloctiy of the tires as the speed of the plane. It's not. The two are not interchangeable properties.

No, it DOES match the plane's speed. But despite that the planes still takes off because the rotating speed of the wheels doesn't matter in relationship to the forward thrust provided by the engines. Don't get caught up with the wheels. What if it was a slick surface and the plane was on skis or skates? Would the plane take off? It doesn't even have wheels now.

The only point at which the speed of the conveyor matters at all is if it can create enough speed to in turn create enough drag to counter thrust. That's it. As long as thrust is sufficiently greater than drag, the plane flies. Like I said before at that point it isn't matching the speed of the plane but vastly exceeding it and outside the scope of the question.

Okay. Maybe this will help.

Pretend you're holding a toy plane in your hand. You go "vroom vroom vroom", and make the plane fly all over the Toy Section at WalMart. With me?

Okay. Your hand is the engine. It's the thrust. Remember this.

Now: You walk with mommy over to the exercise equipment section. Oooh! Cool treadmills, mommy!

You see one running. You put your little toy plane on the treadmill. Oooooh! See how the tires spin!?

Now a saleslady comes over, and turns the treadmill up faster (I don't know why -- that's not safe, you crazy bitch, you'll rip a kid's hand off that way) . . . I digress.

So the treadmill is moving faster. Whee! Oh, the plane's wheels are moving faster too!

Now, you move the plane forward with your hand (thrust). Notice that the plane's wheels are still spinning?! Oooh! The plane is going, like, 500 mph, so fast! And the treadmill is spinning 500 mph in the opposite direction! So fast, mommy! And yet, you are able to easily move the plane forward for takeoff . . .

The treadmill/conveyor belt/rollers/towel rack/bowl of spaghetti/luscious tits/used condom storage rack has NO EFFECT on the plane itself.

Any of that getting through?

The plane will not move forward on a conveyer belt moving the same speed in the opposite direction, wether it is on wheels, or just sliding on its belly.
If the plane does not move forward, it does not take off. If it moves forward on the Conveyer belt, it is going faster than the conveyer belt.

He's gotta be fucking with us. Gotta.

I mean, right?

I believe some people forgot to release the hand brake.
This thread is killing me.

If it moves forward on the Conveyer belt, it is going faster than the conveyer belt...

Since today is Friday, that fact is irrelevant.

No, sweetie, it isn't.

The WHEELS might be moving faster than the belt.

Cessnas lift off at an airspeed around 80 mph, IIRC.

Crank that conveyor belt sumbitch up to 300 mph if you like, the plane will still accelerate to 80 mph and liftoff . . .

.................................
TANGENT:
Do they take off at 80 mph? Or is that the recommended landing speed? Now I can't remember . . .

Lets remove the treadmill for a second and set the plane on some saw horses (figuratively speaking the wheels are off the ground) Now make the wheels spin a million miles an hour can the plane take off?? No because there is no fucking wind over the wings.

.
.
.
.

What happens if the wheels are spinning in the opposite directions in this case?

no no, thats actually right. the plane will move faster. thats the only way it can travel down this long not-a-treadmill.

lets say our plane takes flight, on a runway, at 150 MPH. on runway, ground speed (respective to the runway) = air speed.

On the treadmill, if the plane takes off, its air speed = 150. However, the ground speed is 300 (relative to the tread belt).

You have the plane AND the treadmill both spinning the wheels. Their point is, wheel speed has no effect on the rate of travel.

Heres another example. I am jogging on a treadmill and I fart...I dont move forward do I ?

Let's assume we put the plane in the 3x3 mode, rear diff locked...

Then we'll solve global warming. Huzzah!

I posed this question to my wife, and told her there was a big debate going on at XOC about this.

Her response was: How many XOC members still live with their moms?

She'd appreciate some prompt replies.

We'd appreciate some pictures

And no I dont live with my mom....she might know the answer though

Have to go ask my mom.

OK, I got the plane, heading to the gym now.

I'm back.
It flew, but very low.

Here's my take on it

In the theoretical description of the question, the end result will be a plane throw off the end of the conveyor-belt-runway and destroyed.

In a real-life attempt at the question, the plane will take off.

Explanation:
If the conveyor belt actually move at a rate exactly the same as the relative speed of the plane on the ground (which at ground level would be the same as its airspeed, as soon as there is enough thrust to move the plane forward, the speed of the conveyor belt (and the rotation of the planes tires) would increase exponentially towards infinity to compensate. This speed would result result in catastrophic failure of the plane's wheel bearings and axles, and the plane would then be violently tossed off the end of the moving runway by the infinitely-fast-moving conveyor belt since there was no longer a spinning wheel to aid in friction loss between the plane and runway.

In real-life, it would not be possible to create a conveyor-belt-runway that could increase in speed to compensate for the thrust of the plane's engines, so the conveyor belt would never get up enough speed to keep the plane in one position, and the plane would takeoff.

You can't-flyers check out that thread that's been linked to about five times and scan for posts by TJ or JeffW. They've got good explanations. I like to think some of my analogies were pretty good, too.

One of my examples-The aircraft is already airborne and on approach to the conveyor/runway for a touch-and-go. The runway is spinning at exactly the same speed in the opposite direction, just like when it took off. Now, when the aircraft touches down (no brakes, remember, doing a touch-and-go) will it immediately come to a complete stop and be unable to take off again (do the "go" part)?

After all this I'm left with wondering how a plane on a movable platform (conveyor/treadmill) can generate enough air over the wings to achieve lift.

But doesn't this whole thing ride on if the plane moves forward on this infinite treadmill? If it sits still because the belt keeps up with its thrust, it will never take off.

If the plane can over come the rolling resistance to move forward eventually it will.

That sound right?

The belt can only spin the wheels, it cannot counteract the thrust of the engines. If someone throws a skateboard at you, can you stop it by touching the bottom of the wheels?

The movement of the conveyor and aircraft are independent of each other. The wheels serve to reduce friction and guarantee independent movement.

Another blast from the past:

There's a car in a northbound lane traveling at 60 mph, and a car in the southbound lane traveling at 60 mph. They have no effect on each other.

Now suppose the highway is perfectly straight and the southbound car has an enormous vertical board attached to the left side, miles long. The northbound car has a set of non-geared, free-spinning wheels on its left side. Supposing that both cars drive straight and the wheels remain in constant contact with the board, what happens

Each car travels at 60 mph, the wheels on the side rotate at a rate of 120 mph. If they have a standing start and accelerate at the same rate, they still would be able to move in opposite directions and the free-spinning wheels would spin at twice the rate of the drive tires.

Hence, the cars are not "equal and opposite forces" because they are not opposing, just like the conveyor is not opposing the plane.

In that case...

Maybe this example could convince people...

A hovercraft is over a conveyor belt. It moves foward as it wishes, regardless of the conveyor belt.

Now instead of air being forced down on the conveyor belt, put wheels (FREESPINNING - that's key) on the hovercraft.

No difference. It will STILL move forward.

Well shit...who am I kidding...that STILL is not going to convince people.

Another reason the original question is worded badly - IF the wheels had enough friction to overcome the engine thrust, then the plane would not take off...but that is NOT going to happen - the wheels are going to fall apart before that happens.

And just for the record, I was one of those who thought it would *not* take off - based on the friction problem.

Here's some other helpful information along those lines..

IF the wheels generated so much friction the plane's engines couldn't overcome it, a plane would NEVER be able to take off... It wouldn't move at all...

The reality of it is, you could lock up the wheels completely so they can't rotate at all, and the plane's engines will STILL generate enough thrust to overcome the friction between the tires and the pavement...

So there's no way in hell the friction of the tires spinning will overcome the thrust of the engine...

And to put two and two together... If the friction of the tires CAN'T overcome the thrust of the engine, than the tires can be spinning in ANY direction for ANY reason (a treadmill, in this hypothetical), and the plane still takes off.

Nope, not buying it.

And the skateboard and cars passing each other are poor analogies.

To me this is no different then being on a bike thats on a treadmill. The treadmill moves backwards at the same speed my wheels move forward.

If you come up behind me and push me, and the treadmill compensates for the added forward motion (as the original problem states), I will stay in the same place.

To me, thats what the plane and its thrust do.

That's a fantastic explanation!
I love this thread more and more!

U N F U C K I N G B E L I E V A B L E !

Explain the hovercraft. Or the example I used on ice skates.

The jet engines' thrust is enough to move the plane relative to earth (regardless of what's under it - a treadmill, a conveyor belt, ice, water, whatever). If it's moving relative to earth, it's also moving relative to the air (assuming a calm day). This moves the wings through the air to create lift.

You're killing me...

Just wait 'til your in town next weekend. I'll take you out to the airfield and let you stand behind a 747-200 as it spools up to break-away thrust... It'll be like flying a Kevin Kite.

I assure you. The plane takes off. NOTHING on the ground, spinning the tires, is going to prevent those engines from moving the plane. The earth below it can move at whatever speed it wants; doesn't matter.

Here's an example:

http://www.youtube.com/watch?v=1qkcVGwhzlY

LOL

The treadmill in your scenario does speed up but has ALMOST NO EFFECT on the bike because the wheels on the bike are free spinning. Apply the brakes and that is another story (and a funny video to be sure)

OK. Had a revelation. This is as simple a logic for explanation as you're ever going to see.

Step 1:

Ask yourself, "What moves a plane?".

Answer: Engines pushing air: called thrust (equal/opposite reaction, blah blah.)

Step 2:

Ask yourself, "Can the tires move a plane?"

Answer: No. There is no connection between an aircraft's engine and it's tires; look all you want; there's no driveshaft...

Step 3:

Ask yourself, "If there is a conveyor belt under a tire, and the conveyor belt moves, do the tires spin?"

Answer: Yes.

Step 4:

Finally make the ONLY logical conclusion, "If the conveyor belt spins the tires (Step 3), but the tires don't move an airplane (Step 2), then the conveyor has no effect on the plane moving."

__________________
There. 4 easy steps to think your way through this thing. If you can't get it with those 4 easy steps, then I suggest you repeat steps 1 and 2 until it finally makes sense to you.

Thank you. Goodnight.

Tires dont move the plane....correct.

Air resistance over the wings give it lift.

An airplane on a treadmill has no wind resistnace.

Chumpmann- your name indicates to me that you're trolling us.

The skateboard and touch-and-go analogies are apt. Those who say the plane won't fly are essentially holding the position that you can stop a thrown skateboard by touching the bottom of its wheels while its in midflight, or that a plane attempting a touch-and-go would stop the instant it hits the conveyor.

Both contentions are patently wrong.

::ETA:: I think I realized Chumpmann's hangup. Here ya go-

Lift is not required for an aircraft to move. Planes can taxi without flying, and they do it without powering the wheels. Because the plane can move forward by propelling air, no force against the bottom of the wheels can stop it.

Lift is not required for a plane to gain horizontal movement. Horizontal movement will lead to lift, not the other way around. The conveyor cannot prevent this, not if it spins at 1000x the speed of an aircraft.

::ETA::: Whoops

You all fail to accept that there is relativity involved here. The speed of the treadmill relative to the plane is different to the speed of the treadmill relative to ground observer. I've said it before. In this example, the plane moves forward on the belt at a given speed. The belt moves backward at the same speed. By definition, the plane isn't going anyplace. If you apply more thrust, the plane moves forward faster than the belt is moving backward. In order to take off, the plane must move faster than the belt, otherwise its place in space doesn't change, only it's position on the belt.

Maybe this will clear things up for everyone. If you put a guy on the treadmill standing still and he shoots a radar gun at the airplane, he shows that it is departing his position at 300mph. The pilot shoots a radar gun down at the runway and shows the runway whizzing past at 300mph. Since by definition the treadmill belt is moving, the plane is stationary in space and thus has no air flowing over the wings and thus creating no lift. The engines are simply maintaining the aircraft's 300mph forward movement along the belt. If you shut off the engines, the airplane would drift backward until its wheels lost their inertia, then it too would begin to move backward at 300 mph.

Anybody who has some extra time can try this.

Get a box/window fan and put some wheels on the bottom set it on a treadmill and turn it on high. It should move forward on the treadmill. Now crank the treadmill up to 10mph and observe what happens. The fan is still moving air but likely the fan will break when it goes flying off the treadmill into the wall.

No you wont move forward because the treadmill is supposed to speed up to compensate

So those of you who think it will NOT fly...

Why haven't any of you tackled the ice skate scenario?

Or the hovercraft scenario.

The hovercraft scenario is stupid it is different forces acting...Thats like saying if a plane is flying at 5,000 feet and somebody turns on a treadmill does the plane go backwards.....The ice skating one I haven't read and dont feel like searching for

Actually, it's not different forces. Not if you put those free running wheels on the hovercraft.

Quote:

.....The ice skating one I haven't read and dont feel like searching for

Ah...too lazy to admit you're wrong, then.

You guys do realize that it's been almost a year since the original thread was started.

This helped my friends see... You have a AWD car on a AWD dino, no matter how fast those tires spin the car goes no where. You put a fucking JEt engine on the roof that produces thousands of pounds of thrust and start it up, your telling me that the car would not move? Too many beers drank one night on this one.

The plane will take off.

Infx, the plane moves forward relative to the belt and relative to an outside observer.

The conveyor can only push on the bottom of the wheels, causing them to spin. No matter how fast the conveyor goes, it can only spin the wheels.

The plane moves forward by acting on the air, not on the tread.

BTW, if the aircraft goes nowhere, it has no speed. If it does stay in one position, it has NO SPEED and therefore the conveyor would have no speed. The plane accelerates to 10 KIAS (knots indicated airspeed), the conveyor moves in the other direction at 10 knots, the wheels rotate at a rate of 20 knots. The conveyor is powerless to halt or apply equal force to the aircraft because the thrust works to move the entire plane along, while the conveyor can only puch on the bottom of the wheels.

infx, did you read my examples with the skateboard or the aircraft doing a touch-and-go? If the aircraft doing a touch and go would stop on a dime (as your answer indicates) the navy would save billions on carrier suitability testing and you could land anything with wheels on a 200 mile ling conveyor/runway.

These two explain it all.

Yes the engines will "move" the plane. Who cares about what is holding up the plane, wheels, on ice, hovering or whatever.

The treadmill is going to prevent air resistance from passing over/under the wings, because the airplane is not moving against any air.

No one has said where the air is coming from to provide the lift for the wings.

The plane will move, yes. But not Fly.

John can we set up a real world test next weekend?

Still not buying the the plane will take off. Move forward? Ok. I'll buy that. Achive enough forward motion to generate enough lift?

Nope.

How the hell does a treadmill produce a vacuum???? The air that flows over the wings to create lift is already there...You're making this much harder than it has to be.

If the plane can move, it will take off because the wheels are not providing any propulsion. If the treadmill is moving at all then the plane is moving and if the plane moves then it takes off.

Tyler, I already gave up trying to prove that the plane will take off. It's a lost cause.

Don't give up, this thread is the most entertaining thing I've read in a while.

Tony, I can't give up when I see conceptual leaps across the Grand Canyon...makes my brain hurt

vitaly, check out the original thread...titled something along the lines of "Know that if you don't post in this thread today the world will end" or some such crap.

If it can move forward an inch, then it can move forward enough (given enough take-off distance) to take off. Plain and simple.

The plane cannot move forward relative to both at the same speed. Not going to happen, unless the fixed observer is also moving forward in space, in which case he wouldn't be fixed. A touch and go has nothing to do with it, unless it's a Harrier dropping straight down and going back up, which is outside the scope of the question. In the question the plane is not moving forward in space. In order for it to match the rearward speed of the treadmill, it can't move forward or backward of it's present position in space. Basically, you are trying to tell me that the treadmill is spinning the airplanes wheels and thus it takes off. While there is some airflow from the treadmill, there is not enough to generate lift. In order for lift to occur, the plane has to move forward of its present location in space. Since is is only moving forward of its current position on the belt, it is static in space. The engine just keeps it moving forward on the belt at the current speed of the belt. Now, if you applied more thrust and moved it forward along the belt faster than the belt is moving backward along its track, then yes, the bird will fly, but then it has exceeded the parameters of the question. If you really think the conveyor will just spin the wheels, you're not being realistic. Sooner or later the force of the belt pushing backward will overcome the "at rest" inertia of the plane. It will need forward thrust to maintain a forward speed equal to the belt's reverse speed, i.e. maintain its place in space.

I think this is a question dreamed up by philosophy majors as payback to engineers for making the following joke:
Q: What's an engineer say? A: How Does it work? Q: What's a scientist say? A: Why does it work? Q: What's a liberal arts major say? A: Do you want fries with that?

Geez.

It is utterly amazing how many of you dumbasses haven't taken high school Physics I.

The plane takes off.

Ancient History

The correct answer has been well explained:

Once again, you are not taking into account relativity. From your explanation, the plane will fly because it is moving forward relative to a fixed point in space. By that method, the treadmill is irrelevant to the question. It simply becomes will the plane fly once it reaches a certain speed as observed form a fixed point in space. Of course it will. Now, if observed from the treadmill, which is where I take it the speed is measured from, then the plane is sitting still in space. The plane is maintain its speed relative to the belt, NOT to the surrounding air and space. If it accelerates, then it has moved beyond the speed of the belt beneath it and thus moved forward in space.

Now you are making assumptions and distorting the actual problem at hand. It's been proven that plane takes off and relativity does not matter because relativity has no effect on the forces at hand that do make the plane lift off.

infx, The problem does not state that the plane matches the speed of the belt, it says that the belt matches the speed of the plane.

"Relativity" has fuck-all to do with it. No E=mc'2 here.

The casual observer not on the conveyor would watch the plane take off as any other plane on a normal runway would.

The conveyor cannot keep the plane in place because it exerts force only on its wheels, which rotate to negate friction.

A plane with its gear locked up, if it powered up, would move forward on a fixed surface. It would not be smooth, but it would move. Trust me. Now is that more or less friction than the conveyor acting on free spinning wheels?

Relativity can be brought in play, but from that standpoint what matters is the motion of the plane relative to the air particles that provide the lift.

The engines will cause the plane to move forward relative to the air around it, so it takes off. (assuming the wheels are spinning freely, so the spinning conveyor belt is helpless to counteract the force of the engines' thrust against said air particles.)

Ok, Lets forget all the analogies. Dynos arent a good example, they only move the wheels. A treadmill will move the whole object.

How about the analogy of a plane on a treadmill.

A plane sits on a treadmill, on a calm day, no wind, it is 72 degrees. There is a tree in the ground next to the plane even with the tail.
Now, the treadmill starts to move, the plane starts to move backward on the treadmill. The pilot looks out his window and sees the tree moving from behind him towards him, as the plane is moving backwards on the treadmill. Now the engines start to push the plane to the speed of the treadmill, the tree is now even with the pilot as the engines push the plane, to be even with the tree, on the treadmill. Now as the engines push more the treadmill goes faster, the pilot can look out his window and see the same tree, not moving.
The engines push faster, the treadmill moves faster, the tree is still even with the pilot as he looks out his window. The air around the wings of the plane is as still as the trees next to the plane, the pilot can move his flaps all he wants, he does not have the air resistance to take off.

All you're doing is creating a bit of a tail wind, which the plane's engines will quickly over come.

Unless the pilot throttles back to intensionally not overcome the tree.

How about this, instead of slowly starting the tread mill (with the plane at rest), have it start suddenly/quickly with a jerk, like yanking the table cloth out from under a set table. The planes' inertia will keep it from moving backwards and the wheels will just spin on the tread mill while the plane stays motionless relative to the tree.

Hey Chump.

Please explain how a treadmill rotating the wheels on an aircraft can counteract the force of motion of the plane generated by the plane's engines.

Seriously. Please explain this. It is a physical impossibility that a 1st year physics student must learn in order to pass the course. It's a very simple relationship of forces and moments. A moment (spinning the tire) can NOT cancel out a Force. You sum the FORCES in all directions, and you sum the MOMENTS in all directions. But you can NOT add/subtract a MOMENT from a FORCE. They are two different physical things.

Please, before you continue spouting your insanity, PLEASE do yourself a favor and learn the definitions of forces and moments, and how they are used with regards to motions of an object. Maybe, just maybe, once you figure that out, you will be able to understand why the plane can take off. Until you understand the differences in those two properties, however, you're going to continue walking around with your head in the sand.

So with that, I'm done. If somebody can't understand the simple logic between a Force and a Moment, then they can't have a logical conversation on this simple physics problem. And talking with an idiot only makes everybody else feel like an idiot...

that isnt the question.
It is that the plane is moving at the same speed as the treadmill and vice versa, not faster than the treadmill.
If the plane moves forward on the treadmill, that means it is going faster than the treadmill.

If you suddenly start the treadmill, the plane will eventually start to move backwards, until the engines push it to the same speed as the treadmill.

It doesnt matter if there are wheels or not, if it is sliding on its belly, and the engines are pushing the plane at the same speed of the treadmill, It stays in the same place, with no air resistance under the wings.

All you guys are saying is that the plane can move faster than the treadmill, yes that can happen. But that is not the question.

I understand the physics of a plane taking off.
You arent understanding the question.

If you arent explaining with the actual question in mind, then there is no reason to try and explain it.

[QUOTE]Originally posted by chumpmann:

I understand the physics of a plane taking off.
[/QUOTE}
For some reason I missed your explanation, would you be so kind to please post it again?

Close, but wrong.

as the treadmill increases speed, the plane does NOT increase power to the thrusters. In order to stand still, the plane need only provide enough thrust to overcome the friction of the wheels on the tread belt. The thrust at low treadmill speed is the same at a high treadmill speed. The plane is not making the wheels spin, the treadmill is.

This would be analgous to tethering the plane to a fixed object. The treadmill can go as fast as it wants, as long as the plane remains stationary. The wheels will spin faster and faster, but fast spinning wheels does not make a plane take flight.

New analogy :rolleyes:

lets make this our plane:



and this is our "treadmill"



its well known that even against the current, this plane does take off.

This is where the "it takes flight" crowd ignores the fundamental purpose of a treadmill. They are using runway sized treadmills which is totally cheating. Treadmills are designed to keep the object on it, stationary.

A conveyor belt ..yeah I'll agree. But this is not the conveyor belt thread. This is the treadmill thread. And planes cannot fly on a treadmill. On a treadmill, the plane says at fixed latitude and longitude ... and subsequently .. a fixed altitude becuase it won't frickin take off

Since most treadmills have wheels on the underside, the airplane will push the treadmills, since the wheels will hook the handles, along the runway until it takes off.

The plane remains in one place according to the treadmill, but in space the plane is moving creating lift to take off

Taking off upstream is a lot different. The water places a far larger drag on the landing gear. With engines that are powerfull enough, the plane will take off.

Incorrect.

As has been suggested above, it would be a good idea to take High School Physics I prior to commenting.

You will not that the equation for frictional force is F(f) = Mu x Weight . By using standard physics equations, (as has been well explained above), the plane takes off.

Please do everybody a favor and take the time to read and explanation before making the foolish assumption that free-spinning wheels will affect the plane's absolute velocity. Wheel friction is insignificant compared to 50 tons of thrust. The plane takes off.

and you should take reading comprehension. I didn't say shit about the plane taking off. In fact, I supported your arguement you dumbass.

Actually I said that it does NOT affect the way the plane takes off.

I was stating that more thrust is not needed to make the wheels go faster .. ie .. I'll save you the comprehension part and spell it out for you: thrust of the plane is independant of the spinning of the wheels.

as the plane applies more thrust, its going to move forward no matter how fast the tread belt is going.

MY arguement is that using a runway sized treadmill totally defeats the purpose of using a treadmill. People like you are redefining what a treadmill is so you can spout physics lessons and try to make people feel stupid.

landing gear ...

fuck it. the treadmill sinks.

I still bet it doesnt take off.

How come you changed your arguement/side?

The length of the treadmill has absolutely ZERO bearing on the question.

in case you're serious .. why not?

Ding Ding Ding we have a winner! Finally somebody who realizes if the plane is moving forward at all then the plane is going faster than the speed of the treadmill.

Good God...you make my brain hurt.

Because the plane moves regardless of what the treadmill is doing.

Why would the length matter?

Why would a ten foot treadmill be any different than a 20 foot treadmill?

The wheels are NOT a part of the drive system of a plane.

Put dyno's on the front AND rear wheels of the plane. SAME thing. The plane will move OFF the dyno.

OK. I'm confused.. (not really)

Once again, since the obvious things didn't work...

If a plane is flying at 80 mph (close to stall speed of a Cessna), directly over a treadmill (as long as a runway, so there's enough space to do the test) that is currently running at 80 mph, the two objects are moving at the same speed, are they not?

Ok. So that's confirmed; the plane is flying over the treadmill at 80mph, as the treadmill is moving at 80mph.

Next step. The plane lowers his altitude *just* enough so that his tires are in now contact with the treadmill. The plane continues at 80mph forward. The treadmill continues at 80mph in reverse direction as the plane. BUT, you'll notice, the tires of the plane are now revolving at 160 mph equivalent.

So, multiple choice question:

The plane at this time is now moving at:

(A) 0 mph
(B) 80 mph
(C) 160 mph

If you guessed (A) or (C) you would be incorrect.

The correct answer is (B). Therefore the plane has forward movement at the same speed as the treadmill, in the opposite direction. The tires have an angular velocity of the plane's speed and the treadmill's speed, equivalent. But the plane only has 1 speed: 80 mph.

Angular velocity and velocity are NOT the same thing. They are a product of each other in the case of a wheel, but they are not a 1:1 relationship. They do not add or subtract directly to cancel each other out. Ever. Angular Velocity is the forward velocity divided by the circumference of the tire.

In this particular example, at 80 MPH, when you do the math, you'll find the tires will be spinning (angular velocity) (18.368) / (radius of tire) in radians per second. So if it's a 2' tall tire, the observed motion of the tire is that it's spinning at 36.7 radians per second. You don't observe the MPH equivalent the tires are spinning; it's a DEPENDENT property. The INDEPENDENT property is the net velocity (the sum of the airplane and the treadmill velocity).

In other words, the tires spin as a result of the horizontal motion of the airplane and the treadmill. It is a DEPENDENT motion. It is not physically measurable in "MPH", but is physically measured in RAD/S or DEGREE/S, and then converted using the radius of the tire to a MPH. You have to sort that out in your head, and be able to realize that angular velocity does not EVER get added or subtracted to motion velocity at any time; you can't act like they're the same thing, and add an independent to a dependent; math doesn't work that way, as it's a physical impossibility.

Whoops. Almost forgot. To finish it off, the very next second after proving the airplane will still continue forward at 80 mph, even if his tires are on a moving surface that's moving at negative 80 mph to him, the pilot pulls back on the stick, and viola: THE PLANE TAKES OFF...

If you REALLY want to think about it another way...Take this same example, only the treadmill is moving FORWARD at 80 mph. As the plane touches down onto the treadmill, the plane is moving forward 80 mph, the treadmill is moving forward at 80 mph, and the tires are rotating at a whopping 0 rev/s... The tires stand still, yet the plane is moving at 80 mph forward... And it still takes off. Example/Proof, yet again, that the angular velocity the tires move does NOT control the forward motion of a plane...

And one more, 'cause I just can't resist...Treadmill moving forward at 40 mph, plane moving forward at 80 mph. Plane touches down, and the wheels are only revolving at 40 mph equivalent, yet the plane is still moving at 80 mph... Oops. Lookie lookie...angular velocity of the tires still doesn't control the plane's movement...

But just in case I haven't annoyed you enough, yet..

Let's look at the case when the treadmill goes forward, and let's assume the argument of the "can't fly" bunch... If the plane moves at the same speed as the conveyor in the "backwards running conveyor", y'all have assumed the plane can't take off, 'cause the tires are moving at the same speed as the conveyor.

So, if the conveyor is moving forward at 80 mph, and the tires are moving forward at the same speed (80 mph equivalent), how fast is the airplane going?? If you said 80 mph, you'd be incorrect... the plane would be moving twice as fast as the conveyor, it'd be 160 mph!!

[insert "can't fly" protest]Argh!!! It CAN'T be moving at 160 mph, 'cause the tires are moving at the same speed as the conveyor!! But..........but I don't understand....[/insert "can't fly" protest]

Yep, that's right... the angular velocity of the tires isn't the same thing as the speed of the airplane... And since that's true for the conveyor moving forward, then it's true for the conveyor moving backward as well.

Guess what? The plane takes off.

If the tires are going 160mph how fast is the treadmill going?

80 mph. You don't do so well with the reading comprehension, eh? That was given in the example problem statement...

It says pretty clearly:

Typo.
Fixed.

Now let's assume, it's not a plane but an ostrich running on the treadmill.
The take-off speed of the ostrich is 120mph, and the treadmill is moving backwards at 80mph.
How fast does the ostrich have to run in order to take off?

The question isnt about wether the plane can touch and go.

It is asking if it can take off.

If the plane can move at all, then it can take off. I don't have to run a calculation on how long the runway has to be in order for it to accelerate to lift-off speed. I only have to prove it can move at all. The distance it takes is of no consequence.

If it can move at all, then it can get enough speed to take off.

And if it can move under a "touch and go" scenario, then it can move from standstill, as well. The physics that allow it to move at all are the EXACT same, regardless to the initial velocity being 0 mph, 50 mph, or 2,000 mph.

He has to run 200 MPH EQUIVALENT, or 120 mph ACTUAL. If he had an internal speedo, it'd say 200 mph, and to the ostrich, it doesn't really matter, 'cause he can't fly in the first fucking place. He's an ostrich.

Stop smoking crack.

This has already been explained.

If the plane isn't moving, than the treadmill doesn't turn. The plane does move and it takes off. It has been exaustively explained that the treadmill only adds some extra wheelspin. Please read the abundance of information posted on this subject and retort.

Anybody who can't understand a simple High School Physics problem doesn't need anybody to make them look stupid. They're doing a pretty good job on their own..........

What's really sad (for the "can't fly" crowd), though, is that even a car, who IS powered through the tires, will move forward on the conveyor belt... His speedometer won't accurately show how fast he's moving, though, 'cause his tires will have to spin twice as fast to obtain the same true speed.

Case in point: your speedo is just a calculation of how fast your tires are rotating. It isn't necessarily reflect how fast you are actually moving. Do a burnout, and your speedo says you're going 30+ mph. The reality of it is, you aren't moving at all.

Moving is actual moving. Not angular velocity of tires. So if the plane is MOVING, then it is ACTUALLY MOVING... Guess the "can't fly" crowd doesn't understand what "Moving" means...

I believe an ostrich actually CAN take off at 120mph.

Here's where you aren't getting it.

The treadmill is moving at 160mph relative to the plane's speed. The treadmill is moving at 80mph relative to you standing on the ground next to it.

I'd like to see Mythbusters take that one on!

I simply CANNOT believe that yet another thread on this issue has surfaced! I bet that even after Mythbusters CONFIRMS that the plane will fly, the "can't fly" crowd will find some problem with their methods in order to hold fast to their belief that the plane won't fly.

The funny part is, even if the Mythbusters set the treadmill faster than the planes takeoff ground speed, the can't fly crowd would freak and say that it wasn't a valid test because the treadmill was moving too fast

...and created a vacuum behind the plane which propelled it down the runway - which otherwise would not occur if the treadmill would precisely match the speed of the craft.

I'm always kind of shocked that many people have so much faith in this show "Mythbusters".

It is entertainment. It is NOT science.

They have been wrong and will continue to be wrong on things.

And... I'm not talking about the plane/treadmill thing. I am just talking about the show "Mythbusters" in general.

I don't know for certain, but it'd be a helluva' show!

I get trolled for saying that the plane will take off.

Kick-ass!

Who said I can't fly?

You are oversimplifying things. The classic Newtonian mechanics stops working as soon as the treadmill is powered.
The plane will stay stationary until the wheels reach relativistic angular velocity, then it will disappear and pop up at a random point of the Universe.

Finally, an answer that makes sense.

The wheels don't provide ANY forward momentum to the plane. If the jet engines are going, the plane will move forward and take off no matter what's under the wheels. Think about a seaplane taking off against the current of a river, its no problem at all. Ever wonder why the jet dragsters don't do burnouts at the drag strip? Hello?

The "It won't fly" crowd is probably the same crowd who bought all of Suzanne Sommers' thigh masters... Mom used to say, "the world needs dumb people to make the rest of us look smart."

My official response is that there is not enough information in the question

Quote:

A plane is standing on a runway that can move (like a giant conveyor
belt). This conveyor has a control system that tracks the plane's
speed and tunes the speed of the conveyor to be exactly the same (but
in the opposite direction).

Will the plane be able to take off?

Since the plane is standing on the runway the net movement would be 0 therefore the plane would not take off.

If the question assumes that the plane makes an effort to move forward and the treadmill matches spead of the fusalage..sp? then the plane would take off. The best explanation for this would be that there is a rope attached to the back of the plane that runs to a pulley that attaches to the front of the treadmill as plane moves forward the treadmill would turn back at exact speed that the plane moves forward.

If the treadmill is matching the speed of the plane based on the speed of the tires then the plane would remain static and would not take off .

How can the plane have any speed to match if it's stationary?

Your rope-driven-conveyor is bogus, as that totally changes the scenario and adds a whole lot more friction to overcome. Besides, a traditional drivetrain in a piston-prop might work to drive a conveyor, but how would you accomplish that with a turboprop or jet? A big honkin windmill? still wouldn't keep the plane on the ground.

I was using the rope driven conveyor as an example much like the touch and go and all the toehr stuff people have been using as examples.

Very true - it does not say whether the conveyor belt (or treadmill or whatever) matches the planes speed relative to the ground or to itself.

Neither matters.

Here you go.....

583 pages and over 2 years arguing about the plane on a conveyor belt...

http://forum.physorg.com/index.php?showtopic=2417&st=0

Actually, it does.

If the plane's speed is relative to the belt, the ONLY speed that can be matched by the belt is zero. Otherwise, it's caught in a infinite speed curve up (meaning the belt can't match it). Example - if the plane is moving 2mph relative to the belt, the belt has to go 2mph in the opposite direction - but then the plane is actually moving at 4mph relative to the belt - then the belt has to go 4mph...but then the plane is going 8mph relative to the belt...and so on and so on.

If the plane's speed is relative to the ground, then it takes off no problem, and the belt can match it's speed. In which case, the belt has absolutely no bearing on the plane's movement.

If speed is relative to the belt, then the plane moves forward on the belt at a rate of 10 knots over the belt, the belt spins backwards at 10 knots, and the plane moves forward just the same. That in turn increases the relative speed of the aircraft. Situation: entirely impossible. Even if it were, the plane would still take off.

You're right when you say the only speed the belt could match was zero.

Still doesn't matter, the plane takes off.

::ETA:: even with constant exponential acceleration of the belt, the plane can overcome the minimal friction of the conveyor under its free-spinning wheels.

Exactly.

Why is it so hard to comprehend that the only speed that matters is the speed of the plane relative to air? Not to the observer, not to the treadmill, not to the ground, not to your uncle, nothing else, but the AIR.

if the speed of the treadmill is the same as the speed that the tires are spinning then the plane will not move if the plane is moving forward then the tires are spinning faster than the treadmill is going

I have an impression that some people on this forum have never seen a plane.

We should close this thread. We've been chewing this for too long and there's no way to persuade people to change their beliefs.

Huh?

I'm not arguing that it won't take off. It will. I'm just pointing out that the original problem is worded badly - it never says what the plane is moving in relation to (the ground or the belt).

The "not-take-off" could happen - but ONLY if the speed is relative to the belt - AND it must be zero to do that.

An aircraft's speed is not measured by the rotation of its tires. Ever hear of a pitot tube?

Agreed. Let's nail the plane to the belt and see how that mofo flies.

For this one it is:

All of the necessary information is there. The correct answer has been explained and posted.

Three groups of people will identify themselves:

o Those intelligent enough to understand the correct answer
o Those not intelligent enough to understand the correct answer
o Those who have realized the error of their ways who are too indignant to publicly change their mind

In the event books (how retro!) are too "heavy" for you, one can only ask.....

Just one last thing to add...

Holy shit

Why is it that some people think the plane would move if the engine thrust pushes it forward on a runway...a "normal scenario...."

But suddenly think it moves like a car, with its tire speed somehow relevant...?

The tires do not push the plane!

The engine THRUST moves the Plane!

If the conveyor MATCHES the speed of the plane...

How would the plane produce a speed to match?



It has to be pushed forward by its THRUST!

Thrust DOESN'T turn the tires....it moves the plane through the air...and the tires can ONLY turn, IF THE PLANE MOVES....

IF the plane DOES move when the engine thrust pushes it forward......its moving relative to the AIR...

BECAUSE, the thrust DOESN'T rotate the tires, the plane's MOVEMENT does...

As the Movement is ONLY ABLE TO HAPPEN IF THE PLANE IS PUSHED FORWARD,

AND,

It can ONLY be pushed forward relative to the AIR,

What's rolling under the plane ONLY spins its TIRES, and DOESN'T change the plane's movement through the air.

If the plane sits on the conveyer belt, and the conveyer belt is moving, the plane is moving backwards.
When the engines start to push the plane, it now will stay in one spot, with no possible way to lift itself off the ground.

When the engines push the plane faster(which would be faster than the conveyer belt) it will take off.
It will not take off moving at the same speed as the conveyer belt.

(I'm just gonna' keep on posting it, everytime you say something "smart".)

But just in case you might actually be listening...

A few difinitions for you:

Vp = velocity of plane
Vt = velocity of treadmill

If plane sits on treadmill, and engines turned off, but treadmill starts moving backwards (negative direction):

Vp = Vt, where Vt is some - number

In other words, the plane is moving backwards, at the same velocity as the conveyor.

When plane fires up his engines to prevent backwards movement,

Vp = 0.
Vt = some -#.

Plane isn't moving, now. But it's tires are rotating at an angular velocity necessary to prevent the plane from MOVING backwards with the treadmill. This is not the same as FORWARD movement of the plane. [this is the part you're not grasping]

So when plane starts upping the throttle to actually match the treadmill's velocity, but in the opposite direction,

Vp = some +#
Vt = some -#

And if Vp = some + number, then integral of that velocity (acceleration) will be some + number, too, proving the plane can accelerate, and it will take off.

I dont care what you think about my solution to the question asked.

I am just stating the obvious instead of over analyzing it.

By the way,I am so glad you want to fuck my theory, but you might have to get in line....

This is why these threads are fun, everyone who "just has to be right all the time", or "has to have the last word" or "just cant take the pressure of being wrong", have to resort to name calling and stupid quotes with gay pictures.....

It has nothing to do with people needing to be right, you just happen to be wrong this time and refuse to look at the question with an open mind and realize you could be wrong in order to find the right answer.

All you're doing here is basically introducing a bit of a tail wind, which the plane's engines will easily overcome.

This will basically "push" on the plane, so when the engines kick in, they'll be that much more effective.

This is long, but read it and you'll come to understand why the plane does take off.

we agree that a car (substituted for the airplane for the airplane in the original scenario) on the treadmill will remain staionary to a fixed point on solid ground.

You claim and believe that the plane remains stationary to a fixed point on solid ground when the plane is on the conveyor, much like the car on a treadmill does. However, that assertion is wrong.

The scenario does not say that the plane remains in one spot relative to the ground, only that the conveyor and the airplane have the same speeds in the opposite directions.

The scenario does not say that the plane causes the conveyor to move, but that the conveyor is moved by some other control to match speed of the plane.

So if the plane is taken off of the conveyor and placed onto hard ground and then beings moving towards the conveyor at 10mph, then the conveyor is still going to move at 10mph in the opposite direction of the planes motion...

Now replace the Airplane with a car (make it a Front wheel driven car) and with the same setup as above, but this time the car drives onto the conveyor.
Once the front wheels of this car touch the conveyor the car stops it's forward motion with respect to the ground - with the front wheels on the conveyor spinning at 10 mph on the conveyor and the rear wheels (which were only spinning because the front wheels were moving along the ground and the rear wheels have to follow) are on the ground stationary. We know this is true because the the length of the car and the distance between the wheels remains a constant.

Now replace the Airplane with another car (make it a 2wd Xterra) and with the same setup as above, what happens when the Xterra drives onto the conveyor? When the front wheels contact the conveyor they (being free spinng) double their speed as they continue to move up the conveyor until the rear wheels get onto the conveyor. At that point, all 4 sets of wheels are spinning at 10 mph and the Xterra stays in one spot with respect to the ground. We know this is true because the the length of the Xterra and the distance between the wheels remains a constant.

Now, an Airplane has front wheels and rear wheels, so what happens when the airplane moves onto the conveyor? The front wheels of the plane, which are free spinning, begin to rotate at twice the speed of the rear wheels, which are alos free spinning and on solid ground, and the plane continues to move with respect to the ground...
Does the plane stop when all of the wheel are on the conveyor? No, all of the wheels are free spinning so all of the wheels double their speed, and the plane continues to move with respect to the ground. We know this to be true because the lentgh of the airplane and the distance between the wheels also remains constant, and if the plane remained stationary on the tread mill we would have a problem. We have a problem because the front and rear wheels are all free spinning, they do not provide the forward motion of the plane - they just spin. If your argument is correct that the plane remains staionary with respect to a point on solid ground while on the tread mill and if the front wheels are on the treadmill and the rear wheels are on solid ground, then the front wheels of the plane on the treadmill have a counter motion and so the result can't be greater than zero, so there is no forward motion; yet the rear wheels (on the solid ground) have no counter motion, so those wheels are moving forward...But how can the rear wheels be moving forward if the front wheels are not moving forward when the distance between the wheels remains constant? That is physically impossible!

In fact the front wheels of the plane do not remain stationary in relation to the ground, they move in relation to the ground. That is because the rear wheels are moving in relation to the ground (otherwise planes wouldn't be able to take off of a normal runway) and because the distance between the wheels remains constant the front wheels would have to move forward in relation to the ground on the conveyor to maintain the constant distance. Now (this is important) unlike a car, the front and rear wheels of a plane are all the same in that they are free spinning and do not create the forward motion of the plane, they mearly react to the forward motion of the plane. Since the free spinning front wheels move in relation to the ground on the conveyor this means the rear wheels (being constructed identically) will also move forward in relation to the ground on the conveyor. That means, unlike the wheel driven cars, the conveyor does not cancel out the forward motion of the plane! That means with all the wheels on the conveyor the plane will move forward in relation to the ground, even if the plane starts with all of the wheels on the conveyor.

Since the plane is moving in relation to the ground on the conveyor, then the plane has a groundspeed and a windspeed, and does in fact take off.

The only difference between the plane on a tread mill and the plane on solid ground is that the wheels on the treadmill plane are spinning at twice the rotational speed of the wheels on the solid ground plane.

See what I mean....

why does everyone keep saying that the wheels dont push the plane?
No one has once said that they do.

If the question was asked "can an airplane start on solid ground and move forward onto a treadmill and continue forward?" then you would be explaining it right.

Again, that is not the question.

Yes, that is not the question - but it applies because the way the wheels react to the treadmill must remain constant as well.

If you believe the plane remains staionary on the treadmill, then the planes front wheels must also remain staionary on the readmill while the rear wheels (not on the treadmill) do not - as in the front wheel driven car; or that the plane stops moving once the rear wheels are on the treadmill - as in the rear wheel driven car.

In either case, you must now claim that the either the front or rear wheels are no longer free spinning, which they are.

So I ask you this question - what keeps the airplane stationary on the treadmill?

Guys, it really doesn't matter if it's a plane, bicycle, car, truck, whatever.

The vehicle MUST be moving in order for the treadmill to be moving.

Spinning your tires in one place is NOT moving.

So regardless as to what the speedo says your "speed" is, your actual speed may be different when you're on the treadmill.

Frankly, I do burn outs in my new car all the time. Speedo goes up to about 30 mph. Am I really moving at 30 mph? Hell no. I'm standing on the dyam brake pedal at the moment... The tires are spinning at 30 mph EQUIVALENT, but I'm not actually moving.

Once again, the calculated rotational speed of the tires has nothing to do with the actual motion of the vehicle. If the vehicle is not MOVING forward, the treadmill is not moving. If the vehicle is MOVING forward, the treadmill is moving backwards at the same rate. "Moving" is not spinning your tires in one place. Ever. That's NOT velocity!!

It has nothing to do with "getting the last word in" or anything of that sort. This is a very, very simple physics "problem" that is answered very simply. Assuming you understand WTF "moving" means verses standing still spinning your tires.

Here's another question, I am trying to formulate it as correctly as possible: "Can people be that retarded or are you just fucking with us?"

It's pretty obvious he's just fucking with us. He's probably a member of the Flat Earth Society.
Just trying to produce a counter argument for every bit of evidence presented, ya know.

What is really scary, is that most of the Flat Earth Society members are for real.
It's time for another Heaven's Gate event.

Ha - I always thought it was just a debating society to show that any evidence can be debunked with enough mental exercise. Those guys are serious??

Yup...
http://theflatearthsociety.org/forum/index.php?topic=11211.0

You can't wrap your head around the actual physics involved and that's ok.

fuck that plane on a treadmill bullshit

Shrimp on a treadmill