You have a plane and a conveyor belt.

[Suspicious-Teach8788]

Originally posted by: shenjingbing

Originally posted by: DLeRium

Originally posted by: shenjingbing

Originally posted by: DLeRium

Originally posted by: shenjingbing
I cannot believe how many people think that the plane will take off, it's almost funny. I'm sure some of you are just joking, or are you.

I read the first pages and cannot stop laughing at how something as simple as basic physics are misunderstood.

This point has been mentioned numerous of times before, and that is there has to be LIFT, or wind over the wings for the plane to take off. Regardless how much thrust the engine puts out, and if the conveyor can effectively nullify that thrust, then there are no additional energy generated.

Now for the people that keeps saying that the plane will fly, I have a self powered sail boat with a really large fan on it to sell to you.

I cannot help but laugh that you don't realize that the conveyor belt DOES NOT negate the thrust. Thus there is movement forward.

We're not arguing that there is no lift. We're arguing that there IS lift, and you don't realize that. No one has said anything about 0 lift + takeoff. We know that's not possible.

For those who think it won't take off, try a small scale demo and you'll know what we mean.

Wheels are free rolling, so the conveyor belt does NOTHING but to spin the wheels. The engines still push the plane forward. THERE IS FORWARD MOTION = THERE IS LIFT. Now shut up.

I will shut up, AFTER you can tell me that you feel wind on your face when running really fast on a treadmill.

So your alias is crazyassmofo in Chinese and you want to tell me you know what you're talking about?

We're talking about wheels, not about feet. You lose.

Feel that wind yet? Or is it just hot air?

The problem with you and a lot of other people is you fail to realize how the conveyor belt acts upon the plane's wheels.

The plane's wheels simply roll FREELY. You're thinking of it like a person and a treadmill. The wheels spin, but the plane is STATIONARY. If you put the plane on a conveyor belt and turn the conveyor belt with the plane's engines off, the wheels spin but the plane does not move.

Draw a free body diagram and you will see.

The force of the conveyor belt on the wheel is translated solely into rotational motion. It doesn't move the plane backwards.

I don't know if you've ever taken a statics class, but when you deal with supports and you use rollers, those exert only vertical force (no horizontal force) at all.

But wait, you're just acting like a little boy. I guess you've never taken a simple class like high school physics or even more advanced college physics much less any engineering courses that would help you understand this problem a little better. Or maybe youre just ignorant and unwilling to learn. Go read the responses in this thread. It's stupid people like you who will never be working for Lockheed/Boeing.

 

[Safeway]

You guys that think the plane will take off are fvcking morons. End. of. story.

 

[FoBoT]

no
the wheel isn't connected to anything
there is no connection from the jet engine to the conveyor belt
the jet pushes on the air, not on the wheel or conveyor, so the conveyor is meaningless

its a trick question

 

[Suspicious-Teach8788]

Originally posted by: shenjingbing

Originally posted by: FoBoT
airplanes don't have legs, an airplane cannot run on a treadmill
and you don't have a jet engine on you

Really? Wow... mind boggling.

We're just asking to simulate a self propelling force against another to render the object immobilize (location wise).

Yes we all understand that there are FORWARD movements, but only in relation to the conveyor. To everything else around it, the object is stationary. No wind, no lift. End of stofy.

Honestly, if you want a real discussion, you can go ahead and give me an IM and we'll talk.

 

[Glavinsolo]

Anyone submit this to myth busters yet?

 

[Suspicious-Teach8788]

But this is no myth. This is just a pure misunderstanding by many people.

It's like people who never took physics before think there is centrifugal force in circular motion.

 

[Cerpin Taxt]

Originally posted by: Safeway
You guys that think the plane will take off are fvcking morons. End. of. story.

Wow. Just, wow.

Y'know, it isn't the ignorance of the average person that really depresses me. It is the arrogant surety with which ignorant people like yourself make ignorant claims like this one of yours and refuse to educate themselves about the facts. THAT makes me really, really sad.

-Garth

 

[shenjingbing]

Man, they should just build conveyor belt testers for airplanes instead of wind tunnels then. You guys that are saying the plane will fly are geniuses and I'm an idiot, you win.

 

[Glavinsolo]

What if there were two planes on opposite ends of the conveyor both firing their engines facing each other?

 

[Cerpin Taxt]

Originally posted by: shenjingbing
I'm an idiot, you win.

First thing you've gotten right since your appearance in this thread.

-Garth

 

[Suspicious-Teach8788]

Originally posted by: shenjingbing
Man, they should just build conveyor belt testers for airplanes instead of wind tunnels then. You guys that are saying the plane will fly are geniuses and I'm an idiot, you win.

Why would they build conveyor belts instead of wind tunnels. You're not even making sense. Wind tunnels simulate if a plane were to fly. Conveyor belt does NOTHING. It is essentially a runway. We dont' need to build conveyor belts for planes if we know runways work the same way.

 

[shenjingbing]

Originally posted by: Garth

Originally posted by: shenjingbing
I'm an idiot, you win.

First thing you've gotten right since your appearance in this thread.

-Garth

Please don't quote things out of context, look what the practice has done to this country.

 

[Cerpin Taxt]

Try thinking about it this way:

Could a seaplane take off from water moving in it's opposite direction? Of course it could, and it is even easier to conceive if we suppose zero friction between the pontoons of the plane and the water surface. Then it doesn't matter how fast the water goes, because it causes zero opposing force to the velocity of the plane. It is the same with the conveyor example. There is no opposing force to the forward velocity of the plane. The conveyor only makes the wheels spin faster than usual.

 

[TGS]

Are people just kidding or are still thinking the wheels on the plane have *any* bearing on the planes ability to take off?

The engines (Turbine or Prop) will have to create thrust. The conveyor belt is spining in the opposite direction of the plane generated thrust. The wheels at this point are merely a ruse at this fact. The wheel speed other than the fact they are the object creating friction that allows the conveyor belt to counter act the forward motion of the place. The wheels have nothing to do with the fact once the plane generates enough force to create the neccesary lift, it will take off.

Imagine if you will walking up an escalator going down. If you walk at a exactly the same rate as the step coming down, to the outside observer you would appear to be walking on the same step location. Now imagine a plane, from the outside observer the plane would be stationary but in reality it would be moving equally by in the opposite direction to the belt.

If the belt was able to move at a speed that would allow the plane to take off, when you suddenly stopped the belt, the plane would already have enough force to fly off the belt.

It's all about relativity imo.

 

[Cerpin Taxt]

Originally posted by: shenjingbing

Originally posted by: Garth

Originally posted by: shenjingbing
I'm an idiot, you win.

First thing you've gotten right since your appearance in this thread.

-Garth

Please don't quote things out of context, look what the practice has done to this country.

Forgive me for trying to separate the rare nugget of truth in your post from the rest of the pathetically naive gibberish.

 

[Glavinsolo]

The exhaust air is accelerated and the plane is accelerated relative to the air because of the thrustback. The plane moves forward.
The conveyor belt cannot interfere with this mode of acceleration. It may only lead to an increased backwards drag by increasing the friction loss of the planes wheels.

 

[Glavinsolo]

LOL

 

[csiro]

This is very simple physics. Let's say the engines applies X newton of thrust while the conveyor belt applies Y newton on the wheels. The wheels imparts only a portion of the conveyor belt force on the plane so the total force of the plane would be

Net Force = X - (Y * fc) where fc is the coefficient of friction lets say

Now in pretend that the wheels are 100% efficient and thus are frictionless. This would mean that fc would be 0 and the total force action on the plane would just be X so the plane would move forward regardless of the speed of the belt.

On the other hand, if we bolted the plane onto the belt, fc would be 1. That means that the plane won't move if X = Y.

In real life, the fc for the wheels is somewhere between 0 and 1 and should be alot closer to 0. So for the conveyor belt to stop the plane from taking off, Y must be alot greater than X.

 

[FP]

Just to confirm.

To an external observer sitting in the control tower, the plane will be moving forward correct?

I was in the "no it won't take off" camp but have since been converted

 

[gilligans]

i cant believe how stupid you guys are. there is no way the plane will take off. in order for it to fly, there must be lift on the wings. there will be no lift because the plane isnt moving.

normally, a plane takes off because the jets/propellars drive the plane foward thus getting lift on the airplane. in this situation, the jets/propellars are on but is being negated by the conveyor belt. the faster the plane tries to go forward, the faster the conveyor belt moves in the opposite directing, thus keeping the plane still.

this is the end of it.


THE PLANE WILL NOT FLY. PERIOD.

 

[FP]

Originally posted by: gilligans
i cant believe how stupid you guys are. there is no way the plane will take off. in order for it to fly, there must be lift on the wings. there will be no lift because the plane isnt moving.

normally, a plane takes off because the jets/propellars drive the plane foward thus getting lift on the airplane. in this situation, the jets/propellars are on but is being negated by the conveyor belt. the faster the plane tries to go forward, the faster the conveyor belt moves in the opposite directing, thus keeping the plane still.

this is the end of it.


THE PLANE WILL NOT FLY. PERIOD.

I was thinking the same way you were but have since been convinced otherwise.

No matter how fast the conveyer belt spins the place will not move anywhere... UNTIL the jets are turned on. The plane will then move forward and thus eventually take off.

Imagine this... You have this scenario set up in a 1/100 scale model. The conveyer belt is spinning, the plane is sitting there and the wheels are spinning... Now, if you use your hand and push the plane forward will it move forward?

 

[FoBoT]

Originally posted by: binister
Just to confirm.

To an external observer sitting in the control tower, the plane will be moving forward correct?

yes it will move. the engines push on the air and it moves. the wheels just spin with the conveyor belt, they don't matter

 

[gilligans]

NO. if you push the plane forward, the conveyor belt will speed exactly equal to your push in the opposite direction, thus keeping the plane still.

 

[FP]

Originally posted by: gilligans
NO. if you push the plane forward, the conveyor belt will speed exactly equal to your push in the opposite direction, thus keeping the plane still.

So your arm would feel a force in the opposite direction equal to the forward force you are applying? That doesn't make sense. You would be able to push the plane forward no matter how fast the conveyer was spinning.

 

[FP]

Originally posted by: FoBoT

Originally posted by: binister
Just to confirm.

To an external observer sitting in the control tower, the plane will be moving forward correct?

yes it will move. the engines push on the air and it moves. the wheels just spin with the conveyor belt, they don't matter

So as the plane is moving forward, are its wheels and the conveyers wheels (let's assume the conveyers wheels are the same size as the plane's wheels) moving at the same RPM?

EDIT: Nevermind. Figured it out. They aren't.