/sci/ - Science & Math

no because its a drawing

no because there is no friction with the air, therfore no gap pressure between the top and bottom of the wings and no flying

1/10 made me reply

No because planes work just like cars.

how is it supposed to lift off when it's not moving lol

>>5577090
HA HA HA!
Thats science, live in the reality!

Yes.

http://www.straightdope.com/columns/read/2638/an-airplane-taxies-in-one-direction-on-a-moving-conveyor-belt-going-the-opposite-direction-can-the-plane-take-off

http://mythbustersresults.com/episode97

http://www.airplaneonatreadmill.com/

>>5577088
STOP STOP!
The plane force does not do anything on the ground!!!
Yes the plane is able to lift!!!!!

>>5577143

In this episode the plane moved. If the plane remains stationary then it can't take off, but the Mythbusters showed this scenario was improbable.

While the velocity of the plane is equal to that of the treadmill then the plane won't take off.

This is how

>>5577143
>http://www.airplaneonatreadmill.com/

This one made me shake my head the worst.
The author attempts to prove his opinion by using several conclusions to prove the arguments.

And while he carefully removes some other factors, and clarifies a couple of problems of interpretation, he just gets vastly bogged down in his own:
rather than argue whether the plane would stay static on the treadmill,
all of his argument is about whether two human operators of the two devices could practically defeat each other during the attempt.

That's right, he removes the abstractness of the flight issues and tries to argue that people don't have enough control (reaction time, response of the machinery) to prevent the plane from moving.

And in his estimation, any movement equals flight, which is silly.
He didn't even recognize the potential for the plane to move backward under those conditions.

How is it supposed to take off if theres no airflow over the wings, thats just basic plane principles

How should it take off if there is no friction with the air? I thought this is important for planes to lift off.

An airplane will take off from a standstill if the wind across the wing is strong enough. Does that help?

Everyone who says no is trolling.

There is no lift.

>>5577247
And everyone who says yes is stupid.

>>5577163
>While the velocity of the plane is equal to that of the treadmill then the plane won't take off.
It will take off the wheels will just be going round a twice the rate they would at that speed on a runway, that will not stop the plane accelerating and then taking off.

>>5577210
If the treadmill moves at the speed of the plane it will still move forwards. There is a trust from the engine. The only force that could counteract that force is friction in the wheels but if the plane is only doing a hundred kilometers an hour that friction will not be significant. The trust is unmatched so the plane moves forward and accelerates until it takes off.

>>5577262
what kind of mental gymnastics is this

Lift is generated by the movement of air around the wings. If the speed of the plane RELATIVE TO THE AIR is 0, the plane will not take off. Source: not a fucking retard

>>5577269
Thank you.

Will the tier roll off the threadmill?

>>5577275
>tier
am I being bamboozled

>>5577263
What kind of bullshit reply is that. If you want to criticise my physics try using physics.

>>5577269
Nobody is arguing that. The point is that the plane will not remain stationary with respect to the air.

>>5577279
your physics
it is broken

>>5577279
ITT: you and one guy trolling you

>>5577275
> Comparing apples to oranges
The plane generates thrust.

>>5577262
Do you understand that engines just give plane horizontal speed and helps with accelerating it so with the proper speed it could use the airflow that will lift it up? If there is no airflow, the engines will just be accelerating the plane horizontaly. And considering that the treadmill is accelerating proportionally the plane will stand still. Only its wheels will rotate. Nothing more. If what you are saying would be true, the plane should be momentarily shoot from the treadmill and fly into the air.

For a plane to take off, AIR MUST FLOW OVER THE WINGS. That's it. Nothing more.

In a perfect simulation, with the treadmill constantly matching the speed of the plane as its engines accelerate the plane forward, no it won't take off.

Countless people have "proven" the plane would take off by setting some tarp or something under a plane, only to have the plane's ground speed become greater than the speed of the moving surface underneath it which allows air to flow over the wings and generate lift.

>>5577286
Yes, but the fact that a free-standing tier will be pushed off a threadmill means that the threadmill is capable of excerting an opposing force onto the plane.

The way OP worded this particular example means that the plane would take off. But the original plane on threadmill example suggests the threadmill is in a feedback loop that ensure it's stationary.

>>5577284
That may be but unless you formulate a rational response I'm going to assume you're just a shitty troll and move on.

>>5577294
>tier

>>5577296
>you're wrong
>ur just a shitty troll stop trolling me

>>5577279
Ok, tell me how will it look? I mean how plane will lift off? Will it slowly start floating in the air, or is it shoot of into the sky?

>>5577210
>Here are the absolute, 100%, bet-your-life-on-it answers to these rewordings:
lol, absurd

>>5577294
>Yes, but the fact that a free-standing tier will be pushed off a threadmill means that the treadmill is capable of exerting an opposing force onto the plane.
Nobody is disputing that.
>The way OP worded this particular example means that the plane would take off.
Glad we're in agreement.
>But the original plane on threadmill example suggests the threadmill is in a feedback loop that ensure it's stationary.
A feedback with what the tires or the plane? In both situations the plane would not be kept stationary. It wouldn't take off in the former but it would move.

>>5577302

The engines are not connected to the wheels. It doesn't matter if the wheels are rotating a billion times per second, the plane will move horizontally relative to the air that surrounds it.

>>5577289
>Do you understand that engines just give plane horizontal speed and helps with accelerating it so with the proper speed it could use the airflow that will lift it up?
Yes.
>If there is no airflow, the engines will just be accelerating the plane horizontaly.
Right again.

>And considering that the treadmill is accelerating proportionally the plane will stand still. Only its wheels will rotate
let's deconstruct this statement to see where you are wrong.
The speed of the tread mill matches the speed of the plane. So if the plane is stationary the treadmill is. So the plane cannot be stationary with the wheels moving.

Initially the engine applies a trust, the plane and treadmill are stationary so the plane starts to move with a lack of significant friction. Now the plane is going at speed x and the tread mill -x, the wheels are going at twice the speed they would at that plane speed on a runway, however the friction is still tiny. The friction is small and so the plane accelerates until it takes off.

>>5577302
No it will gain speed an move along the treadmill just like it does on a runway. Like I said.

Assuming the treadmill is as long as the distance needed to travel on a normal runway before liftoff - yes.

>>5577324
The treadmill is connected to a computer and it accelerates backwards as the plane accelerates.

The only possibility the plane has of flying is that it starts hovering over the treadmill.

>>5577323

Yep.

People actually have a hard time understanding that a frictionless wheel can not stop a jet engine from moving forward. Astounding.

>>5577327
Even with a wheel with normal amounts of friction it wouldn't be enough to stop it.
>>5577329
No as I've said before the treadmill does not stop the plane accelerating:
>>5577323
>
Initially the engine applies a trust, the plane and treadmill are stationary so the plane starts to move with a lack of significant friction. Now the plane is going at speed x and the tread mill -x, the wheels are going at twice the speed they would at that plane speed on a runway, however the friction is still tiny. The friction is small and so the plane accelerates until it takes off.

>>5577337
Why won't it stop accelerating? I stated in the OP that the treadmill will accelerate just as the plane does. The acceleration of the plane will be the same as the treadmill, if the wheels of the plane need to go twice the speed, the treadmill will go twice the speed too.

>>5577345
>if the wheels of the plane need to go twice the speed, the treadmill will go twice the speed too.
No. The original problem stated as you said that the treadmill matched the speed of the plane not the wheels. So if the plane is going at x, the treadmill will go at -x and the wheels will turn at a rate of 2x.

Yes becouse F=ma and there is a trust force acting to plane but no force from treadmill. This is also good example how fast brain fails but educated slow brain wins.

>>5577347
Why the fuck would i draw the vector on the wheels if i was talking about the speed of the plane?

>>5577352
Because you were talking about the speed of the plane. From the OP:
>speed of the treadmill is the same as the speed of the plane.
The speed of the plane is not the speed of the wheels. You fucked up your problem not anyone else.

Even then the plane would move.

Yes it will takeoff, but a car wouldn't.

>>5577365
So a plane is a big ass fan?

>>5577348
>but no force from treadmill.
Rotational inertia of wheels.
Friction.

If you don't belive in inertia, here's a DIY at home experiment you can try.

>Take a spare car tyre, take it to a threadmill that's perfectly level.
>Set threadmill to maximum speed.
>Stand right behind the threadmill with legs separated, exposing your scrotum to your belief in the nonexistence of inerta.
>Drop the wheel onto the threadmill.
>Because there is no inertia, the wheel will instantly start spinning with the same speed as the threadmill and will remain stationary on it for all eternity until an outside force moves it.

>>5577373
No it is a rocket with wings.
>>5577411
>Rotational inertia of wheels.
>Friction.
All small compared to this situation where you have huge jet engine attached to huge object. Now go back to physics a.

>>5577088
How does a plane fly?

By creating a pressure differential on the opposite sides of the wings. This pressure difference causes the plane to lift.


The answer to the question below will be the same as the answer to your original question.

Does the treadmill move air across the wings?

>>5577423
>No it is a rocket with wings.
Rockets don't need wings. A rocket on a threadmill will always take off unless it falls over and explodes before.

>>5577244
>An airplane will take off from a standstill if the wind across the wing is strong enough. Does that help?

There is no wind given in this scenario.

>>5577088
They did it on mythbusters and it took off just fine.

>>5577262
>>While the velocity of the plane is equal to that of the treadmill then the plane won't take off.
>It will take off the wheels will just be going round a twice the rate they would at that speed on a runway, that will not stop the plane accelerating and then taking off.
Twice? They move at just that speed; plane wheels have no pushing power.

>>>5577210
>If the treadmill moves at the speed of the plane it will still move forwards. There is a trust from the engine. The only force that could counteract that force is friction in the wheels but if the plane is only doing a hundred kilometers an hour that friction will not be significant. The trust is unmatched so the plane moves forward and accelerates until it takes off.

The thrust is equal to the backward movement of the treadmill;
therefore, it does NOT move forward because of engine thrust.

The problem specifically states that the thrust is matched by the backward movement of the treadmill. (they are equal forces, so the plane is NOT moving)

>>5577282
>Nobody is arguing that. The point is that the plane will not remain stationary with respect to the air.


Why not?
The problem specifically states that the plane is not moving forward in the air -- so why would it start moving forward?

>>5577286
>The plane generates thrust.

Yes; how much?
The problem states that the treadmill is moving backward at the amount to counteract the forward movement.
(Thrust forward = rolling backward, therefore 0 movement)

But people keep insisting that the plane is going to move forward, anyway. Why?

Pic very related

pressure surrounding wings remains unchanged, no lift, no fly

>>5577269
>If the speed of the plane RELATIVE TO THE AIR is 0, the plane will not take off.

Good thing it won't be stationary relative to the air, then.

>>5577275
>Will the tier roll off the threadmill?

Discounting rolling resistance, no. It will just spin in place. Realistically there is always some rolling resistance, so yes, it will roll off the treadmill eventually.

>>5577517
>The problem states that the treadmill is moving backward at the amount to counteract the forward movement.

No, it says it moves backwards at the same speed the plane moves forwards. Which doesn't affect the plane at all, because the wheels can spin freely anyway. It just takes off like normal.

>>5577163
>plane remains stationary
The plane won't remain stationary.

The thrust from the engines and the friction from the wheels are independent.

>>5577506

>The problem specifically states that the thrust is matched by the backward movement of the treadmill.

No it fucking doesn't, troll.

Note this isn't quite the classical plane on a treadmill question, its slightly different.
In the classical problem, the engine thrust pushes the plane forward and the landing gear confers independence from the motion of the treadmill; it will take off.
This problem states that forward motion of the plane is met with an equal and opposite motion by the treadmill. That is, if the plane moves forward at 5km/h, then the treadmill moves backward at 5km/h and so on. The treadmill speed maxes out at takeoff velocity. Given the parameters stated above, it will still take off: the landing gear allows the plane independent motion from the ground.
If you wanted to break this system, however, the problem can be tweaked that if the plane does manage to move forward, the treadmill will try to compensate to hold it at zero velocity. If we hold that the treadmill must move fast enough to prevent the plane from moving forward, then it could hypothetically move so fast that the friction on the landing gear can become so great that it either seizes up, or the tires explode, causing the plane to crash.

I hope that answers your question, OP.

ITT: Autists incapable of understanding a hypothetical question

Air pressure would never increase. Troll question

Well the plane AND treadmill are obviously already in a state of suspension, as we can see in the picture... So yea, they are already flying.

The treadmill takeoff, the plane will stay on the ground.

the wheel would spin freely at 2v. /thread

Why dont they just strap a barometer to a model plane and then run the experiment again, if theres not enough pressure the plane isnt going to take off

Depends on the velocity of the plane

The plane would definitely take off. Everyone who says it wouldn't is confused about the workings of a plane. The plane's wheels don't drag it along the ground, the engines drag it through the air. It doesn't matter how fast the ground below it moves or how fast the wheels turn, the plane moves itself relative to the air around it, which is stationary.

>>5578006

>the plane moves itself relative to the air around it, which is stationary.


then how do you expect it to take off? the plane isnt moving through any air so it cant generate any lift

>>5578117
The plane drags itself through the air, which causes it to move over its wings, eventually generating lift when it's moving fast enough

>>5578144
Right so the plane has to move faster than the treadmill to move forward to get air to flow over the wings and generate lift.

If the treadmill matches the speed of the plane at all times it won't take off. If the plane can eventually move faster than the treadmill it will take off.

>>5578151
No because the wheels are simply to stop the bottom of the plane from scraping along the ground. The plane moves itself forward using the air. The ground below it has no bearing on its movement.

If you held a toy car on a treadmill, with the treadmill moving backwards at the same speed that you move the car forward, would you be able to move the car? Of course you would - the force moving the car (your hand) is completely independent of the treadmill. The wheels would spin faster and faster and faster because of the movement of the treadmill, but they have no bearing on the movement of the car.

>>5578144

the plane isnt dragging itself through the air though in this situation the plane isnt moving through the air around it

youre telling me there is 80mph+ of wind flowing over the wings of the aircraft so that it can take off?

>>5578183
yes. can't into newtons laws?

also:

http://www.youtube.com/watch?v=YORCk1BN7QY

you guys are all fucking stupid

>>5578190
>http://www.youtube.com/watch?v=YORCk1BN7QY

>cites mythbusters

HURRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRR

theres already been confirmed mistakes in that experiment, the speed of the plane and the speed of the tarp werent matched

where is this magic 80mph of wind coming from? the air is static dumbfuck so the plane has to move through the air

>>5578190

the airspeed is 0 meaning there CANT be any lift generated

>The true airspeed (TAS; also KTAS, for knots true airspeed) of an aircraft is the speed of the aircraft relative to the airmass in which it is flying.

relative to the air around the plane, the plane is moving at a speed of 0

>>5578191

Why are you trying to troll? Don't you have something better to do? Do you moonlight as an idiot are do you do it full-time?

>>5578227

>cant come up with a refutation
>HURR UR A TROLL DURR

absolutely pathetic

>>5577707
>o
Seems legit.