Will it fly?

>>8683216
the conveyor belt is moving in the OPPOSITE direction as the wheels?!

>>8683216
well, the 747 is powered using jet engine which blows compressed air in one direction to propel itself forward.

If there is not enough friction acting on the plane wheels by the conveyor, then 747 probably will be able to take off but if there's enough friction, then the plane will stay in the place

>>8683216
https://blog.xkcd.com/2008/09/09/the-goddamn-airplane-on-the-goddamn-treadmill/

original troll plox

>>8683224

sure, a jet engine is what propels it forward, but what do you think makes it fly?


Anyone thinking this would make the plane take off is an idiot. Air on top of the wings must move faster than air on the bottom of the wings. This air is not generated on the treadmill, you would just stay in place.

Runways are super long for a reason.

>>8683242
well if the treadmill is infinitely long and 747's fuel capacity is infinite, then if the 747 is accelerating at some way, no matter how slow but is accelerating, it will eventually get some lift and takeoff.

>>8683254
it will take off exactly as fast as it would on a normal runway

>>8683242
the issue with this "problem" is that people don't understand it in the same way, and both sides assume the other is making an obvious mistake

the problem is what the wheels are, and what they do. they aren't tied to the engine, so the runway can't match their speed without a contradiction

>>8683254

no, it won't. how are you not understanding this still? the conveyor matches the 747 speed, that's the rules in the OP. Air pressure along the wings is what technically makes the airplane fly. The speed is almost negligible, but speed is the most efficient way we can put the plane in the air. The air pressure moving above the wings must be less than the air pressure moving below the wings.


Now, if you put a 747 still and blasted it with an air tunnel, THAT would cause it to take off! You wouldn't have to move the 747 at all, the air will still move at a fast speed past the wings, meeting the requirement for takeoff.
This is why aerospace engineers have wind tunnels and not fast treadmills.

>>8683273
The wheels on a plane are free spinning. So the conveyor matching the wheel speed just means the wheels spin faster during takeoff than on a normal runway

>>8683271

No, that isn't the problem. The problem is people don't understand what causes flight, and flight mechanics. Flight ONLY happens when air pressure is less on the top of the wings than the bottom. Speed causes this, but only because it's the most efficient method we can make it happen.


This is why cars have spoilers that look like an inverted plane wing, it keeps the car on the GROUND. The air pressure is less on the *bottom* of the spoilers, and greater on the top. Alternatively, plane wings cause air to take a longer path when going over the top than under the bottom, which causes flight.


This has nothing to do with wheels, nothing to do with speed itself, 100% to do with the wings and air pressure.


>>8683277

That's not what OP's image is asking, and you know that. That changes the rules of the experiment.


If you can eventually get your aircraft up to speed required for takeoff, it would have already gone off the runway. You would need the crazy guy's "infinite runway" to make this happen, and you would just be doing this the hard way. You would require much more fuel, much more energy to fight the force of the runway, much more distance required for takeoff, much more time. This is the least pragmatic approach one can take towards flight.

>>8683285
You're confused.
>>8683277 got it right.
The plane will still accelerate forward. The moving runway will have only minor impact on the take-off. The aircraft will take off.

>>8683299
yes, this. Only thing that will stop the plane from taking off is have the treadmill spin fast enough to put some friction force on the wheel to cancel out the force produced by the engines

>>8683285
>the conveyor belt is designed to exactly match the speed of the wheels

the problem is clear.

>>8683216
The question is ambiguous. It asserts that the conveyor is preventing the plane from accelerating, but provides no mechanism for it to do so.

>>8683285
I say No.
The plane would be stationary so not enough air would pass the wings to give lift.
When taking off planes built up speed over time and distance, but on the belt it would have only what little air the jets would draw past the wings.

Someone one day will do it with a toy jet, cause people have too much money and free time.

People who think the airplane will take off also must believe you would feel wind on your face if you put your bicycle on a treadmill and pedaled really hard

If the belt is long enough for the airplane to build up enough speed, it flies

The belt in the picture is insufficient, though, the plane would just roll off

>>8683381
you will, from the wheels turning

I dont know how a boeing works, but my instant intuition is that if the jets are parallel to the ground then it wont lift off (since force from the air goes to speed up the plane in the horizontal direction), if they are angled to the ground then the weight of the plane will be lower but will im sure the lifting force from the jets arent larger than m*g of the plane so it shouldnt lift off?

>>8683393

you won't feel wind in your face, but that's not the reason why it doesn't matter.


If you put wings on a car, the car eventually would come off the ground, but there would be no more propulsion keeping it in flight. That's the difference with AIRplanes.


It would fly because of this reason. The wheels are not the propulsion method.


But you wouldn't feel wind on your face if you were on a bike on a treadmill, though

>>8683381
>implying planes accelerate due to wheeled power...

Considering the conveyor belt wouldn't be able to affect plane's velocity like that in any big degree. Yes it will take off.

>>8683401
the wheels on the bike turning blow the air around. Just like the conveyor belt would convey the air backwards by turning around and around.

It seems to me like, according to muh reference frames, it's literally the same as if the plane wasn't moving at all.

>>8683620
the plane does move though.

You don't feel the wind in your face when running on a treadmill. Why would the plane move at all?

>>8683216
no, i mean if you think about it the plane when it "takes off" in this scenario wouldn't be moving at all

even if you don't know that a plane uses air pressure you should know that a plane can't get off the ground with no velocity

>>8683662
the wheels move and the "floor" moves with it

File: 1486484437452.jpg (57KB, 400x404px) Image search: [Google]

57KB, 400x404px

>>8683227
>https://blog.xkcd.com/2008/09/09/the-goddamn-airplane-on-the-goddamn-treadmill/
>(For the record, the answer to Feynman problem, which he never tells you in his book, was that the sprinkler doesn’t move at all. Moreover, he only brought it up to start an argument to act as a diversion while he seduced your mother in the other room.

>>8683216
Kukukuku
This is an excellent way of teaching someone about airplanes.
Thank you anon.

>>8683216 Noting that the velocity of the converbelt is dependent upon the plane instead of vice versa, we can state that at each speed at which the plane moves the ground beneath it moves at the same speed. This means the the planepassengers will never reach Hawaï or Fiji. < Simply an assumption.

File: wat.jpg (3KB, 125x119px) Image search: [Google]

3KB, 125x119px

what if the belt moves the air fast enough to generate lift and the engines just counter the drag

>>8683216
>the converyor belt is designed to exactly match the speed of the wheels
this phrase fucks with my head so much

>>8684165
How does it not make sense?

>>8684022
a 747 is not a sprinkler. Different problems.

The plane will take off because thrust is given by jet engines and not by friction between wheels and the ground like a car, so it doesn't matter if the ground is moving or not. The plane's equivalent to the ground for a car is air, and air is still so its jet engines will be able to provide thrust and therefore, by movement through air, the wings will provide lift.

You people are fucking retards, It does not matter how much thrust its putting out or how fast the wheels or belt are moving when there is zero airspeed the plane does not fly

>>8684404
Who said that there is zero airspeed

>>8684417
this

>All these brainlets thinking that the conveyor belt will work like it does in Looney Toons.

>>8684417
It says nothing about a headwind

>>8684424
>The conveyor belt is designed to exactly match the speed of the wheels

The plane is not moving at all

>>8684429
The plane moves! When will you understand that thrust is not given by rotation of wheels as for a car. Thrust is given by jet engines, no matter if the groud is still or moving. Think about a little model plane hanging mid-air suspended by a rope, it's not touching the ground, now turn on the engine and the plane will move because propeller is moving air backwards. Now do that experment with a fucking car, obviously the car won't move. You need to understand that since the plane is able to move air backwards it will move forward, no matter if the ground is moving!

god damn im retarded.


yes it can take off, the plane will still go forward.

File: 1474043023483.jpg (5KB, 200x161px) Image search: [Google]

5KB, 200x161px

the wheels don't do anything, it's a plane.

>>8684457
This is a 747 with jet engines the aircraft must physically move forward to attain the airspeed to be able to take off, the only way it will take off otherwise is if the there is a headwind = to the takeoff speed of the aircraft.
If this was a microlight with a somewhat powerful prop on the front then yea it will takeoff but this 747 no its not going anywhere

>come to /sci/ for the first time in months
>this is the first thread
>remember why I never come here anymore

>>8683216
Once it will reach the end of the conveyer belt it will take off

>>8684524
The plane will move forward right off the treadmill and eventually take off. The wheels will simply turn more in the process, but the plane will still move forward.

it would have to be a long conveyor belt i guess

>>8684589
The Image in OP states the that the conveyor belt will match the speed of the wheels so no it is not going anywhere.
More thrust = faster wheel speed = faster belt = zero AIRSPEED

All the energy the engines put into the plane is removed through the wheels. It won't take off.

If the plane stays in place it won't be able to elevate due to the fact that the air doesn't move around the wings, which is what causes takeoff.

it will take off when you switch of the belt

>>8684618
The fact that the conveyor belt is able to cancel wheels' speed doesn't mean that the airspeed is zero! Airspeed has nothing to do with the speed of wheels. As i said before, the plane will take off. (I'm not talking about wind speed, just to be clear)