/sci/ - Science & Math

[Anonymous No.10413340]

Yes it would

[Anonymous No.10413343]

>>10413340

[Anonymous No.10413351]

>>10413343
yes You are actually retarded

[Anonymous No.10413372]

Why post it if you answered it yourself and won't accept different answers? it won't

[Anonymous No.10413410]

>>10413372
Because you're wrong dipshit

[Anonymous No.10413419]

>>10413410
Ok then explain how it would take off

[Anonymous No.10413420]

>>10413340
By that logic we all would fly off the earth because of its spin

[Anonymous No.10413425]

The runway isn't long enough

[Anonymous No.10413429]

1. It's an unpropelled toy plane. It can't take off anyway.
2. If the whole thing was scaled up and still worked and the plane replaced by a real one that can accelerate on its own, it would rip off its wings when crashing against the bars.

[Anonymous No.10413436]

>>10413340
How would a treadmill ever take off..?

[Anonymous No.10413439]

>>10413419
the plane would move forward and eventually get going fast enough to take off
newsflash: jets are faster than treadmills
>>10413425
there is floor in front of it and It's just a model plane It's not gonna break
>>10413429
I agree the whole premise is retarded but with those problems removed yeah it would take off

[Anonymous No.10413466]

>>10413340
What exactly is the argument?

[Anonymous No.10413471]

>>10413351
stfu you fucking retarded nigger
I play kerbal space program

[Anonymous No.10413478]

>>10413439
>jets are faster than treadmills
if you are going to be retarded then the wings are going to hit the bars

[Anonymous No.10413481]

>>10413478
OK IF YOU'RE ACTUALLY RETARDED IT WILL GET FLUNG OFF THE FUCKING MILL WHENIT'S TURNED ON
MYTHBUSTERS DID THIS SHIT AND IT HAPPENED EVERY TIME

[Anonymous No.10413491]

>>10413340
Nah it won't it would crash onto the 2 rails infront.

[Anonymous No.10413494]

>>10413481
>IT WILL GET FLUNG OFF THE FUCKING MILL WHENIT'S TURNED ON
That depends on a few variables. Are the wheels glued to the treadmill? If not, then are they well lubed and are there bearings to speak of? What is the speed of the treadmill? What is the mass and the weight of the model plane? Is OP a retard? Will the wings break when they hit the sides of the treadmill as it is being catapulted off?

[Anonymous No.10413498]

>>10413481
did none of you see this troll before? how did mythbusters mess it up so much? what would it prove to just turn a treadmill on with a plane ontop

you're suppose to assume the treadmill will match the speed of the plane.
Is that not a required assumption for this troll ?

[Anonymous No.10413517]

>>10413340
unless you're also shooting air at the front of the airplane, how would it? it can't be stationary relative to the ground that the treadmill's on

[Anonymous No.10413523]

>>10413517
What if the airplane weighs 400 kilograms and the windmill 40 kilograms?

[Anonymous No.10413544]

>>10413340
depends on its genetics, some people can't take off

[Anonymous No.10413550]

>>10413523
a windmill that's 40 kg? it must be a hard gainer lmao

[Anonymous No.10414730]

>>10413340
>spinning wheels create lift

[Anonymous No.10414997]

>>10414730
> Aircraft generate forward movement by spinning their wheels.

Holy shit nigger you dumb

[Anonymous No.10415069]

>>10413439
>newsflash: jets are faster than treadmills
got 'em

[Anonymous No.10415076]

Earth is flat?

[Anonymous No.10415094]

>>10414997
Well im just pointing out what you're saying in the OP

[Anonymous No.10415127]

>>10415094
Do you understand why an airplane would move? That's not a hypothetical question. I genuinely want you to explain this to me- when the pilot actually wants to go forward, what part of the aircraft lets him do that?

[Anonymous No.10415145]

>>10415127
Airplanes fly because they have air moving over their wings, an airplane moving with respect to the ground wont fly if the air over its wings is stationary.

[Anonymous No.10415163]

>>10413466
Dubs got it right.

[Anonymous No.10415181]

>>10415145
A complete irrelevant answer. If you seriously thought this was a valid response to that question, you're even dumber than I thought.

[Anonymous No.10415241]

>>10415145
>he doesnt get it

[Anonymous No.10415278]

>>10413340
some help me if i got this right

if there were no friction the airplane would always take off
but in the real world you could actually make the threadmill always spin excatly fast enough that the airplane would never move relative to the ground, so it would not take off
i would guess that the threadmill would need to spin pretty fast if the airplane was going full power

because if a push against a car i can make it move. but if that car is standing on a moving threadmill, my pushing attempt may only make the car stand in place. because i now need to work against the threadmill, because of the friction between the car and the threadmill

[Anonymous No.10415306]

>>10413498
the entire thing comes down to which speed of the plane is being used.
air speed = fly
ground speed (belt surface as ground) = no fly

[Anonymous No.10415340]

>>10415278
goddammit i looked it up further and increasing the threadmill speed wont make it harder for the plane to stay stationary so the plane will always take off

[Anonymous No.10415502]

Jesus Christ.

[Anonymous No.10415522]

>>10413419
The turbines create a pressure differential above and below the wings so that they are pushed up. The forward thrust is a useful secondary consequence.

I'm guessing btw.

[Anonymous No.10415527]

>>10415127
The engine. Planes don't have powered wheels, they're just lube.

[Anonymous No.10415528]

>If I slap a box of unspecified mass with an unspecified amount of force at an unspecified angle, will it reach a target an unspecified distance away?

[Anonymous No.10415531]

>>10415522
If turbines did this planes wouldn't need runways.

[Anonymous No.10415542]

>>10413340
So the treadmill creates air friction on the wings?

[Anonymous No.10415561]

>>10413340
if the conveyor belt is matched to the speed of the plane to keep the plane in perfect place upon the conveyor belt, then no.

if the conveyor belt moves at a static speed, then yes because it will eventually accelerate enough to create lift by moving forward as a normal plane would. The wheels would just be moving alot faster, otherwise theres no difference between it and a normal takeoff besides what Id presume to be a longer time to reach takeoff.

[Anonymous No.10415568]

>>10415145
>pilot flips a switch
>suddenly out of goddamn nowhere air is rushing over stationary wings at several hundred miles per hour
>somehow this makes the entire aircraft move in the opposite direction of the following air

[Anonymous No.10415570]

Let's say you're standing on an infinitely long treadmill. You're wearing roller skates and are grabbing onto two chains, each chain attached to a car on each side of the treadmill. The treadmill is configured to match the tangential speed of the wheels but in the opposite way. Now, if the cars suddenly start moving forward, would you move forward?

[Anonymous No.10415572]

>>10413491
Only correct post in this entire thread.

[Anonymous No.10415575]

If the treadmill could handle it, acceleration would make it at the very least do a backflip if it wasn't secured to the ground.

A much better piss take was the helicopter photoshoped onto an old record player 'will it take off'

[Anonymous No.10415580]

>>10415575
Shit didn't notice a plane on the thing. Won't take off unless it's got the lift under its wing to do so. A RC plane only needs 1m on a windy ass day. But it'd hit the rails before that

[Anonymous No.10416035]

>>10413340
It won't, wings will hit the treadmill

[Anonymous No.10416101]

>>10413340
No, its gonna crash against the stand

[Anonymous No.10416124]

Assume the wheels are able to rotate without slipping. When the treadmill turns on, they will rotate without impacting the plane's position. There is a force on the wheels, but we can think of it as not impacting the fuselage.
Now turn engines on. There is a net force on the fuselage, which acts on the wheels. Thus the plane moves.
Same applies when friction and slipping is considered.
Am I a brainlet?

[Anonymous No.10416264]

>>10415069
No he didn't
>>10413478

[Anonymous No.10416280]

airspeed is what provides lift
the treadmill would need to make the air move as well
and then there would be problems as soon as you leave the proximity of the artificially moving air

[Anonymous No.10416304]

>>10415340
No.

>>10415522
No. Airflow OVER the wings creates the pressure differential required for the plane to take off. The turbines themselves won't cause enough unless we are now perhaps using fantasy turbines as well.

The real question is if the plane, an airliner in this case, would be able to achieve a forward speed great enough to generate the airflow over the wings required to take off, and the answer is no. Even if the wheels were frictionless, so long as we are assuming the treadmill can go at whatever speed is required the wheels will tear themselves apart before the plane moves anywhere. If we are imagining fantasy wheels and treadmill then there's a stalemate right up until the speed of light, at which point we need a fantasy atmosphere and planet and physics in general to keep the experiment running.

And, yes, the Mythbusters experiment was probably the worst thing they have ever done with the shittiest "treadmill" possible and a plane that the presenters could have thrown into the air.

>>10416124
Yes.

[Anonymous No.10416310]

So listen to me all of you brainlets in this thread, there is not an answer for this problem or at least the answer is not yes or no. The fact is that this problem is impossible:
The threadmill can always match the wheels speed right?
But jet engines do not rely on ground friction for propulsion as a car does so their thrust is not precluded by the threadmill.
Now it must be clear that the airplane should be able to move forward since it only needs air, but that cannot be true otherwise the first statement "threadmill matches speed.." is not true.
It is clear then that the threadmill and wheels will instantaneously reach an infinite speed which is phisically impossible!
Finally if you want to look at it by a more realistic point of view since it's impossible to reach infinite speeds the threadmill will imediately broke up and then the airplane will eventually take off, but keep in mind that this means that the hypothesis "threadmill will match speed..." has fallen.

[Anonymous No.10416440]

>>10413340
Yes. It will shortly take off when it falls off the treadmill backwards.

[Anonymous No.10416466]

>>10413340
>>10416440
Based on what parameters? The wheels being glued to the belt? Or perhaps the model plane weighing a ton? Or perhaps, the treadmill's max speed is 4 cm per minute? You are just assuming things. You know nothing about the problem at hand. OP has provided nothing to work with.

[Anonymous No.10416585]

>>10413340
It like a bottle rocket on a skateboard
Will it take off ?
Is there fuel and cargo in your plane ?
You would need a canard on the nose.

[Anonymous No.10416598]

>>10413340
Am I the only one who finds this Pic cute?

[Anonymous No.10416610]

>>10416310
>irst statement "threadmill matches speed.." is not true.
>It is clear then that the threadmill and wheels will instantaneously reach an infinite speed which is phisically impossible!
This but it will be the wheels that exceed their speed rating and come apart since the treadmill is magic.

[Anonymous No.10416756]

>>10416304
imagine being so dumb you think the forward impetus for a plane is transmitted by the wheels

[Anonymous No.10416841]

I think this board is full of literal retards who didn't pass physics in highschool
actually most people here are prob in middles school

[Anonymous No.10416845]

>>10413340
>no air lift
>taking off

[Anonymous No.10416852]

>>10416756
KEK
golden.

[Anonymous No.10416854]

>>10416845
This!

What kind of retard are you OP.
Your not even getting a (you)

[Anonymous No.10416860]

>>10416310
let's say the entire runway is a threadmill.
>threadmill matches speed of wheels/plane
if this holds true, logic dictates that since the plane's thrust and the threadmill's "drag" cancels out each other, it should be "stationary."
since there is no thrust, the plane cannot generate lift from the pressure difference in the wings. the plane then cannot overcome gravity.

but suppose the threadmill moves very fast that it produces boundary layer effect. is the moving air produced enough to generate lift for the aircraft? will it hover for a bit then just crash due to turbulence? I dunno.

[Anonymous No.10416930]

>>10413340
The wings would hit the vertical bars before it took off. So no, in the case of your specific picture, the plane would not take off, but it has nothing to do with the treadmill running backwards under the wheels.

[Anonymous No.10417021]

>>10416304
You're just talking about the treadmill moving at the speed of light without connecting that in any way to the overall movement of the craft. Yes the wheels are going to fall apart before you can spin them at the speed of light but why are you even doing that in the first place? Why not just spin them at real world treadmill speeds?

[Anonymous No.10417043]

>>10413340
No.
It has to move through wind or move relative to surrounding air to build pressure up. Moving the ground does not move the wind.

[Anonymous No.10417050]

>>10413340
No.
The wings would get caught in the treadmill's support bars.

[Anonymous No.10417072]

>>10417050
Says who?

[Anonymous No.10417078]

>>10416466
Wheels don't keep you perfectly in one place on a moving surface like that without any additional power being applied to keep it there.

[Anonymous No.10417081]

The things different from a normal takeoff are:
>slightly increased friction on the (non-powered, free) wheels
>(related) assuming the wheel axle having greater than no friction, needing to use a slight bit of engine power to prevent from falling off
>a significantly shorter runway

It's that last one that matters. Assuming those bars weren't there, it would roll off the front and either crash or eventually take off as normal.

[Anonymous No.10417092]

>>10417081
>Assuming those bars weren't there, it would roll off the front and either crash or eventually take off as normal.
You assume too much.

[Anonymous No.10417099]

>>10417092
>Craft's wings are wider than the treadmill
>Outside of treadmill's bars are equal distance of treadmill
Sorry to hear about your brain injury, anon.

[Anonymous No.10417105]

>>10417099
So funny. You really think you understand the problem at hand do you? And then you tell others they have "brain injury". We are reaching Dunning Kruger levels that should not be possible? Where did OP state that the treadmill is actually moving?

[Anonymous No.10417108]

>>10417105
That... does not actually change anything about anything I said.

[Anonymous No.10417353]

>>10415145

[Anonymous No.10417448]

If the treadmill were to move so fast as to counteract the force of the engines through the low friction wheels its extreme speed would generate so much headwind through air friction that the plane would take off

[Anonymous No.10417730]

>>10416756
It very much is.
Sure, you could replace the wheels with skids or something instead, but we tend to choose lower friction gear so that less of the energy is lost.

The point is that the wheels won't survive, and then you definitely won't be taking off.

[Anonymous No.10417763]

>>10417448
Na, the air would be extremely turbulent. If the plane was lifted up by it one of two things would happen.
It would either slam back down in the turbulence and rape the landing gear, or it would lack the air speed to maintain lift once clear of the treadmill and crash.
Now I guess you could class both of those as victories depending on what your conditions are, but either way.

[Anonymous No.10417838]

This thread confirms there aren't Aerospace Engineers in this board.

[Anonymous No.10417860]

>>10415127
The trust lever or the TO/GA button.

[Anonymous No.10418091]

>>10417763
That's a win in my book

[Anonymous No.10418303]

>>10413340
I really don't understand how this problem is so persistently unintuitive to people.

1. Planes do not take off by driving with their wheels until they reach take off speed. The wheels around there precisely to /decrease/ friction from the ground, not for thrust.
2. As a result, even if the treadmill is moving extremely fast, it only takes a small amount of force keep the plane from moving, just like a bike coasting on a treadmill being held from the sides.
3. Planes use jet engines for thrust, by burning fuel to spin a compressor which mixes air with more fuel to spin a turbine which, as the plane increases in speed, becomes more efficient, until it is eventually able to power the compressor too.
4. Lift (not thrust) comes from air moving past the wings of the plane. As the plane increases in speed, the treadmill's already small impact on the plane would get smaller and smaller.

So essentially, as long as the plane can produce enough thrust at rest to overcome the backwards force from the treadmill, which is essentially made constant, regardless of speed, by the bearings in the plane's wheels, then it'll be able to take off, just like you'd be able to easily push a bike forward on a treadmill going backwards at 100mph as long as you are not standing on the treadmill.

L

[Anonymous No.10418312]

wouldnt it act like a spring? The plane wouldnt be moving but once it takes off it'll immediately shoot forwards

[Anonymous No.10418468]

>>10418312
biggest retard in this thread congrats

[Anonymous No.10418964]

>>10418303
>which is essentially made constant, regardless of speed, by the bearings in the plane's wheels
But that's wrong. You're basically saying the effect of friction doesn't increase with speed, which is in the frictionless wheels territory.

No mattee how you spin it, there's no way the wheels are surviving until takeoff.

[Anonymous No.10418996]

>>10418964
>You're basically saying the effect of friction doesn't increase with speed
There is no V in the equation for calculating friction force.

[Anonymous No.10419003]

>>10413340
of course, only the wheels will be spinning twice as fast

[Anonymous No.10419005]

>>10413340
Of course yes

[Anonymous No.10419011]

>>10413340
the plane would take off normally but the landing gear would be spinning twice as fast on take-off, which may or may not be a problem

[Anonymous No.10419451]

Hi everyone,
I can't believe you are still discussing about that while i simply gave you the official and only reasobable answer here
----> >>10416310
>>10418303
I just specified above that an airplane do not rely on wheels for thrust, you don't have to repeat that, but thank you for the support. Btw you must remeber that the hypothesis in this problem is that the threadmill can always match the wheels speed and if the airplane is moving forward the hypothesis falls because this would mean that wheels are rotatibg faster than threadmill, otherwise whithout this hypothesis it would be obvious that the airplane would take off.
As i said in the previous post (i recommend all of you to read it and think about it) the only solution is that wheels and threadmill reach and istantaneous infinite speed and the airplane won't take off, but as you can imagine infinite speeds are absurd so this problem simply doesn't make sense.

[Anonymous No.10419891]

>>10415570
Wouldn't the treadmill and your wheels accelerate to infinite speed? That doesn't make sense.

[Anonymous No.10419909]

>>10415278
>but in the real world you could actually make the threadmill always spin excatly fast enough that the airplane would never move relative to the ground, so it would not take off
The wheels of a plane spin freely. Their spinning speed has no impact on the actual groundspeed of the plane, unless you're at a level where the friction of the bearings becomes relevant and the plane starts breaking apart.

[Anonymous No.10419916]

>>10419909
That's not how inertia works

[Anonymous No.10419928]

>>10413340
No it wouldn't. If we use a shrink ray on a conventional airliner so that it will fit on a treadmill it won't be able to take off because the wings won't be generate enough lift to support its weight. Also putting the entire weight of an airliner on a treadmill will cause the treadmill to break

[Anonymous No.10419931]

>>10419916
>let's object by throwing out random terms

[Anonymous No.10419946]

>>10419931
Brainlets are usually unable determine context from small replies. It takes at least some thinking.

[Anonymous No.10419956]

Planes only take off when air moving relative to the wings has enough velocity and density to create a pressure differential between the top and bottom of the wing. If this treadmill was matching the velocity of the plane, but in the opposite direction, then the plane would be unable to take off because the velocity of the air relative to the wings would be essentially 0.

[Anonymous No.10419963]

>>10419946
>I can't communicate properly

[Anonymous No.10419968]

>>10419963
That's okay. We can't all be smart.

[Anonymous No.10419971]

>>10419968
>I also don't know what a quote is
>help

[Anonymous No.10419976]

>>10419971
You sure are a dummy lomaf

[Anonymous No.10419996]

>>10417730
>The point is that the wheels won't survive, and then you definitely won't be taking off.
if you start with objections like that then we have to start talking about how the treadmill will also inevitably break down

[Anonymous No.10420102]

>>10413340

An airplane can only get lift if there is an airflow over the wing. The shape of the wing makes the air flow faster over the top of the wing creating a negative pressure lift.

Is air flowing over the wing on the treadmill?

If you put huge fans in front of the treadmill then air would flow over the wings and you would get lift (This is called a wind tunnel).

Unless air is flowing over the wings there will be no lift.

When you run on a treadmill do you feel a wind force on your chest? Do you experience any airflow around you? NO

Therefore an airplane on a treadmill will NOT get any lift.

M.S. Aerospace Engineering

[Anonymous No.10420125]

>>10420102
>Is air flowing over the wing on the treadmill?
Yes. The engines are on and the plane has forward velocity, putting air over the wings. An airplane's wheels are fee to spin and airplanes put no torque through them on takeoff. The takeoff procedure is exactly the same as if the treadmill is not there.
>>10418303
>backwards force from the treadmill
There is no backwards force.

[Anonymous No.10420162]

>>10420125
>The engines are on and the plane has forward velocity, putting air over the wings

Unless their are giant fans in the room (moving the air over the wings), then the airplane (and the wings) must move relative to the still air. Unless the airplane moves relative to the still air, it is not going to get any lift.

The airplane can be moving 1000 miles an hour, if the treadmill is moving just as fast and the wheels are spinning, keeping up. Then the airplane is not moving relative to the still air and there is no airflow over the wings, so there is no lift.

An Airplane can be moving 500 miles an hour relative to the ground, if it flies into a tail wind of 500 miles an hour, then it lose lift and fall from the sky. Even though is is moving over the earth at 500 miles an hour (actually more since tailwind will push it (pilots love tailwinds for a the added speed bump))

Airplane lift as nothing to do with ground speed, it only has to do with the speed of the air over the wing (and other things like angle of the wing, etc) but basically airplanes can only fly if air is flowing over the wings.

Airplanes are "sucked" into the air and rockets are "pushed". Rockets do not need any air to work they will work in space.

[Anonymous No.10420165]

>>10420162
The only forces on the plane are gravity, a vertical normal force from the wheel bearings, and forward thrust from the engines. The plane accelerates forward. Forward motion put air over wings. Plane gets lift.
>MS in Aerospace
why are you getting BTFO by an ME undergrad

[Anonymous No.10420181]

>>10420165

Is the plane moving relative to the still air. Yes or no?
The treadmill is not moving relative to the air.

Stand next to someone on a treadmill do you feel any air flow. Look at their shirt is it being pushed back by some airflow. Get on a treadmill do you feel any wind flowing on you. NO.

Explain how air is flowing over wings?

[Anonymous No.10420191]

>>10420181
>Is the plane moving relative to the still air. Yes or no?
Yes
>Explain how air is flowing over wings
Turbines make forward thrust, giving forward velocity.

[Anonymous No.10420199]

>>10420191
>>Is the plane moving relative to the still air. Yes or no?
>Yes

The treadmill is no moving relative to the air and the plane is? The the plane will run into the front of the treadmill.

It is easy to get a plane to fly and stay stationary over a point on the ground (say a treadmill) IF you have giant fans moving the air over the wing (we do this all the time in wind tunnels).

You could put the treadmill on a truck and drive fast enough that the plane could get lift, and by carefully controlling the speed of the truck the airplane could remain stationary relative to the treadmill.

[Anonymous No.10420207]

>>10420199
>The treadmill is no moving relative to the air and the plane is? The the plane will run into the front of the treadmill.
No? The surface of the treadmill is moving backwards at takeoff speed v and the airplane is accelerating forward (relative to stationary ground) up to speed v, unhindered as no horizontal force is transferred to the plane from the wheels. Please explain what role you think the treadmill plays in preventing normal takeoff. Im really starting to doubt that MS.

[Anonymous No.10420215]

>>10413340
this is stupid, the wheels on a plane dont deter the distance needed for it to take off. all the treadmill does is speed the wheels up faster. the movement of the plan is independant of the speed of the "ground" the plane is on.

[Anonymous No.10420217]

>>10416841
Congrats, you've realized that there is spill off from the morons in other boards who passed clac 1 after their 5th try and now think they're the 2nd coming of gauss.

[Anonymous No.10420225]

>>10420207

Where is the airflow over the wing?

Airplanes fly by airflow over the wing. PERIOD.
(Jets can act like rockets, but this is not what a fat ass commercial airplane like the one pictured in OP image can do)

Now a helicopter or a drone can hover in one spot because their blades are spinning (moving air over the blades producing negative pressure lift).

If you want that airplane to remain stationary over one spot on that treadmill, and that treadmill is NOT moving, then the air has to be moving relative to the treadmill (i.e giant fans in from of the treadmill) otherwise there will be no airflow over the wings and thus no lift.

There must be movement of air over the wings for the plane to get lift. If the treadmill is stationary relative to the air, then the plane needs to move relative to the air (and treadmill).
If the plane is moving relaitive to the treadmill then it is NOT staying over one spot on the treadmill.

You can not get lift without air flow (unless you turn the airplane into a rocket).

so it is NOT stationaryu over obne point.

[Anonymous No.10420233]

>>10420225
>Where is the airflow over the wing?
I just fucking explained. Read my post again.

[Anonymous No.10420235]

>>10420207
Because it's the same thing as just spinning the wheels really fast.

[Anonymous No.10420240]

>>10420233
youre retarded

[Anonymous No.10420242]

>>10420240
>t. lies about his experience

[Anonymous No.10420244]

>>10420225
>(Jets can act like rockets, but this is not what a fat ass commercial airplane like the one pictured in OP image can do)
that's exactly what turbine engines do. they suck air in the front, combust some fuel, and throw it out the back fast enough to move the plane forward

[Anonymous No.10420254]

>>10419891
Yes, this problem doesn't make sense that's what i said here
>>10416310

[Anonymous No.10420257]

>>10419891
No, they would accelerate to twice the take off velocity.

[Anonymous No.10420270]

>>10420242
im a different anon you half wit

>the surface of the treadmill is moving backwards at takeoff speed v and the airplane is accelerating forward (relative to stationary ground) up to speed v
not only are you arguing that the plane will take off, you are arguing that it will fly against a treadmill moving faster than the fucking plane.

[Anonymous No.10420277]

>>10420244
>to move the plane forward

That is just it, forward to what?

To get lift it has to move forward through the AIR. This airplane on a treadmill is staying in one spot relative to the surrounding air.

All the engines are doing is proving forward motion, because the treadmill is moving at the same speed as the forward motion, there is NO wind flow over the wings, thus no lift.
The engines are pushing the plane forward, but without motion of air over the wings there is no lift.

As stated earlier a plan can be moving 500 miles an hour relative to the ground, but if it enters a 500 mile an hour tail wind, it will lose lift and begin falling. Lifty tin an airplane comes ONLY from air flow over the wing.

Air[plane lift It has NOTHING to do with how fast it is moving relative to the ground ONLY in how fast it is moving relative to the air.

[Anonymous No.10420282]

>>10420270
Lets do this together. The treadmill is set to run a fixed speed. The nature of airplane are such that there is no torque applied to them by the plan, they are free to spin at any speed and are taken to have frictionless bearings. Because there is no friction, there is no rearward force the airplane. With the engines off, it only has two forces acting on it: gravity and a normal force. Thus everything besides the wheels and the treadmill surface are stationary before the engines are lit. Turn on the engines now and the exert a forward thrust on the body of the plane. There are three forces now: gravity, upward normal force, and forward thrust. Newton's second law says the plane accelerates forward. Forward motion means the wing has velocity compared to still air. The principle of lift says the wings produce lift. So it takes off. What did I say that is incorrect?

[Anonymous No.10420286]

>>10420277
>confuses turbine thrust with wings
Air does not need to be in motion to get thrust out of a jet engine, brainlet.

[Anonymous No.10420304]

>>10420277
>Air[plane lift It has NOTHING to do with how fast it is moving relative to the ground ONLY in how fast it is moving relative to the air.
Right. And air is taken to be still relative to the ground in this scenario.

[Anonymous No.10420306]

>>10420286
Jet engines do not produce LIFT, they produce thrust.. The air flow over the wings produce lift.

The trust here will push the airplane forward at the speed of the treadmill, but there will be no lift.

I see what you error is. Thrust is not lift.

You could put a just engine on a brick with wheels and you would get the same result.
No lift, but the trust would keep the brick in the same position.

Wings only get lift with air flow over the wings.
No air flow over the wings, no lift.

[Anonymous No.10420315]

>>10420306
>Jet engines do not produce LIFT, they produce thrust.. The air flow over the wings produce lift.
Yes. Now draw a free body diagram, if you even have that sort of rudimentary knowledge. There is a net thrust in the forward direction. I don't need to spell out what this means.
>brick
We aren't talking about a brick that has friction with the ground. We are talking about something with wheels and lifting bodies.
>Wings only get lift with air flow over the wings. No air flow over the wings, no lift.
You already conceded forward thrust. That means forward motion. Forward motion means air over the wings.

THERE IS AIR MOVING OVER THE WINGS

[Anonymous No.10420324]

>>10420277
>This airplane on a treadmill is staying in one spot relative to the surrounding air.
there's nothing keeping it in place relative to the surrounding air. if it throws air backwards, it is free to move forwards

[Anonymous No.10420327]

>plane is stationary
>engines turn on
>engines push plane forward
>stationary surrounding air moves over the wings
>lift is generated
>repeat until plane takes off

[Anonymous No.10420336]

>ITT a bunch of Dunnings who argue over what makes a plane fly
>All are oblivious as to the "non-argument" nature of OP's post.
>mfw

[Anonymous No.10420337]

>>10420315
>THERE IS AIR MOVING OVER THE WINGS

The airplane is remaining stationary over the same spot on the treadmill, the treadmill is stationary to the air around it. Therefore the airplane is stationary to the air as well.

Where is your airflow coming from?

When you running stationary on a treadmill you do NOT have any airflow over you.

Why do you magically think the airplane does?

The engines provide thrust to move the airplane at the same speed as the treadmill is spinning, but since there is no airflow over the wings there will be no lift.

Go ahead and try the experiment the airplane is NOT going to take off.

You need air flow to get lift in an airplane.

This is why pilots are very careful when landing planes to make sure they know the wind speed and direction: a tailwind means they have less lift but more speed when landing, and a headwind the opposite.

(Roughly) They need to adjust the angle of the wings to modify the lift and adjust braking to account for the speed.

[Anonymous No.10420339]

>>10420337
>The airplane is remaining stationary over the same spot on the treadmill
I JUST PROVED THAT IT ISNT

[Anonymous No.10420353]

>>10420337
the airplane is only stationary relative to the air if the engines are turned off. once you turn the engines on it's not true

[Anonymous No.10420377]

>>10420339

I thought the entire idea was if an airplane sits on treadmill and stays in the same postilion on the treadmill as the treadmill is made to spin VERY fast, will the airplane take off.

No. the airplane will not get any lift,. there is no airflow over the wing.

if you allow the airplane to move forward over the treadmill (NOTE: treadmill is stationary to the surrounding air) then airplane will be moving relative to the stationary air, thus getting airflow over the wings and you will get lift.

All the engines do is give forward thrust. The trust pushes the airplane forward at the same speed as the treadmill, there is no airflow over the wings, thus no lift.

[Anonymous No.10420411]

>>10420377
>The trust pushes the airplane forward at the same speed as the treadmill,
at some point the thrust applied to the plane will overcome whatever frictional forces are applied through the wheels to the plane and the plane will begin to move forward.

[Anonymous No.10420413]

>>10420377
>thought the entire idea was if an airplane sits on treadmill and stays in the same postilion on the treadmill as the treadmill is made to spin VERY fast, will the airplane take off
NO ALREADY EXPLAINED WHY THAT ASSUMPTION IS BAD

[Anonymous No.10420414]

>>10420353
>the airplane is only stationary relative to the air if the engines are turned off. once you turn the engines on it's not true

The treadmill and the air are stationary, the airplane remains in the same spot on the treadmill, therefore it remains in the same spot in the air, STATIONARY.

You do not need ANY thrust to get lift all you need in airflow over the wing.
Aim a 747 into hurricane strength winds and it WILL take off ( get lift) with no thrust applied.

The wings do not care how the airflow is generated only that it is generated and they will NOT make lift without air flow over them.

[Anonymous No.10420415]

>>10420413
>NO ALREADY EXPLAINED WHY THAT ASSUMPTION IS BAD

Then airplane will crash into front of treadmill.

[Anonymous No.10420416]

>>10420414
sure, if you define the problem so that you never allow the airplane to move no matter what happens, the airplane will take off.

but if you ever allow the airplane to attempt to take off, generating anything more than minimal thrust will be sufficient to let the plane move forward, generating lift.

[Anonymous No.10420417]

>>10420414
>the airplane remains in the same spot on the treadmill
But that is fucking wrong

[Anonymous No.10420421]

>>10420416
>so that you never allow the airplane to move no matter what happens, the airplane will not take off.
fixed

[Anonymous No.10420422]

>>10420415

[Anonymous No.10420428]

>>10420417

If you allow the airplane to move relative to the non-treadmill ground position (the airplane is not fixed to one position on the treadmill) then it will move through the air and get lift.

Then you have a catapult launcher like you have on EVERY aircraft carrier. The airplane is pushed into the air by catapult allowing a MUCH shorter distance to take off,

YES, if you use the treadmill to accelerate the airplane it would take off, it is much easier to just catapult it, but you could build a treadmill on a aircraft carrier and use that to accelerate the airplane.

[Anonymous No.10420452]

>>10420428
>If you allow the airplane to move relative to the non-treadmill ground position (the airplane is not fixed to one position on the treadmill) then it will move through the air and get lift
So you concede the point I've been trying to make this whole time. Thanks.

[Anonymous No.10420484]

>>10413340
no it wouldn't , because it's the air under the wings that moves it, not the wheels on the ground.

[Anonymous No.10420490]

>>10420452
>So you concede the point I've been trying to make this whole time. Thanks.

Yes. If thew plane is is accelerated by the treadmill then it will be moving through the air and get lift. BUT that is is a moving sidewalk (like you find in big airports) and NOT a treadmill.

What the original picture showed was treadmill with an an airplane on it, so it is correct to assume the airplane was using the treadmill similar to how a human does, in that they stay in the same position as the treadmill moves blow them.

Moving sidewalk: airplane gets lift, treadmill: airplane gets no lift.

Now you know the fucking nightmare it is dealing with a customer who incompletely describes what they want, then they get upset when you spend 3 weeks in meetings trying to get them to clearly state what they really want.

A moving sidewalk and a treadmill are the same thing, BUT they interacted with totally differently.

You interpreted a treadmill as a moving sidewalk.
Which is OK, but NOT what the image shows.

[Anonymous No.10420497]

>>10420490
Nigga just draw a force diagram like holy shit

[Anonymous No.10420498]

I'm going to assume that, according to the picture, the treadmill is active at some speed (otherwise, why even have it), and will move the opposite direction the plane wants to move (as that is the implied orientation). Thus, either
A: the plane doesn't use its engines enough, and due to friction in the wheels, the treadmill pulls it off.
B: the plane keeps enough speed to stay on, but otherwise doesn't go forward. No air over wings = no takeoff.
C: the plane throttles up, but hits the bars of the treadmill, resulting in no takeoff.
D: the actual treadmill in OP's picture is just to explain the premise, and does not reflect the actual "treadmill" being used. Assuming enough runway, the plane throttles up, and the wheel's axle's come under higher rotational stress than normal. Assuming nothing breaks, the plane takes off.
E: we imagine a hitherto unknown gigantic fan somewhere in front of the plane, completely changing the problem. IF a massive fan or other source of wind creates enough headwind to create lift, and IF the plane thrusts JUST enough to keep from crashing, then the plane would be able to take off, while appearing to levitate.

A plane's wheels, ideally, have very little friction - unless the brakes are activated, the speed, or indeed direction of the treadmill is almost entirely irrelevant. Key word: ALMOST - it will matter more with extremely high or low speeds.
A jet engine does not create lift. It creates thrust. This thrust moves the plane, which causes air to move across the wings, creating a low-pressure zone above the wings, generating lift.
It takes time to accelerate. Without enough speed (that is: wind moving across the wings), the plane would not be able to generate enough lift to take off. Thus, if the treadmill in OP's picture is the one being used, since we (I assume) aren't using a helicopter or VTOL, unless the plane falls off and remains functional, takeoff is effectively impossible.


This thread is dumb as hell.

[Anonymous No.10420501]

>>10420490
ok but that's completely fucking stupid. in order for that to happen the pilot would ahve to be applying the barest feather touch of thrust, just enough to overcome the small amount of friction in the wheels. the pilot would have to be TRYING to keep the plane still. why the fuck would you ask if the plane could take off if the pilot must be trying not to take off?

[Anonymous No.10420506]

As long as the wheels can keep up with the speed, you will take off. The only situation where you wouldn't would be at extreme speeds where the friction of the wheel and axel started to matter.

[Anonymous No.10420511]

>>10420501
>why the fuck would you ask if the plane could take off if the pilot must be trying not to take off?

Because the treadmill could be moving 600mph and some people think that just because an airplane is moving 600mph it somehow magicly ally get lift.

Lift ONLY comes from air movement over the wing, PERIOD.

Except for rockets and some some fighter aircraft with jets so powerful that they can literally fly upward purely on the jet thrust alone like a rocket .

[Anonymous No.10420513]

>>10420506
If the bearings are frictionless, a negligible a.oint of thrust is needed to "keep up." In the idealized version of the problem no thrust at all is needed and the moving threadmill doesn't interact with the body of the plane.
The treadmill is an obstacle for brainlets.

[Anonymous No.10420631]

>>10413340
This is actually a terrific idea for aircraft carriers.
It beats the ramp.
It beats the stupid pulley system.
You're a genius.

[Anonymous No.10420633]

>>10420511
if the airplane is moving at 600 mph it WOULD get lift. it's not magical, it's air.

[Anonymous No.10420646]

There's so many "if"s involved in this it's impossible to have a single answer. Everyone just goes "well what about if ...".

The answer is 50/50. It'll either take off or it won't.

[Carbon No.10421768]

>>10413340
lift from planes comes mostly from the motion of air around the wings
Why wont this meme die?

[Jesus Christ No.10422360]

>>10415502
What

[JFL !4sM/I/Auxg No.10422523]

>Guys, like, /pol/ is totally the dumbest board!
lmao

[Anonymous No.10422552]

>>10422523
run on a treadmill.
you will feel air going past you.
it would provide lift to fixed wing craft

[Anonymous No.10423152]

>>10422552
>you will feel air going past you.
That's just the air conditioning set up to blow across the treadmills.

[Anonymous No.10423566]

>>10420286
I hope you realize jet engines fundamentally work by putting air into motion

[Anonymous No.10423609]

>>10423566
Yep, I realize that.

[Anonymous No.10425114]

>>10423609

now imagine attaching a rope on the airplane and imagine you pulling on that rope to make the airplane move in the opposite direction the treadmill is moving. Do you think that would be hard? Maybe imagine frictionless wheels. Maybe even better, imagine the plane is floating. Im not the guy that responded to you earlier btw.

[Anonymous No.10425127]

>>10413420
>I don't know what gravity is.

[Anonymous No.10425149]

>>10413491
Came to post this.

[Anonymous No.10425158]

>>10425114
It would be hard, since the turbines thrust in the opposite direction as the rope tension. Not sure what your point is. The plane still gets forward velocity and thus lift in the original problem.

[Anonymous No.10425175]

>>10416756
Underrated comment.

[Anonymous No.10425201]

>>10425158
it doesnt get sufficient forward velocity to generate enough lift for takeoff
it gets *some* of the lift, but theres a reason runways are so fucking long

[Anonymous No.10425242]

>>10413340
It is faced backwards on the treadmill.

[Anonymous No.10425245]

>>10425201
The question obviously assumes a treadmill of arbitrary length

[Anonymous No.10425259]

>>10425242
This guy gets it!

[Anonymous No.10425482]

>>10413340
If that scale model had an engine and was moving while the machine was also on, theoretically the friction created between the moving model jet and the moving walker floor would likely burn and might even have enough force to break apart the model IF it had a speed equal or greater than the movement of the machines surface, if it had a speed less than the movement of the surface it would slide away, and both the surface and the model will likely be badly burned... if the surface was moving at a fast rate (10 m/s or more?)