STATIONARY, the myth is about if a plane can take off from a conveyor belt that is size of plane itself. Thats the whole point the myth so we didn't need entire runways. Were the power comes from is irrelevant, wheels, jet, propeller, rocket it doesn't matter, it will not and can not take off with zero airspeed. Trying to maintain zero airspeed on a conveyor would be difficult and is another story.
A conveyor belt at airports would be very useful at airports if the plane was facing the same direction as the belt travel as long as the plane had it's brakes on. It would be a very short takeoff.(as in aircraft carrier catapult)
About this video...: Relative to the airplane itself the camera stays focused on the plane at the speed the airplane is traveling except in the first few seconds. If trees and other stationary objects were standing by but not on the conveyor belt, then they would accelerate by just as you would see looking out the window of the plane as it zooms down the runway. Airplanes are gliders with motors, the motors are the planes way of making head winds so it can travel.
So hilarious people think this way. I ran this across my family, two of them insisted the plane would not be moving anywhere. I had to show them the evidence, and then they debated it for a long time before they finally saw why the plane still takes off.
There IS still forward movement, period. Treadmill example is pointless, because the plane does not push off the ground like our feet do, but off the air.
At airports it would be pointless, the plane still needs the same air space to take off.
@Thornbrier It becomes completely irrelevant to even talk about this, if the plane still needs to move forward on the conveyor belt to take off. Isn't the conveyor belt meant to match the speed of the wheels at all times in the opposing direction? meaning there is no forward motion in the aircraft, meaning there is no wind creating lift, meaning the plane won't fly.
@discombobulated87 That's my point, it does not need to move forward 'on the conveyor belt' it needs to move forward through the air. Since the propeller/jet engine pulls on the air, not on the wheels, the speed of the wheels is irrelevant.
You say as you increase the speed of the wheels you increase the speed of the conveyor to accommodate. But this automatically increases the speed of the wheels until either the conveyor gives out trying to keep up, or the ball bearings of the wheels do.
@Thornbrier But it is the same thing, i agree that the wheel speed is irrelevant, but you can't tell me that the plane is not moving forward at take off. It is basically saying the plane stays in a stationery position relative to the environment, then shoots to 150mph-220mph as soon as it lifts off the Conveyor belt. A plane might be able to take off from a Conveyor runway, but it wouldn't be useful to use anywhere, and becomes pointless.
@discombobulated87 The plane does not remain stationary relative to the environment. It moves forward whether the ground moves backwards under it at an increased speed or not. The Conveyor belt effectively has NO effect on the planes take off. It neither helps nor hinders. The point is that it does not stop the plane from taking off as many claim it would, not that it helps it take off, that is scientifically ludicrous.
Im tired of seeing IDIOTS thinking that airplanes on conveyor belts take off. If planes took off on conveyor belts, the airports would be FUCKING SMALL!!! It doesnt matter how fast the wheels are spinning or the proppeler thrust, THE WIND SPEED IS NONE! If there is no wind speed, there is no lift! Just because the proppelers are running full speed it doesnt mean the plane is flying DUH...there are guys that are just clueless.
take a physics course, IDIOT, like mentioned 100000000000000000000 times before EVERYwehre, the fucking planes are propelled by THRUST, the wheels only support the fucking things off of the ground, the conveyor belt would only "ideally" double the speed of the wheels, the take of distance would not change, not like you claim, you are under the assumption that the plane would lift of in one place... no, ti would look exactly the same as it does on a runway.
@aemravan So the air planes are propelled by thrust? Then I gess that by your line of thought (if you are capable of thinking at all..) is that thrust alone will lift the plane. So then I gess you could take the wings of the plane away that It will fly regardless...Its IDIOTS like you that give science a bad name. A plane will always have to move forwards in order to gain wind. WIND IS NOT THE SAME THING AS THRUST! Go play with your building blocks and shut up like a good boy.
I watched the mythbusters attempt, and don't believe it to have been satisfactorily done, surely if the ground is moving in the opposite direction at the exact same speed as the aircraft, then there would be no forward motion, which there was plenty of on the mythbusters test. I thought that was the whole point of a treadmill, so you could run without going anywhere, it would be f**king pointless if you still moved forward.
Aeronautics 101: Aeroplanes need wind passing over the wings to achieve lift. This is due to the aerofoil design of the wings... Like when the plane accelerates through air on the ground from the thrust of the engines.
If the plane stays still, (like on a conveyor belt) no air is passing over the wings, no lift = no take off.
The wheels are largely irrelevant to the flying fuction of a plane.
Myth busted with year 11 science (Note, not in highschool anymore)
Youre presumption that the plane will stay still is incorrect. The Plane will not stay still...the conveyor belt is long and the plane moves along it regardless of the speed its moving.
Think of it this way if it helps. A plane "swims" through the air in the same way a fish swims through the water. It is using the thrust from its tail to push it through the water. If you put little wheels on the fish and put it on an underwater treadmill it wouldn't stop the fish from swimming away, would it? And don't bother with theories about air over the wings and 'lift'. Lift allows the plane to rise, but you could cut the wings off and it would still jet right off the end of the conveyor.
The plane is pushing against the air, not the ground. The speed of the conveyor doesn't matter. It won't stop the plane from pushing itself through the air.
Don't worry, this myth is just always poorly phrased. The concept behind the myth is more properly this; let's assume you need to go 30 mph in order to take off. If a plane exerts the same amount of throttle to go 30 mph under normal conditions and nothing additional, will it still be able to take off while on a conveyor belt going 30 mph in the opposite direction.
I wasn't actually saying it would take off without the wings. What I meant was even without the wings the plane would still be propelled forward (unless the engines happened to be on the wings, but you get what I'm saying).
How do you guys not get this? The plane is pushed through the air by jet thrust (or pulled through the air by a propeller). The wheels just free wheel, they are not involved in the propulsion of the plane. The only difference the conveyor belt would make is the wheels would be spinning twice as fast when it takes off. I'm starting to think that people who say the plane remains motionless are just saying that to drive other people crazy.
@jimboinlimbo Nobody thinks the wheels propel the plane! The wheels allow the plane to make contact and move across a stationary surface so that sufficient wind speed can be built up, which is only done by having sufficient GROUND speed, which requires WHEELS. Lift if generated by the wings low pressure zone. Look up airfoils on wikipedia. Or an encyclopedia if you know what and where a library is.
@QuantumCarl Well Carl, I think you might be missing the point. Of course the wheels support the plane and allow it to build up ground speed. The point is that the relative speed of the wheels is irrelevant. If the wheels are turning twice as fast because the conveyor is running in the the opposite direction it will have no effect on the forward momentum of the plane. BTW, yes I do know where the library is, your mom and I meet behind it every thursday.
@jimboinlimbo FORGET THE DAMN WHEELS. They could be donuts for all anyone cares, the point is that it's a connecting point of friction between the plane and the ground. The plane is effectively holding itself in place!
@jimboinlimbo they probably are. The physics are impossible (I worked as an engineer on planes, pushbacks, and conveyor belts, so I know) and it'd just waste fuel to overcome the doubled static friction (...course you could run the belt in the other direction lol)
The video is funny though. I kept waiting for the little model plane to fly off the end of the conveyor belt and go crashing into a wall, followed by someone going "WTF? not in my milk dude!" and a shaky camera at the end.
im one of the non believers but think about it. the thrust created by the jet has to exceed the speed its going against. there also has to be wind for lift!!!!
@exa0777 Whether you believe it or not, Mythbusters did this full-scale and the plane took off just fine. Think about THIS: The thrusters on the jet DONT have to exceed anything, the belt just spins the wheels on the plane, it doens't matter how fast its going. And there doesn't need to be wind for a jet to fly, the propulsion comes from the ENGINES, not lift on the wings
A Plane requires Air to pass over the wings to generate Lift, So it the Conveyor belt is matching the Speed that the plane is accellerating then there it is effectivley standing still. SO, No air passing over the wings means no lift!
Incorrect, The wheels of an aircraft have no motor so they freewheel as the Conveyor belt runs under the aircraft however the air around the aircraft is standing still so when the aircraft uses the jets they pull through the air speeding the aircraft forward, although the tires are moving at twice the speed the aircraft itself is moving at the same speed as normal
The conveyorbelt will never be able of making the airplane standing still. If you're talking about a CAR with WINGS on it, then you are correct. However, cars are moved forward by wheels, and not by propellors.
Jeez, like jimboinlimbo said, how are you guys not getting this? Click the "more info" to the right and read through it and perhaps it will be more clear to you...
"you could cut the wings off and it would still jet right off the end of the conveyor."
Oh come on, most of these comments suck, This, And let me be honest, was one of the greatest video I ever saw, I just loved the effects and the white board too.
If the conveyor belt matches the plane's speed to make the plane stand still it CAN NOT take off. No wind over the wings=no lift=no flight. The plane is effectively standing still.
What pushes the plane forward is the props/engines, not the wheels. The conveyor belt could be moving at warp 9 in the opposite direction and the it would have no effect on the plane's ability to take off. You're thinking of it in terms of a plane being a car with wings. If the forward motion of a plane was caused by power in the wheels pushing it forward, then yes, the conveyor belt would stop it.
the conveyor belt won't have any effect on the plane taking off... because power isn't going to the wheels, it's going to the propeller (or jets). The wheels would just move way more fast, that's the only difference there would be.
It'd work if you had a big enough and strong enough belt, and a powerful enough motor to drive the belt. Nonetheless, a Boeing 737 would still take off because the engines move the planes, not the wheels.
actually it all doesn't matter. as long as the thrust of the engine generates enough airspeed for take off, the plane can take off. What you would see is that the plane at take off will suddenly accelerate and fly off.
BUT ...if your plane is huge, like a airliner, there is a chance the plane at take off will crash down. reason is because large planes depend partially on the momentum to generate lift.
if it is a small redbull airrace type plane, it will shoot off into the sky.
What he is saying is that the conveyor belt can't go 100mph backwards and the plane 100mph forwards. The realistic speeds have to match, forcing the treadmill to make speeds of exponential numbers to allow the kinetic energy of the wheels to cancel the thrust of the engines. Therefore, if the treadmill is going 500,000 mph (theoretically causing a -200mph of thrust) and the plane is going 200 mph of thrust, then it would go no where.
The propellers push the air back, Yes. And that pushes the plane Forward. But if the treadmill is pushing the plane back. and both have equal forces (Thrust from engines = the back motion of the Convyer) it wont take off.
If you have a vector of 5n left. and a vector of 5n right That will equal ZEROn Not some weird bullshit number that allows motion in one direction. 5-5=0 not 5-5=100n so it would take off durr.
well actually if the conveyor moves sufficiently fast the friction on the wheel axel will cause the aircraft to remain stationary. any attempt to move forward will result in the destruction of its wheels followed by the destruction of the aircraft
so yeah. mythbusters phail as they could not find a suitable conveyor belt
if a plane is parked on such a belt it will move backwards. why? because a force is applied to it, however miniscule. (mainly "cancelled out" due to the spinning wheels, but) even if the engine does generate a force to the opposite direction, if the "pulling" force is sufficient the plane WILL remain stationary. (i.e. the wheels will melt from the heat generated by the friction if its moving fast enough)
It's true. The plane was supposed to remain stationary but Mythbusters coulden't match the speeds perfectly. It woulden't take off anyway because there's no air traveling over/under the wings. To a stationary observer, the plane is moving 0 (measurement units)/hour. As if the plane were parked. And a plane coulden't take off if it were parked and could not take off of the treadmill either[\wall of text]
that solves the problem. i thought the original question is a threadmill whose speed is determined by a sensor that would record the plane's speed and attempt to slow it to 0. by this logic, the threadmill would end up moving infinitely fast trying to slow down the plane which will cause some problems.
but...as u have stated that the speed of the threadmill is the plane's liftoff speed...then theres nothing to debate about.
7 bits of working memory. wow. u sure thats not the "word length"?
Look at it this way. The engine in the aircraft powers the propellers, not the wheels. The propellers push the air back, not the surface it's rolling on. That's the wheel's job. When the conveyor belt begins to go, the surface is moving, but the air is still stationary. Because the air isn't moving , the propellers are able to push the air back, therefore creating thrust which pushes the plane forward. So unless the air was blowing from behind the moving plane, the lift would become sufficient.
remember that the wheels "roll" on the surface, which generates friction. if you have a conveyor belt which would attempt to slow the plane's velocity down to 0, it will keep accelerating as the power it exerts on the plane isn't doing anything but heating the wheel up. eventually they wheels will melt away before the plane could take off
On a windless day, the air is still. Because the air isn't going anywhere, the propellers are able to push the wind back causing the plane to move forward. The conveyor belt might be moving at the take off speed of the airplane, but the airplane is still pushing the air back making it move forward. So the wheels can be spinning twice as fast as the airplane's actually speed and still not affect whether or not the airplane can take off. The belt has nothing to do with it, it's the wind factor.
eh...get a model plane, put a piece of paper under it, and pull back. the plane WILL move with the paper. why? because there is a force applied to it. and now imagine the apper moving at near light-speed. you think the plane's gonna take off without ruining its wheels? (yes, i realize that the plane will still move forward, but at sufficient speeds the friction on its wheel axel is enough to "drag" it back/melt off the wheels)
The forward motion is generated by the ENGINES pushing the AIR, not the WHEELS pushing the TREADMILL. Therefore, the treadmill moving backwards has no effect on the plane, as it is using the engines to constantly generate forward momentum.
Additionally, what the hell is up with the video?? It just seems to be a model attached to a stick.
Apparently, too many people still think airplanes move like cars. That's why they have this prejudice that the plane remains stationary if the conveyor belt matches its forward speed.
the experiment was not flawed. the conveyor belt does not affect the plane at all. The plane moves forward, thanks to AIR being pushed backward (by a propeller in the MythBuster experiment). Newton's 3rd law accounts for a force driving the plane forward. The plane will never stand still, even if its speed remains constant and the conveyor belt's speed increases tenfold. In the words of Adam Savage, " He just took off like it wasn't even there".
The problem with the Myth Busters experiement is that the plane foward momentum overcomes the treadmill; they were not equilly matched. Therefore, air traveled over the wins, creating lift, and overcoming gravity. If you watch the video; you will see the aircraft pass some stationary cones, indicating foward movement. The Myth Busters emperiement was flawed!
That's not flawed, that's how it's supposed to work. The engine transfers power via air thrust, not through the wheels. In result, the wheels don't matter. Regardless of what's happening below the plane, it's still going to move forward.
NO. There must be enough air traveling over an airfoil to create lift. A conventional, stationary aircraft will not take flight. An aiborne jet that does not have enough air traveling over the wing, creating lift will stall and fall out of the sky. The treadmill is opposing the foward thrust of the plane, therefore no flight!
A plane generating thrust will NOT remain stationary on a treadmill. No matter how fast the treadmill is moving. That's what the Mythbusters experiment proved.
If the plane won't remain still, then the plane will be able to gain airspeed and eventually take off. Ergo, myth busted.
The whole point of the experiement was to prove that an aircraft would not take fligt on a conveyor belt traveling the same speed as the aircraft take off speed in the oppisite direction of the launch. I know what I'm talking about. I spent eleven years working on jet aircraft in the USMC. It a matter of physics. For every action, there is an equil, but oppisite reaction. The conveyor belt would cancel foward momentum of the engines, just as a head wind will slow down an airborne aircraft.
The Myth Busters just proved that the conveyor belt will not cancel forward motion. And no disrespect to your position, but your grasp of the physics is wrong. The wheels are decoupled from the plane's thrust. Thus they will happily spin faster from the treadmill, but very little energy will be transferred back to the plane itself to overcome the engine thrust
That's why the pilot Myth Busters hired was so surprised. He also expected the plane to remain still and it didn't. It moved forward.
An aircraft MUST travel in a foward direction and at a specific speed. At this speed there is suffecient amount of air flowing over the wings to create LIFT. This is an absolute MUST; without airflow over the wing the aircraft will NOT take flight. Now, if you have two objects traveling in oppisite directions, the inertia will cancel each other, ie. the aircraft will be stationary on the treadmill. Physics doesn't care whether you are an auto or an aircraft.
but the only thing the conveyor belt does is make the wheels spin. The plane will still be pulled forward by the propeller! The conveyor belt just makes the wheels spin faster.
The engine does NOT turn the wheels, it turns the propeller which in turn pulls the plane. Regardless of how fast the wheels are spinning. Infact you count put the conveyor belt x100 times faster aslong as the wheels dont break.
if it stays on the conveyer belt, the power is going to the wheels. but even if it does take off, once the back set leaves the ground, the plane would shoot forward instead of just hovering.
the plane would never hover, the plane uses air to take off, not the ground. All of it's thrust comes from the engines; the wheels just decrease friction and allow for a smoother ride (as thaibu says). The wheels, however, may break at a certain speed. Theoretically, the plane would take off given the wheels do not fall apart. Happy flying!
How is it possible that so many people fail to understand that the single most important component in aircraft flight is airflow over the wings? The treadmill exists as a way to stop the plane from moving forwards. If the plane does not move forwards, it will NEVER take off. This is not secret knowledge, people!
Quote: "The treadmill exists as a way to stop the plane from moving forwards."
That's the problem with your understanding - the treadmill *can not* prevent the plane moving forward. No matter what the treadmill does (instead of trying to match the plane's speed you could have it travel at 10x the required takeoff velocity) the plane will still move forward and take off.
Then, I'm afraid the problem lies in the original question. Had it been worded "Can the treadmill keep the plane on the ground?" then I would agree with you. However, that is not what is being asked.
In my experience, the question is usually phrased "Can a plane take off from a treadmill?" - merely the inverse of your example.
Sometimes, the question is asked in such a way as to mean "Can an aeroplane take off from stationary, by means of a treadmill" - the answer is a simple no, as it would not remain stationary. That is all that is relevant. The point about lack of airflow over stationary wings is a non-issue.
leetheweedall, how is it that you fail to understand airplanes do not push off the ground to move like a car or human. A treadmill will not hold an airplane stationary like a car or human. The plane takes off with no problem.
The question originally states will the airplane take-off. If the question were to ask "Will the treadmill be able to stop the plane moving forwards?" then I would agree with you. However, it assumes that the treadmill can match the plane, thus removing forward motion altogether.
The treadmill is going 25mph one way, the plane is moving 25mph the other way, the speeds are matched and the plane takes off. Just because the speeds are matched does not mean the plane is stationary.. the belt and the plane are totally seperate, only connected through free spinning wheels, the belt can only impart a tiny force on the plane body. There is no way a treadmill can stop a plane from moving if it trys. Planes dont push off the ground to move like a car or human does.
the question says that the conveyor belt goes as fast as the wheels. for the plane to even move it uses thrust from the engine, so say if the plane was moving at 100mph(on the ground), the wheels would be moving at 100mph(not any slower,not any faster). there for the conveyor belt will be moving at 100mph in the opposite direction, making the plane stationary relitive to the ground, and with no air flow under/over wings, theres not a chance of take-off
The fallacy is here: the conveyor belt cannot go as fast as the wheels. However fast the conveyer belt runs, the wheels will run faster. The plane is not using the wheels to propel itself forwards: it is pushing against the air. Its speed through the air is not influenced by the conveyer belt: it takes off.
An airplane is a fixed winged aircraft in which its wings are fixed in sense to the fuselage, but has moving flaps which control take-off, steering and landing. So besides sufficient airflow over the wing, the ailerons must be in correct position. If the engines were not to thrust, or the brakes were locked, the plane would move backwards on the treadmill. In reality, relative to nothing.. 'nothing is standing still' ...well besides the camera 'your eyes' fixed on the airplane.
A) This is a magic conveyor belt that matches even the speed of bullets and causes them to hold still even if there is no wheels or touching... that is the question... the plane and it's speed is not relivant... the question is not if the object can move off the treadmill as the question says it is on the treadmill but: Can the plane take off?
B) Extend the precepts to create a treadmill of infinite length and ask can it any object on the treadmill move forward fast enough to move off the treadmill of infinite length? Or extend the condition so rather than just magically matching the speed of the craft (even a bullet high above it), that it matched it +1 actually driving the thing above it backwards thru space.. would you be so quick to think it would also go up?
This video I created is merely 'movie magic' and don't prove the plane will take-off as like other U-tube vids. The magic is (supposed to be) the camera is fixed on the plane and the conveyor tarmac thats running. If your eyes are fixed on the plane then the plane isn't moving; only the surroundings. However the plane relative to you is moving(forward) wether its thrusting down a runway, on a treadmill, or soaring in the skys.
As an aeronautical engineering student i know that an aircraft must have a substantial amount of lift to be able to gain altitude. However if the conveyor belt was sufficently long enough to move the aircraft to a reasonable speed to gain efficent lift then it would takeoff. Not for long though as the air over the aerofoil will be to little to gain full flight. It would simply loose speed and fall out of the sky. (STALL).
Its just basic aerodynamics. If the wings cant create lift then the aircraft won't fly. No matter how fast the conveyor belt is running the aircraft will have no lift. That means no flight. If the conveyor belt ran faster the only thing that would happen is the wheels would fall off due to stress.
Commercialpilot0012, what if a conveyor belt cannot stop an airplane from moving forward? The airplane moves forward and takes off normally regardless of the treadmill.
This comment has received too many negative votesshow
OK, here is why the airplane CAN'T takeoff on a conveyor belt.
Lets say that at 25% power a cessna can go 70 knots. Then if the conveyor belt can go 70 knots the airplane will be stationary, like if you can on a treadmill. The big thing here is that if the airplane is stationary it would be just like if it was parked in a hanger, it wouldn't have any air under the wings and if you know anything about airplanes, they need air to create lift. Simplified: IT CAN'T FLY WHEN ON A CONVEYOR BELT!!!!!
The relatively low friction of the wheel bearings is the only leverage that the treadmill has on the plane, the rest of the energy goes to spin the wheels. I'm not sure why an airplane would not be able to take off just because the wheels are spinning faster. Unless your treadmill is blowing the surrounding air mass backwards at the same speed, how is it going to overcome the thrust of a jet engine that needs only a fraction of its power to overcome the friction?
Actually, increasing the air flow would only help it to take off. I'm finding fewer and fewer ways to keep the plane from taking off. The arguments against it are seeming more and more ludicrous.
I always thought that it wouldn't, mostly because I'm an idiot. I figured that if the plane wasn't moving relative to the air, you would get no lift under the wings. The part that I was missing was that it's the jets that create that movement under the wings, not the relative speed of the plane.
No, no, you're wrong there. The jets/props create thrust. The speed relative to the air is what matters. But since the plane's wheels are free-spinning, the treadmill can't apply more than a slight amount of backward force to stop the plane from moving forward, it WOULD TAKE OFF, but NOT stationary with respect to the ground. It would move forward as if there was no treadmill!
Propellors and jet engines are only used to get the plane moving to created the needed amount of air going against the wing so that the wing can create lift. If there is no air travelling underneath the wing, it will not go. This is done assuming the plane is kept at 1 spot on the treadmill keeping the same speed as it. No airflow under wings = no take off. If you could take off like this with a treadmill, many armies would have done it already.
But the lynchpin is: a treadmill COULDN'T stop the plane from moving forward. In other words, the plane WOULD take off, but it would take just as long a runway as if there was no treadmill. The plane won't take off in place, it will move forward and take off normally regardless of what the treadmill is doing!
Theoretically speaking 1. the airplane will go forward. 2. the plane will take off if the plane can provide enough lift. 3. This will only happen if the engine can produce enough thrust to counter act the treadmill. 4. If you have enough treadmill to attain the airspeed for takeoff.
Now realistically, that would never happen. There is not a big enough treadmill. nor will there be tires that can overcome the speed of the treadmill plus the forward speed that it must have to reach takeoff speed.
"tires that can overcome the speed of the treadmill"
In order for the tires to "overcome the speed of the treadmill" the tires would have to be overcoming, which means they would have to be DOING SOMETHING. They don't. That is, they don't actually take action. The propellers do, and they don't pull vs the ground, they pull vs the air. All the wheels do is keep the plane from scraping against the ground while the propellers pull the plane forward.
And yes, this frictional loss is very small at realistic speeds, but at infinite speed this frictional force is enough to counter the thrust of the engines.
Well that depends on the avail power of the engines, Airliners have wheel breaks and if they locked, it'll burn the tires? then the landing gear, soon the belly of the plane. with strong enuf thrust the plane airborne regardless.
What everyone is overlooking is whether this is a hypothetical problem or a real world problem. In the real world the belt could never turn fast enough the create enough friction in the wheels to counter the forward movement( needed for lift ) of the plane. In the hypothetical problem it states that the belt matches the speed of the plane - indefinitely. The plane will not move an inch because the wheels will be creating friction to counter the forward thrust of the engines.
I think it's meant to be taken as the real world version, with the intent to trick people into thinking the backward motion of the conveyor would counteract the forward movement of the aircraft like it would if it was a car on the runway.
Perhaps a better question to discuss is, what if there were no conveyor belt, but there were some kinds of barriers on the runway that could inhibit the plane's forward motion, but not it's upward motion. Hence the plane's lift would have to all come from air being thrust past the wings by the engines. In most (or all) plane designs, I'm sure that's inadequate (airspeed is needed). Question is, it it possible to design a plane that could get all its upward lift from airflow from the engine?
I've been reading about this issue on StraightDope and other sites, & in many cases the wording is the cause if confusion. Those who (correctly) advocate that the plane does take off aren't always adequately explaining that, at take-off time, the plane is NOT motionless relative to the ground (or ambient air). Rather, it's because the conveyor is incapable of inhibiting the forward motion (relative to ground) of the plane, no matter how fast it moves backwards. (Please tell me I'm right! :-/ )
OK, the wheels have nothing to do with lift...they are only there to hold the plane up off the ground, and make it easier for the plane to reach take off velocity.
also, the engines and trust created by them also have nothing to do with lift, they are only there to get the plane up to speed, and create WIND against the wings.
the only thing that makes a plane "fly" is the force of the air against it's wings.
without lift, the plane will just stay on the conveyor belt
Wrong, the plane will NOT stay on the belt. It will move forward regardless of the speed of the converyer belt. This forward motion will generate airflow over the wings which will generate lift which will allow the plane to take-off. You could even run the treadmill twice as fast in the opposite direction and you still could not stop the plane from moving forward. The friction of the wheels against the treadmill is almost non-existent compared to the thrust of the engine (or propeller).
the arguement was originally that the plane would be stationary...meaning, the prop would be spinning just enough to counter-act the frition of the wheels.
I myself, as an aviationist, has tested this theory and i know the truth behind it. For e.g, lets take a car on a conveyor belt. The car is travelling 80mph, and the conveyor belt is going 80mph the opposite way. The car gets its thrust from its wheels. But an airplane gets its thrust from its engines. Its wheels have nothing to do with it. So when a plane is taking off at 180mph, and the conveyor belt is going 180mph the opposite way, it can still take off.
Part-1 An airplane needs Air Speed, not Wheel speed, to take off. The aircraft needs the required airflow to fight the gravity and take off, the wings need enough air flow in order to do their job and lift the aircraft.
Let's first take an example aircraft, the Boeing 747-8I. It has an empty weight of 466,700 lb and a max take-off weight of 970,000 lb. It's engines produce a combined 266,000 lb of thrust. It has a take-off speed of around 180mph. If the treadmill was moving in the opposite direction at 100mph the 747 would have to produce enough thrust to get the plane to what would be 280mph (wheel speed) before it could take off.
That's 100 mph faster than normal in order to cancel out the opposite motion of the treadmill and reach still reach it's take off speed (air speed, not wheel speed). So while it would be able to take off once it got up to speed it would still require the normal run-way length to reach the 180mph (air speed) necessary for the wings to create enough lift.
I must clairfy. If the engine thrust moves the plane faster than the treadmill. Then there is air over the wing and it might get lift. But what is the use of the treadmill? There is no advantage in ramp reduction because it would have to move down the ramp (ground) at lift-off speed. Same distance as without the treadmill. This is becoming more stupid by the minute.
Bottom line is, there has to be airflow around the wings, caused by forward motion relative to the atmosphere. And this happens once the plane overcomes the friction of the conveyor belt.
Cool, you spent all that time and energy to announce to the world that you don't understand the myth.
taiddan 1 day ago
strong work. lol. mad props for the Airplane! references...
azminivanracer 8 months ago
STATIONARY, the myth is about if a plane can take off from a conveyor belt that is size of plane itself. Thats the whole point the myth so we didn't need entire runways. Were the power comes from is irrelevant, wheels, jet, propeller, rocket it doesn't matter, it will not and can not take off with zero airspeed. Trying to maintain zero airspeed on a conveyor would be difficult and is another story.
detectiveinspekta 10 months ago
@detectiveinspekta Another swing and miss from someone who doesnt understand the wording of the myth.
philritter21 10 months ago
This has been flagged as spam show
@philritter21 Please educate me.
detectiveinspekta 10 months ago
@detectiveinspekta It WILL take off, because it has JET ENGINES. Those give it airspeed, dummy
Stillwater900 4 months ago
It'd be actually useful if it pushed air towards the plane to generate more lift ._.
DIMATIF 1 year ago
We have clearance Clarence.
Roger Rodger.
Whats your vector Victor?
DucknCoverin 1 year ago
R.I.P. Leslie Nielsen
Airplane!:Dr. Rumack
thaibu 1 year ago
The lines on the belt shouldn't be moving
hairyfatslobpig 1 year ago
This has been flagged as spam show
FAIL
Congratulations you earned that. Enjoy it. Don't spend it all in one place.
GeneralHoohah 1 year ago
lol and over did it
narcovice 1 year ago
Ten-Four LOL so that's a police plane? XD
Renard380 1 year ago
@Renard380 Ten-Four can be used everywhere :p
DamperenDK 1 year ago
@DamperenDK Really?
Renard380 1 year ago
surely you can't be serious... "of course i'm serious.. and don't call me Shirlie"
whyhatestrangers 1 year ago
@whyhatestrangers The ol' Mile High Club Quote. Cod4.
ConzoMcF 1 year ago
yeahhhhh the wheels might ummm BREAK OFF?
Danielkchoi 1 year ago
Lawl'd at teh Airplane! 1+2 the music sounded familiar was that airplane as well?
roblinux2 1 year ago
A conveyor belt at airports would be very useful at airports if the plane was facing the same direction as the belt travel as long as the plane had it's brakes on. It would be a very short takeoff.(as in aircraft carrier catapult)
chueffer 1 year ago
About this video...: Relative to the airplane itself the camera stays focused on the plane at the speed the airplane is traveling except in the first few seconds. If trees and other stationary objects were standing by but not on the conveyor belt, then they would accelerate by just as you would see looking out the window of the plane as it zooms down the runway. Airplanes are gliders with motors, the motors are the planes way of making head winds so it can travel.
thaibu 1 year ago
love the Airplane! reference :D
dezkit 1 year ago
So hilarious people think this way. I ran this across my family, two of them insisted the plane would not be moving anywhere. I had to show them the evidence, and then they debated it for a long time before they finally saw why the plane still takes off.
There IS still forward movement, period. Treadmill example is pointless, because the plane does not push off the ground like our feet do, but off the air.
At airports it would be pointless, the plane still needs the same air space to take off.
Thornbrier 1 year ago
@Thornbrier It becomes completely irrelevant to even talk about this, if the plane still needs to move forward on the conveyor belt to take off. Isn't the conveyor belt meant to match the speed of the wheels at all times in the opposing direction? meaning there is no forward motion in the aircraft, meaning there is no wind creating lift, meaning the plane won't fly.
discombobulated87 1 year ago
@discombobulated87 That's my point, it does not need to move forward 'on the conveyor belt' it needs to move forward through the air. Since the propeller/jet engine pulls on the air, not on the wheels, the speed of the wheels is irrelevant.
You say as you increase the speed of the wheels you increase the speed of the conveyor to accommodate. But this automatically increases the speed of the wheels until either the conveyor gives out trying to keep up, or the ball bearings of the wheels do.
Thornbrier 1 year ago
@Thornbrier But it is the same thing, i agree that the wheel speed is irrelevant, but you can't tell me that the plane is not moving forward at take off. It is basically saying the plane stays in a stationery position relative to the environment, then shoots to 150mph-220mph as soon as it lifts off the Conveyor belt. A plane might be able to take off from a Conveyor runway, but it wouldn't be useful to use anywhere, and becomes pointless.
discombobulated87 1 year ago
@discombobulated87 The plane does not remain stationary relative to the environment. It moves forward whether the ground moves backwards under it at an increased speed or not. The Conveyor belt effectively has NO effect on the planes take off. It neither helps nor hinders. The point is that it does not stop the plane from taking off as many claim it would, not that it helps it take off, that is scientifically ludicrous.
Thornbrier 1 year ago
Im tired of seeing IDIOTS thinking that airplanes on conveyor belts take off. If planes took off on conveyor belts, the airports would be FUCKING SMALL!!! It doesnt matter how fast the wheels are spinning or the proppeler thrust, THE WIND SPEED IS NONE! If there is no wind speed, there is no lift! Just because the proppelers are running full speed it doesnt mean the plane is flying DUH...there are guys that are just clueless.
miguelgaio 1 year ago
@miguelgaio
take a physics course, IDIOT, like mentioned 100000000000000000000 times before EVERYwehre, the fucking planes are propelled by THRUST, the wheels only support the fucking things off of the ground, the conveyor belt would only "ideally" double the speed of the wheels, the take of distance would not change, not like you claim, you are under the assumption that the plane would lift of in one place... no, ti would look exactly the same as it does on a runway.
aemravan 1 year ago
@aemravan So the air planes are propelled by thrust? Then I gess that by your line of thought (if you are capable of thinking at all..) is that thrust alone will lift the plane. So then I gess you could take the wings of the plane away that It will fly regardless...Its IDIOTS like you that give science a bad name. A plane will always have to move forwards in order to gain wind. WIND IS NOT THE SAME THING AS THRUST! Go play with your building blocks and shut up like a good boy.
miguelgaio 1 year ago
hahahahahahaha love it
krazyk86cu 1 year ago
I watched the mythbusters attempt, and don't believe it to have been satisfactorily done, surely if the ground is moving in the opposite direction at the exact same speed as the aircraft, then there would be no forward motion, which there was plenty of on the mythbusters test. I thought that was the whole point of a treadmill, so you could run without going anywhere, it would be f**king pointless if you still moved forward.
discombobulated87 1 year ago
lololol POWER IS AT 90% LIGHT SPEED!
freakin1random 1 year ago
This was gayer than AIDS
jbaker88 2 years ago
This is so fake. That is not a real plane or runway.
christeehan 2 years ago
@christeehan No Shit!!!
MrChrisJEllis 2 years ago
O_O
Did you seriously just feel the need to make this comment? XP
Forir8 2 years ago
Really, you can't be serious...
Aeronautics 101: Aeroplanes need wind passing over the wings to achieve lift. This is due to the aerofoil design of the wings... Like when the plane accelerates through air on the ground from the thrust of the engines.
If the plane stays still, (like on a conveyor belt) no air is passing over the wings, no lift = no take off.
The wheels are largely irrelevant to the flying fuction of a plane.
Myth busted with year 11 science (Note, not in highschool anymore)
diventian 2 years ago 4
Comment removed
Wcoltd 2 years ago
Youre presumption that the plane will stay still is incorrect. The Plane will not stay still...the conveyor belt is long and the plane moves along it regardless of the speed its moving.
one33seven 2 years ago
Whoever just downrated your comment earns my eternal rage.
I'm glad that somebody in this world properly understands the aerodynamics of plane wings.
Fenizrael 2 years ago
the mythbusters tested it in reallife and the plane took off ;)
dvdboy275 2 years ago
Mythbusters also wouldn't know scientific method if it bit them on the ass.
Fenizrael 2 years ago
well they tested it... and thats enough for me
dvdboy275 2 years ago
No, I was over Unger and he was under Dunn...
bluehazer 2 years ago
lol
TemplerCrustinatorII 2 years ago
good idea....lol
MrEinstain 2 years ago
COD 4 lol
HellMuTx 2 years ago
Think of it this way if it helps. A plane "swims" through the air in the same way a fish swims through the water. It is using the thrust from its tail to push it through the water. If you put little wheels on the fish and put it on an underwater treadmill it wouldn't stop the fish from swimming away, would it? And don't bother with theories about air over the wings and 'lift'. Lift allows the plane to rise, but you could cut the wings off and it would still jet right off the end of the conveyor.
jimboinlimbo 2 years ago 3
it cant go off the end of the conveyor if the plane is moving at the exact same speed as the conveyer belt
the plane would remain stationary and remain on the ground
argh
lafontanaverdez 2 years ago
ur a dumbass if u think that lol its a plane not a car
RafiaFaLife 2 years ago
The plane is pushing against the air, not the ground. The speed of the conveyor doesn't matter. It won't stop the plane from pushing itself through the air.
jimboinlimbo 2 years ago
Don't worry, this myth is just always poorly phrased. The concept behind the myth is more properly this; let's assume you need to go 30 mph in order to take off. If a plane exerts the same amount of throttle to go 30 mph under normal conditions and nothing additional, will it still be able to take off while on a conveyor belt going 30 mph in the opposite direction.
beamerfan 2 years ago
Comment removed
breed0328 2 years ago
I wasn't actually saying it would take off without the wings. What I meant was even without the wings the plane would still be propelled forward (unless the engines happened to be on the wings, but you get what I'm saying).
jimboinlimbo 2 years ago
How do you guys not get this? The plane is pushed through the air by jet thrust (or pulled through the air by a propeller). The wheels just free wheel, they are not involved in the propulsion of the plane. The only difference the conveyor belt would make is the wheels would be spinning twice as fast when it takes off. I'm starting to think that people who say the plane remains motionless are just saying that to drive other people crazy.
jimboinlimbo 2 years ago 19
@jimboinlimbo Nobody thinks the wheels propel the plane! The wheels allow the plane to make contact and move across a stationary surface so that sufficient wind speed can be built up, which is only done by having sufficient GROUND speed, which requires WHEELS. Lift if generated by the wings low pressure zone. Look up airfoils on wikipedia. Or an encyclopedia if you know what and where a library is.
QuantumCarl 1 year ago
@QuantumCarl Well Carl, I think you might be missing the point. Of course the wheels support the plane and allow it to build up ground speed. The point is that the relative speed of the wheels is irrelevant. If the wheels are turning twice as fast because the conveyor is running in the the opposite direction it will have no effect on the forward momentum of the plane. BTW, yes I do know where the library is, your mom and I meet behind it every thursday.
jimboinlimbo 1 year ago
@jimboinlimbo FORGET THE DAMN WHEELS. They could be donuts for all anyone cares, the point is that it's a connecting point of friction between the plane and the ground. The plane is effectively holding itself in place!
QuantumCarl 1 year ago
@jimboinlimbo they probably are. The physics are impossible (I worked as an engineer on planes, pushbacks, and conveyor belts, so I know) and it'd just waste fuel to overcome the doubled static friction (...course you could run the belt in the other direction lol)
The video is funny though. I kept waiting for the little model plane to fly off the end of the conveyor belt and go crashing into a wall, followed by someone going "WTF? not in my milk dude!" and a shaky camera at the end.
dvdprui 1 year ago
@jimboinlimbo Wrong.
Plains get lift by the air passing over the surface of the wing.
fluffisback2 1 year ago
@jimboinlimbo
im one of the non believers but think about it. the thrust created by the jet has to exceed the speed its going against. there also has to be wind for lift!!!!
exa0777 8 months ago
@exa0777 Whether you believe it or not, Mythbusters did this full-scale and the plane took off just fine. Think about THIS: The thrusters on the jet DONT have to exceed anything, the belt just spins the wheels on the plane, it doens't matter how fast its going. And there doesn't need to be wind for a jet to fly, the propulsion comes from the ENGINES, not lift on the wings
Stillwater900 4 months ago
@jimboinlimbo plane will actually go backwards in time.
sharpnova2 6 months ago
A Plane requires Air to pass over the wings to generate Lift, So it the Conveyor belt is matching the Speed that the plane is accellerating then there it is effectivley standing still. SO, No air passing over the wings means no lift!
fluffisback2 2 years ago
Incorrect, The wheels of an aircraft have no motor so they freewheel as the Conveyor belt runs under the aircraft however the air around the aircraft is standing still so when the aircraft uses the jets they pull through the air speeding the aircraft forward, although the tires are moving at twice the speed the aircraft itself is moving at the same speed as normal
Destinysrage 2 years ago
@ Fluffisback2
Destinysrage 2 years ago
The conveyorbelt will never be able of making the airplane standing still. If you're talking about a CAR with WINGS on it, then you are correct. However, cars are moved forward by wheels, and not by propellors.
Jeez, like jimboinlimbo said, how are you guys not getting this? Click the "more info" to the right and read through it and perhaps it will be more clear to you...
"you could cut the wings off and it would still jet right off the end of the conveyor."
-jimboinlimbo = +rating
xxxx85 2 years ago
So how do you think the plane moves forward in air then? with the wheels? xD
00je00 2 years ago
Man this is awesome! I just had to say that! I faved this! *crowd cheers*
nonobaOMGWEEGEE2 2 years ago
hahaha nice video man!!! 5*
yankeesfan135 2 years ago
Oh come on, most of these comments suck, This, And let me be honest, was one of the greatest video I ever saw, I just loved the effects and the white board too.
5/5 And definitly faved.
Great work.
xXRedyzXx 2 years ago
If the conveyor belt matches the plane's speed to make the plane stand still it CAN NOT take off. No wind over the wings=no lift=no flight. The plane is effectively standing still.
IdiotTelevision 2 years ago
What pushes the plane forward is the props/engines, not the wheels. The conveyor belt could be moving at warp 9 in the opposite direction and the it would have no effect on the plane's ability to take off. You're thinking of it in terms of a plane being a car with wings. If the forward motion of a plane was caused by power in the wheels pushing it forward, then yes, the conveyor belt would stop it.
Trakanon123 2 years ago 14
totally right
doubleutubefan5 2 years ago
the conveyor belt won't have any effect on the plane taking off... because power isn't going to the wheels, it's going to the propeller (or jets). The wheels would just move way more fast, that's the only difference there would be.
bmwalshe 2 years ago 2
One thing people don't disagree on.
If you put a car pn a convyer belt it won't take off.
epicspacemushroom 2 years ago 5
I like the epic music
freakincrod 2 years ago
It'd work if you had a big enough and strong enough belt, and a powerful enough motor to drive the belt. Nonetheless, a Boeing 737 would still take off because the engines move the planes, not the wheels.
BeebeCh1972 2 years ago
Okay, because planes don't have wings
dnRoystonDotCom 2 years ago
Comment removed
pipeguy2270 2 years ago
actually it all doesn't matter. as long as the thrust of the engine generates enough airspeed for take off, the plane can take off. What you would see is that the plane at take off will suddenly accelerate and fly off.
BUT ...if your plane is huge, like a airliner, there is a chance the plane at take off will crash down. reason is because large planes depend partially on the momentum to generate lift.
if it is a small redbull airrace type plane, it will shoot off into the sky.
Naiping 2 years ago
Just shoot off into the sky like magic? By that fallacy, spinning up the wheels of an airplane magically gives the wings lift and TaDA!
xIntoThePitx 2 years ago
+1 rawduke
What he is saying is that the conveyor belt can't go 100mph backwards and the plane 100mph forwards. The realistic speeds have to match, forcing the treadmill to make speeds of exponential numbers to allow the kinetic energy of the wheels to cancel the thrust of the engines. Therefore, if the treadmill is going 500,000 mph (theoretically causing a -200mph of thrust) and the plane is going 200 mph of thrust, then it would go no where.
monkaypants 2 years ago
@ Cyberneticwarrior
The propellers push the air back, Yes. And that pushes the plane Forward. But if the treadmill is pushing the plane back. and both have equal forces (Thrust from engines = the back motion of the Convyer) it wont take off.
If you have a vector of 5n left. and a vector of 5n right That will equal ZEROn Not some weird bullshit number that allows motion in one direction. 5-5=0 not 5-5=100n so it would take off durr.
raw619luke 2 years ago
The plane does not have any relation to the conveyor belt for long because the plane eventually lifts up and is free of the belt.
kenanscott24 2 years ago
well actually if the conveyor moves sufficiently fast the friction on the wheel axel will cause the aircraft to remain stationary. any attempt to move forward will result in the destruction of its wheels followed by the destruction of the aircraft
so yeah. mythbusters phail as they could not find a suitable conveyor belt
THISNAMEOWNS 2 years ago
if a plane is parked on such a belt it will move backwards. why? because a force is applied to it, however miniscule. (mainly "cancelled out" due to the spinning wheels, but) even if the engine does generate a force to the opposite direction, if the "pulling" force is sufficient the plane WILL remain stationary. (i.e. the wheels will melt from the heat generated by the friction if its moving fast enough)
THISNAMEOWNS 2 years ago
It's true. The plane was supposed to remain stationary but Mythbusters coulden't match the speeds perfectly. It woulden't take off anyway because there's no air traveling over/under the wings. To a stationary observer, the plane is moving 0 (measurement units)/hour. As if the plane were parked. And a plane coulden't take off if it were parked and could not take off of the treadmill either[\wall of text]
Konoton01 2 years ago
You are right about that, most people who say it will fly do not consider wheel friction.
But
If the treadmills top speed is based off of the planes lift off speed (as in the original question),
there will not be enough friction to cause a problem.
This question is designed specifically to show the fault in human cognition.
We have to go at a problem from the bottom up or the top down considering each part with little consideration of relationships
Human working memory is estimated at 7 bits
xraptor10 2 years ago
that solves the problem. i thought the original question is a threadmill whose speed is determined by a sensor that would record the plane's speed and attempt to slow it to 0. by this logic, the threadmill would end up moving infinitely fast trying to slow down the plane which will cause some problems.
but...as u have stated that the speed of the threadmill is the plane's liftoff speed...then theres nothing to debate about.
7 bits of working memory. wow. u sure thats not the "word length"?
THISNAMEOWNS 2 years ago
That was in my psychology book,
it is based on our ability to retain and use different size sets of numbers.
So the results are skewed slightly,
because the human mind isn't really designed for numbers.
But it is a good indicator of just what were dealing with.
We human beings are fraught with the uncertain destiny of being just smart enough to see how dumb we are
xraptor10 2 years ago
Look at it this way. The engine in the aircraft powers the propellers, not the wheels. The propellers push the air back, not the surface it's rolling on. That's the wheel's job. When the conveyor belt begins to go, the surface is moving, but the air is still stationary. Because the air isn't moving , the propellers are able to push the air back, therefore creating thrust which pushes the plane forward. So unless the air was blowing from behind the moving plane, the lift would become sufficient.
CyberneticWarrior 2 years ago
remember that the wheels "roll" on the surface, which generates friction. if you have a conveyor belt which would attempt to slow the plane's velocity down to 0, it will keep accelerating as the power it exerts on the plane isn't doing anything but heating the wheel up. eventually they wheels will melt away before the plane could take off
THISNAMEOWNS 2 years ago
On a windless day, the air is still. Because the air isn't going anywhere, the propellers are able to push the wind back causing the plane to move forward. The conveyor belt might be moving at the take off speed of the airplane, but the airplane is still pushing the air back making it move forward. So the wheels can be spinning twice as fast as the airplane's actually speed and still not affect whether or not the airplane can take off. The belt has nothing to do with it, it's the wind factor.
CyberneticWarrior 2 years ago
eh...get a model plane, put a piece of paper under it, and pull back. the plane WILL move with the paper. why? because there is a force applied to it. and now imagine the apper moving at near light-speed. you think the plane's gonna take off without ruining its wheels? (yes, i realize that the plane will still move forward, but at sufficient speeds the friction on its wheel axel is enough to "drag" it back/melt off the wheels)
THISNAMEOWNS 2 years ago
That is wrong "THISNAMEOWNS", because rolling friction does not increase with speed, it is a constant.
mitchio83 2 years ago
the comment that made the most sense. im convinced
THISNAMEOWNS 2 years ago
twin cities....more like twin towers =P
THISNAMEOWNS 2 years ago
The forward motion is generated by the ENGINES pushing the AIR, not the WHEELS pushing the TREADMILL. Therefore, the treadmill moving backwards has no effect on the plane, as it is using the engines to constantly generate forward momentum.
Additionally, what the hell is up with the video?? It just seems to be a model attached to a stick.
dynamitehack0 2 years ago 3
Aha, I like the soundtrack for Airplane. ;D
carveriscool 2 years ago
Apparently, too many people still think airplanes move like cars. That's why they have this prejudice that the plane remains stationary if the conveyor belt matches its forward speed.
259 2 years ago 2
Just realize the plane is glued on a flat piece of glass, very interesting, got me mystified.
LTF85199 2 years ago
the experiment was not flawed. the conveyor belt does not affect the plane at all. The plane moves forward, thanks to AIR being pushed backward (by a propeller in the MythBuster experiment). Newton's 3rd law accounts for a force driving the plane forward. The plane will never stand still, even if its speed remains constant and the conveyor belt's speed increases tenfold. In the words of Adam Savage, " He just took off like it wasn't even there".
flamingice007 2 years ago 2
The problem with the Myth Busters experiement is that the plane foward momentum overcomes the treadmill; they were not equilly matched. Therefore, air traveled over the wins, creating lift, and overcoming gravity. If you watch the video; you will see the aircraft pass some stationary cones, indicating foward movement. The Myth Busters emperiement was flawed!
98JOJO 2 years ago
That's not flawed, that's how it's supposed to work. The engine transfers power via air thrust, not through the wheels. In result, the wheels don't matter. Regardless of what's happening below the plane, it's still going to move forward.
thewiirocks 2 years ago
NO. There must be enough air traveling over an airfoil to create lift. A conventional, stationary aircraft will not take flight. An aiborne jet that does not have enough air traveling over the wing, creating lift will stall and fall out of the sky. The treadmill is opposing the foward thrust of the plane, therefore no flight!
98JOJO 2 years ago
A plane generating thrust will NOT remain stationary on a treadmill. No matter how fast the treadmill is moving. That's what the Mythbusters experiment proved.
If the plane won't remain still, then the plane will be able to gain airspeed and eventually take off. Ergo, myth busted.
thewiirocks 2 years ago
The whole point of the experiement was to prove that an aircraft would not take fligt on a conveyor belt traveling the same speed as the aircraft take off speed in the oppisite direction of the launch. I know what I'm talking about. I spent eleven years working on jet aircraft in the USMC. It a matter of physics. For every action, there is an equil, but oppisite reaction. The conveyor belt would cancel foward momentum of the engines, just as a head wind will slow down an airborne aircraft.
98JOJO 2 years ago
The Myth Busters just proved that the conveyor belt will not cancel forward motion. And no disrespect to your position, but your grasp of the physics is wrong. The wheels are decoupled from the plane's thrust. Thus they will happily spin faster from the treadmill, but very little energy will be transferred back to the plane itself to overcome the engine thrust
That's why the pilot Myth Busters hired was so surprised. He also expected the plane to remain still and it didn't. It moved forward.
thewiirocks 2 years ago 2
its a stupid myth, since the propeller pulls the plane, not the wheels
GauntV 3 years ago 2
An aircraft MUST travel in a foward direction and at a specific speed. At this speed there is suffecient amount of air flowing over the wings to create LIFT. This is an absolute MUST; without airflow over the wing the aircraft will NOT take flight. Now, if you have two objects traveling in oppisite directions, the inertia will cancel each other, ie. the aircraft will be stationary on the treadmill. Physics doesn't care whether you are an auto or an aircraft.
98JOJO 2 years ago
exactly!
but the only thing the conveyor belt does is make the wheels spin. The plane will still be pulled forward by the propeller! The conveyor belt just makes the wheels spin faster.
The engine does NOT turn the wheels, it turns the propeller which in turn pulls the plane. Regardless of how fast the wheels are spinning. Infact you count put the conveyor belt x100 times faster aslong as the wheels dont break.
Comprende?
GauntV 2 years ago 4
if it stays on the conveyer belt, the power is going to the wheels. but even if it does take off, once the back set leaves the ground, the plane would shoot forward instead of just hovering.
HappyLappyNappy 3 years ago
the plane would never hover, the plane uses air to take off, not the ground. All of it's thrust comes from the engines; the wheels just decrease friction and allow for a smoother ride (as thaibu says). The wheels, however, may break at a certain speed. Theoretically, the plane would take off given the wheels do not fall apart. Happy flying!
GameLord64 3 years ago
How is it possible that so many people fail to understand that the single most important component in aircraft flight is airflow over the wings? The treadmill exists as a way to stop the plane from moving forwards. If the plane does not move forwards, it will NEVER take off. This is not secret knowledge, people!
leetheweedall 3 years ago
Quote: "The treadmill exists as a way to stop the plane from moving forwards."
That's the problem with your understanding - the treadmill *can not* prevent the plane moving forward. No matter what the treadmill does (instead of trying to match the plane's speed you could have it travel at 10x the required takeoff velocity) the plane will still move forward and take off.
daichi2097 3 years ago
Then, I'm afraid the problem lies in the original question. Had it been worded "Can the treadmill keep the plane on the ground?" then I would agree with you. However, that is not what is being asked.
leetheweedall 3 years ago
In my experience, the question is usually phrased "Can a plane take off from a treadmill?" - merely the inverse of your example.
Sometimes, the question is asked in such a way as to mean "Can an aeroplane take off from stationary, by means of a treadmill" - the answer is a simple no, as it would not remain stationary. That is all that is relevant. The point about lack of airflow over stationary wings is a non-issue.
daichi2097 3 years ago
leetheweedall, how is it that you fail to understand airplanes do not push off the ground to move like a car or human. A treadmill will not hold an airplane stationary like a car or human. The plane takes off with no problem.
mitchio83 3 years ago
The question originally states will the airplane take-off. If the question were to ask "Will the treadmill be able to stop the plane moving forwards?" then I would agree with you. However, it assumes that the treadmill can match the plane, thus removing forward motion altogether.
leetheweedall 3 years ago
The treadmill is going 25mph one way, the plane is moving 25mph the other way, the speeds are matched and the plane takes off. Just because the speeds are matched does not mean the plane is stationary.. the belt and the plane are totally seperate, only connected through free spinning wheels, the belt can only impart a tiny force on the plane body. There is no way a treadmill can stop a plane from moving if it trys. Planes dont push off the ground to move like a car or human does.
mitchio83 3 years ago
fake fake fake fake fake fake fake fake fake fake fake fake fake fake fake fake fake fake fake fake
condoms180 3 years ago
the question says that the conveyor belt goes as fast as the wheels. for the plane to even move it uses thrust from the engine, so say if the plane was moving at 100mph(on the ground), the wheels would be moving at 100mph(not any slower,not any faster). there for the conveyor belt will be moving at 100mph in the opposite direction, making the plane stationary relitive to the ground, and with no air flow under/over wings, theres not a chance of take-off
loinzy 3 years ago
The fallacy is here: the conveyor belt cannot go as fast as the wheels. However fast the conveyer belt runs, the wheels will run faster. The plane is not using the wheels to propel itself forwards: it is pushing against the air. Its speed through the air is not influenced by the conveyer belt: it takes off.
coolaun 3 years ago
An airplane is a fixed winged aircraft in which its wings are fixed in sense to the fuselage, but has moving flaps which control take-off, steering and landing. So besides sufficient airflow over the wing, the ailerons must be in correct position. If the engines were not to thrust, or the brakes were locked, the plane would move backwards on the treadmill. In reality, relative to nothing.. 'nothing is standing still' ...well besides the camera 'your eyes' fixed on the airplane.
thaibu 3 years ago
A) This is a magic conveyor belt that matches even the speed of bullets and causes them to hold still even if there is no wheels or touching... that is the question... the plane and it's speed is not relivant... the question is not if the object can move off the treadmill as the question says it is on the treadmill but: Can the plane take off?
strawman101 3 years ago
B) Extend the precepts to create a treadmill of infinite length and ask can it any object on the treadmill move forward fast enough to move off the treadmill of infinite length? Or extend the condition so rather than just magically matching the speed of the craft (even a bullet high above it), that it matched it +1 actually driving the thing above it backwards thru space.. would you be so quick to think it would also go up?
strawman101 3 years ago
You sound familiar.. are you TX1000 from the mythbusters site? Didn't we already show you how you're wrong over there?
endergt 3 years ago
This video I created is merely 'movie magic' and don't prove the plane will take-off as like other U-tube vids. The magic is (supposed to be) the camera is fixed on the plane and the conveyor tarmac thats running. If your eyes are fixed on the plane then the plane isn't moving; only the surroundings. However the plane relative to you is moving(forward) wether its thrusting down a runway, on a treadmill, or soaring in the skys.
thaibu 3 years ago
dum cunt, this is a bull shit video, get a life, and figure out how a plane actually takes off
seannz56 3 years ago
As an aeronautical engineering student i know that an aircraft must have a substantial amount of lift to be able to gain altitude. However if the conveyor belt was sufficently long enough to move the aircraft to a reasonable speed to gain efficent lift then it would takeoff. Not for long though as the air over the aerofoil will be to little to gain full flight. It would simply loose speed and fall out of the sky. (STALL).
Commercialpilot001 3 years ago
You don't seem to understand the scenario.
tracco 3 years ago
Its just basic aerodynamics. If the wings cant create lift then the aircraft won't fly. No matter how fast the conveyor belt is running the aircraft will have no lift. That means no flight. If the conveyor belt ran faster the only thing that would happen is the wheels would fall off due to stress.
Commercialpilot0012 3 years ago
Commercialpilot0012, what if a conveyor belt cannot stop an airplane from moving forward? The airplane moves forward and takes off normally regardless of the treadmill.
mitchio83 3 years ago
This comment has received too many negative votes show
OK, here is why the airplane CAN'T takeoff on a conveyor belt.
Lets say that at 25% power a cessna can go 70 knots. Then if the conveyor belt can go 70 knots the airplane will be stationary, like if you can on a treadmill. The big thing here is that if the airplane is stationary it would be just like if it was parked in a hanger, it wouldn't have any air under the wings and if you know anything about airplanes, they need air to create lift. Simplified: IT CAN'T FLY WHEN ON A CONVEYOR BELT!!!!!
arpnlaei 3 years ago
The engine is what makes the plane move, not the wheels. The wheels are just there so it CAN move on the ground.
Air under the plane helps it stay in the air, it's not what makes it go up in the first place.
Lutukor 3 years ago
The relatively low friction of the wheel bearings is the only leverage that the treadmill has on the plane, the rest of the energy goes to spin the wheels. I'm not sure why an airplane would not be able to take off just because the wheels are spinning faster. Unless your treadmill is blowing the surrounding air mass backwards at the same speed, how is it going to overcome the thrust of a jet engine that needs only a fraction of its power to overcome the friction?
ctoyer 3 years ago 2
Actually, increasing the air flow would only help it to take off. I'm finding fewer and fewer ways to keep the plane from taking off. The arguments against it are seeming more and more ludicrous.
ctoyer 3 years ago
stuff the debate! i am loving the music for this vid, taken from the movie 'Airplane' i presume?
tehweaver 3 years ago
This is obviously fake >_>
Tankbustabro 3 years ago
NNNNNNNNNNNNNNNaaaaaaaaaaaaaaaaaaaaaaaaaaaaahgahhHHHHHHHHHHHHHHH
NOWAY
grendelee 3 years ago
I always thought that it wouldn't, mostly because I'm an idiot. I figured that if the plane wasn't moving relative to the air, you would get no lift under the wings. The part that I was missing was that it's the jets that create that movement under the wings, not the relative speed of the plane.
Freecell82 3 years ago
No, no, you're wrong there. The jets/props create thrust. The speed relative to the air is what matters. But since the plane's wheels are free-spinning, the treadmill can't apply more than a slight amount of backward force to stop the plane from moving forward, it WOULD TAKE OFF, but NOT stationary with respect to the ground. It would move forward as if there was no treadmill!
rmessenger 3 years ago 2
Propellors and jet engines are only used to get the plane moving to created the needed amount of air going against the wing so that the wing can create lift. If there is no air travelling underneath the wing, it will not go. This is done assuming the plane is kept at 1 spot on the treadmill keeping the same speed as it. No airflow under wings = no take off. If you could take off like this with a treadmill, many armies would have done it already.
w3tw1llydac 3 years ago
But the lynchpin is: a treadmill COULDN'T stop the plane from moving forward. In other words, the plane WOULD take off, but it would take just as long a runway as if there was no treadmill. The plane won't take off in place, it will move forward and take off normally regardless of what the treadmill is doing!
rmessenger 3 years ago 2
Theoretically speaking 1. the airplane will go forward. 2. the plane will take off if the plane can provide enough lift. 3. This will only happen if the engine can produce enough thrust to counter act the treadmill. 4. If you have enough treadmill to attain the airspeed for takeoff.
Now realistically, that would never happen. There is not a big enough treadmill. nor will there be tires that can overcome the speed of the treadmill plus the forward speed that it must have to reach takeoff speed.
skymaster337 3 years ago
"tires that can overcome the speed of the treadmill"
In order for the tires to "overcome the speed of the treadmill" the tires would have to be overcoming, which means they would have to be DOING SOMETHING. They don't. That is, they don't actually take action. The propellers do, and they don't pull vs the ground, they pull vs the air. All the wheels do is keep the plane from scraping against the ground while the propellers pull the plane forward.
jordinyc 3 years ago
And yes, this frictional loss is very small at realistic speeds, but at infinite speed this frictional force is enough to counter the thrust of the engines.
jwpsycho2007 3 years ago
Well that depends on the avail power of the engines, Airliners have wheel breaks and if they locked, it'll burn the tires? then the landing gear, soon the belly of the plane. with strong enuf thrust the plane airborne regardless.
thaibu 3 years ago
What everyone is overlooking is whether this is a hypothetical problem or a real world problem. In the real world the belt could never turn fast enough the create enough friction in the wheels to counter the forward movement( needed for lift ) of the plane. In the hypothetical problem it states that the belt matches the speed of the plane - indefinitely. The plane will not move an inch because the wheels will be creating friction to counter the forward thrust of the engines.
jwpsycho2007 3 years ago
I think it's meant to be taken as the real world version, with the intent to trick people into thinking the backward motion of the conveyor would counteract the forward movement of the aircraft like it would if it was a car on the runway.
KingNast 3 years ago
it would work because the wheels arent whats propelling an aircraft foreward. the prop or engine is what is.
skillman28 3 years ago 3
Perhaps a better question to discuss is, what if there were no conveyor belt, but there were some kinds of barriers on the runway that could inhibit the plane's forward motion, but not it's upward motion. Hence the plane's lift would have to all come from air being thrust past the wings by the engines. In most (or all) plane designs, I'm sure that's inadequate (airspeed is needed). Question is, it it possible to design a plane that could get all its upward lift from airflow from the engine?
TroyOi 3 years ago
You're getting into how would one describe a helicopter on an elevator or ecsalator.
The Boeing AV-8B can lift from engine thrust alone. however planes like that and choppers uses considerable fuel than fixed wing aircraft.
thaibu 3 years ago
I've been reading about this issue on StraightDope and other sites, & in many cases the wording is the cause if confusion. Those who (correctly) advocate that the plane does take off aren't always adequately explaining that, at take-off time, the plane is NOT motionless relative to the ground (or ambient air). Rather, it's because the conveyor is incapable of inhibiting the forward motion (relative to ground) of the plane, no matter how fast it moves backwards. (Please tell me I'm right! :-/ )
TroyOi 3 years ago
OK, the wheels have nothing to do with lift...they are only there to hold the plane up off the ground, and make it easier for the plane to reach take off velocity.
also, the engines and trust created by them also have nothing to do with lift, they are only there to get the plane up to speed, and create WIND against the wings.
the only thing that makes a plane "fly" is the force of the air against it's wings.
without lift, the plane will just stay on the conveyor belt
sk80soarus 3 years ago
Wrong, the plane will NOT stay on the belt. It will move forward regardless of the speed of the converyer belt. This forward motion will generate airflow over the wings which will generate lift which will allow the plane to take-off. You could even run the treadmill twice as fast in the opposite direction and you still could not stop the plane from moving forward. The friction of the wheels against the treadmill is almost non-existent compared to the thrust of the engine (or propeller).
gatormike77 3 years ago
that's not the concept of the myth though...
the arguement was originally that the plane would be stationary...meaning, the prop would be spinning just enough to counter-act the frition of the wheels.
sk80soarus 3 years ago
I myself, as an aviationist, has tested this theory and i know the truth behind it. For e.g, lets take a car on a conveyor belt. The car is travelling 80mph, and the conveyor belt is going 80mph the opposite way. The car gets its thrust from its wheels. But an airplane gets its thrust from its engines. Its wheels have nothing to do with it. So when a plane is taking off at 180mph, and the conveyor belt is going 180mph the opposite way, it can still take off.
RunescapeComics 4 years ago
Part-1 An airplane needs Air Speed, not Wheel speed, to take off. The aircraft needs the required airflow to fight the gravity and take off, the wings need enough air flow in order to do their job and lift the aircraft.
ElRazTheGreat1 4 years ago
Let's first take an example aircraft, the Boeing 747-8I. It has an empty weight of 466,700 lb and a max take-off weight of 970,000 lb. It's engines produce a combined 266,000 lb of thrust. It has a take-off speed of around 180mph. If the treadmill was moving in the opposite direction at 100mph the 747 would have to produce enough thrust to get the plane to what would be 280mph (wheel speed) before it could take off.
System48 4 years ago
That's 100 mph faster than normal in order to cancel out the opposite motion of the treadmill and reach still reach it's take off speed (air speed, not wheel speed). So while it would be able to take off once it got up to speed it would still require the normal run-way length to reach the 180mph (air speed) necessary for the wings to create enough lift.
System48 4 years ago
I must clairfy. If the engine thrust moves the plane faster than the treadmill. Then there is air over the wing and it might get lift. But what is the use of the treadmill? There is no advantage in ramp reduction because it would have to move down the ramp (ground) at lift-off speed. Same distance as without the treadmill. This is becoming more stupid by the minute.
SingleyTools 4 years ago
The saying is what if the conveyor was traveling in opposite of the planes forward motion. that is the question.
thaibu 4 years ago
Bottom line is, there has to be airflow around the wings, caused by forward motion relative to the atmosphere. And this happens once the plane overcomes the friction of the conveyor belt.
Premier141 4 years ago