Plane on a conveyor belt just shows how abysmal the average person is at problem-solving. A plane generates lift by the passage of air over its wings (or fuselage in the case of lifting-body aircraft). Therefore, the only thing that matters is how fast the plane is travelling relative to the air. The conveyor belt is a red herring. It doesn't matter.
Also, the speed of the conveyer belt is a red herring. It could be moving 10x faster and it would have no effect on the plane's ability to take off. What it will effect, however, is the speed that the wheels will free spin. The faster the conveyer belt moves, the faster the wheels move. I think that's something that could help people understand this more intuitively.
What they stated at the beginning "If a conveyor belt matches the plane's speed", and what they later stated "If a conveyor belt matches the plane's *takeoff* speed" are vastly different things. In the first one the plane literally never moves forward, because the belt is matching it's speed, and therefore cannot generate lift and take off.
@@allanshpeley4284 The wheels generate drag, they don't actually free spin. That is the force that would hold the plane in place. What they tested is not what the actual thought experiment is, because the thought experiment is not possible to physically test since you can't actually get a conveyor belt or wheels or propellor moving infinitely fast. They specifically stated they were testing: "If a conveyor belt matches the plane's *takeoff* speed", rather than matching it's actual speed and holding it in place.
@--Dan- - yeah. Kind of. But, since all working aeroplanes are thrust-powered, it really doesn't matter how fast the conveyor belt moves, as long as it doesn't burn out the wheel bearings. A plane's speed is governed by Newton's third law of motion (every action has an equal and opposite reaction), not by what the wheels are doing.
@@nigeldepledge3790 both jet turbines and propellers are limited in the amount of air they can intake. Even spinning infinitely fast they will very quickly create a near vacuum in front of themselves and their thrust will plateau. Meanwhile a treadmill moving infinitely fast will impart infinite force onto the wheels, and could certainly hold the plane still. That's why in the physics thought experiment the plane cannot take off.
A plane on a treadmill, its not as though it uses the wheels to take off, all the treadmill will effect is the speed of wheel rotation, not the forward pull of the propeller, utterly ridiculous how anyone can question the outcome lol.
I love how annoyed Jamie is about the plane myth! :D Actually after reading some commenters still not understanding the concept, I'm getting annoyed as well. :D
I think the plane myth is only a myth because of differences in how people perceive the matching of speed. You can match the ground speed or you can match the instrument speed (for the plane that's air speed, for the conveyer its ground speed). If you perceive it as a plane matching the ground speed of a conveyer, and therefore stationary to an observer, its a very different test.
Exactly this. I think the people who argue for the myth interpret it to mean that since there's no power exerted by the wheels to contribute to the acceleration of the plane, the treadmill only increases wheel speed and therefore does nothing to prevent the plane from accelerating and lifting off, which is really a no-brainer and what we see happening here. People who argue against the myth interpret it to mean that a treadmill under the plane should essentially eliminate the need for a runway and that the plane should be able to take off without any horizontal acceleration for the myth to be confirmed, which we clearly see is not possible. Both sides understand how lift works and that the wheels contribute nothing to the take-off, and simply disagree on the semantics of the myth itself.
I thought the conveyer belt was supposed to exactly counter the wheel rotation of the plane? That's how I read it on the internet. In that case, putting a plane on that conveyer belt would be the equivalent of forcing the wheels to not rotate on a conventional runway, which would produce so much friction that the vast majority of real airplanes could not overcome it.
@@uzefulvideos3440 it depends in how much friction the there is in the wheels. the plane pushes off against the air so as long as the force from the propellers is higher than the drag force of the wheels than it should take off.
@@aowest5904 Yes, but real planes are very heavy, so they put a lot of pressure on the ground until they've gained speed, which they can't when the wheel's are not allowed to spin fast enough to move the plane forwards, so essentially blocked. For small light machines, with a good amount of power it might still work in this scenario, scenario, or extremely powerful planes like fighter jets.
I think the entire plane on a treadmill myth is misunderstood here. the myth I heard is that the plane is completely stationary with its landing wheel spinning on the treadmill only.
@@gwhizz5878 Nope. Because its not a car. If it was a car, you'd be right. At the end of the day, if the plane moves relative to the stationary ground (not the treadmill), i.e. it moves forward on the treadmill, as long as it moves forward quickly enough it will take off. Imagine you're sitting next to a treadmill, holding a 1:8 scale toy car on treadmill. If you hold your hand steady behind the car, the car won't move, but its wheels will spin. The force backwards is equal to the rolling resistance of the wheels, so not that much force. It would take very little EXTRA force to push the car and accelerate the car forwards on the treadmill. The wheels would still be rotating on the treadmill at 1:1, the car would just be moving foward. The question is kind of a trick question because it doesn't tell you everything. At the end of the day, a plane still requires airflow over the wings to produce lift to take off. If the propeller on produced the same force as the rolling resistance, it would hold it self still, it would be still and wouldn't take off, as there's no airflow over the aerofoil. If the relative velocity = 0 the plane wont take off. The plane is NOT driven by it's wheels though (it uses THRUST), and doesn't have to "accelerate" its wheels, and is equivalent to pulling your self along a rope with roller blades on.
It is actually impossible to have the plane stationary on a treadmill. The engines don't care, if you are on a treadmill or on solid ground. They WILL move you forwards. The wheels will just take on the speed of the conveyor + the air speed provided by the engines. You either move forwards OR backwards, but standing still is NOT an option.
The longest conveyor belt in history actually belongs to the Bou Craa phosphate mine in Western Sahara in 1973, at 98km in 11 sections (According to wikipedia)
I think a more intuitive way for people to think about the plane on the conveyor belt is that when the plane takes off its wheels are actually moving at twice the speed they normally would. Another thing is, it makes no difference how fast the conveyor belt is moving. The faster it moves, the faster the wheels will free spin, but it will still take the same propeller power to get off the ground because that's what's pulling the plane forward and creating lift over the wings.
So if you tried to use a jet powered plane it would not work as the jet is just producing thrust out the back and not blowing air over the wings producing lift like a prop does is that correct?
@@CrocodileKeyboards you misundertood OP's comment. The propeller is pushing the plane forward, just like a jet engine. The air moving around the wings and creating lift is a consecuence of the SPEED of the plane. The propeller is NOT "blowing" air to the wings, it is pushing the air to gain speed. Think about it like a RWD and a FWD car, but instead of "pushing the ground" to move the car, you are pushing the air to move the airplane. Or like a boat. The thing is that the plane is using the air to generate speed, so you can "move" the ground however you want (the threadmile), it just doesn't matter. Pd: english is not my first language, but you get the idea.
People use lots of stuff without truly understanding how it works. It is a black box to them and will just work using the corect 'incantations'. Examples are radio, tv, magnetron, mobile phone, electrical infrastructure and there is lots more. All of them require a lot of deep knowledge to create and build them. These days no one is able to know everything.
I think that this myth is mostly a misunderstanding between people seeing a plane with its engine spinning while staying in one place and a plane that is moving forward. The conveyor belt is just useless information to determine wether the plane will take off or not.
@@YippingFox Something is deeply wrong with this busting attempt (as usual with Mythbusters). Namely, it didn't prove anything. The myth isn't about the plane not being able to lift off from a conveyor belt, it's about not being able to generate lift because it is staying in one volume of air. Here we can see that the plane is moving forward faster than the tarp below it, so what does that prove? Nothing. We don't even get the (presumably changed) lift off distance (both in world and tarp space), and plane-tarp relative velocity, which is incredibly important for anyone to gather any intuition about this.
Rolling resistance is independent of speed, so conveyor can only create a limited amount of force. This force, dragging the airplane back, will be easily overcome by the force of airplane's thrust, pushing it forward.
If you configure a feedback system that increases or decreases the conveyor belt speed to *try* to keep the plane stationary, once the propellor stars to pull the plane forward, the belt would rapidly speed up, limited only by the power supply. If the conveyor belt itself doesn't catch fire, the plane's tyres very well might, in which goopy burning molten neoprene will offer considerably more resistance.
All the conveyor/plane experiment did was to cause the wheels to spin faster than they normally would have. The speed of the conveyor + the speed of the plane moving forward. The conveyor has nothing to do with the ability of the plane to move forward through the air. If the plane needed a speed of 80MPH to lift off, and you had an 80MPH head wind, the plane could fly without an engine. And it would fly without any forward motion too. It's the speed of the air over the wings that causes the lift. If the wind speed was higher than the speed needed for flight, a plane could even fly backwards. Many years ago, I used to fly RC planes. On very windy days I could just hang the plane in the air right beside me. I could do vertical take-offs and landings. It's all a matter of balancing the forces. Thrust, drag, lift and gravity.
Indeed, the wheels speed has nothing to do with the speed of the plane. They could have dragged the belt 10X faster, the wheels would rotate 10x faster, but that does not affect the plane.
They are called German cockroaches as the first scientific description of the species came from a German entomologist, so a different entomologist who was responsible for naming the species decided to call them the German Cockroach. @@Albasapiens_Flinthandwerk
@@Albasapiens_Flinthandwerk maybe they originally lived in Germany, and when the first wave went to America, they sent word back, and they all packed their bags and fucked off.
The key to this airplane experiment is the observation that the tarp was tearing when Adam's feat were pinning it to the ground through friction. The plane and pilot were also pinning the tarp to the ground but not tearing it. Why? Obviously the pilot and plane were heavier than Jamie alone. The difference was that the plane wheels were rolling and so the pin-time was less. The pinned section of tarp was able to catch up with the rest of the tarp because it was able to bunch up as it passed under the wheels of the plane. The key point to all of this is that the wheels were not being dragged backwards by the tarp.
Plane on a treadmill. 1. The Mythbusters should have measured the wheel speed of the planes. This should show the wheels moving at twice the normal speed. 2. With a model (or in full size?), it would have been interesting to have something blowing air over the wing at take off speed. An air compressor spray attachment would work if you could get the speed right for the model. With that setup, you should be able to have the plane take off while stationary with respect to the ground.
I remember seeing a video of a plane landing in place due to the wind speed matching the airplane's airspeed. Why a conveyor belt would have any relevance is beyond me.
@@markadler8983 My thinking was how to show this. With such a setup you could show that it is the air speed that matters, not the relative ground speed. Hope that helps.
You need to have a cutoff at some point, you cant address EVERY way people can get it wrong. But yeah, it seems that way the main error, people thinking that wheels make plains take off, they should of concentrated on that.
Plane on a conveyor is really quite simple. A plane can have all the thrust it likes, but without air moving over the wings, there's no lift for flight.
As a Pilot, Airplane can only lift when air is enough past the wing, SO what happens to the wheels has no bearing except that the drag from the wheels either on grass, dirt or hard paved runway does add into take off distance charts you need to do in certain situations. So if you are pulling a runway under the wheels backwards and the plane needs to go forwards a certain ground speed for lift, THEN YES, the plane may take more time as extra drag on the wheels being over come by the fixed engine power BUT the plane still wont lift either way till airspeed past that wing gets to certain threshold. Interesting, if you have a say 60 kt head wind on the ground, the plane MAY start to lift standing still as the wing has enough left at that point without ground roll forward to make extra.
There are plenty of video's on here of planes 'taking off' when not secured during a storm, relative airspeed over the wing is the only thing it cares about. And I don't mean btw blown sideways, I mean actually suddenly jumping almost straight up from their moorings when they break in a hurricane, when the wind is coming straight from the front off course ( or else it will start flipping right away ).
@@MarvinWestmaas Yes, theres small metal rope to ground tie down rings under the wings and at the tail as gusty wind can play havoc. I remember this a while back and people were arguing exactly what are they saying for this myth? Is it that if the belt is pulled backwards, the plane cant move forward to get Lift or do they think wheels spinning gives you takeoff? Bit confusing but Jamie said it that power is from the propeller so besides a little extra drag, the plane given enough HP, can pull forward even if wheels where in very deep grass and eventually get to take off speed although this can be dangerous just as taking off from high elevation and hot conditions requires much long take off roll. The Ultralight pilot should have know the answer but they arnt schooled with standards of a private pilot licence and you dont even need training or licence except when plane gets bit heavier and diff category some formal training and theory is required. The slick material pulled under his plane wont didnt... add much drag and he pulled forward easily and they didnt bother to measure his distance to take off which i guess was a touch further? showing the myth is slightly right in that it will effect take off a little but holding you in position NO, its all about drag on the wheels and power pulled to overcome it which will be plenty usually.
They missed the ball on some very basic principles here, I mean they took a badly worded myth and 'tested it' without actually considering the physics. The myth is indeed about 'what makes a plane fly, is it the speed it gets relative to the 'ground' ( which is the same as we keep the plane steady but move the ground under it, aka treadmill ) and anyone vaguely familiar with the Wright brothers knows about relative airspeed. Heck even the biggest 'dumb guy' only has to watch a news item about planes taking of from a carrier where they explain once they sometimes have to adjust heading to accommodate launches since a catapult only get's a plane to a certain speed relative to the carrier, and it needs the headwind to generate enough lift based on the relative airspeed. Once you 'know' the only relevant bit to lift is relative airspeed ( and shape and size of a wing off course ), the whole notion of a stationary plane on a treadmill taking off should be dismissed as one of those dastardly devil cartoon pranks. @@xx3868
My thoughts exactly. I mean, if the hypothetical airplane can be designed with a prop length approaching a wingspan then it will be able to create enough airflow over and under the wings to make it take off with 0 ground speed, but normal airplanes are not designed that way. Or, maybe, if the treadmill has giant "sails" that will waft air onto the plane's wings it would work.
Well, he did say that if the speed of the wheels match the speed of the conveyor, he would sit like a brick. That would be true, IF the wheels matched the speed of the conveyor, per definition the relative velocity of the airplane would be zero, thus not creating any lift. However, the velocities of the wheels and belt did not match.
@@plerikmetselaar1152 Oh, no... The velocity of the plane is controlled by the propeller, not the wheels. The spin of the wheels has noting to do with the plane's ability to take off. No matter what the wheels / ground (the belt) are doing, the propeller will speed the plane up to the take of speed. It's the air-speed that matters, not the ground-speed.
@@iqnill Oh, yes... I am aware of the fact how an aeroplane gets into the air. However, if the prop delivers just enough force to overcome the friction of the wheels, the rotational speed of said wheels match the linear speed of the belt. Of course it can take off due to the proppellor delivering the thrust, but how they showed it, the rotational speed of the wheels is larger than the speed of the belt. What I am saying is that IF the velocity of the wheels match that of the conveyor, the plane's relative velocity wrt the ground (or air alike if there is no wind speed) would be zero and thus it would not take off.
@@plerikmetselaar1152 Um, again, no, plane takes off... the rotational speed of the wheels will always be greater than the speed of the conveyor belt... what you describe is a stationary plane with the conveyor belt running underneath. That is not the myth here. The PLANE moves forward, the conveyor belt moves backward. Forget the damn wheels already.
I had the lucky opportunity to fly about Northern Ontario one summer in a small plane. The pilot (great guy, crazy!) once slowed the plane down on a windy day so much that we were flying backwards! Very freaky looking down as I recall but same principle I think.
Lots of psychology in this one. How people can be wrong about something that goes wrong against simple rules they take for granted(conveyor plane) or how people react to bugs experiment. Comments are good!
Get high enough air speed, to create low pressure above an object, and create a higher pressure below the object, and anything can fly. Ground speed does not directly effect lift. Trailers can fly for example in high wind. they don't have wings to sustain the flight for long, but they can be lifted off the ground. How many non anchored structures go on an airborne trip during a hurricane or tornado? no wheels to get them moving, just high and low air pressure and a cushion of air to ride on.
Jamie actually thought so as well. However when Adam produced a 6 inch thick pile of paper of comments on it from the fansite and presented it to the producer the decision was made.
Controversy isn't always a good commercial though ;) Most will likely forgive them, to many fond childhood memories of the 'mythbusters' when I actually still considered there was actual science taking place. @@MrMarinus18
There was apparently a boob size myth, which Adam talked about on his podcast... I would imagine that was worse, but yah. Once you understand a free wheel on a plane is different to a powered wheel on a car, this is dumb.
@@jontymalice1336 actually the boob size myth was about a real scientific test and the outcome was very surprising to EVERYONE. but even every CHILD knows you need wind (aka airspeed) to get lift on a kite. which basically is an airplane. every child has experimented with paper airplanes too. i´m quite certain that the people who got this myth to the tv, were actually just trolling. (i mean the people "fighting" about this on the forum or whatever)
i just ... never could fathom how someone putting a threadmill on the ground could affect an airplane, say for instance, 10 miles up in the sky. or how someone could think that. instant energy transportation via quantum enganglement or a wormhole? and yea i´m so old i wathced the episode when it first aired on telly. could not stop hitting my forehead into the wall.
The plane myth is easy to understand : The only thing that matters for a plane is its true airspeed. So the speed of the incoming air hitting the "front" of the plane. Wheels are free and useless, they're only here to roll during the takeoff and landing phases.
11 месяцев назад
They do more than roll during landing (and pre-takeoff, obviously).
So many people still don't believe the plane can take off on a treadmill. I was team take off, long before this episode aired, it was a fun subject to discuss. Many of my friends that were on team no flight still won't back down on this subject even after seeing this episode. Best way to think of it, the air is a planes road and the plane gets pulled forward through that air by the propeller, what speed the tires are spinning at has nothing to do with the planes forward progress. Jamie could have been going triple the speed and the plane would have still pulled forward and up through the air. If you put revolution counter on the wheels of the airplane, they would have matched Jamie's speed plus the needed 26 mph for take off.
@@aowest5904 You best be changing your wheel bearings on your Cessna there pal. lol you crack me up, yeah wheel drag is factor for a 180 HP motor. Best you have a Snickers because you suck at trolling when your hungry.
@@TheRattleShark I am not trying to troll but the speed of a plane is a result of the total force of the propeller minus air drag resistance and wheel drag resistance combined, if that wheel drag is high enough then it can't take off. i do agree that in practice this will not be easily the case off course.
@@aowest5904 How much wheel drag do you think there is to hold back a plane? You watched the video, they proved it. The plane they used needed 26 MPH to take off and Jamie went faster than that in the opposite direction. The plane throttled up at the same time and it took no less time or distance to take off. Sure there is wheel drag but it is miniscule. Go back and listen to Adam when he has the car on the treadmill, he talks about how effortless it was for him to hold the car in place, wheel drag was a non factor. I'm done discussing this with you if you can't get it, I have better things to do with my time other than giving you a free physics lesson. Have a good day while you go discuss this with someone else.
The wheels spin twice as fast, but they don't propel forward. Why is this so hard to understand? It would likely take off if the conveyor belt was going twice the speed of takeoff. The x factor that could prove the myth is severe friction in the wheel bearings. But you'd have needed a really fast treadmill. (+100mph?)
Any pilot should know that the moment of take-off only depends on the airspeed over the wings, not the ground speed... a plane can even take off standing completely still as long as the wind is fast enough... fail
The thing with the plane is there are two interpretations of the myth that people argue. One is what was shown here, that the conveyor belt is moving at the (minimum) take off speed of the plane in which case the plane is able to accelerate and take off. The other is that the conveyor belt is moving at a speed matching the forward speed of the plane, which creates a paradoxical loop that is physically impossible. I.e the plane accelerates, then the conveyor belt accelerates at the same rate to cancel the speed out, in which case the planes velocity is cancelled out so it did not accelerate to begin with. So whilst it might be a semantic point to argue in online threads, in practice physics only allows the first case to be possible.
wrong, in either case the plane wont care, the plane wheels are not connected to the engine, the wheels spin only twice as fast in both cases, and people that say that the plane cares about the stationary ground also are wrong, the plane only cares about wing wind speed, a plane can fly "stationary" or even backwards if a strong enough wind is applied to the wings, the propeller is only connected to the engine so that it can move air around the plane fairing so that the plane can reach a speed relative to the wind that is enough for the wings to generate lift
@@xzinik2961 You're missing the point about the second scenario. It's physically impossible to have the conveyor belt speed up to match the forward speed of the plane. This state can only exist when stationary. Otherwise you have a paradoxical feedback loop. Therefore the only interpretation of the thought experiment that is physically possible is where the conveyor belt is moving at the take off speed of the plane in which case as you said the plane effectively doesn't see the movement of the plane and will accelerate regardless thus taking off. I'm not arguing for the other scenario, just explaining how the riddle has been interpreted in different ways, which is what sparked the internet debate, and how of the two possible interpretations, one is physically possible and the other is not.
@@nicholascrow8133 why do you say its impossible to have the belt speed up to the same speed as the plane? a fixed pulley would do the trick with the same setup of the mythbusters only that this time instead of moving the conveyor with a car its the same plane pulling it, if the plane acelerates at 5m/s² and it pulls on the conveyor belt with a pulley, the conveyor will move at the same 5 m/s² but in the other direction, the only one that is affected is the wheel that notices 10m/s², that in this case the plane wont care either because it pushes against the air nothing else
@@xzinik2961Hold up, I got a bit confused (Drinking and physics don't mix well lol) I meant the other scenario is where the conveyor belt speeds up to match the speed of a wheel driven plane... (The situation they explained in scale with the whole car vs plane conundrum) So a third scenario I guess. That's fundamentally where people get confused when trying to argue the plane can't take off.
As in to say, if one was to believe a plane is driven through the wheels, it is impossible to have a conveyor belt matching the speed of the accelerating vehicle, as any acceleration would be cancelled out, killing that train of thought before it can take off (very bad pun intended)
I think they were unfair on the pilot with this one, he wasnt wrong in the presumption that if they managed to keep the airplane stationary then it wouldn't fly, which is what they showed in their animations. Of course he forgot to take into account that the plane wouldn't stay stationary because their "treadmill" could not move fast enough to assert enough drag on the freewheels to stay stationary. Their animations were actually highly deceptive. In the animation they portray a plane on a treadmill and give two possible scenarios. 1) the plane stays still and cannot fly. 2) the plane stays still but then levitates and starts flying. But then the other option they did not portray was 3) the plane does not stay still and still manages to takeoff because it's still going forward. IF they actually made it a rule that the plane must stay stationary in the Y axis, as in not moving forward, then the plane would never take off. And it doesn't matter whether the plane is powered by the wheels or the propeller in the end because even if the airplane were powered by the wheels on a normal takeoff strip it would still take off because of the lift generated by moving forward but then it would come back down afterwards because of it's inability to maintain acceleration. So when they stated that the pilot was wrong because he failed to understand that the drive didn't come from the wheels is just wrong.
I hate the plane myth because everyone tells it differently Some say it matches the planes speed Some say it matches the wheels speed The former is in the video The latter is super complicated since the wheels matches the speed that is the difference between the planes forward speed and the grounds speed, but here the ground is trying to match that speed causing a positive feedbackloop. Something has to give. Either the wheels, the conveyor belt or the loop itself being too slow
i certainly wouldnt risk a private airplane on their stupid conveyor belt, if it lifts and connects with the propellar your looking at some damage probably.
I felt like the whole thing was a missed chance. I also thought that the whole point of the converyor belt would be to see what happens when a plane reaches its takeoff speed, yet stands completely still to the neutral observer. I do not think the myth was supposed to say 'here is your takeoff speed in reverse, can you get fast enough to overcome the speed deficit and actually roll forward to the neutral observer, then with enough speed do a takeoff? Because that was never questioned. Also, what a stupid myth, the air stands in the room, not on the belt. So if you do not move through the room to move through the air, you will never generate any lift. In the same vein, you can make a plane fly 'one the spot' by blowing at it with wind that has a speed correlating to the plane's takeoff speed. Woooh, you just invented a new kind of flying machine capable of standing in the air!! Its name shall be....kite! Wasted 4th grade thought experiment. 5th graders would laugh at this. Thousands of pages discussing this, written by adult human beings, as claimed in the intro? Where? America? Jamie realizes the sheer simplicity of the solution instantly and has some fun narrating the outcomes of experiments he clearly thinks are totally worthless. Which they are. Thinking gives the solution in less than 2 seconds.
so you would have to build an air conveyer belt aka a huge blower fan / air tunnel and test it with a plane in there... the plane will take off but remain stationary... I have even seen this happening to planes in real life conditions like very strong winds.... the plane will just not move but it will fly... because for it to fly it will only need airspeed, but if the speed of the surrounding air matches the airspeed at which the plane flies normally it will just stand still relative to the ground
While most people hate cockroaches and while I never seen one myself I am facilitated with a few facts about them such as them living over a week after decapitation and as they’ve show they can survive over half an hour underwater
but didn't the plain moved on the runway before taking off? I could be wrong but I think I saw the plain moving forward (of course slower than what it would if it wasn't on the belt) before taking off.
Of course it does, it’s impossible for a treadmill at any practical speed to prevent an airplane moving forward, because the airplane doesn’t get thrust from the road, it gets thrust from the propeller (or jets or whatever) pushing against the air. And the air doesn’t change speed with the treadmill.
I was gonna comment about how the plane myth is plain dumb, and how I would doubt more than a tiny minority could fail to understand the plane's engines are thrusting against the air, not the runway... But then I see the comments and remember how dumb the internet can be *facepalm
The pilots answer is correct,he taking all sorts of differentials into consideration, first is the safety factor needed to keep humans safe means the air force created by the propeller isnt enough to push the amount of air need over the wings and flaps to lift the weight of the plane.....buuuut... with wind speeds and the extra velocity of the propeller......?????? Who really knows so I'm about to watch them try with a tarpaulin as a conveyor belt! Personally I believe there's too many variables for the myth to be tested correctly!
It doesn't hinder or help with take off or landing. When landing, the plane is travelling at the same air speed no matter what the ground is doing. When it lands, the wheels will spin faster, but the brakes still have to convert the same amount of kinetic energy to heat, as the additional kinetic energy of the faster spinning wheels is negligible. The plane will come to rest relative to everything other than the conveyor belt in the same amount of time as normal, and then begin to move backwards as the wheels continue to slow relative to the conveyor.
@The mistake here is thinking we are only dealing with two different speeds, airspeed and conveyor belt speed. There is a third to consider, ground speed. Relative to the ground, the planes airspeed is equal to its ground speed (ignoring wind). But relative to the conveyor belt, it would be equal to its ground speed plus the conveyor belt speed. It is the aircraft's speed through the air that determines when it takes off. While the conveyor belt was moving under the aircraft, it was not drawing any air over the wings. This is why the plane moved relative to the ground before taking off. When landing, it is friction between the landing surface and the aircraft's wheels (as they are braked) that determine the stopping distance. Therefore, relative to the ground, its take off distance will be as normal, but its landing distance will be shorter. Whereas, relative to the conveyor belt, take off distance will be longer than normal, but its landing distance will be as normal.
Well even tho it worked, and I didn’t think it wouldn’t work. That was not a good test. The belt moves over smooth rollers and not a rough ground. There was no loss of traction.. as seen by the holes Adam put in it when running on it… therefore it was not a fair test.
How is this plane myth even a thing? A plane needs airspeed to lift off. If the plane is sationary, it doesn't genrate lift... Is this actually something people argue about? Of course the plane is going to move forward if it's being driven by a prop. The wheels are not relative to airspeed in any way..
Conveyor belt is utterly irrelevant, unless you use the wheels to measure air speed, which in itself is nonsense. All that matters is the speed of the air over the wings. So, put the plane in a huge wind tunnel and it will fly in situ. But put it on a rolling road and, without wind speed, it will sit there. What the plane is standing on and whether it’s moving or not, has no effect whatsoever on the physics of flight, which are only concerned with air flow.
You just made world founding discovery that a plane can take the sky just spining its wheels fast eneough. No runways needet anymore. Wright Broters shuold invent this at begining.
@@MarvinWestmaas Their rationale for the conclusion they reach was just incorrect. As I said in another comment: A treadmill moving infinitely fast generates infinite force on the place via it's wheels. But a propeller (or jet engine) spinning infinitely fast does not generate infinite thrust, because there is diminishing returns as the propeller pushes air faster than the air can return, and create a near vacuum. So as both speeds increase to infinity, the plane never takes off.
but this is a physics question not an engineering question. what the wheel and belt does is irrelevant to the lift on the wings. the belt and wheel moving infinitely fast would go into the realm of special relativity and i would have no idea how that would effect the lift on the wings. the wheels are free spinning only the thrust generated by the rotor/jet would matter on whether or not it would move forward. since this is a physics question with the expectations of Newtonian physics, then we assume that the wheel is an Ideal wheel with zero friction on its bearings. it would still take off since the wheels are just there to keep the plane upright, they have nothing to do with moving the plane forward
@@richarderguiza7080 Assuming 0 friction would be the absolute last thing you could do, because it would mean the conveyor belt would do literally nothing. Friction is the only force the conveyor belt imparts on the plane. Also, no, aerodynamic principles are both engineering and physics.
Actually the plane will always take off because it's the propeller that pulls the airplane trough the air not the wheels. Even if you had proper gigantic threadmill , all it would do is make the wheels spin infinitely faster, but the plane will still take off. The wheels have essentially nothing to do with airplane taking off @@--Dan-
Cockroaches though are tropical insects and are quite vulnerable to the cold. They can't survive in temperate climates without artificial heating by humans. After a nuclear war they likely would die out in most of the developed world cause they rely on humans to keep the cold away. It's also why the wild range of cockroaches is expanding due to climate change.
Wheel speed is irrelevant for the plane to take off. You could run the conveyor belt at 10 times the speed and the plane will still move forward and take off, because the wheels will always just take on the speed of the conveyor + the air speed.
I have always hated when editors fast forward Grant's explanations. Why didn't they just put him in a clown suit of they didn't want people to lose interest for a minute /s.
The plane CANNOT remain stationary. It simply isn't possible. It either moves forward by the power of the engines or backwards by the power of the conveyor belt. Being stationary is simply impossible for a plane in that situation. As explained in the video, it is not a car. The engines are completely separated from the ground. As such, the speed is separated from the ground as well!
@@m.h.6470 all righty then! I would think that the plane just "levitate" from the ground as soon both contrary forces reached the same speed. Am i making any sense?
@@vascoapolonio2309 There are no contrary forces here. There is one force acting on the plane (forward, from the engine) and there is one force acting on the wheels (backwards, from the belt). But the wheels are free spinning and therefore have literally no influence on the plane. As such, the forward force is unhindered and the plane moves forward and lifts off.
@@m.h.6470 i dont think i get it. Even if the "ground" is going backwards, for the plane only counts the speed from the wheels. Im no engineer, obviously!!! The engine is the driving force propeling it?
@@vascoapolonio2309 The plane only counts the speed coming from the engine. The wheel speed is totally irrelevant. It literally doesn't matter, what happens below the plane: Stationary ground, same speed backwards, same speed forwards, double speed backwards, etc. The plane WILL move forwards regardless and the wheel speed will adjust accordingly. If you had a conveyor belt that goes same speed forward for example, the wheels wouldn't move at all, but the engines are running. But if the engines weren't running, the plane would NOT go forward (at least not much)... remember: the plane wheels are free spinning, so the inertia of the plane would cause it to roughly stay at the same place - moving backwards from the conveyor belts perspective. That is the counterintuitive thing.
The only thing I miss from that airplane myth: Tyres are rated to a maximum speed. Having the wheels turn twice as fast as they normally do will exceed the limit significantly. Surely no problem on a small ultralight, but this might be the small detail that could prevent an airliner to take off...
As long as the wheel bearings can handle it, there's more than enough power to spin the wheels twice as fast, and the tyres may be rated to a certain speed, but that rating would be a lot higher than anything that would be expected in normal conditions, and even then, the actual failure speed would be higher still.
The plane will ALWAYS move forward relative to the ground. It doesn't matter how fast the conveyor belt goes. That is because the propeller or turbine simply doesn't care, that there is a conveyor belt, as it moves the plane THROUGH THE AIR and not on the ground. That is the main thing that people don't understand. There literally is no way for the plane to stand still with the engine(s) running. It either goes forward, propelled by the engine(s) or it moves backwards being dragged by the conveyor belt. Standing still with engine(s) on is NOT an option.
@m.h.6470 The plane could stand still if the propeller was providing exactly the amount of thrust needed to counteract the very small amount of friction due to the wheels rotating on the conveyor. A plane does not normally move forward when an engine is at idle with the brakes off, meaning it has to overcome some frictional forces before it can.
@@kiwibob8967 I obviously meant "with the engines on and not on idle" and didn't feel the need to state that. And engines do not have that much control to deliver that little thrust to ONLY counteract the friction. They are way to powerful for that kind of delicate movement.
A plane just needs wind under its wings from the prop. It doesn't need to move to take off. Stupidity of this myth blows my mind.😅😅😅 Use a jet engine plane for this myth.
I think I have a simple explanation of why the plane myth busts so easily. A thought experiment: Imagine an infinite treadmill with the plane on it. The plane's takeoff speed is whatever it is, and we set the treadmill to match that. We start the treadmill and give it a minute with the brakes applied to the wheels to get the plane actually moving backward with it at speed before we start the engine. At this point, the wheels aren't spinning because the plane is stationary relative to its spot on the treadmill, hence the plane moving backward relative to the observer. Now, we start the prop going (and release the brakes), and as soon as it generates enough force to move it forward on a regular runway, it will also start moving forward from its relative position on the treadmill. And the wheels have started spinning, of course. At this point, the treadmill no longer matters because all it's doing is spinning the wheels. The plane should very quickly start moving forward relative to the observer because it's pushing against air, which the treadmill has no effect on. The wheels don't matter because all they do is spin; unless the brakes are applied, they have no impact on the motion of the plane whatsoever. That's the difference from a car or a person. They're pushing back against the treadmill itself to get forward momentum. The plane isn't. It literally doesn't matter HOW fast the treadmill is going once that prop starts spinning.
Plane Myth: The conveyor will prevent the plane from taking off. Reality, The engine provides thrust to the body of the plane. The Conveyor is moving the wheels at 25 mph, but the plane is not moving in relation to the wheels and there is negligible rolling resistance. As the plane accelerates to 2mph the wheels are now spinning at 27 mph. When the plane body reaches 25 mph the wheels are actually spinning at 50mph because of the additional speed from the belt. The wheels contribute nothing. If you could get a giant fan to blow a tail wind at the same speed as the plane, it would cancel out the movement of the air over the wings and prevent flight.
Finally someone else using the same explanation as me. They never addressed the speed of the wheels in this episode. I think it would help more people make sense of what's happening. They could have also pulled the conveyer at higher speeds.
@@JasmineJDMgirl Gonna call some BS on that, as spell check would not have triggered. Both 'plain' and 'plane' are correctly spelled words - you just didn't use the right one. Good try though! 🤣
TL;DR: A plane stationary, relative to the ground, will not take off, no matter how fast the planes propeller thrusts and no matter how fast its wheels are turning. Ok, so, i have never heard this plane myth before, but here we go.. First, a better way to test this myth would have been to put it on a dyno, making it spacially stationary and seeing if it will take off by its thrust. Or, a reverse dyno, where it makes the planes wheels spin up to take of speed. But, of course would never happen as lift is generated by its wings not its wheels or its method of forward p As air moves faster, its pressure decreases, so planes generate lift by having air flow faster over its wing and slower underneath it, thus creating more pressure underneath the wings the faster its moving forward and allowing it to lift off the ground. If the plane was truly stationary relative to the ground with only it's wheels to spin at take off speed, there is not enough air speed to create the pressure under its wings required for lift - if this were the case they wouldn't need a runway. And regarding the question of "will a planes propeller with generate lift?", the answer is no. The only way would be if the propeller was directed to force air towards the ground, in which case, would essentially make it a helicopter.
a stationnay plane can absolutely take off. Happens in every hurricane or high wing. The only thing that matters is air speed over the wing. The wheels or ground movement doesnt matter .
@@Nordic_Mechanic Sure, i suppose that's possible, but I would assume its a pretty rare occurrence. Airports are often closed and planes regularly get diverted during hurricanes and strong wind events - not sure if there is regulations around that, im not a pilot but surely it wouldnt be safe to attempt, especially in a light plane.
The propeller on most (many?) Directs more moving air under a wing than over it both by the shape of the wing and the actual up/down (y axis) placement... this causes lift.
The actual test would be to speed up the treadmill and advance the throttle until thrust keeps the plane stationary... ANY thrust beyond that point will start forward motion and contribute lift..
I don't know whether you are for or against this myth. If you want to keep the plane stationary just tie it to something heavy. Then see if it can take off. If you're asking whether it can take off from the thrust of the propellers alone, then probably not as although the propeller does direct some air over the wing, it's main job is to give the plane momentum, and then maintain that momentum.
This isn't a myth is it? I mean, who the hell thinks a plane will take off with no relative airspeed? Groundspeed, or speed compared to a treadmill is entirely irrelevant.
Such an odd 'scientific experiment' lol.. well if we make the plane go a bit faster then the treadmill, will it still get enough relative airspeed for the plane to take off? And if it does, is it representative of an actual plane on a treadmill, or is this plane's mass to weight ratio playing a role in it's short take off capabilities / meant for indoor flying with no wind )? God I can't believe I watched this as a kid and thought they were actually 'solving myths' instead selling a tv program
Jamie was definitely thinking "You're an absolute moron AND you're a Pilot!" When that pilot was suprised he took off..
Plane on a conveyor belt just shows how abysmal the average person is at problem-solving.
A plane generates lift by the passage of air over its wings (or fuselage in the case of lifting-body aircraft). Therefore, the only thing that matters is how fast the plane is travelling relative to the air.
The conveyor belt is a red herring. It doesn't matter.
Also, the speed of the conveyer belt is a red herring. It could be moving 10x faster and it would have no effect on the plane's ability to take off. What it will effect, however, is the speed that the wheels will free spin. The faster the conveyer belt moves, the faster the wheels move. I think that's something that could help people understand this more intuitively.
What they stated at the beginning "If a conveyor belt matches the plane's speed", and what they later stated "If a conveyor belt matches the plane's *takeoff* speed" are vastly different things. In the first one the plane literally never moves forward, because the belt is matching it's speed, and therefore cannot generate lift and take off.
@@allanshpeley4284 The wheels generate drag, they don't actually free spin. That is the force that would hold the plane in place. What they tested is not what the actual thought experiment is, because the thought experiment is not possible to physically test since you can't actually get a conveyor belt or wheels or propellor moving infinitely fast. They specifically stated they were testing: "If a conveyor belt matches the plane's *takeoff* speed", rather than matching it's actual speed and holding it in place.
@--Dan- - yeah. Kind of. But, since all working aeroplanes are thrust-powered, it really doesn't matter how fast the conveyor belt moves, as long as it doesn't burn out the wheel bearings. A plane's speed is governed by Newton's third law of motion (every action has an equal and opposite reaction), not by what the wheels are doing.
@@nigeldepledge3790 both jet turbines and propellers are limited in the amount of air they can intake. Even spinning infinitely fast they will very quickly create a near vacuum in front of themselves and their thrust will plateau. Meanwhile a treadmill moving infinitely fast will impart infinite force onto the wheels, and could certainly hold the plane still. That's why in the physics thought experiment the plane cannot take off.
A plane on a treadmill, its not as though it uses the wheels to take off, all the treadmill will effect is the speed of wheel rotation, not the forward pull of the propeller, utterly ridiculous how anyone can question the outcome lol.
It's actually somewhat understandable given most people's everyday experience is with cars which have their power delivered to the wheels.
That Cobalt 60 source is one of the scariest things ever. An unassuming brass capsule with "Drop and Run" written on it...
Too late.
I love how annoyed Jamie is about the plane myth! :D Actually after reading some commenters still not understanding the concept, I'm getting annoyed as well. :D
People really should understand now surely! 😂
Rip to that beautiful Volvo 740 who sacrifised herself for science
"Beautiful Vovlo"? Myth busted!
@@shannonkohl68 beauty is in the eye of the beholder
I think the plane myth is only a myth because of differences in how people perceive the matching of speed. You can match the ground speed or you can match the instrument speed (for the plane that's air speed, for the conveyer its ground speed). If you perceive it as a plane matching the ground speed of a conveyer, and therefore stationary to an observer, its a very different test.
Exactly this. I think the people who argue for the myth interpret it to mean that since there's no power exerted by the wheels to contribute to the acceleration of the plane, the treadmill only increases wheel speed and therefore does nothing to prevent the plane from accelerating and lifting off, which is really a no-brainer and what we see happening here. People who argue against the myth interpret it to mean that a treadmill under the plane should essentially eliminate the need for a runway and that the plane should be able to take off without any horizontal acceleration for the myth to be confirmed, which we clearly see is not possible. Both sides understand how lift works and that the wheels contribute nothing to the take-off, and simply disagree on the semantics of the myth itself.
theoretically, if the wind is strong enough you could lift the plane stationary attached to a rope like a kite.
I thought the conveyer belt was supposed to exactly counter the wheel rotation of the plane? That's how I read it on the internet. In that case, putting a plane on that conveyer belt would be the equivalent of forcing the wheels to not rotate on a conventional runway, which would produce so much friction that the vast majority of real airplanes could not overcome it.
@@uzefulvideos3440 it depends in how much friction the there is in the wheels. the plane pushes off against the air so as long as the force from the propellers is higher than the drag force of the wheels than it should take off.
@@aowest5904 Yes, but real planes are very heavy, so they put a lot of pressure on the ground until they've gained speed, which they can't when the wheel's are not allowed to spin fast enough to move the plane forwards, so essentially blocked.
For small light machines, with a good amount of power it might still work in this scenario, scenario, or extremely powerful planes like fighter jets.
I think the entire plane on a treadmill myth is misunderstood here.
the myth I heard is that the plane is completely stationary with its landing wheel spinning on the treadmill only.
you would have to anchor it to the surrounding ground to prevent it from travelling with the conveyor if the propellor isnt producing power
@@marhanen You just need a good pilot who can match their position to the cones.
@@gwhizz5878 Nope. Because its not a car. If it was a car, you'd be right.
At the end of the day, if the plane moves relative to the stationary ground (not the treadmill), i.e. it moves forward on the treadmill, as long as it moves forward quickly enough it will take off.
Imagine you're sitting next to a treadmill, holding a 1:8 scale toy car on treadmill. If you hold your hand steady behind the car, the car won't move, but its wheels will spin. The force backwards is equal to the rolling resistance of the wheels, so not that much force. It would take very little EXTRA force to push the car and accelerate the car forwards on the treadmill. The wheels would still be rotating on the treadmill at 1:1, the car would just be moving foward.
The question is kind of a trick question because it doesn't tell you everything. At the end of the day, a plane still requires airflow over the wings to produce lift to take off. If the propeller on produced the same force as the rolling resistance, it would hold it self still, it would be still and wouldn't take off, as there's no airflow over the aerofoil. If the relative velocity = 0 the plane wont take off. The plane is NOT driven by it's wheels though (it uses THRUST), and doesn't have to "accelerate" its wheels, and is equivalent to pulling your self along a rope with roller blades on.
It is actually impossible to have the plane stationary on a treadmill. The engines don't care, if you are on a treadmill or on solid ground. They WILL move you forwards. The wheels will just take on the speed of the conveyor + the air speed provided by the engines. You either move forwards OR backwards, but standing still is NOT an option.
and anchored to the ground it won't take off. @@marhanen
you could do same experiment on one windy day to lift off with 0 ground speed but 20mph wind speed... bushcraft pilots do that on regular basis...
The longest conveyor belt in history actually belongs to the Bou Craa phosphate mine in Western Sahara in 1973, at 98km in 11 sections (According to wikipedia)
Wikipedia is not a source.
could you link the Wikipedia page, id like to see the cited source as it sounds interesting
@@AstoundingAmelia en.wikipedia.org/wiki/Bou_Craa#cite_note-5
there's an interesting link to Nasa's website in the source section.
Simpler times. RIP Grant.
I think a more intuitive way for people to think about the plane on the conveyor belt is that when the plane takes off its wheels are actually moving at twice the speed they normally would.
Another thing is, it makes no difference how fast the conveyor belt is moving. The faster it moves, the faster the wheels will free spin, but it will still take the same propeller power to get off the ground because that's what's pulling the plane forward and creating lift over the wings.
So if you tried to use a jet powered plane it would not work as the jet is just producing thrust out the back and not blowing air over the wings producing lift like a prop does is that correct?
@@CrocodileKeyboards you misundertood OP's comment.
The propeller is pushing the plane forward, just like a jet engine. The air moving around the wings and creating lift is a consecuence of the SPEED of the plane.
The propeller is NOT "blowing" air to the wings, it is pushing the air to gain speed.
Think about it like a RWD and a FWD car, but instead of "pushing the ground" to move the car, you are pushing the air to move the airplane. Or like a boat.
The thing is that the plane is using the air to generate speed, so you can "move" the ground however you want (the threadmile), it just doesn't matter.
Pd: english is not my first language, but you get the idea.
We all miss you Grant. Rest In Grace.
not really
@@karls8103 edgelord alert
@@karls8103 Love how you took a moment of your time to be an asshole :)
It was an intracranial aneurysm en.wikipedia.org/wiki/Grant_Imahara
That pilot not understanding how a plane flies baffles me.
Damn, so true !
People use lots of stuff without truly understanding how it works.
It is a black box to them and will just work using the corect 'incantations'.
Examples are radio, tv, magnetron, mobile phone, electrical infrastructure and there is lots more.
All of them require a lot of deep knowledge to create and build them.
These days no one is able to know everything.
But as a pilot, you are taught concepts of airspeed. It’s actually very logical. With 10 years experience, the pilot should NOT be surprised 😂😂😂
I think that this myth is mostly a misunderstanding between people seeing a plane with its engine spinning while staying in one place and a plane that is moving forward. The conveyor belt is just useless information to determine wether the plane will take off or not.
@@YippingFox Something is deeply wrong with this busting attempt (as usual with Mythbusters). Namely, it didn't prove anything. The myth isn't about the plane not being able to lift off from a conveyor belt, it's about not being able to generate lift because it is staying in one volume of air. Here we can see that the plane is moving forward faster than the tarp below it, so what does that prove? Nothing. We don't even get the (presumably changed) lift off distance (both in world and tarp space), and plane-tarp relative velocity, which is incredibly important for anyone to gather any intuition about this.
Rolling resistance is independent of speed, so conveyor can only create a limited amount of force. This force, dragging the airplane back, will be easily overcome by the force of airplane's thrust, pushing it forward.
If you configure a feedback system that increases or decreases the conveyor belt speed to *try* to keep the plane stationary, once the propellor stars to pull the plane forward, the belt would rapidly speed up, limited only by the power supply. If the conveyor belt itself doesn't catch fire, the plane's tyres very well might, in which goopy burning molten neoprene will offer considerably more resistance.
All the conveyor/plane experiment did was to cause the wheels to spin faster than they normally would have. The speed of the conveyor + the speed of the plane moving forward. The conveyor has nothing to do with the ability of the plane to move forward through the air.
If the plane needed a speed of 80MPH to lift off, and you had an 80MPH head wind, the plane could fly without an engine. And it would fly without any forward motion too. It's the speed of the air over the wings that causes the lift. If the wind speed was higher than the speed needed for flight, a plane could even fly backwards.
Many years ago, I used to fly RC planes. On very windy days I could just hang the plane in the air right beside me. I could do vertical take-offs and landings. It's all a matter of balancing the forces. Thrust, drag, lift and gravity.
Indeed, the wheels speed has nothing to do with the speed of the plane. They could have dragged the belt 10X faster, the wheels would rotate 10x faster, but that does not affect the plane.
He says cockroaches are everywhere, but I must live nowhere.
i dont get why they are called german cockroaches, i live in Germany for my entire life and have never seen one
They are called German cockroaches as the first scientific description of the species came from a German entomologist, so a different entomologist who was responsible for naming the species decided to call them the German Cockroach. @@Albasapiens_Flinthandwerk
@@Albasapiens_Flinthandwerk maybe they originally lived in Germany, and when the first wave went to America, they sent word back, and they all packed their bags and fucked off.
The key to this airplane experiment is the observation that the tarp was tearing when Adam's feat were pinning it to the ground through friction. The plane and pilot were also pinning the tarp to the ground but not tearing it. Why? Obviously the pilot and plane were heavier than Jamie alone. The difference was that the plane wheels were rolling and so the pin-time was less. The pinned section of tarp was able to catch up with the rest of the tarp because it was able to bunch up as it passed under the wheels of the plane. The key point to all of this is that the wheels were not being dragged backwards by the tarp.
Because the wheels are free turning, they will always be at the same speed as the tarp until the plane itself reaches 25mph and takes off.
Thank you this explanation!
Plane on a treadmill. 1. The Mythbusters should have measured the wheel speed of the planes. This should show the wheels moving at twice the normal speed. 2. With a model (or in full size?), it would have been interesting to have something blowing air over the wing at take off speed. An air compressor spray attachment would work if you could get the speed right for the model. With that setup, you should be able to have the plane take off while stationary with respect to the ground.
I remember seeing a video of a plane landing in place due to the wind speed matching the airplane's airspeed. Why a conveyor belt would have any relevance is beyond me.
@@markadler8983 My thinking was how to show this. With such a setup you could show that it is the air speed that matters, not the relative ground speed. Hope that helps.
You need to have a cutoff at some point, you cant address EVERY way people can get it wrong. But yeah, it seems that way the main error, people thinking that wheels make plains take off, they should of concentrated on that.
Plane on a conveyor is really quite simple. A plane can have all the thrust it likes, but without air moving over the wings, there's no lift for flight.
How is ground speed relative to takeoff when the prop and wings are in the air?
As a Pilot, Airplane can only lift when air is enough past the wing, SO what happens to the wheels has no bearing except that the drag from the wheels either on grass, dirt or hard paved runway does add into take off distance charts you need to do in certain situations. So if you are pulling a runway under the wheels backwards and the plane needs to go forwards a certain ground speed for lift, THEN YES, the plane may take more time as extra drag on the wheels being over come by the fixed engine power BUT the plane still wont lift either way till airspeed past that wing gets to certain threshold. Interesting, if you have a say 60 kt head wind on the ground, the plane MAY start to lift standing still as the wing has enough left at that point without ground roll forward to make extra.
There are plenty of video's on here of planes 'taking off' when not secured during a storm, relative airspeed over the wing is the only thing it cares about. And I don't mean btw blown sideways, I mean actually suddenly jumping almost straight up from their moorings when they break in a hurricane, when the wind is coming straight from the front off course ( or else it will start flipping right away ).
@@MarvinWestmaas Yes, theres small metal rope to ground tie down rings under the wings and at the tail as gusty wind can play havoc. I remember this a while back and people were arguing exactly what are they saying for this myth? Is it that if the belt is pulled backwards, the plane cant move forward to get Lift or do they think wheels spinning gives you takeoff? Bit confusing but Jamie said it that power is from the propeller so besides a little extra drag, the plane given enough HP, can pull forward even if wheels where in very deep grass and eventually get to take off speed although this can be dangerous just as taking off from high elevation and hot conditions requires much long take off roll. The Ultralight pilot should have know the answer but they arnt schooled with standards of a private pilot licence and you dont even need training or licence except when plane gets bit heavier and diff category some formal training and theory is required. The slick material pulled under his plane wont didnt... add much drag and he pulled forward easily and they didnt bother to measure his distance to take off which i guess was a touch further? showing the myth is slightly right in that it will effect take off a little but holding you in position NO, its all about drag on the wheels and power pulled to overcome it which will be plenty usually.
They missed the ball on some very basic principles here, I mean they took a badly worded myth and 'tested it' without actually considering the physics.
The myth is indeed about 'what makes a plane fly, is it the speed it gets relative to the 'ground' ( which is the same as we keep the plane steady but move the ground under it, aka treadmill ) and anyone vaguely familiar with the Wright brothers knows about relative airspeed. Heck even the biggest 'dumb guy' only has to watch a news item about planes taking of from a carrier where they explain once they sometimes have to adjust heading to accommodate launches since a catapult only get's a plane to a certain speed relative to the carrier, and it needs the headwind to generate enough lift based on the relative airspeed.
Once you 'know' the only relevant bit to lift is relative airspeed ( and shape and size of a wing off course ), the whole notion of a stationary plane on a treadmill taking off should be dismissed as one of those dastardly devil cartoon pranks.
@@xx3868
My thoughts exactly. I mean, if the hypothetical airplane can be designed with a prop length approaching a wingspan then it will be able to create enough airflow over and under the wings to make it take off with 0 ground speed, but normal airplanes are not designed that way.
Or, maybe, if the treadmill has giant "sails" that will waft air onto the plane's wings it would work.
the earth is stationary geocentric and fIat, all pilots know this
It's insane, that the pilot took of without understanding why. Maybe he thought those wheels actually pull the plane.
Well... he's a pilot who flies an ultralight without any head protection, clearly it is not worth protecting ;)
Well, he did say that if the speed of the wheels match the speed of the conveyor, he would sit like a brick. That would be true, IF the wheels matched the speed of the conveyor, per definition the relative velocity of the airplane would be zero, thus not creating any lift. However, the velocities of the wheels and belt did not match.
@@plerikmetselaar1152
Oh, no...
The velocity of the plane is controlled by the propeller, not the wheels. The spin of the wheels has noting to do with the plane's ability to take off. No matter what the wheels / ground (the belt) are doing, the propeller will speed the plane up to the take of speed. It's the air-speed that matters, not the ground-speed.
@@iqnill
Oh, yes...
I am aware of the fact how an aeroplane gets into the air. However, if the prop delivers just enough force to overcome the friction of the wheels, the rotational speed of said wheels match the linear speed of the belt. Of course it can take off due to the proppellor delivering the thrust, but how they showed it, the rotational speed of the wheels is larger than the speed of the belt. What I am saying is that IF the velocity of the wheels match that of the conveyor, the plane's relative velocity wrt the ground (or air alike if there is no wind speed) would be zero and thus it would not take off.
@@plerikmetselaar1152 Um, again, no, plane takes off... the rotational speed of the wheels will always be greater than the speed of the conveyor belt... what you describe is a stationary plane with the conveyor belt running underneath. That is not the myth here. The PLANE moves forward, the conveyor belt moves backward. Forget the damn wheels already.
I had the lucky opportunity to fly about Northern Ontario one summer in a small plane. The pilot (great guy, crazy!) once slowed the plane down on a windy day so much that we were flying backwards! Very freaky looking down as I recall but same principle I think.
Nope.
I've seen a bird flying backwards on a windy day before XD
Airspeed is everything. Groundspeed can be whatever.
When your stall speed is 40 knots but you have 50 knot headwind.
@@JinKeethe only right answer
“Confused flour beetles”
they sure are
what has a treadmill with the lift of the airflow?! not even worth my time...🤣
you dont have to understand physics to be a pilot in the us?
Why is the video only in 240p picture quality? I can't change quality settings.
The tower to the pilot: Do you see the runway?
The pilot: yes , it's short but incredible wide!
Yeah! That was Rad!
Planes comes up with VIND SPEED! no because there are JUST rolling "F--K!"
17:22 Safe. Unsafe. Safe. Unsafe. She could be Homer Simpson. Like in Australia. XD
One of the other potential nuclear event survival insect species should’ve been a type of ant.
The Ontario Science Centre had a live, radiated ant farm as one of the exhibits in The Haull of Life at one time.
well I don't feel safe in aircraft now! lol
Lots of psychology in this one. How people can be wrong about something that goes wrong against simple rules they take for granted(conveyor plane) or how people react to bugs experiment. Comments are good!
Get high enough air speed, to create low pressure above an object, and create a higher pressure below the object, and anything can fly. Ground speed does not directly effect lift.
Trailers can fly for example in high wind. they don't have wings to sustain the flight for long, but they can be lifted off the ground.
How many non anchored structures go on an airborne trip during a hurricane or tornado? no wheels to get them moving, just high and low air pressure and a cushion of air to ride on.
plane on a threadmill is the absolutely stupidest myth ever on mythbusters.
Jamie actually thought so as well.
However when Adam produced a 6 inch thick pile of paper of comments on it from the fansite and presented it to the producer the decision was made.
Controversy isn't always a good commercial though ;)
Most will likely forgive them, to many fond childhood memories of the 'mythbusters' when I actually still considered there was actual science taking place.
@@MrMarinus18
There was apparently a boob size myth, which Adam talked about on his podcast... I would imagine that was worse, but yah. Once you understand a free wheel on a plane is different to a powered wheel on a car, this is dumb.
@@jontymalice1336 actually the boob size myth was about a real scientific test and the outcome was very surprising to EVERYONE.
but even every CHILD knows you need wind (aka airspeed) to get lift on a kite. which basically is an airplane.
every child has experimented with paper airplanes too.
i´m quite certain that the people who got this myth to the tv, were actually just trolling. (i mean the people "fighting" about this on the forum or whatever)
i just ... never could fathom how someone putting a threadmill on the ground could affect an airplane, say for instance, 10 miles up in the sky. or how someone could think that. instant energy transportation via quantum enganglement or a wormhole?
and yea i´m so old i wathced the episode when it first aired on telly.
could not stop hitting my forehead into the wall.
The plane myth is easy to understand : The only thing that matters for a plane is its true airspeed. So the speed of the incoming air hitting the "front" of the plane. Wheels are free and useless, they're only here to roll during the takeoff and landing phases.
They do more than roll during landing (and pre-takeoff, obviously).
So many people still don't believe the plane can take off on a treadmill. I was team take off, long before this episode aired, it was a fun subject to discuss. Many of my friends that were on team no flight still won't back down on this subject even after seeing this episode. Best way to think of it, the air is a planes road and the plane gets pulled forward through that air by the propeller, what speed the tires are spinning at has nothing to do with the planes forward progress. Jamie could have been going triple the speed and the plane would have still pulled forward and up through the air. If you put revolution counter on the wheels of the airplane, they would have matched Jamie's speed plus the needed 26 mph for take off.
I'm shocked the pilot would believe in this myth, though. If he has so little understanding of how his plane works, I'd be worried to fly with him.
well i agree and disagree with you, as long as the wheel drag force does not exceed the force of the propeller than i could start accelerate forward
@@aowest5904 You best be changing your wheel bearings on your Cessna there pal. lol you crack me up, yeah wheel drag is factor for a 180 HP motor. Best you have a Snickers because you suck at trolling when your hungry.
@@TheRattleShark I am not trying to troll but the speed of a plane is a result of the total force of the propeller minus air drag resistance and wheel drag resistance combined, if that wheel drag is high enough then it can't take off. i do agree that in practice this will not be easily the case off course.
@@aowest5904 How much wheel drag do you think there is to hold back a plane? You watched the video, they proved it. The plane they used needed 26 MPH to take off and Jamie went faster than that in the opposite direction. The plane throttled up at the same time and it took no less time or distance to take off. Sure there is wheel drag but it is miniscule. Go back and listen to Adam when he has the car on the treadmill, he talks about how effortless it was for him to hold the car in place, wheel drag was a non factor. I'm done discussing this with you if you can't get it, I have better things to do with my time other than giving you a free physics lesson. Have a good day while you go discuss this with someone else.
Well this shows you dont need to be a genius to be a pilot.😮
Ridiculous. No airflow. No lift.
airflow, exactly. wheels and ground speed has no bearing on lift
The wheels spin twice as fast, but they don't propel forward. Why is this so hard to understand? It would likely take off if the conveyor belt was going twice the speed of takeoff.
The x factor that could prove the myth is severe friction in the wheel bearings. But you'd have needed a really fast treadmill. (+100mph?)
Any pilot should know that the moment of take-off only depends on the airspeed over the wings, not the ground speed... a plane can even take off standing completely still as long as the wind is fast enough... fail
nice wheel design on the plane
The foam in a car thing is obviously inspired by the movie "Demolition Man".
Neeee fan inte 740in :(
The thing with the plane is there are two interpretations of the myth that people argue. One is what was shown here, that the conveyor belt is moving at the (minimum) take off speed of the plane in which case the plane is able to accelerate and take off. The other is that the conveyor belt is moving at a speed matching the forward speed of the plane, which creates a paradoxical loop that is physically impossible. I.e the plane accelerates, then the conveyor belt accelerates at the same rate to cancel the speed out, in which case the planes velocity is cancelled out so it did not accelerate to begin with. So whilst it might be a semantic point to argue in online threads, in practice physics only allows the first case to be possible.
wrong, in either case the plane wont care, the plane wheels are not connected to the engine, the wheels spin only twice as fast in both cases, and people that say that the plane cares about the stationary ground also are wrong, the plane only cares about wing wind speed, a plane can fly "stationary" or even backwards if a strong enough wind is applied to the wings, the propeller is only connected to the engine so that it can move air around the plane fairing so that the plane can reach a speed relative to the wind that is enough for the wings to generate lift
@@xzinik2961 You're missing the point about the second scenario. It's physically impossible to have the conveyor belt speed up to match the forward speed of the plane. This state can only exist when stationary. Otherwise you have a paradoxical feedback loop.
Therefore the only interpretation of the thought experiment that is physically possible is where the conveyor belt is moving at the take off speed of the plane in which case as you said the plane effectively doesn't see the movement of the plane and will accelerate regardless thus taking off.
I'm not arguing for the other scenario, just explaining how the riddle has been interpreted in different ways, which is what sparked the internet debate, and how of the two possible interpretations, one is physically possible and the other is not.
@@nicholascrow8133 why do you say its impossible to have the belt speed up to the same speed as the plane? a fixed pulley would do the trick with the same setup of the mythbusters only that this time instead of moving the conveyor with a car its the same plane pulling it, if the plane acelerates at 5m/s² and it pulls on the conveyor belt with a pulley, the conveyor will move at the same 5 m/s² but in the other direction, the only one that is affected is the wheel that notices 10m/s², that in this case the plane wont care either because it pushes against the air nothing else
@@xzinik2961Hold up, I got a bit confused (Drinking and physics don't mix well lol) I meant the other scenario is where the conveyor belt speeds up to match the speed of a wheel driven plane... (The situation they explained in scale with the whole car vs plane conundrum)
So a third scenario I guess. That's fundamentally where people get confused when trying to argue the plane can't take off.
As in to say, if one was to believe a plane is driven through the wheels, it is impossible to have a conveyor belt matching the speed of the accelerating vehicle, as any acceleration would be cancelled out, killing that train of thought before it can take off (very bad pun intended)
Did they do one about cars running on water? (Hydrogen combustion engines?)
on an open ground conveyor.... no, never
but in a windtunnel... ?
it's about the air speed passing the wing(s) to create lift
I think they were unfair on the pilot with this one, he wasnt wrong in the presumption that if they managed to keep the airplane stationary then it wouldn't fly, which is what they showed in their animations. Of course he forgot to take into account that the plane wouldn't stay stationary because their "treadmill" could not move fast enough to assert enough drag on the freewheels to stay stationary.
Their animations were actually highly deceptive.
In the animation they portray a plane on a treadmill and give two possible scenarios.
1) the plane stays still and cannot fly.
2) the plane stays still but then levitates and starts flying.
But then the other option they did not portray was
3) the plane does not stay still and still manages to takeoff because it's still going forward.
IF they actually made it a rule that the plane must stay stationary in the Y axis, as in not moving forward, then the plane would never take off.
And it doesn't matter whether the plane is powered by the wheels or the propeller in the end because even if the airplane were powered by the wheels on a normal takeoff strip it would still take off because of the lift generated by moving forward but then it would come back down afterwards because of it's inability to maintain acceleration.
So when they stated that the pilot was wrong because he failed to understand that the drive didn't come from the wheels is just wrong.
I hate the plane myth because everyone tells it differently
Some say it matches the planes speed
Some say it matches the wheels speed
The former is in the video
The latter is super complicated since the wheels matches the speed that is the difference between the planes forward speed and the grounds speed, but here the ground is trying to match that speed causing a positive feedbackloop. Something has to give. Either the wheels, the conveyor belt or the loop itself being too slow
i certainly wouldnt risk a private airplane on their stupid conveyor belt, if it lifts and connects with the propellar your looking at some damage probably.
I felt like the whole thing was a missed chance.
I also thought that the whole point of the converyor belt would be to see what happens when a plane reaches its takeoff speed, yet stands completely still to the neutral observer.
I do not think the myth was supposed to say 'here is your takeoff speed in reverse, can you get fast enough to overcome the speed deficit and actually roll forward to the neutral observer, then with enough speed do a takeoff?
Because that was never questioned. Also, what a stupid myth, the air stands in the room, not on the belt. So if you do not move through the room to move through the air, you will never generate any lift.
In the same vein, you can make a plane fly 'one the spot' by blowing at it with wind that has a speed correlating to the plane's takeoff speed. Woooh, you just invented a new kind of flying machine capable of standing in the air!! Its name shall be....kite!
Wasted 4th grade thought experiment. 5th graders would laugh at this. Thousands of pages discussing this, written by adult human beings, as claimed in the intro? Where? America? Jamie realizes the sheer simplicity of the solution instantly and has some fun narrating the outcomes of experiments he clearly thinks are totally worthless. Which they are. Thinking gives the solution in less than 2 seconds.
so you would have to build an air conveyer belt aka a huge blower fan / air tunnel and test it with a plane in there... the plane will take off but remain stationary... I have even seen this happening to planes in real life conditions like very strong winds.... the plane will just not move but it will fly... because for it to fly it will only need airspeed, but if the speed of the surrounding air matches the airspeed at which the plane flies normally it will just stand still relative to the ground
While most people hate cockroaches and while I never seen one myself I am facilitated with a few facts about them such as them living over a week after decapitation and as they’ve show they can survive over half an hour underwater
but didn't the plain moved on the runway before taking off? I could be wrong but I think I saw the plain moving forward (of course slower than what it would if it wasn't on the belt) before taking off.
Of course it does, it’s impossible for a treadmill at any practical speed to prevent an airplane moving forward, because the airplane doesn’t get thrust from the road, it gets thrust from the propeller (or jets or whatever) pushing against the air. And the air doesn’t change speed with the treadmill.
The wheels are free-spinning. As soon as power is applied by the props the plan moves forward.
I was gonna comment about how the plane myth is plain dumb, and how I would doubt more than a tiny minority could fail to understand the plane's engines are thrusting against the air, not the runway... But then I see the comments and remember how dumb the internet can be *facepalm
The pilots answer is correct,he taking all sorts of differentials into consideration, first is the safety factor needed to keep humans safe means the air force created by the propeller isnt enough to push the amount of air need over the wings and flaps to lift the weight of the plane.....buuuut... with wind speeds and the extra velocity of the propeller......?????? Who really knows so I'm about to watch them try with a tarpaulin as a conveyor belt! Personally I believe there's too many variables for the myth to be tested correctly!
Of course the plane took off. It had forward momentum, therefore it had lift.
easy to see that the conveyor belt doesn't help to lift off. I think it would reduce the braking distance at landing. i would love to see.😶
It doesn't hinder or help with take off or landing. When landing, the plane is travelling at the same air speed no matter what the ground is doing. When it lands, the wheels will spin faster, but the brakes still have to convert the same amount of kinetic energy to heat, as the additional kinetic energy of the faster spinning wheels is negligible. The plane will come to rest relative to everything other than the conveyor belt in the same amount of time as normal, and then begin to move backwards as the wheels continue to slow relative to the conveyor.
@The mistake here is thinking we are only dealing with two different speeds, airspeed and conveyor belt speed. There is a third to consider, ground speed. Relative to the ground, the planes airspeed is equal to its ground speed (ignoring wind). But relative to the conveyor belt, it would be equal to its ground speed plus the conveyor belt speed.
It is the aircraft's speed through the air that determines when it takes off. While the conveyor belt was moving under the aircraft, it was not drawing any air over the wings. This is why the plane moved relative to the ground before taking off. When landing, it is friction between the landing surface and the aircraft's wheels (as they are braked) that determine the stopping distance.
Therefore, relative to the ground, its take off distance will be as normal, but its landing distance will be shorter. Whereas, relative to the conveyor belt, take off distance will be longer than normal, but its landing distance will be as normal.
That poor Volvo... 😪
Well even tho it worked, and I didn’t think it wouldn’t work. That was not a good test. The belt moves over smooth rollers and not a rough ground. There was no loss of traction.. as seen by the holes Adam put in it when running on it… therefore it was not a fair test.
Ya, thats what I call....traction.
26:51 that camera can survive a nuke i would like to know what make n model lolz
How is this plane myth even a thing? A plane needs airspeed to lift off. If the plane is sationary, it doesn't genrate lift... Is this actually something people argue about? Of course the plane is going to move forward if it's being driven by a prop. The wheels are not relative to airspeed in any way..
is it safe to handle stuff that has been subject to high radiation??
how can you be a pilot and believe that myth....scary ahhaha
Conveyor belt is utterly irrelevant, unless you use the wheels to measure air speed, which in itself is nonsense.
All that matters is the speed of the air over the wings. So, put the plane in a huge wind tunnel and it will fly in situ.
But put it on a rolling road and, without wind speed, it will sit there. What the plane is standing on and whether it’s moving or not, has no effect whatsoever on the physics of flight, which are only concerned with air flow.
Poor Volvo, i would have taken it home instead that having it messed up.
You just made world founding discovery that a plane can take the sky just spining its wheels fast eneough. No runways needet anymore. Wright Broters shuold invent this at begining.
Replace the plane wheels with skis, still will fly .....
RIP Grant. 😢
Wtf can't get better than 240
Same here, only 240p quality available
Those are tiny cockroaches.
and if you pull the tarp the other way you should have take off hehe hehe
And the Earth is FLAT yeah?
Engineers everywhere triggered by their conclusions of plane on a treadmill.
You mean, not just the conclusions but the whole approach / thought process?
@@MarvinWestmaas Their rationale for the conclusion they reach was just incorrect. As I said in another comment: A treadmill moving infinitely fast generates infinite force on the place via it's wheels. But a propeller (or jet engine) spinning infinitely fast does not generate infinite thrust, because there is diminishing returns as the propeller pushes air faster than the air can return, and create a near vacuum. So as both speeds increase to infinity, the plane never takes off.
but this is a physics question not an engineering question. what the wheel and belt does is irrelevant to the lift on the wings. the belt and wheel moving infinitely fast would go into the realm of special relativity and i would have no idea how that would effect the lift on the wings. the wheels are free spinning only the thrust generated by the rotor/jet would matter on whether or not it would move forward. since this is a physics question with the expectations of Newtonian physics, then we assume that the wheel is an Ideal wheel with zero friction on its bearings. it would still take off since the wheels are just there to keep the plane upright, they have nothing to do with moving the plane forward
@@richarderguiza7080 Assuming 0 friction would be the absolute last thing you could do, because it would mean the conveyor belt would do literally nothing. Friction is the only force the conveyor belt imparts on the plane. Also, no, aerodynamic principles are both engineering and physics.
Actually the plane will always take off because it's the propeller that pulls the airplane trough the air not the wheels. Even if you had proper gigantic threadmill , all it would do is make the wheels spin infinitely faster, but the plane will still take off. The wheels have essentially nothing to do with airplane taking off @@--Dan-
Cockroaches though are tropical insects and are quite vulnerable to the cold. They can't survive in temperate climates without artificial heating by humans. After a nuclear war they likely would die out in most of the developed world cause they rely on humans to keep the cold away. It's also why the wild range of cockroaches is expanding due to climate change.
The most hilarious thing is people _STILL_ arguing about this.
The airplane speedometer reads the air speed, not wheels speed, so the pilot accelerates until having 25 mph...it remains a myth.
Wheel speed is irrelevant for the plane to take off. You could run the conveyor belt at 10 times the speed and the plane will still move forward and take off, because the wheels will always just take on the speed of the conveyor + the air speed.
that plane stunt is rubbish, its clearly moving forward!!!!
Why ‘The boys’ These men are so intelligent. I don’t understand the script writer. Nothing against the narrator.
Why did they not use elefant tootpaste?
While elephant toothpaste does expand a lot, it also collapses extremely fast. All you end up with is a wet car.
@@m.h.6470 Ah, did not realise that, thanks
I have always hated when editors fast forward Grant's explanations. Why didn't they just put him in a clown suit of they didn't want people to lose interest for a minute /s.
The plain should have remained stationary. I didnt watch it like that. I saw the thing moving
The plane CANNOT remain stationary. It simply isn't possible. It either moves forward by the power of the engines or backwards by the power of the conveyor belt. Being stationary is simply impossible for a plane in that situation. As explained in the video, it is not a car. The engines are completely separated from the ground. As such, the speed is separated from the ground as well!
@@m.h.6470 all righty then! I would think that the plane just "levitate" from the ground as soon both contrary forces reached the same speed. Am i making any sense?
@@vascoapolonio2309 There are no contrary forces here. There is one force acting on the plane (forward, from the engine) and there is one force acting on the wheels (backwards, from the belt).
But the wheels are free spinning and therefore have literally no influence on the plane. As such, the forward force is unhindered and the plane moves forward and lifts off.
@@m.h.6470 i dont think i get it. Even if the "ground" is going backwards, for the plane only counts the speed from the wheels. Im no engineer, obviously!!! The engine is the driving force propeling it?
@@vascoapolonio2309 The plane only counts the speed coming from the engine. The wheel speed is totally irrelevant. It literally doesn't matter, what happens below the plane: Stationary ground, same speed backwards, same speed forwards, double speed backwards, etc. The plane WILL move forwards regardless and the wheel speed will adjust accordingly.
If you had a conveyor belt that goes same speed forward for example, the wheels wouldn't move at all, but the engines are running.
But if the engines weren't running, the plane would NOT go forward (at least not much)... remember: the plane wheels are free spinning, so the inertia of the plane would cause it to roughly stay at the same place - moving backwards from the conveyor belts perspective. That is the counterintuitive thing.
I miss the team
Its called aeronautics not wealonautics
The only thing I miss from that airplane myth: Tyres are rated to a maximum speed. Having the wheels turn twice as fast as they normally do will exceed the limit significantly. Surely no problem on a small ultralight, but this might be the small detail that could prevent an airliner to take off...
👍 I put exactly this point in the response to another comment here, before I read yours (2× ω = 4x f).
As long as the wheel bearings can handle it, there's more than enough power to spin the wheels twice as fast, and the tyres may be rated to a certain speed, but that rating would be a lot higher than anything that would be expected in normal conditions, and even then, the actual failure speed would be higher still.
@@mikejosef2470 it's not about power, but the mechanical load and heating on the tyre ply. If you go over the tyres' limits, they might even explode.
Yes, but show me a conveyor that isn't outside it's specified envelope moving a 380 tonne 747 at 360 km/h. 😁
@@Deipnosophist_the_Gastronomer that's the problem on these thought experiments 🙂
The plane still moved forward relative to the ground.
Fully bungled.
The plane will ALWAYS move forward relative to the ground. It doesn't matter how fast the conveyor belt goes. That is because the propeller or turbine simply doesn't care, that there is a conveyor belt, as it moves the plane THROUGH THE AIR and not on the ground. That is the main thing that people don't understand. There literally is no way for the plane to stand still with the engine(s) running. It either goes forward, propelled by the engine(s) or it moves backwards being dragged by the conveyor belt. Standing still with engine(s) on is NOT an option.
@@m.h.6470 you really haven't thought this through.
@@chuzzbot And what exactly do you think is wrong?
@m.h.6470 The plane could stand still if the propeller was providing exactly the amount of thrust needed to counteract the very small amount of friction due to the wheels rotating on the conveyor. A plane does not normally move forward when an engine is at idle with the brakes off, meaning it has to overcome some frictional forces before it can.
@@kiwibob8967 I obviously meant "with the engines on and not on idle" and didn't feel the need to state that. And engines do not have that much control to deliver that little thrust to ONLY counteract the friction. They are way to powerful for that kind of delicate movement.
A plane just needs wind under its wings from the prop. It doesn't need to move to take off. Stupidity of this myth blows my mind.😅😅😅 Use a jet engine plane for this myth.
The Runway should theoretically pull half the take off wind speed with it, Should make it slightly shorter take off.
I think I have a simple explanation of why the plane myth busts so easily. A thought experiment:
Imagine an infinite treadmill with the plane on it. The plane's takeoff speed is whatever it is, and we set the treadmill to match that. We start the treadmill and give it a minute with the brakes applied to the wheels to get the plane actually moving backward with it at speed before we start the engine. At this point, the wheels aren't spinning because the plane is stationary relative to its spot on the treadmill, hence the plane moving backward relative to the observer.
Now, we start the prop going (and release the brakes), and as soon as it generates enough force to move it forward on a regular runway, it will also start moving forward from its relative position on the treadmill. And the wheels have started spinning, of course.
At this point, the treadmill no longer matters because all it's doing is spinning the wheels. The plane should very quickly start moving forward relative to the observer because it's pushing against air, which the treadmill has no effect on. The wheels don't matter because all they do is spin; unless the brakes are applied, they have no impact on the motion of the plane whatsoever.
That's the difference from a car or a person. They're pushing back against the treadmill itself to get forward momentum. The plane isn't. It literally doesn't matter HOW fast the treadmill is going once that prop starts spinning.
Also.. treadmill has ground effect dragging adjacent air along with the belt.
At such speeds that's negligible. You can't ever hope to reproduce the ground effect with this setup.
Plane Myth: The conveyor will prevent the plane from taking off. Reality, The engine provides thrust to the body of the plane. The Conveyor is moving the wheels at 25 mph, but the plane is not moving in relation to the wheels and there is negligible rolling resistance. As the plane accelerates to 2mph the wheels are now spinning at 27 mph. When the plane body reaches 25 mph the wheels are actually spinning at 50mph because of the additional speed from the belt. The wheels contribute nothing. If you could get a giant fan to blow a tail wind at the same speed as the plane, it would cancel out the movement of the air over the wings and prevent flight.
Finally someone else using the same explanation as me. They never addressed the speed of the wheels in this episode. I think it would help more people make sense of what's happening. They could have also pulled the conveyer at higher speeds.
This plane myth is completely dang stupid omg really 😂
You don't help things when you spell 'plane' wrong.. 🤪
Lol dang not got me glasses on an spell check took over lol 😅 😂 all fixed now lol 😆 😂 😅 🤣 😄 🙃
Plus I was multi tasking 😆 🤣 lol
@@JasmineJDMgirl Gonna call some BS on that, as spell check would not have triggered. Both 'plain' and 'plane' are correctly spelled words - you just didn't use the right one. Good try though! 🤣
@@JasmineJDMgirl Chewing gum and typing is not 'multi-tasking'. :D
TL;DR: A plane stationary, relative to the ground, will not take off, no matter how fast the planes propeller thrusts and no matter how fast its wheels are turning.
Ok, so, i have never heard this plane myth before, but here we go..
First, a better way to test this myth would have been to put it on a dyno, making it spacially stationary and seeing if it will take off by its thrust.
Or, a reverse dyno, where it makes the planes wheels spin up to take of speed.
But, of course would never happen as lift is generated by its wings not its wheels or its method of forward p
As air moves faster, its pressure decreases, so planes generate lift by having air flow faster over its wing and slower underneath it, thus creating more pressure underneath the wings the faster its moving forward and allowing it to lift off the ground.
If the plane was truly stationary relative to the ground with only it's wheels to spin at take off speed, there is not enough air speed to create the pressure under its wings required for lift - if this were the case they wouldn't need a runway.
And regarding the question of "will a planes propeller with generate lift?", the answer is no. The only way would be if the propeller was directed to force air towards the ground, in which case, would essentially make it a helicopter.
a stationnay plane can absolutely take off. Happens in every hurricane or high wing. The only thing that matters is air speed over the wing. The wheels or ground movement doesnt matter .
@@Nordic_Mechanic
Sure, i suppose that's possible, but I would assume its a pretty rare occurrence. Airports are often closed and planes regularly get diverted during hurricanes and strong wind events - not sure if there is regulations around that, im not a pilot but surely it wouldnt be safe to attempt, especially in a light plane.
The propeller on most (many?) Directs more moving air under a wing than over it both by the shape of the wing and the actual up/down (y axis) placement... this causes lift.
The actual test would be to speed up the treadmill and advance the throttle until thrust keeps the plane stationary... ANY thrust beyond that point will start forward motion and contribute lift..
I don't know whether you are for or against this myth. If you want to keep the plane stationary just tie it to something heavy. Then see if it can take off. If you're asking whether it can take off from the thrust of the propellers alone, then probably not as although the propeller does direct some air over the wing, it's main job is to give the plane momentum, and then maintain that momentum.
This isn't a myth is it? I mean, who the hell thinks a plane will take off with no relative airspeed? Groundspeed, or speed compared to a treadmill is entirely irrelevant.
They reached the conclusion that it would. (They're wrong, but that was their conclusion)
Aand you are wrong.
Havent you even watched this episode?
Such an odd 'scientific experiment' lol.. well if we make the plane go a bit faster then the treadmill, will it still get enough relative airspeed for the plane to take off? And if it does, is it representative of an actual plane on a treadmill, or is this plane's mass to weight ratio playing a role in it's short take off capabilities / meant for indoor flying with no wind )?
God I can't believe I watched this as a kid and thought they were actually 'solving myths' instead selling a tv program
Because they made the plane move forward over the treadmill, so they gained some relative airspeed.
In which case it would be possible.
@@--Dan-
Back to school you go kiddo@@ddnn1142
Important for a plane is air speed, not ground speed. It can't lift of on a conveyer, but it can lift off while standing still with enough wind.
35:40 notice the plane is strapped down. Because if the air blows, the plane will move.
Why 1908 at 31:18 ? The Wright flyer first flew in Dec 1903. By 1908 they already built the Flyer III. Was to make just 60 years before the Jumbo?