Mythbusters - Plane on conveyor belt the practice!

Mythbusters test the myth!

[@merpins]

Here's something to clarify: the plane will always move on a conveyer-belt, and will move forward at a normal speed regardless of the speed of the conveyer-belt once it starts to move. The reason: the plane is being pulled through the air, not by powered wheels. So as the plane moves forward, all the conveyer belt does it pull the wheels in the same direction they were moving, causing them to spin faster, but not hindering the speed of the plane at all once it gets moving.

[@aweDelan]

But if the conveyor belt always matches the speed of the wheels, the plane cannot move because its being kept in place by the wheel stuck to the belt. This experiment was flawed because they didn't observe the actual speed of the wheels and conveyor belt. The wheels were spinning faster.

[@lolzlolz102]

@@aweDelan The plane will ALWAYs move forward regardless of the speed of the conveyor. The plane is being pulled along by its own propeller, the propeller is not influenced at all by the conveyor. The wheel is not connected to the engine so all it does is freewheel.

[@flyingshane1392]

@@lolzlolz102 If the treadmill moves backwards to counter the wheels moving forward as the airplane pulls the wheels forward, this thought experiment is very similar to the one Cris More at Dalhousie University gets toddlers to perform kzbin.info/www/bejne/oV7ViHVnn7Snb9U

[@taggerung890]

This explanation here is perfect. I think most people miss this point

[@mouseded]

@@aweDelan You're confused

[@Anonymous01959]

Ok simple explanation which the myth busters didn't explain. If you watch the videos of the model and full sized plane you will notice that both are moving forward when they take off generating air flow over the wings. This is because the propulsion is a propeller not a drive wheel. If a car were on that conveyor belt it would be brought to a standstill because the (ground) is moving backwards at the same speed as the wheel providing propulsion. But the aircraft's propulsion is independent of the surface. So all that happens is the wheels just spin faster to compensate for the conveyor belt and the plane still reaches take of speed.

[@drmaudio]

+Anonymous01959 Precisely right.

[@TRX450RVlogger]

+Anonymous01959 I'm so glad there are people like you with Brains.

[@jokeplay00]

+Anonymous01959 i thought exactly the same. when watchin this episode i was confused cause it is so easy to think abot and find out

[@batmmannn1379]

+Anonymous01959 Nope you are wrong. This Mysthbusters result is hacked. The problem is an always has been stated a Jet not a propelled machine and the conveyor always matches the speed in the opposite direction therefore no air ever gets over the wings to cause lift and the plane would never lift. On a Jet the engines are under the wings. Mythbusters totally Sucks. They don't do Science they do fake enetertainment with tainted bad results.

[@1951split]

+Batmmannn Jet or propeller makes no difference. They both create speed relative to the surrounding air, not to the conveyor, so the plane is still able to take off. Ground speed is virtually irrelevant for take-off, it's the air speed that counts...

[@ComandanteJ]

i dont get it. What has the turning rate of the wheels to do with airspeed?

[@RoboTekno]

ComandanteJ Exactly! haha

[@Juhujalp]

+ComandanteJ on the other hand... how the fuck did this pilot get his license? even he said that he didn't expect it...

[@ComandanteJ]

Haha, yeah, i bet he also didn't expect to get the license when he got it LOL.

[@dhw89]

+Juhuja LP It's an experimental type plane. You build it in your backyard, find an old honda, take the motor out of it and find a way to mount it on the plane, and viola, you're a pilot.

[@smileycanada13]

+dhw89 It is very apparent that it's an ultralight. They don't have the same license as pilots do, at least in Canada. The myth's outcome was very clear before it even began... Aircraft wheels are free spinning, so it doesn't matter.

[@foxkenji]

This doesn’t make any sense. The plane is still going forward regardless of the conveyor belt. That means the wings are creating lift. The conveyor belt is not pulling at the same velocities as the plane is moving forward.

[@kasparsburbeckis6241]

I agree it does not make any sense. The wheels of the plane are spinning freely and the propeller is ''pushing'' against ''static'' air.

[@ethenallen1388]

If you think that doesn't make sense, apparently there are people who say the experiment was wrong. I don't understand either.

[@VMpastore]

It does make sense, you could theoretically increase the speed of the conveyer belt infinitely and the plane would still take off. The logical flaw is believing that the conveyer belt has any impact on the plane, it doesn’t. (Realistically it has a minor impact on the friction of the bearings and wheels, but it’s minimal and not relevant) A simple question would be to ask yourself, if the wheels spin freely, and I place the plane on the conveyer belt at 25mph, does the plane move backwards at 25mph? It doesn’t, it stays relatively still and the wheels spin and the plane just sits in place. This tells you that the conveyer belt has an input value of nearly 0 on the plane. Then the plane rotor is able to pull the plane off of the conveyer belt because it is pulling air and pushing it backwards. The air is giving the plane forward momentum and it is independent of the conveyer belt.

[@deadrem]

Came here from this video kzbin.info/www/bejne/robNlHuNbLh7l6s&feature=emb_title and Adam makes a valid argument that the confusion lies in how the questions worded. People (like the pilot) assume that a plane that can't move forward is no different than a plane sitting still and the plane that is sitting still will not generate lift (in a normal environment). It's just a simple misunderstanding that the act of accelerating forward creates lift in and of itself.

[@usedcarsokinawa]

@@ethenallen1388 it’s about the air over the wings, period. Otherwise it wouldn’t matter if you took off into the wind or not

[@10001willy]

when i was younger, i always thought the debate was whether or not a still standing plane would be able to take off with a spinning propeller. now i realize the argument is based on the whether or not the propeller would outperform the spinning wheels, but if they are just circles around an axis, it seems glaringly obvious the air pressure on the blades would overcome the rotation of the wheels. it always seemed to me that a plane that was not moving (either brakes acting on the wheels or a cable preventing movement) would obviously not gain any lift since the plane itself was not cutting through air.

[@281cu6]

It is quite misleading. In their experiments on the show, they don't keep the plane stationary. It moves just fine on the conveyor belt. The real question would be if it could take off being held back by a rope.

[@andre10feb]

This clearly was a fail. The plane moved from its original position. Was that not the point of the whole myth?

[@Ryansanders80]

That's not the question

[@mosab643]

+andre10feb it totally did

[@fatherofwar1203]

+andre10feb No, not really. The idea is that the plane won't be able to move if the conveyor belt is moving at it's take-off speed in the opposite direction. Except that the plane doesn't use it's wheel to accelerate sit really doesn't do much.

[@Pong-Lenis]

+George Holland That-s exactly the same thing

[@3DFLYLOW]

you sir are right

[@FPSGHoST808]

It would be stuck on the ground if his propulsion was touching the ground. Since his propulsion is NOT driven by the wheels, the wheels can rotate freely and don't affect lift on the plane's wings.

[@WetOlde]

well you do have a bit of resistance in the wheels since they go twice the speed you do :P but yeah... small difference

[@lancebaker1374]

What the hell does that mean? The wheels have NOTHING to do with lift. The flow of air over the wings causes lift.

[@faltomjager5823]

Lance Baker that’s what they are saying. Fully read the comments next time.

[@duxxxhm]

Lift does not have anything to do with type of propulsion. It hapens when air flows aroud wings. Glider has no propulsion of its owns but takes off when pulled by something else. Why? Because it moves in fluid, in this case air. So arodinamic shape of the wings provide it with lift and it goes UP. And YES air is a fluid. I don't even know why we are discusing this nonsence. Do you realy think that it was posible, US Navy, for example wouldn't build trademills/conveyor belts on its carriers. No, they are so stupid. They build steam cataputs instead.

[@nexus1g]

James, he's not a licensed pilot, I can guarantee you. The aircraft he's flying is experimental, so he doesn't need to be licensed to fly it. Given his lack of basic knowledge, he's definitely not licensed.

[@David1010100ROBLOX]

*facepalm* It's not the wheels providing thrust, its the propellers.

[@JadeMythriil]

I think I can see why. This myth assumes that the propolsion is caused by the wheels and so if the conveyer is moving opposite at the same speed then it would've stayed in place. But the propellor pushes air behind it like a toy car pushed on a treadmill so it can move forward. Using that analogy, your hand on the toy car is like the wind that is pushing the plane.

[@subplantant]

It's nice to watch a video where all the intelligent stuff is in the comments...

[@majorphysics3669]

Ronald Simkin yea, I don't understand why people are so confused. Plane sits on conveyor. Plane engine on. Propellor creates thrust, thrust moves plane. Like, come on, its that easy. The wheels are irrelevant because they aren't powered.

[@weatherphobia]

He knows better how to pilot than you how to comment ONE TIME. And when did 'disagree' become 'troll' to you Buddy? Next you will call it HATE SPEECH and demand people get banned or better go to prison..likely.

[@The_Conundrum_Crew]

I remember this one. I remember all the fights and battles it generated on their website. Too bad they didn't put a disclaimer in the episode saying "WARNING: CONVEYOR BELT CAN'T KEEP A PLANE STATIONARY." Planes are designed to use lift to reduce friction against the ground, which makes forward movement easier, and in return further increases the lift. Otherwise how would a water plane take off in strong water currents.

[@kennybauer4181]

... but he moved forward... The whole point of the myth is that the plane stays stationary relative to the ground. But moves at takeoff speed relative to the conveyor belt surface. If it were truly the case a plane could never take off. It would need sufficient airflow.

[@ShadowFalcon]

+Kenny Bauer So what you're proposing is, tethering the plane to some outside structure, and then pulling a tarp under the wheels?!?

[@jeremydare8960]

0:29 - 0:40 in the video, the myth did not state that the plain had to be stationary, only that the conveyor belt be moving reverse to the direction of take off. if the plane recived thrust from its wheels (think a car on the belt) than it would have stayed still, but a plane gets its thrust from its propeller, leaving the wheels to do whatever the f*** they want to do.

[@ShutUpAndSmokeMyWeed]

it could work if the tarp creates enough drag to simulate a wind tunnel... lol

[@faltomjager5823]

Kenny Bauer but that’s now how airplanes work. The wheels move freely or have the brakes on and don’t move. The wheels just had to spin twice as fast.

[@kevinstephens9019]

You wouldn't have to tether the plane. The plane moving forward means that the tarp was OBVIOUSLY not moving at the same speed as the plane while it was on the ground.

[@Ihaveanamenowtaken]

Remember, friction is minnimal (near zero) between the track and the plane, so it matters not if it is a conveyor belt moving faster than the plane, as there's no friction between the plane and the belt (this is because the wheels are spinning freely) the thrust that the engines generate will push the plane forward and will start accelerating and will take off. When an plane touches the track, the pilot applies the brakes to increase the friction to a maximum, helping the plane to stop.

[@TheArctanx]

wheels are free to turn, so does matter how fast they turn, the thrust produced by the prop is pushing the aircraft to reach take-off speed regardless how fast the wheels are turning.

[@SDCromwell]

+TheArctanx It sounds simple but I have to admit that I needed it explained to me over a dozen different times and different ways before I figured it out. It's tough because I was thinking of a plane on a treadmill the same way I picture a person on a treadmill and of course now I know that's not how any of this works.

[@3DFLYLOW]

+Kazza FDM lol

[@evilhorde1]

+TheArctanx I think that the only thing that is at all surprising about this is that a pilot of ten years doesn't understand how a plane works.

[@GhostInTheShell29]

+evilhorde1 The pilot said if there's no airflow over the wings he expected to sit there like a brick. But there was airflow over the wing, the conveyor belt did not affect his forward momentum, he probably wrongly assume it would affect his forward momentum. But hey how often do pilots take off of treadmills?

[@manfredwesteroth8241]

+TheArctanx All the belt does is make the wheels turn faster, it has absolutely nothing to do with holding the plane back.

[@m0ther_bra1ned12]

This was literally the dumbest thing ever. All the tarp did was make the wheels spin faster. XD

[@dakotachurch8377]

It's not as dumb as you, apparently. Read through the comments, figure out what is actually going on.

[@m0ther_bra1ned12]

***** Might have. But since you felt the need to call me dumb, nope. Go fuck yourself maggot. :-/

[@dakotachurch8377]

Motherbrain Jr You felt the need to insult others work first, don't get mad when people retaliate. Grow up.

[@m0ther_bra1ned12]

***** I am grown up. That's why I don't care. The only person that was "triggered" and acting like a child is you. Try to control your misguided sympathy's. Your a little angst social justice keyboard warrior and your accomplishing *nothing*...

[@dakotachurch8377]

Motherbrain Jr Oh my god, people like you are real? I honestly though people as fucking stupid and ignorant as you were a myth created to make the internet seem hostile.

[@Scientist_Albert_Einstein]

This day was a very sad and dark day for the world because it showed us that man's ignorance about physics is of enormous proportions. RIP physics!

[@weatherphobia]

RIP US Constitution, 1st Amendment to be sure.

[@devingriffith1391]

The confusing part here is that the frames of reference are never explained. If the conveyor belt is moving at 25 mph backwards relative to the ground, and the airplane is moving at 25 mph forwards relative to the ground, then yes it will take off, which is what happened in the video. However, if the plane were moving 25 mph forward RELATIVE TO THE CONVEYOR BELT, then it would not take off, because it would be moving 0 mph relative to the ground. I think the difference here is the total source of confusion.

[@noidea91]

To solve the problem it's critical to understand that a plane will move forward with no relation to the speed or the direction of turning of it's wheels (there is a possibility though that if the conveyor will move too fast, the wheels will be destroyed and there will be nothing to support the plane, but that's another story). The propellers or the turbines interact with the air and pull the plane forward relative to the air up to the speed when there is enough pressure difference below and over the wings to create the force greater than the weight of the plane.

[@fredfinks]

In both Mythbuster's tests the plane moved forward. The hypothetical question is really referring to a stationary plane (belt magically matching the foward speed). In this case the plane as you say, it will not take off. Your wont lift up because there's no air moving past the wings. Theres' no air moving past the wings cause the plane isn't moving forward. If you held on to the plane with prop at 100% and let go, the plane must move forward to lift. It the same thing as a belt

[@ModelLights]

For an easy way to understand this, put two lightweight strings on the end of the wings, holding the plane just barely in place, and a long belt. Have the strings hold the wingtips in place at just the same strength as the friction of the wheels rolling at 45mph take off speed. So the plane sits there motionless as the conveyor is going backwards at 45mph, and the wheels are rolling at 45mph. Now crank the engine and give the prop full thrust. Since you were already at the 45mph rolling resistance strength of the strings, they immediately break and the prop pulls the plane/wing forward about as normal and it takes off. Extra rolling resistance of the wheels being +45mph will barely slow the prop pulling the plane against the plane's mass + air resistance at all.

[@kloug2006]

Yes, this is what I understand from this experiment. Whatever speed the belt is going backwards, the plane will take of as usual.

[@Damaged7]

Here's an easier way. A plane is pulled through the air not pushed via friction with the ground. It doesn't matter what the ground is doing. The explanation is in how the plane interacts with its surroundings, you're going off way too long on the ground and wheels which do not matter.

[@ModelLights]

@@Damaged7 'Here's an easier way.' That's not 'easier', that is the end goal to understand. I separated out the functions on purpose so everyone could easily see it, it doesn't need further adjustment.

[@trainzillamodelrailroading9905]

Well of course. It would be different if the planes wheels were powered but all they were doing was spinning twice as fast.

[@p7outdoors297]

The reason why it didn't stay in the same spot is because the tires were turning freely, whereas the planes thrust pulled it forward.

[@unfortunately_fortunate2000]

that would matter if the wheels of aircraft were powered... they arent, there is no need for them to be and having them wouldnt only waste fuel, it would be a waste of weight savings.

[@SebastianKaronte]

I don't care that I'm a Speeder... I see JMR I press like

[@kashmirha]

So they did not match the speed of the aircraft with the conv belt. So it was not standing in one place. We know a plane can fly, whats new in this than? Its a fake answer...Speed is not a rotational speed of the wheel of the car. Thats not the speed of the airplane.

[@lancebaker1374]

Only an idiot could believe that some fabric under the wheels of an airplane can make it lift. If this were true, we could save a lot of acreage by using gigantic belts in place of 1,000 foot runways to lift 747 planes into flight. Nonsense with a capitol N!!!! The plane was not stationary at all. It was going forward fast enough to lift a near-ultralight plane, belt or no belt.

[@GregaMeglic]

The myth was that the plane would stay still and not lift off. Also the belt can not match teh planes speed. Its impossible. The plane is propelled by the propeller, not by the wheels. Its irrelevant how fast the ground moves below the wheels, the plane will move forward.

[@gogogooner]

Yeah, dont know what the hell they where cheering about. Worst bust ever. Totally ignoring the fact that the plane is moving forward 😀

[@ksthebest]

The myth was that the plane would NOT be able to move forward, smartass. If the plane didn't move in relation to the ground then it would be confirmed.

[@SweMisterB]

You don't think, since the propeller, and not the wheel, drives the plane forward, it wouldn't matter what airplane, or what speed the conveyor had, it would take of regardless?

[@opyner]

what I want to know is where this guy learned about flying.

[@extreamemineing]

wich one?

[@opyner]

the pilot. if he really believed his airplane would NOT take off 1:55 he clearly doesn't know how wings work. why would the propeller and wings care about what's going on down there? aircraft fly on skis, floats, big wheels, little wheels, this isn't hard to figure out guys.

[@nexus1g]

mrslayer, the only thing that's moving the plane backwards is the frictional force on the wheels, which, thanks to the nature of wheels and bearings, is extremely small. It's almost nothing for the prop to overcome that minimal backwards force from the friction to attain the same speed as the truck moving in the opposite direction. Now, if you worded it that the force moving the plane backwards equaled the force of the prop, then it wouldn't take off, but the belt would have to be moving MUCH faster than the plane's takeoff speed to do that.

[@nexus1g]

James, "It's physically impossible to produce motion cancellation when the forward force is acting upon a different medium than the reverse force." You're right, but the prop still has to overcome the rolling resistance provided by the wheels.

[@nexus1g]

opyner, this is an experimental aircraft. He probably isn't even a Part 91.

[@bored.in.california2111]

Imagine pulling a toy car by a string off a conveyor belt and then actually driving the toy car off the conveyor belt. You pulling the car by a string will still pull the car off, only difference is that the wheels will spin faster.

[@robertbunea9502]

that is exactly the problem, because the myth implies the conveyor to constantly match the speed of the wheels, which is no longer the case when you pull the car by a string (in which case, the wheels will move faster than the conveyor). So, the entire myth is a paradox.

[@christianmetzger7074]

Yeah if you pull it FASTER than the belt

[@VMpastore]

@@robertbunea9502 it isn’t really a paradox, just misleading. For all intents and purposes, the plane propeller functions exactly like the string.

[@jackmcslay]

The problem is that any airplane generates it's forward momentum by propelling the air backwards, not the ground. The only way you can have a plane trotthling forward and not move is if you have a wind matching the same speed in the opposite direction, in which case the plane should take off because air pressure is being applied to the wings.

[@giantegg1]

this dude got it right, the plane was still moving forward... they didn't match the speeds exactly, this is why it took off. Often find the mythbusters overlook some quite obvious errors in their experiments. Also the wind from the propeller would not NEARLY be enough to create lift, remember that once a plane is moving, the propeller creates very little wind, because the air around it is already moving at the speed that the propeller would try to push it

[@OpiateX]

The only reason he was able to take off was because the plane was accelerating faster than the belt was moving. If they would have been the same speed, the plane would have had no air moving under its wings and wouldn't be able to take off.

[@smh9902]

The air moving under its wings comes from the propeller, also because the propeller is the source of thrust and not the wheels like a car, it will take off like normal, its wheels will just spin faster. Imagine a belt moving at the same takeoff speed as a F15 fighter jet. Now, we both now the belt wont do crap because the source of thrust is the massive jet engines on the back. Same logic applies to a propeller aircraft.

[@OpiateX]

Brian the Brain I could believe that if the propeller was closer to the same width of the wings, but it's not. The flow of air off the propeller going around the body of the plane and over the wings isn't enough to provide enough lift for takeoff by itself. If that were the case, the wingspan of a plane would only need to be the same as the diameter of the propeller.

[@audiotecmark]

The propeller doesn't make the plane take off by pushing air into the wings. The propeller pushes air backwards past the plane, and as we know that all actions have equal and opposite reactions, the plane is pushed forwards as the air is pushed backwards. It's the forward speed of the plane that provides lift, not the airflow from the propeller itself.

[@smh9902]

OpiateX "The flow of air off the propeller going around the body of the plane and over the wings isn't enough to provide enough lift for takeoff by itself." -You're right, its not enough. If it were then the airplane would require no distance to take off. HOWEVER, there are some aircraft with such incredibly powerful engines, that can literally take off vertically by vectoring the thrust straight down (the Harrier). Here's whats happening, the propeller provides ALL the thrust to the airplane, and so it builds momentum in a very short time to allow it enough air flow over the wings to take off. The wheels, those are really inconsequential. Here's why: In this situation, they would just be spinning at twice the RPM. Think about this, if the extra friction on the wheels could prevent the thrust of an airplane from being able to propel itself forward, then imagine we have the SAME treadmill runway, except that the plane is now LANDING on the runway, and the planes landing gear has no physical brakes, it just slowly stops due to the lack of thrust and aerodynamic drag and a little friction from the bearings. Would the treadmill be able to stop the plane IMMEDIATELY, a virtual near dead stop, if it equally matched the planes speed? Furthermore, lets say a plane already in flight was travelling at 120 MPH and it touch down and "landed" on a giant treadmill also set at 120 MPH with its landing gear engaged, but the plane remains at its 120 MPH and the wheels only provide friction from the bearings and tires making contact to the surface. There are two possible outcomes by this logic: 1: Would the treadmill stop the plane dead in its tracks or 2: Would the wheels just spin at twice the RPM, as though the plane were going 240 MPH when it hit the runway? This is really very simple, a planes thrust comes from pushing air behind it, thats how it builds momentum. A plane on a treadmill is entirely unaffected by the treadmill because those wheels are like toy wheels, they spin freely. All that happens is that the wheels spin twice as fast. In fact, due to the boundary layer effect of air, the treadmill if it kept accelerating to keep up with the planes speed, would actually help the plane takeoff as it would essentially act like a really really inefficient fan blowing air towards the plane. To really get a visualization, I want you to replace the plane with a rocket powered car on a treadmill that will keep the ground speed the same as the cars speed. Of course since the power doesn't come from the wheels, it comes from a huge ass rocket shoved up the cars ass pushing the air behind it, the wheels just spin twice as fast.

[@smh9902]

audiotecmark All that airflow is _cumulative_ from the thrust of the propeller. That's what I was getting at.

[@Ihaveanamenowtaken]

Actually, the wheels on a plane, any plane, accomplish one function: to control the friction between the plane and the track. Friction is minnimal (if not zero) when the plane is taxing to get airborne. If friction is zero between the plane and the track, in this case the belt, the only thing that keeps the plane on the ground is inertia of the plane and the aerodynamic drag. When the thrust gets equal or more than those factor, the plane starts moving forward.

[@MrPepelongstockings]

What's really gonna blow your mind is that a blimp can fly if it's tethered to the ground that's what happened to the Hindenburg

[@JiM-SWEET-art]

In the end the answer is, the wheels of the plane would never stay matching the speed of a treadmill, so the variables of the question are just impossible to create, as the plane will always move forward as it slices through the air.

[@azim680]

if the entire atmosphere around the plane was moving in the opposite direction and equal to the thrust produced by the propellers then the plane would have stayed at the same point. But the belt does not take the atmosphere with it. I guess the wheels simply spun at twice the speed they would on a still ground. Remember, the wheels aren't attached to any gears or power transmission in the plane. Myth busters should have measured the rpm of the wheels on still ground and then on the conveyor. Now, if you had a huge fan about the size of the plane kept in front of it, and it blew air on the plane at a speed which would produce a force about the same as produced by the propellers, then the plane would have stayed at the same point.

[@AdrianDiemer]

It wouldn't have moved forward, yes. But it would still take off since it would be moving relative to the air surrounding it.

[@azim680]

Adrian Diemer yes, technically, the wings would still experience lift so it should take off. kind of a vertical take off, maybe ?

[@mikem2915]

@@azim680 The planes speed matches the conveyor, not the wheel speed. It dont matter how fast the conveyor moves it will just increase the wheel speed but the plane itself would still be moving forward so therefore it wouldnt be a "vertical" takeoff. The plane would take off as normal but with much faster wheel speed.

[@carultch]

@@azim680 That's precisely why airports plan for airplanes to land and takeoff with a headwind rather than a tailwind.

[@josephsummers2427]

They failed both experiments (Small and Large scale). The conveyor (tarp) was supposed to be going the same speed as the wheels of the plane beneath it. It was obviously going slower if the plane was moving forward. In the real life (large scale) example, the plane simply took off at a slow speed (the tarp was going 20 mph the opposite way and the plane probably 40-50 mph, meaning about 25 mph take off. Since it's an ultra-light, they have insanely low take-off speeds and distances, like 25 mph and 100 feet). All they really did was make a plane take off at a slow speed.

[@Spinachh3]

Joseph Summers The wheels and the tarp were moving at the same speed, but because the wheels are independent to the engine the plane took off anyways.

[@josephsummers2427]

DC356 Then they had to make the tarp go faster to compensate. I thought the plane was effectively not supposed to move (relative speed is 0 to ground). The plane essentially just took off, but with a bit more effort. So obviously a plane can take off if it's going fast enough to take off. Thousands do daily.

[@Spinachh3]

Joseph Summers And obviously a plane that's not moving can't take off. It's basic aeronautics. They just wanted to see if having a moving surface under the plane would cause the plane to stay stationary or if it would still be able to move forward.

[@josephsummers2427]

DC356 What? So they just wanted to see if the tarp would make the plane move too slow to take off? That's a stupid experiment then.

[@Spinachh3]

Joseph Summers Yeah... What were you expecting?

[@JohanStendal]

One way to think of it is that it doesnt matter how fast you are spinning the wheels because the wheels are not actually providing any propulsion, only the propeller is. In other words, only the airspeed matters, not the speed that the wheels are spinning or groundspeed.

[@AcmeRacing]

Lift is generated by airspeed, not ground speed. A stationary plane in a wind tunnel will generate plenty of lift if the airspeed is high enough. In the experiment it doesn't matter how fast the wheels are turning; if the thrust from the prop can move the airfoil fast enough through the air, the plane will fly. I had no question what would happen with the full-scale trial.

[@user-el4gx7ge3f]

Разрушители легенд как всегда опять накосячили! У них самолет движется быстрей импровизированного конвейера. Подъемная сила крыла не зависит от скорости вращения колеса на шасси! Если самолет будет оставаться на месте то и подъемной силы крыла не будет. Разрушители легенд не добились синхронизации самолета с неподвижной точкой на земле, так что опять потратили чью-то кучу денег, своего и нашего времени. Считаю, что эксперимент не удался!

[@enty111]

Не совсем, от винта поток идет. Но грязно, да.

[@AntonKolyadin]

Давно думал над этой задачей и тоже думал, что не взлетит. И действительно, если самолет стоит относительно земли, то не взлетит (если только он не может в обычных условиях взлететь с места). Но в том-то и дело, что он стоять не будешь как ты ленту не крути(если трения нет). Со стороны ленты сила не действует, а со стороны пропеллера действует (отталкивается от воздуха). Значит он будет набирать скорость относительно земли при любой скорости ленты.

[@Moo0000000000]

Да чтож вы все, ну в самом-то деле? Чтобы самолет оставался на месте, нужна сила равная силе тяги, обратная по направлению! Этой силы нет! Сила трения в подшипниках колес слишком незначительна. Значит самолет будет двигаться при любой скорости коневеера. Как это будет происходить: самолет разгоняется и конвеер тоже. самолет имеет некоторую скорость Vc а коневеер имеет скорость Vк=-Vc относительно точки на земле. Что с колесами? Они просто крутятся с удвоенной скоростью! Если это объяснение не устраивает, то рекомендую прочитать учебник физики за 7-8 классы. И расписать уравнения на бумажке.

[@cultskaro5500]

ОН не может оставаться на месте. Колеса просто прокручиваются. Двигатель их не вращает.

[@RRask8lnik8v]

Сергей Пирогов,полностью с Вами согласен. Подъемной силы возникать не будет. Это все равно что самолет стоит. Этот самолет (УВП - укороченного взлета и посадки) может взлететь с места при большом лобовом ветре(возникает огромная подъемная сила).Сам гоняю на СП-30)))

[@gdxd7956]

Easily knew it was going to take off. The "conveyor belt" will ONLY makes the wheels spin faster. The wheels are NOT the ones pushing the plane forward, it is the propeller. On the other hand if it was a car on the "belt" than yes, it would stay in the same place. because the wheels are the moving force. And to add a bit, if the air is the one being moved (like high winds), only THEN the plane will stay in place. It will "take off" but it wont move forward.

[@mach.8715]

But the conveyor belt was NOT moving backward at the same speed the plane was moving forward. The plane actually HAD forward speed (and presumedly the winds were calm, otherwise the experiment means nothing) and it's that forward speed through the air that allowed it to fly. If you had an ultralight with thrust greater than its weight or a full size V/STOL jet aircraft, you can obviously takeoff regardless of speed. But that's not the situation we're talking about here.

[@clarenceroller7897]

The whole thing was that the plane was not stationary, it was moving therefore wind was moving over the wing and thus there was lift. If on the otherhand the conveyor belt movement was matched by the plane in the opposite direction there would be little to no air movement over the wing(other than that caused by the propeller) and no lift and no takeoff!

[@romanhalaj835]

A simple physics: 1. Wheels of landing gear are free to turn, with no direct propulsion or connection to engine(s) whatsoever. Of course brakes are also off. There is just a slight transfer of force by bearings of landing gear, but it's negligable. 2. Propeller moves mass of air and gives thrust, it has nothing to do with ground. 3. Airplane will move in direction oposite of airflow generated by propeller (Newton's laws of action and reaction), with speed measured by flow of air, also called airspeed. Speed over ground, measured by spinning of wheels has nothing to do with it. 4. Lift is generated by flow of air around specially shaped wings. 5. If You have enough airspeed and lift is greater than weight of airplane, it starts fly.

[@512TheWolf512]

This myth is flawed The thing that counts to the take-off, is the speed of the plane relative to the GROUND or the AIR, not the conveyor belt! We can clearly see, that the plane HAVE moved from it's original position on the ground, no wonder it was able to take off! They definitely fucke-up there

[@Adam.Ibrahim1]

I agree

[@takumi2023]

Eugene InLaw rather than they fked up i think they just didnt explain it well enough.

[@3DFLYLOW]

you almost got it right well half right. its relative to the airspeed. ground speed doesn't mean anything. if I have an air speed of a 120 mph and I'm flying into a headwind of a 120 my ground speed will be zero but I will still be able to maintain flight. what I think is funny about this video is they're trying to suggest that if your wings have zero airspeed that you can take off. that's just not possible.

[@SDCromwell]

+Eugene InLaw I'm one of the people who took FOREVER to figure this one out, so I can sympathize with your argument. The point is that the airplane is moving through the air, and the speed of the conveyor belt is irrelevant. The plane CAN NOT stay in place the way a person would, running on a treadmill. It is impossible to make the plane stay stationary relative to the ground. Regardless of how fast your treadmill is going, the plane will continue to accelerate up to airspeed velocity. There is no way to keep the plane stationary relative to the ground short of chaining it to a post.

[@dead_p1xl964]

+3DFLYLOW They specifically timed this experiment to when there was zero wind. There was no headwind, so the experiment should have been to see if a plane can take off with zero ground speed(it can't).

[@Slarti]

I find it slightly concerning that the pilot has such a poor understanding of physics - of course the plane will move forwards as it is not the wheels that the engine powers but the propeller which works against the air and not the ground.

[@mach.8715]

Of course it's not the wheels the cause the plane to move. But everybody seems to be getting hung up on that true statement and they're ignoring the conditions set forth in the problem itself -- i.e, that the conveyor belt would move at a rate necessary to prevent forward motion of the plane with respect to the ground (AND, more importantly -- and necessarily, the AIR.)

[@possle]

​@mach.8715 it can't prevent forward motion of an aircraft as thrust is created by air moving, not rotation of wheels on the conveyor belt

[@icushfu732]

Guys the reason it worked is cause the wheels and conveyer equalized so the only thing that could move them was the propeller. Its practically like if we could float and use a propeller we would move forward. Thats how this worked.

[@sthurston2]

A plane is not a car. The propulsion is from contact with the air, NOT the tarpaulin. Thus the tarpaulin will merely spin the wheels. Were the engine to be left switched off, the plane would GENTLY start moving backwards because the wheel bearings are GOOD at reducing friction. Thus the extra power needed is only that to counter the small bit of additional friction in the wheel bearings.

[@patricksoo]

Isn't the 'conveyor belt' supposed to move at the plane's speed? That clearly didn't happen there!

[@akula9716]

It's very very concerning that a pilot doesn't even know that the plane isn't propelled by the tires..

[@mach.8715]

No, it's not. He correctly understood the situation. Watch the video. The plane is moving FORWARD when it takes off, violating the preconditions demanded by the problem.

[@chrisjacobsen1659]

This test is like seeing if my car can drive forward into a light headwind.

[@timothystockman7533]

The airplane is moving forward. This means that the conveyor belt is not matching the speed of the airplane's wheels; if it was, the airplane would remain stationary. So, where in this scenario would the energy input of the engine be dissipated? In the friction of the wheel bearings and tires. However it's hard to get them to dissipate that much energy. I declare Mythbusters BUSTED, for violating the conditions of the experiment, namely that the conveyor belt must exactly match the linear speed of the surface of the airplane's tires. This would mean that the airplane wouldn't move. The fact that it moved means that the surface speed of the tires was faster than the conveyor belt.

[@mosab643]

the plane has to be moving relative to the surrounding air, not necessarily the ground, to achieve lift. If the experiment had been done correctly i don't see the plane going anywhere........

[@L3uX]

Lmao. Think a few steps ahead.. Plane has a propeller that moves air to generate speed which is not affected by a backwards moving conveyor belt.

[@tiporari]

You couldn't pull a conveyor fast enough to stop a plane from taking off. the bearings in the wheels make ground speed irrelevant because there is not enough friction.

[@nexus1g]

tiporari, there is some rolling friction, so you could technically pull the tarp fast enough to overcome the forward force from the prop, but the speed you'd have to pull the tarp would probably set it on fire. lol

[@arunanderson5903]

Who came here after MR.GK 🔥🔥

[@aravind_free_fire_india]

Me 🤓

[@gpurkeljc]

The problem with this experiment is that the runway can't possibly accelerate fast enough to match the rotational speed of the wheels to create a meaningful result.

[@TimothyChapman]

The plane has wheels. This is actually quite simple: The wheels simply rotate faster than they normally would during take-off because of the backwards motion of the conveyor belt. The plane is being pulled forward by a propeller, not an engine physically connected to the wheels by a drive shaft. If they were trying to hold back a car of the same weight, they would have succeeded because the engine RPM increases as the vehicle's speed increases. If they got that conveyor belt going 100 mph, the plane would have still taken-off because the propeller can easily overcome the excess motion of the plane's wheels.

[@trefod]

I don't understand what this test was supposed to prove... That wheels will turn? That planes don't rely on powered wheels, but gain speed by the propeller? What?

[@dreed100]

+trefod people don't grasp the concept of how planes operate so they believe that plane should not move forward on conveyor belt when trying to lift of.

[@trefod]

+dreed100 Sad, maybe it was a good idea to cancel Mythbusters.

[@DLockX]

+trefod Noo no no. The show itself didn't have much problems. The myths and the reasoning behind them occasionally were flawed, like this one.

[@Tekrothebountyhunter]

How about they put that plane on an actual conveyor belt system rather than just a large rag...

[@xavierh.5102]

you mail them a check of $2,000,000 and maybe they'll do it

[@Tekrothebountyhunter]

xavier k. haberle They could have stitched the two ends of that rug together to make a ring and wrap it around two motorized rollers. Easily built with parts in their shop, $1,000 tops if not.

[@lesto12321]

Tekrothebountyhunter because that belt should be long as the runway, so the rag sould be doubled, and a construction to help to maintain the weight (the rag would broke) ad let it turn around is very hard to build, especially if very long. Notice that the trick is that the plane MOVES ANYWAY, because its propeller geenrate speed relative to AIR not to GROUND.

[@brianhawkins]

It's not a actual conveyor belt? It's a belt of fabric which conveys things riding on top. Why does it need to loop back around underneath? That would have no effect on anything on top.

[@allesklarklaus147]

Brian Hawkins Exactly right. And for 1000 dollars your not gonna be buying just the aluminium or steel required for a rig that size

[@generallykaiden]

but... the whole premise of the experiment is that the plane is supposed to have no forward momentum because the speed of the conveyer belt is supposed to match the velocity of the airplane. Like it's very clearly moving forward before take off.

[@jcrr2012]

My current understanding is that there are two opposite forces, the plane thrust trying to progress in the runway and the conveyor belt trying to convince the plane to continue static. The conveyor belt acts over the plane movement not only through the friction in the wheels bearings, but also dragging an air stream towards the plane. The balance of both effects will decide if the plane will lift or not before the tires are ripped apart. For a 747, it is a balance between the maximum speed in the tires (nominal is 235 mph) and the minimum speed for taking off, let’s say the stall speed (about 100 knots) Anyway, in this solution we are neglecting at least the inertial effects in a conveyor belt of 3 km length.

[@elrondsch]

I see there is a big confusion in the community about what were they actually testing=) So I am posting the myth they are referring to "A plane is standing on runway that can move (some sort of band conveyer). The plane moves in one direction, while the conveyer moves in the opposite direction. This conveyer has a control system that tracks the plane speed and tunes the speed of the conveyer to be exactly the same (but in opposite direction). The question is: Will the plane take off or not? Will it be able to run up and take off?" And I must say they executed everything perfectly.

[@shooterqqqq]

Until they increased the speed of the aircraft so it could taxi to take off speed.

[@mattsez2879]

A plane.....with jet or propeller thrust is not effected by ground speed in ANY way........with enough head wind, a small plane can take off from a dead stand still.....silly myth.....but was fun to watch

[@batmmannn2900]

On a conveyor belt under a Jet as the problem describes there would be no head wind reaching the wings....no lift.

[@FreeGumFighter]

+batmmannn no.

[@Scoat]

I'll elaborate on the "no.", FreeGumFighter kindly gave you. If you copied what happened and replaced the propeller plane with a jet you would have the same result. If you actually matched the speed correctly so the plane didn't move, then yes, nothing would happen. Apparently though, this was not the myth they were testing. To me, just having watched the video, it looks as if they just performed a standard take-off, only difference being the tarp, which was just super pointless,

[@SweMisterB]

@kradia: There is no speed the conveyor can be run at, that will prevent the plane from taking of.

[@SirSpinalColumn]

I just can’t believe that fool thought it wouldn’t fly.

[@julunted024]

i think the easiest way to explain this to people that just dont seem to understand is this. you have a treadmill, a toy car(with really good bearings in the wheels), and you stand next to the treadmill... you hold the car on the treadmill belt, and turn the treadmill on... your hand holds the car in place on the belt, and you increase the belt speed, and keep increasing the belt speed until its screaming along under the toy car with good low friction wheel bearings.

[@jordanrobinson3231]

It's impossible for the conveyor to match the speed of the wheels once the pilot overcomes the rolling friction in the wheels and so the plane will take off normally.

[@mach.8715]

What you're saying is that the plane WILL take off because it's not possible to achieve the conditions laid out in the problem. That is NOT the same as saying the plane will take off, given the requirements of the problem. You'll note that in the video, when the plane took off, it had FORWARD MOTION in relation to the ground. (I.e., the presumption is that it has airspeed.) It could not possibly do that if the conveyor belt were moving at the same speed as the aircraft except in the opposite direction. All of these arguments seem a little bit like asking the question, what is 25 divided by 0? And people answer 0. And when you point out that you can't divide by zero, they simply say, "We know you can't divide by zero, so we'll DEFINE the answer as being zero. You can't violate the conditions of the problem and then claim that whatever answer you come up with answers the problem.

[@jpian0923]

A poorly conceived myth test, improperly using the theory of relativity. If the conveyer belt is moving (backwards) at the planes take off speed (and the plane is held still) and your reference frame is of the conveyer belt, then the plane looks like it's moving at take off speed. The question is, "Will the plane take off?" Obviously not, since there is no airflow over the wings to create lift. The planes take off distance would have been the same without the conveyer. They didn't think this one through. If they would have done this in a wind tunnel with a wind equal to the take off speed, the plane would have lifted off.

[@cultskaro5500]

This can't be, engine doesn't affect the wheels, wheels just start slew cause friction force is too weak

[@ernieee42]

+James Pian this version of the myth would make more sense, yes. But it is a stupid myth either way. I think the reason for the myth is, that people think of cars, when they think about speed.

[@SDCromwell]

+James Pian The tough part for me was to figure out that the speed of the treadmill is irrelevant. The plane won't be 'held' in place by ANY speed, because the belt is transferring all it's movement to the WHEELS where as the propeller is transferring all it's movement to the BODY of the plane, the treadmill is simply NOT CAPABLE of holding the body of the plane stationary, regardless of speed.

[@CYDeviant]

The animation is what gets everyone. They didn't want to give away what they already knew, but they should have just shown all the possible outcomes and explained them better.

[@SM-dt1pr]

Nowhere in the myth does it say that the plane is held still. Only that the treadmill matches the wheel speed.

[@herbert264]

@Jonneymarket So, you're right. And it's the propeller that's giving the thrust and there's just not enough friction between the belt and the plane wheels to drag the plane back that much, but just understand that there will be a large number of people who will say that this practical experiment doesn't seem to match the profile of the thought experiment that was raised in the first place, which was also ambiguously worded, for example the idea of the conveyor speed matching the plane speed.

[@tannerlawless6657]

The fact that the plane was moving proves that they were going at different speeds or the weight of the plane was pinning a portion of the tarp giving it just enough traction on the actual ground to start moving.

[@svpremkumar6397]

Anyone after watching Mr gk🌛

[@aravind_free_fire_india]

Yes

[@jfan4reva]

I thought the plane was supposed to remain stationary (relative to the ground) while the conveyor belt moved underneath. If the plane is allowed to move forward, what's the point? We already know the plane will take off if it achieves enough forward AIRSPEED. Mythbusters busted! :(

[@atsernov]

+jfan4reva I'm not sure what the point to this myth busting episode is to begin with. Anyone with a basic grasp of physics knows that the airspeed over the wings is the only thing that really matters.

[@reversegreenpotato]

+jfan4reva just look at all the idiots writing comments on this youtube video... I guess that's kinda why they felt compelled to bust the """myth""".

[@smh9902]

Well for one, the plane started at zero, and of course what was going to get up to a speed thats faster than the truck eventually. Wanna know why? That landing gear has wheels that are very low in friction. ALL the damned belt is doing is spinning those little wheels faster. The belt could be pulled at a speed of mach 10 and guess what? The plane would take off as normal (that is assuming the wheels bearings dont melt). The air moving under its wings comes from the propeller, also because the propeller is the source of thrust and not the wheels like a car, it will take off like normal, its wheels will just spin faster. Imagine a belt moving at the same takeoff speed as a F15 fighter jet. Now, we both now the belt wont do crap because the source of thrust is the massive jet engines on the back. Same logic applies to a propeller aircraft. Let me make another analogy. Imagine you have a MASSIVE rocket, we are talking like the Saturn 5 space rocket here, tilted on its side and held up by some axles. Its on a belt, a huge belt. The rocket thrusts with over 7.5 million pounds of thrust and the belt underneath it is moving at an equal speed to the rockets speed. Guess what? Those wheels will just spin twice as fast because those little wheels are NOT where the thrust is being applied. SAME logic applies to aircraft.

[@MrMarinus18]

Hundreds of thousands of people thought it wouldn't and the mythbusters will test it if enough people believe it. That's what they do, a myth is a myth because a lot of people believe it. Not because it actually has to make sense.

[@larryjohnson5385]

Because the truck was going in the wrong direction. In order for the tarp, conveyor, to move in the opposite direction, he truck would have to tow from the rear of the plane.

[@sephfyr]

I would be terrified to have this guy as my pilot!

[@bryce7285]

Damn. The idea that a pilot could not understand this is pretty wild. I understand the confusion but that's something that is hammered into you at the beginning of learning to fly any airplane. Ground speed is just a junbdr that helps indicate your travel over the ground which gives you a realistic track of how you are moving distance wise. While airspeed is what will allow your plane to fly. When it is windy near our local airport it is common practice to get up to about 5k feet agl, point the plane into the wind and make the ground speed read 0 while the airspeed could be reading 60kt... the plane will be standing still and, in effect, hovering.

[@free_spirit1]

REVOKE HIS LICENCE! REVOKE IT NOW!

[@nexus1g]

It's an ultralight. He doesn't need a license.

[@SonofPencilHead]

Let's talk practical application. Could you use a conveyor belt to shorten runway lengths?

[@RodrigoML]

If the conveyor belt is moving at the same speed as the wheels in opposite direction should'nt the plane be stationary in relation to the ground?

[@garfellow5038]

There's a lot of understandable confusion here. Basically the point is, that the plane will move forwards regardless of how fast the conveyor goes, it will never stay put. This is because the wheels are independent of the plane's motion, because unlike a car, they are only there to reduce friction. They could be turning at an entirely different speed compared to the speed of the plane

[@angelosalamat6824]

the plane didnt stay on its place,, their not synchronized i guess this experiment not accurate

[@Spinachh3]

angelo salamat The plane didn't stay in place because they turned on the engine and took off, which is the entire point of the experiment

[@kevinmathewson4272]

Do whatever you want with the ground, the propeller does not care. You could spin the conveyor belt at mach 1 and the plane would still take off.

[@bro-nation_7th_cav_echo]

something a lot of people are not getting right here is that the plane has weight, the plane in the video is an ultralight, they are not a technical plane, they are a recreational vehicle, with the weight of an actual airplane keeping it on the belt, the belt would hold it in place, a lot of people are saying that the thrust creates forward momentum, but that forward movement is in relation to the wheels. if the wheels are moving, and the plane is not, then it cannot take off because the air is not flowing over the wings.

[@kevinmathewson4272]

John Ross, it wouldn't be moving backwards on the belt at mach one, because the plane has wheels that can spin freely. When a plane comes in to land on a runway, does it stop dead in its tracks the moment its wheels touch the ground? Of course not, the entire purpose of wheels is to mediate a difference in speed between two adjacent masses.

[@kevinmathewson4272]

Alright, let's recognize a subtle distinction here. Force and momentum are two different things. When a conveyor belt accelerates a plane very slowly, it is imparting very little force, and that's why the acceleration is slow. Once you have the plane moving backwards very fast, the plane now has a lot of momentum in that direction, but _there still isn't much force from the belt._ Once you start the plane's engine, you push the plane forward a lot harder than the belt pushes it back. The plane pushes until its backwards momentum is gone, then it takes off normally. You've only made the whole process take longer.

[@ivanaswinn]

Mr GK

[@Slarti]

Animated Anatomy1 said "finally someone smart :) 1. Airplane propeller does give the plane speed to move FORWARD according to 3 Newton law of action and reaction." Actually that is no the case with a propeller - with a jet engine it is. However a propeller bites on the air and primarily moves through the air through corkscrew action. This is why a propeller aircraft's speed control reacts much more quickly to pilot input than a jet does.

[@Sorcelon]

Quite simple really as the relation is between the plane and the air. That's why planes take off into a headwind, not a tailwind. I would have liked to see them also try with the tarp moving in the same direction as the plane and then comparing the length of runway required to take off from both experiments. It would certainly be minimal but I'm curious to know if it would have any effect at all.

[@unknownff6665]

Mr.gk❤️

[@shubhambhuyan]

Mythbusters!! U r busted instead of the myth being busted!!.. The plane should have had zero velocity with respect to ground. But I could clearly see the plane moving forward. Hence there was air flow over wings, and it generated lift.

[@SweMisterB]

Explain to me how moving a conveyor under the wheels of an airplane, will make it not move forward... The myth is that the conveyor will keep the plane stationary. The propeller will always move it forward. The myth is, busted.

[@Barshki]

did no one (including the mythbusters themselves) notive that their treadmill didn't work and that the plane was still traveling across the ground. With as much movement forward through physical space, of course it got air lift and took off! The plane is supposed to be stationary in relation to the ground on a treadmill. If they had done this right, they would have discovered that it won't take off.

[@zacstephenson1286]

You can clearly see in the video that the plane was moving forward. It was moving forward in the small scale too. The speed is irrelevant relative to the ground. They were trying to measure groundspeed instead of airspeed. The wings don't care about groundspeed, why do you think they takeoff into the wind?

[@SweMisterB]

The myth is, that putting the plane on a conveyor, would keep it from going forward, and hence make it unable to generate lift, and take of. Since the propeller drives the plane forward, and it has nothing to do with the conveyor, no matter what speed the conveyor is at, you will always have the plane moving forward, and taking of, as soon at you give it some throttle. The plane moving forward is the plane busting the myth, not invalidating the test.

[@abi4513]

Mr gk

[@55spirithockey]

Mythbusters should have just talked to a real pilot. They spent a lot of money and time to test a pointless myth. This pilot of 10 years needs to go back to flight school. The wheels have nothing to do with lift over the wings or the forward motion of the plane. The motion is created by the prop, not the wheels. If planes could take off in no space on a conveyor belt, wouldn't they be able to take off anywhere like a helicopter?

[@cultskaro5500]

plane can't take off in no space, but he can take off on a conveyor belt

[@MrMarinus18]

Mythbusters is also somewhat democratic. If enough people request it then they will test it no matter how little sense it makes. It's not the first time this has happened either, they tested free energy. They even tested pyramid power before then stating they would never do magic again.

[@evansnyder8461]

Hunter TheAviator. Also notice they didn't use a ga aircraft, so I'm assuming this "master" pilot of 10 years has at best a sport or GA license. I highly doubt he's a private pilot that's that dumb, but still able to afford his own sport class aircraft, or ultralight depending on said aircraft's weight.

[@MrMarinus18]

It was apparently the smallest manned plane they could get access to that was without any doubt a plane.

[@MrMarinus18]

+James Insalaco I didn't mean in terms of what the FAA says but in terms of the public mind. That things looks like a plane so it's a plane.

[@davidnovakovich5583]

Think of the tarp pulling the plane backwards as a tailwind. Assume the plane lifts off at 60 mph air speed. If, when the plane’s engine is idling, it does not provide enough forward thrust (or pull, whatever) to move the plane forward, it will sit idling on the tarp. If the truck pulls the tarp at 60 mph, that in effect would create a tail wind of 60 mph. The plane will go backwards at 60 mph in relation to the ground (for this example, let’s assume that the tailwind can’t move the plane’s position on the tarp, since the tarp isn’t a perfect analogy of a tail wind) and will have an air speed of -60 mph. When the pilot increases the throttle to 60 mph, the plane will roll on the tarp at 60 mph, and the airspeed will now be zero. The pilot would need to increase the throttle to 120 mph to achieve an airspeed of 60 mph in order to take off. Conversely, if the plane were facing the truck, it would have a head wind of 60 mph, could lift off with throttle at -0- mph. Many an Alaskan bush pilot has pulled off stunts like that with strong head winds. (Note, when saying “increases the throttle to 60 mph” that’s really not how it works, but let’s make the example easy to understand)

[@kellecetraro4807]

Can a stationary plane become airborne? Yes. We can make a brick that's sitting firmly on stationary ground airborne? Yes. With enough air flow 😂

[@mach.8715]

That's not the question being asked in this matter. Of course any plane with a thrust to weight ratio greater than one can take off with no airspeed (assuming it's a V/STOL aircraft that directs its thrust downward and has the appropriate vectoring jets to give it control.

[@kellecetraro4807]

@@mach.8715 Yeah it is. And by the way any airplane can become airborne without any "thrust" or "Airspeed". 'Airflow' 🙃😉

[@mohamedriyas154]

Mr. Gk

[@KRAUCH74]

These guys are really not that smart are they.. humans have had a very good understanding of the difference between AIRSPEED and GROUNDSPEED for a very long time.. Every Pilot in the world now thinks you guys have an I/Q roughly the same as a cinder block!!!! A plane can take off without airflow under the wings.. NOW IVE HEARD EVERYTHING.. P/S, Why is the plane doing the same ground speed as it would normally take off at during the test?? OMG this is beyond comprehension...

[@lesto12321]

MATT CRAWFORD the plane move forward because it powered by propeller, so take off speed is relative to the AIR not to the ground. The wheel will just spin at double speed (take off speed + belt speed)

[@michaelbuckers]

MATT CRAWFORD You started off with distinguishing Airspeed and Groundspeed and calling people who fail to comprehend the difference dumb as a cinderblock, quote on quote, and then you proceed to * drumroll * failing to comprehend the difference between the two! That's just fucking hilarious. But hey, you were right about one thing - those people are indeed *that* dumb, the bad news is that you're one of them. When the prop starts spinning, it pulls the plane through the airflow, raising it's airspeed. When airspeed becomes sufficient, wing lift overcomes plane weight and it starting to climb. Even completely stationary plane can take off given sufficient winds blowing at it (and yes there *is* a video of it, just in case some douchebag thinks that laws of physics alone aren't a valid argument). Similarly, plane would have to reach batshit groundspeed to take off if such winds happened to blow the opposite direction. Which is why jets lift off from carriers against the wind at ship's full speed, and landing in the same direction but from the opposite end of the ship. Because going fast against the wind increases airspeed. So prop is raising plane's airspeed and it lifts off. The conveyor belt going in opposite direction at the same speed increases the groundpeed (doubles it) which, as we've already established, has shit to do with airspeed.

[@KRAUCH74]

And you think Im dumb, how do you get any airflow over a stationary object? Prop wash perhaps?? At least I got a great laugh I guess..!!!

[@KRAUCH74]

+Sigma Centauri (Shifty) Maybe while achieving a 100% score in my pilots licence I should have had you scoring me instead so I was correctly educated.. Stick to whatever it is you do for job mate..

[@michaelbuckers]

MATT CRAWFORD I understand, after all it's an extremely common misconception because not understanding basic physics is also extremely common, let alone understanding curved 4d space-time manifold in which we all exist. Like, have it occured to you that gravity is not a real force and it's just how space-time curvature manifests itself, with straight geodesic line through it appearing parabolic? And that when you think you're "stationary" under Earth's "gravity", you are in fact accelerating upwards against said geodesic straight line of unaccelerated inertial motion you'd otherwise follow? But just because you're falling victim to the same error as most other people, doesn't makes you right, not at all. Prop generates thrust => plane is accelerating => wings gain lift. There's practically no friction to speak of coming from the wheels, so they barely make ever so slightest impact on plane speed, even if they rotate extremely fast - which they aren't, only 2x the groundspeed.

[@PeterLiuIsBeast]

Take note that they said TAKE OFF SPEED. The wheels can be going at the speed of light for all we care as long as in effect the plane is going at its take off speed and the belt is the same in the opposite direction.

[@apunahasapemapetilan]

one thing that most of you understand wrong is, that the aircraft does NOT accelerate with its wheels. It uses the thrust generated by the propellermovement in effect to the AIR which is completely independant to anything that happens on the ground. The result of the conveyor with the same speed as the aircraft is that the aircraft's wheel spin two times faster but that doesn't detain the aircraft from taking off. I hope that was clear.

[@maclypse]

It's a bit scary that they found a licensed pilot who couldn't predict that result with 100% confidence. His license ought to be revoked.

[@nexus1g]

Ultralight in the US doesn't need a license.

[@nexus1g]

Ronald, it depends on the tricky wording of the myth. If it's a matter of the conveyor belt moving backwards so that it is traveling itself at the takeoff speed of the aircraft, then the pilot is wrong. There is not nearly enough rolling resistance between the wheels and belt to overcome the prop's thrust. If it's a matter of the conveyor belt moving at significantly higher than takeoff speeds of the aircraft so as to overcome the efficiency of the rolling resistance so the plane is at full power and in place on the belt, then the plane won't take off.

[@frankalcala6766]

maclypse oh yeah because pilots need to know if they’ll be able to take off with the floor somehow moving underneath the plane in the opposite direction

[@frankalcala6766]

James Insalaco yeah I understand

[@user-xn9xh7ez3w]

Many people do not understand why this myth is so controversial in theory. Of course, the plane is pushing by propeller, the problem is that the ground is perceived as something that impedes movement, like the friction of the car tire on the asphalt.

[@Quicksilver_Cookie]

It's controversial because idea of a riddle is to make plane stationary relative to it's environment. It's literally nothing to do with wheels and friction. It's a thought experiment. Of course in their example plane takes off. It MOVES relative to the air, it still gains speed as normal. But in a specific case the riddle makes it should be possible to make plane stationary, in which case it would never take off. This is why pilot said plane wouldn't take off. He thought they'd make his plane stationary relative to the air. He understood the riddle in a way it should be understood, and not in a clown way these guys test it as.

[@VMpastore]

@@Quicksilver_Cookie it isn’t really a riddle. The pilot, and you, both don’t understand why the plane would take off. There is no way to make the plane stationary, that is the fallacy that the problem wants you to believe. The conveyer belt has literally no impact on the planes ability to move forward. As soon as the propellers, or turbine engines, start to apply thrust, the plane is moving forward on that conveyer belt regardless of how fast the belt is moving.

[@glennsagario6972]

The weight of the plane still acted on the ground because they are using clothlike material not a real conveyor. Thats why the plane moves forward.

[@SweMisterB]

You don't think, since the propeller, and not the wheel, drives the plane forward, it wouldn't matter what airplane, or what speed the conveyor had, it would take of regardless?

[@amcheli]

the plane was still moving forward, which means the belt and the plane did not have the same speed. Also the propeler was also generating wind which is push to the wings.

[@Treadstone7]

the solution is: because the plane moves with prop-power, it doesn't need the friction of the ground. The plane is neither moving faster nor slower with the tarp, just the wheels are spinning faster with the tarp as they would do with a normal takeoff. That is why they think they move the plane faster just by pulling the tarp in the opposite direction

[@masteryoda41309]

@YourUsernameBoresMe That's the best illustration of this concept I've heard! Great job, and thanks!

[@notydino]

Just adding to Djinn, the floor has no relantionship to the plane at all because the forward velocity is obtained from air. The plane would not take off, if like a car, the plane velocity was obtained by rolling the wheels, which it wasn't. However, the plane WILL stay in position, if subjected to a 50mph head wind. You can see birds to this on a windy day.

[@gregslone4874]

The plane was clearly moving forward. They showed it rolling past the cones so it wasn't, in fact, stationary. Lift is based off air passing over the wings. A stationary plane would get no lift. The plane's air speed is relative to the ground, not to the tarp.

[@danblecher]

Two problems with this experiment. 1) The plane moved from it's original position. How are propeller thrust vs treadmill speed being exactly matched. 2) the prop on the plane is not parallel to the ground. It's tilted upward.

[@SM-dt1pr]

Are you a troll?

[@evahxh]

If the wheels were propelling the plane, it would work. But the way it is, the propeller is pulling the plane, so even if the tarp was moving 1000 mph, it would still work just fine. It would still take off like normal. The plane is pulling itself, and it could have an indefinite ground speed, as long as the wind is moving the right speed.

[@haruhisuzumiya6650]

The conveyor belt acts like a endless runway

[@MultiPAVEL86]

Adam reaction is priceless

[@shananagans5]

When they first did this myth it's so obvious I thought I misunderstood what the myth was. I am amazed at how many people get thrown by it. I guess they aren't separating the wheel speed & air speed. The only thing that matters for an aircraft is the speed of the air over the wings. The wheels themselves could be doing anything, even going backwards. They have zero effect on the speed of the air over the wings. What amazes me is the pilot they had was surprised he took off. If he doesn't understand that, should he really be flying?

[@thelearningartist3162]

+shananagans5 Well, millions of people drive. Most of them probably don't have even the most basic understanding of how an engine works.

[@dhw89]

+shananagans5 He doesn't have to have a pilot's license to fly that experimental aircraft. If you wanted to build one and find any old motor laying around with enough horsepower to spin the prop, you could fly one of those... or you could just buy his, if you trust the way he built it, that is.

[@shananagans5]

dhw89 Yea, I am aware the ultralights & experimental aircraft bypass lots of the regs. License or not, should he really be flying if he doesn't understand the very basics?

[@p11357]

+dhw89 You don't need a license to fly over your own private property in low altitute in any country. You need a license to fly over foreign property or in heights, where an accident could endanger other people (or their property). No innovation is harmed and freedom has it's border, where it limits the freedom of others.

[@shananagans5]

p11357 I am pretty sure you can fly over peoples property without a license. I am sure there are some limitations but I used to live near an ultralight airport & people flew over light residential areas all the time. That area had one home on a minimum lot size of 1 acre so it wasn't house after house crammed together. lol Even if they did crash they weren't likely to hit your house. I know they couldn't fly over the shopping center & there very well may have been restrictions over a standard residential area. Anyways, I agree, for these light or experimental aircraft they shouldn't need a license but that doesn't mean it's smart to try to fly one if you don't understand the basics of flight & know how to operate it well.