It’s hard to believe this hasn’t been on Boing Boing before—often it’s posed with the word “treadmill” instead of “conveyer belt” but that search isn’t bringing anything up either
Anyway it’s a standard joke reference in the XKCD world
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Chances are the conveyor belt will fail before the wheels. The plane’s wheel bearings only need to spin freely and the tires only need to handle the friction against the belt. The belt itself needs it’s own bearing wheels spinning at the same speed, it needs drive wheels to move the conveyor at that speed, and the conveyor belt needs the handle the friction with the tiers but also the bending stress at the ends of the belt and the tension of being pulled around all those bearing wheels.
We could just go physics optional on the conveyor belt and say it moves at near the speed of light without any stress, but then friction with the air would probably just create a giant ball of plasma before the plane can take off.
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Yet, as he mentions in the vid, people will still reject this reality and substitute their own.
He’s right though in that how the premise is framed is key here and it’s easy to fall into the trap of thinking the plane should be stationary and folks shouldn’t be shamed if they do think that until the light bulb moment of realising the wheels don’t provide motion. I feel like the BBS just had this discussion! It’s never going away.
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I think the plane on the treadmill is a useful analogy in explaining how Bitcoin wastes so much energy
except in that case nothing takes off, it just sits there throwing away power in both directions
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It’s treadmills all the way down with bitcoin, imagine a kind of pyramid if you will. 
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How can you say people who watched the video and yet deny that it can fly are not stupid??
On the other hand, this is a clear explanation of the Qanon nonsense–they’re the same sort of people who see the video and say it won’t fly.
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Downwind fast than the wind is possible, but it take a bit of imagination to see how you get through the wind speed point. It works, but only if the wheels grip the ground well enough. I remember puzzling over this, and I realised that we could describe a mechanism that goes fat=ster than the wind, but broke some of the rules…
Three parts; one bit that grips the ground, a folding umbrella, and a stretchy cord that connects the two.
One: the first bit grips the ground and opens the umbrella. This sails off downwind, stretching the cord.
Two: the umbrella folds. The cord propels it back towards the first bit. This is still gripping the ground.
Three: the two bits continue until air resistance slows them down. Then repeat. The tension energy in the cord is converted to kinetic energy in the three parts. We haven’t given their mass, so they could go at any speed but real materials will impose some upper limits, and not the wind speed. And we need some power supply to actuate the gripper and the umbrella open and close. But, given this, it could go faster than the wind on average (this was the cheat).
And it goes upwind.
I’m tired, and I misread that as “Dan Savage”, of Savage Love fame (the very definition of NSFW). I figured if he cared about the subject, his input would be delightful.
Adam Savage is pretty good too.
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Directly downwind faster than the wind is one of those things that seems like it should be impossible, and is highly counterintuitive. I must admit I initially thought it was not possible. The trick to seeing how it works is to realize that the wheels are geared to provide power to the prop and drive the vehicle forward, not the other way round. With a vehicle that drives into the wind, the prop is geared to provide power to the wheels.
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No. Because lift exists, and isn’t a 1:1 relationship with the thrust of the propeller. You don’t need to thrust an entire plane’s mass of air to lift the plane. You just have to thrust enough air that its interaction with the wing generates a plane’s mass of lift.
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That, and the fact that the system itself stores energy to some extent. The flexion of the chain or the rubber in the wheels stores some of the wind energy and can release it at a rate faster than the wind.
You can absolutely go faster than the wind if you store up some wind energy and then release it very quickly.
He could probably go even faster with electric motors a battery and a wind turbine.
This came up in the “downwind faster than the wind” series of posts, I’m sure.
How far do you think you could get like a car with wings to fly?
This assumes the plane is being influenced by the belt somehow. Imagine that the bearings on the landing gear are frictionless. In this idealized case, it doesn’t matter how fast the belt is moving backward - the plane’s movement with respect to its native medium, the air (not the belt, or the ground) is unaltered by the movement of the belt (i.e., there’s no equivalent tailwind). The movement of the plane forward is entirely independent of the movement of the belt, and depends only on its interaction with the air, since contact with the belt does not provide any motive force in any direction. That’s the point Adam is making.
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No discussion of this topic (and I still see it pop up once every few months) is complete without a reference to Randall Munroe’s explanation, which perfectly and concisely captures the problem with the question: It can be interpreted in two different ways, such that the people who interpret it one way will think that the people who disagree (i.e. who interpreted the other way) don’t understand something basic.
You would think that Randall’s article (and the Mythbusters episode) would settle it once and for all. But of course, with about 10,000 people finding out about it per day ;] apparently it can take over 12 years to get the word out.
In any case, I came here to post a link to Randall’s post, so, thanks Smulder for making me feel that others appreciate it.
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Does Savage do the Feynman sprinkler?
I think this one could be settled by a very simple thought experiment.
Imagine a conveyor with the plane at rest on it. Then imagine you start the conveyor moving the plane backwards but do not turn on the planes motor.
Obviously the plane starts moving backwards at the same speed as the conveyor.
So, then you turn on the plane’s motor so that enough thrust is provided to overcome the wheel friction. You would then be able to get the plane up to where is stationary with respect to the ground again. But of course you have now used up a little bit of the plane’s motor’s available power.
So, given that the plane’s motor has only a limited amount of thrust available, shouldn’t it be obvious that there will be a speed where the drag on the wheels is enough that the plane remains stationary even with the plane’s motor at full throttle?
Why would people think that the backwards motion of the conveyor would not have an effect on the available forward thrust of the plane when the wings are not providing lift?
I’m probably missing something here but bearing drag is real and gets exponentially larger as you go faster.
Haha I can’t believe I spent thst much time writing about such a ridiculous scenario! lol 
Have a great weekend everyone!
Edit- I guess it can be possible for some planes to get enough wash from the motor thrust passing over the wings to get a tiny bit of lift - enough to release the wheels and take off. So I suppose the answer would depend a lot on the plane. Would a typical plane get enough wash to release the wheels? Oh probably. The way to really test would not be with a treadmill, but with just a vertical plate to block the wheels so the plane would need to rise a foot or two before being allowed to move forwArds… did they do that in myth busters? I didn’t see the show heh…
Whatever the case, I’m sure everything I just said has been said like 10,000 times before lol.
But that’s not how a jet turbine engine works.
A jet engine is sucking in air, that is correct, but you are then compressing it, adding fuel, and igniting the mixture. The result is a larger volume of gas under higher pressure that creates thrust to push the engine and plane forward. The exiting exhaust is what is creating the propelling force, not the vacuum of the air intake. A ramjet or scramjet engine has no mechanism for pulling air into itself. It would sit between a conventional jet engine and a rocket engine, but uses conventional fuel and air to work.
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Well, sure, but ordinarily you get that lift by bringing the plane up to speed first. If the propeller could move enough air to generate enough lift on the wings to lift the plane just from the prop wash, surely it would therefore also be sufficiently powerful to lift the plane, no?
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Analogies, people!
Automobile: conveyor belt :: airplane: wind tunnel.
I suspect that the plane will then have difficulty taking off.
