Risking My Life To Settle A Physics Debate 

If you want more detail on the explanation here it is: 1. The car is powered only by the wind. There is no motor or batteries of any kind. 2. The propeller does NOT spin like a windmill. The wind does NOT push it and make it turn. 3. Instead the wheels are geared to the propeller to turn it the opposite way, like a fan, so it pushes air backwards. 4. To start the vehicle the wind simply pushes on the whole vehicle (like a block of styrofoam) and gets it moving. 5. The wheels are turning so they turn the propeller in the opposite direction to how the wind is pushing it. 6. The prop is pushing air back so air pushes the prop forwards, accelerating the car. 7. Once you get up to wind speed there is no apparent wind on the vehicle. If the prop were spun like a windmill this would mean no more thrust. But, since the prop is operating like a fan, it still accelerates air backwards, generating thrust. 8. You can go faster than wind speed continuously because even when going faster than the wind, the prop can still accelerate air backwards (in the car's frame of reference) generating thrust. In a stationary frame of reference you would see that the wind behind the propellor is slower than the surrounding air. So it's clear that the energy is coming from the wind. FAQ: If power is coming from the wheels to turn the prop, why doesn't that slow down the wheels more than it gets the prop to push back? A: Because the wheels are moving over the ground much faster than the prop is moving through the air (because there's a tailwind). Example: Let's say the car is going 12m/s in a 10m/s tailwind, so faster than the wind (note the prop will be moving through an apparent headwind of 2m/s). Power = Force x Velocity Let's say the chain applies a drag force of 100N on the wheels to drive the prop. This means we're taking power from the wheels = FxV = 100N x 12m/s = 1200W If we apply this power to the fan, it can create a force of F = P/V = 1200W / 2m/s = 600N Admittedly I've assumed no losses, but even if we waste half the power, we'd still get 300N of thrust which is more than the 100N of drag the prop adds to the wheels. The key is that we're harvesting power at higher speed, lower force, and deploying it at lower speed, higher force (which is only possible because we have a tailwind - in still air this wouldn't work because the relative velocity of the wheels over the ground would be exactly the same as the relative velocity of the prop through the air).

"I expect a lot of pushback in the comments." That's okay, this thing is driven by pushback.

"That's great in practice, but how does it work in theory?"

This is totally the post-apocalyptic extraplanetary desert science-fantasy vehicle of unfathomable awesomeness.

I was blown away that so many physicists called it fake or impossible.

When your online argument with random people is so heated you ended up building a vehicle that seems to defy logic....

It's not breaking the laws of physics, it's breaking the laws of understanding.

As a windsurfer already going (much) faster than wind while sailing sidewind seems magic, but the physic involved it's not so difficult in the end: just some vectors. The very brilliant thing here is to have made a device that can go "sidewind" while going downwind.

The best part is even when they had a working model people on the internet told them it was impossible. If you have an idea you think will work don't let the internet stop you.

The inventor must have been grinning so hard in that shot where he's holding the wind sock. Basically got the best shot possible with great equipment that he was right all along.

"If I put two sailboats, that's a prop" that explanation was mind-blowing.

Now just give it a few years and we will have the first-ever cylinder earthers.

As a yacht racer and captain it took me 25 years to accept and understand apparent wind and going faster than the wind. So as a base level I think I already understand more than your average person. But I did have to watch every second to understand how this works. Mind still boggles.

everyone: the earth is a sphere flat earthers: the earth is flat this guy: imagine the earth is a cylinder

Lazy Physics Teachers: "Can't be done." Crazy Desert man: "Hold my beer."

Once you mentioned the "fan driven by the wheel" it really starts to make sense. Imagine that the fan is just a giant sail, then it would go down at wind speed; and by converting the energy at the wheel to the fan it gets this additional oomph that pushes it faster.

8:05 was my absolute favorite part of the video. jumping from an intuition to an abstraction to a mechanical solution. amazing stuff

lol true inventor spirit: _"how do I stop this?"_ _"you, uuh... I dunno, push the lever."_ _"which lever?"_ _"the one that stops it!"_

Experiments made out of spite to prove people wrong is the best kind of science

Always love when people prove other “know it alls” wrong

This setup is an active sail(s) combined with wills paired by an accurate rotation ratio I like to see if some telltale thing is placed behind the fan this fan is redirecting a large volume of air in another direction in a cone shape which a blackbird in the center of it This system will work as long as the wheels are on the ground. Rick explained how it worked, clear in minutes 8:00 to 8:30.

Damn the explanation with the two sailboats was amazing.

"JUST GO WITH WHAT FEELS LIKE IS SLOWING YOU DOWN" SCIENCE!!!!!!!!

Amazing. One of the best things I've seen for a while👍. Absolutely loved it.

Oh I finally get this. The wings turn because you move forwards. The wings then generate lift in the forwards direction which makes the wings spin faster. Nice

Sending this video to my mom! She’ll be so proud of me..... for once.....

"I am not a stupid person, but i cannot understand" is now my new favorite quote

The fact that people that are actually physicists had a hard time understanding this, makes me feel so much better about myself.

It's like paddling a canoe with the current.

The sailboats around a tube explanation is genius!

i was following this internet debate like 15 years ago, when it spanned three different message boards, including 30 maxed out threads at talk rational. i can't believe it's still going on. that fight was BRUTAL

I had the same problem happen to me in a middle school science class… teacher asked if a plane could lift off if it was on a treadmill going backwards as fast as the plane going forwards. If the speed came from the propellers and not the wheels then it shouldn’t matter if the wheels were turning backwards… I was the only one in class saying the plane would lift off. Interesting thing (taught me a lot about people) is that I got threats and was even on the receiving end of violence when I would not change my stance. When we watched a mythbusters video that showed the plane did lift off they still wouldn’t believe and continued to threaten and bully me. Perhaps the most dangerous people in our society are the ones who think they know and will not listen.

20:22 the windsock and the telltale pointing at each other. I wish physics had been taught like this when I was in high school.

I forget who said it -- several years ago -- but went something like: "Sure they made it work in practice, but can they make it work in theory?"

this is going to become a trick problem on a physics exam.

Very interesting, it’s hard to believe but you did a good job explaining and proving it. It looks like a fun home project!

Never underestimate the lengths people will go through to refuse to accept something is true for the sole reason that it's counterintuitive.

Derek* “I expect a lot of push back in the comments” The comments* “THE EARTH IS A CYLINDER”

The way the creator explained the prop mechanic of a "cylindrical earth" is mindblowing, and that kind of out of the box thinking is the mark of a genius.

I love how simple questions and problems produces so beautiful answers and solutions. What a time to be alive

Oddly enough, this actually feels really intuitive to me. Maybe you just explained it super well, but it just makes sense, haha. Super cool!

This broke my mind until you showed the sail boats in a cylindrical world. The creator explained it the best way, your addition of the animation helped tremendously. 👍🏼

physicist, "nope not gonna work" engineer, "Imma assume the earth is like a cylinder"

You tube recommended videos hit a home run. Amazing video. Very educational. I love this.

Great vid. i loved all the nervous build up about it being dangerous and hoping to survive just to move at walking speed

Here´s a civil comment: This is scientifically possible. There are no laws broken here. Keep up the good work!

That's it Derek, you settled the debate: *I'm a Cylindrical Earther now.*

the fan lowers the wind speed delta behind it, thus allowing it to move faster.

Even after seeing the more detailed video about this, I'll just categorize this into the "okay I accept it, but I do not understand it" section in my brain.

"Derek slow down" Derek: *I am speed*

The jump from cylindrical earth to prop is pretty much the spark of genius.

I think the sailboat tacking is akin to what happens with the propeller pitch. Further more the boat's keel and it's interactions with the waters friction probably have similarities with the cars propeller mechanism, momentum energy and friction with the ground. In any event, it is most likely the same fundamental as the balloon and the tacking boat.

This vehicle is for sale on ebay motors right now for $2550. Hopefully it goes to a good home or is donated to a museum.

"If the Earth were a cylinder...", hey, don't give them any ideas!

That cylindrical earth argument was something really elegant and beautiful.

This is probably my favorite episode. I fully understand how it works, and that it does work. Yet, It still boggles my mind.

You did a fantastic job explaining how it works. Makes perfect sense. 😉

Veritasium: "How do I stop?" *The creators watching each other akwardly* "We don't do that here..."

"If I want to slow down at the end, I pull it back. Right?" Famous last words of Veritasium

I want to see a new version of that thing built that would be sick!!

I feel like the fan analogy he uses says it most simply. Imagine an electric fan blowing the car forward. In this case the fan is powered by the cars wheels moving over the ground rather than electricy. Move forward motion gives more fan power. The wind just gets you going and keeps you going when friction would want you to slow down. So does the raw wind power have to at least = the resistance of the vehicle for it to work? I think it does.

As a sailor and physicist, the only one thing, that drives me crazy about this is that I didn't have this idea myself. The cylinder earth is brilliant!

This bug will be fixed in the next update.

Nice “I told you so” machine

Another way to think of this is in terms of air pressure acting on the wing surfaces of the propeller it may make more sense. A sail boat going straight down wind reaches its maximum speed when the force from the difference in pressure from the back to the front of the sale equals that of the drag of the boat. By using the forward motion to drive the propeller from the wheels the pressure at the back of the propeller stays higher than if it were not rotating. Therefore, a pressure difference (and therefore a force) between the front and back of the propeller remains even above the wind speed.

that idea of the cylindrical earth and two sailboats being like a propeller was genius

"Slow it down derek!" Derek: *"i'm speed"*

Just when I understand and master the basics Derek has a way of blowing my mind.

So elusive to grasp the concept; to be honest I couldn't teach it so I'm not sure I really get it even when I'm sure I've finally gotten it. 'Props' to the idea-man. PS: I'm greatly relieved the title wasn't misleading, not that I wanted you in danger, but I'm glad both your well-being and integrity are healthy.

The sail boat metaphor was really clear, everything just clicked for me after that.

Man, the explanation of "if the earth was a cilynder" was so straightforward.

Unbelievable. Well done. This is fascinating.

It makes sense to me from a sailing perspective, and it makes sense from a mechanical perspective that there is some way of using gearing with air. A venturi increases velocity and creates a pressure difference, so it is no great leap to figure there may be a way to manipulate the air in a continuous process to replicate what sailors have already demonstrated is possible.

“Is it safe? It feels makeshift.” The hallmark of any proper, reliable machine.

"I expect a lot of pushback in the comment section" The whole comment section: Wholesome appreciation of this marvelous phenomenon.

That's so good! I'm going to discuss it with my physics teacher for sure!

Hi all, This is so counter intuitive! I'm starting to get it and almost there to understand but not quite.... I'm starting to see this experiment as a big screwing device which generates a relative wind to the wings that is not tailwind anymore. The relative wind generates a component that points to the front (this is the most complicated to admit though....) The energy type explanation of 10mph in front of prop and 8 mph behind is nice but says why it works but not how it works.... I'm making a parrallel with skating with rollers: forces are left and right but you move to the front faster than your leg speed All of this requires a very high level of understanding in physics. I hope fans of perpetual movement won't take it as an example..... Thank you Veritasium. This is excellent

I felt the most happiest for the guy who dreamt this up, had the balls to share the idea and was then mocked for it, and called out as some kind of liar when showing a working model. Vindication feels good. Those are the types of people that push technology forward, by not caring what others believe, believing in their own ideas and just doing it. Bravo Sir!

That shot when the man is standing clearly showing the wind s blowing opposite to what the piece of string is showing on the blackbird is ICONIC!

GREAT video great man build this Idea, as a aerospace engineer always wonder there is wind 🍃 flow with great amount of kinetic energy and this says and this concept explains it well and the propeller too

I think the best analogy was the sailboats on a tube(shaft). I totally got it when you put it like that. I just didn't think the blades were big enough to work. That being said, with balanced, possibly bigger blades and a better (more expensive/professional structure), this would be better proven. It would definitely produce better results.

Engineering: Assume some values to find solution. Engineer: Ok then, let's assume earth is a cylinder.

Several times throughout that video I was like, “oh! That makes sense, I get it now,” only to be like a few moments later, “ah? Yeah, I don’t get it anymore.”

yep it's got my eyes knocking, the analogy of the two downwind ships helps :)

Just needs another sail to get the initial push. Guess it would have to be able to be disengaged once you are approaching the tailwind speed.

"It's a little unbalanced, isn't it?" The entire propellor threatening to crush down on Derrick

the two boats on a cylinder acting like a propeller! That's amazing

No copyrights man do whatever you want with it please pass it around I love you so much you are a huge part of this when I watch that video of how you got into doing this on RU-vid that was it dude I was done I was like this guys golden. Have a great day and thank you so much for everybody out there he’s put so much effort into getting this done thank you thank you thank you and you know the big person up above whatever it is is absolutely it’s all around us what I mean up above good gosh if your heartbeat and you know it loves you if you got a thought in your head you know it’s there too right inside the same one almost and figure that part out yet

this observation might be interesting. The car is straight downwind, but the blades of the propeller are at an angle. They resemble that of the sail of a boat sailing at an angle.

Hope this video doesn’t become foundation of the Cylindrical Earth Society

The guy's mind experiment of the cylindrical earth with the two sail boats immediately clicked for me.

Due to the propellor blades set so that they turn opposite way causes a wind barrier behind the vehicle hence increase in push like two magnets pushing away increasing thrust

Let's talk about the Propellers! They create a low pressure area in front of the vehicle. So, keeping all the constants, friction on the wheels against the ground transfer energy to the propellers, which create a low pressure area in front of the vehicle; thereby PULLING the vehicle forward faster than all the other constants.

Scientists always say, "Extraordinary claims require extraordinary proof." This is a rare case of someone making that effort.

"It's like a coffin Shoddily put together" - total Savage to say that right in front of the builder and owner

I'm a physicist,but also an engineer. If it works and some people don't understand it, that doesn't stop it from working...

I propose two modifications to this vehicle: 1. There should be a gearbox between the wheels and the propellor to allow it to go even faster. 2. Add a retractable metal sheet to get the thing going as quickly as possible up to the speed of the wind.

"To steer, push back on forth on one of the levers. To stop, pull on one of the other ones. Probably" --The Designer, probably

This takes "someone was wrong on the internet" to a whole new level

Looking at a sailboat, it's direction of travel is (neglecting drift here) determined by the hull's heading. For every meter the wind pushes the sail downwind, the boat must also travel x meters (depending on the heading) perpendicular to the wind. This is even more true for a land sail vehicle, which has practically no drift. The same happens with the fan-car, for every meter forward travel of the blade, the blade has to travel x-meters perpendicular to the wind direction. (In this case, in a circular path, instead of a linear path, nonetheless traveling in a plane perpendicular to the wind). The gear ratio between the wheels and the blade determines how much perpendicular travel will happen for each downwind meter traveled by the 'sails'. So with the correct gear ratio and with low enough drag, it is possible to have a velocity made good of the blades that surpasses the wind speed.