Risking My Life To Settle A Physics Debate

Publisert 29. mai. 2021
Everyone will say this craft breaks the laws of physics. This video is sponsored by Kiwico, For 50% off your first month of any subscription crate from KiwiCo (available in 40 countries!) head to www.kiwico.com/Veritasium50

A HUGE thanks to Rick and Neil for letting me drive Blackbird. Check out Rick's NOwine Channel for more in depth videos and explanations on going faster than the wind downwind -- ve42.co/Rick

Gene Nagata made the shoot possible. If you’re a video nerd like me, check out his channel, Potato Jet: nowine.infof... .

Xyla Foxlin for made the model cart used in this video. Xyla builds amazing things like rockets and canoes, check it out! nowine.info

Jack Goodman's NOwine video -- ve42.co/Goodman
Rick's treadmill footage -- ve42.co/Treadmill
Rick's multiple explanations of how Blackbird works -- ve42.co/DDWFTTW
Forum discussions -- ve42.co/forum Blog -- ve42.co/blog1 and retraction ve42.co/BlogRetraction

Gaunaa, M., Øye, S., \u0026 Mikkelsen, R. F. (2009). Theory and design of flow driven vehicles using rotors for energy conversion. In EWEC 2009 Proceedings online EWEC

Md. Sadak Ali Khan, Syed Ali Sufiyan, Jibu Thomas George, Md. Nizamuddin Ahmed. Analysis of Down-Wind Propeller Vehicle. International Journal of Scientific and Research Publications, 3, 4. (April 2013) ISSN 2250-3153. (www.ijsrp.org)

Special thanks to Patreon supporters: Bill Linder, Paul Peijzel, Crated Comments, Anna, Mac Malkawi, Michael Schneider, Oleksii Leonov, Jim Osmun, Tyson McDowell, Ludovic Robillard, Jim buckmaster, fanime96, Juan Benet, Ruslan Khroma, Robert Blum, Richard Sundvall, Lee Redden, Vincent, Marinus Kuivenhoven, Alfred Wallace, Arjun Chakroborty, Joar Wandborg, Clayton Greenwell, Pindex, Michael Krugman, Cy 'kkm' K'Nelson, Sam Lutfi, Ron Neal

Thanks to James Lincoln for building the initial prototypes for a model blackbird.

Written by Derek Muller, James Lincoln, and Petr Lebedev
Animation by Mike Radjabov and Iván Tello
Filmed by Gene Nagata, Derek Muller, Trenton Oliver, AJ Fillo and Emily Zhang
Edited by Trenton Oliver
Music from Epidemic Sound epidemicsound.com
Additional video supplied by Getty Images
Produced by AJ Fillo


  • 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'm mind blown

    • @дмитрий иванов >> How does the structure behave in calm weather? It just sits still in no wind. Or if you prefer - it can go 3X wind speed in 0 wind. :)

    • @eyytee "MIT aerodynamicist Mark Drela : "In my view, the most closely controlled and unambiguous DDWFTTW demo is the cart climbing up the tilted treadmill." in the article: "What I’ve Learned About Wind Carts" by Mark Frauenfelder" Here's what I think "could" also work, though some people would still think that there are too many potentially hidden energy imputs being applied to the vehicle. Use the treadmill apparatus, sure, but in a different way, completely level. Just to prevent the vehicle from rolling forward, at first, when a fan starts to apply wind velocity/pressure from behind (I mean there is only a limited amount of runway on a treadmill). At some point as the fan is being ramped up in output air velocity/pressure, the vehicle is going to start rolling forward. At this very precise moment, stop the fan speed increase and hold it at that point (showing the audience that the fan is no longer being ramped up). Now also at this very precise moment start the treadmill to keep the vehicle in the center, by gradually ramping up the belt backward rotation in unison with the vehicle's tendency (now that the wind is pushing it forward) to NOT roll forward. At a very precise belt velocity, we will witness that the vehicle is not continually accelerating indefinitely, that the fan is set at a very precise velocity. We will be able to measure and record the vehicle speed in relation to the belt's m/s. We will be able to measure and record the velocity of the wind in m/s and compare the two. Simple. But, again, some people will think there is hidden inputs. This is why a tunnel/pipe with nothing but a fan, a vehicle on a rail (keeping it straight and giving it the wheel to ground contact required for rotation) would/should sooth these people's suspicions.

    • @Fred Meister look up mechanical doping in cycle racing then tell me he checked properly, science-hating crackpot.

    • It still does not explain why the speed of the prop is accelerating instead of decelerating when the vehicle is slowed down.

  • At 19:08 you make the point that the tail wind has been reduced because of the fan effect of the blades and as a result that tail wind differs from the surrounding wind. Question: can the vehicle go faster than the surrounding wind speed which has not been reduced by the fan effect?

  • so could you do this with a boat as well? ^^

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  • mars when

  • That thing looks like its straight from Tatooine in Star Wars

  • Great explanation. I have a Bachelors in Physics and I loved your explanation and demonstration.

  • An interesting experiment to prove the propeller is actually working would be to build a second identical vehicle, but its propeller is fixed in position (disconnected from the gears and locked in place). Let both vehicles start at the same position side by side. If the propeller is really working, the vehicle with the connected propeller will pull ahead and leave the other behind, proving the propeller is actually doing the work.

  • The fear of dying in a terrible 5 km\h crash.

  • im gonna recreate it in a game and hope it works so i can get free internet clout 🤗🤗🤗🤔🤭😫😯🤫😔😯🤒🤯🤤

  • kite surfers could fly their kite in figures of eight and should be able to do this without such an amazing rig/setup

  • I might be dumb but I thought that we could travel faster than wind before ! With these propellers n stuff

  • I was so dumb 20 minutes ago

  • So, they got disappointed by Internet's arguments about magnets and fakes, so they decided to build a big thing (where you can hide a whole electric motor) to be criticized again. I don't see where the plan could go wrong, do you?

  • And now we wait for the black SUV's visiting these inventors.

    • More than a decade. Still waiting.

  • Side note : No laws of physics were harmed by making this video. And here is your sail propeller explanation : 8:05

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  • Wow guys figured out how turbo turbine works and scaled it... lol

  • Well ok, but why is the propeller rotating on a differrent direction (against the model 8:10 - from top to down behinde the " cylinder")? And that windboats. If thay can be faster than the ball, than it means, that also the wind boats are faster than wind in stright line...

    • And if is it true, than is sufficient to prove the speed of boats, no wind car is needed.

  • me encanto el video, las explicaciones y las demostraciones... muy bueno

  • The string in the front of the vehicle is CGI. It's not actually there and you're misrepresenting your speed. You're going no faster than a normal person walking. I kid of course. This is amazing and I'm glad the inventors said, fine.. We'll prove you're all wrong!

  • As someone said below: there is a difference between the wind speed at tell-tail height on the cart and the wind speed at propeller height. They should have had a tell-tail at propeller height too. This does make me sceptical about what they were proving and whether this was intended to be a scientific experiment or not. It didn't prove anything if it was (or maybe I just can't work it out so I'm picking holes..) But very entertaining and thought provoking nonetheless.

  • This broke my brain. But then it healed stronger and better than before!

  • 4:17 Schrödinger's blackbird's brakes' rule

    • @vbddfy euuyt "speed x" depends upon the direction you are pushing, considering you meant in the direction of spin, that means you change the speed hence accelerate it a bit. This acceleration causes certain force which will increase the speed of spin. Now if you keep the force constant the spin would keep on increasing but if its just a little push then it just increase its speed to a new constant value.

    • the corkscrew spins thru the cork. No friction, so once you get it spinning it goes forever, at constant velocity. Now, what happens if you push the cork forward at speed x? Ther

  • Dang! I want to build this on my own! :D We have a lot of wind in north Germany - not so many straight roads though. But maybe some night time activity on the Autobahn might do the job. Probably a one-time chance though

  • Thank you for this and other videos.

  • It's basically like swimming in a river, isn't it? If I just let myself float I will never be faster than the current, but should I start swimming I will be. The propeller is it's way of swimming through the wind, pushing air behind.

  • First of all, the system only works with an external force, in that case the wind. So the wind needs to be felt in the same direction of movement. What got me through that puzzle was realizing that the secret relays on the shape of the propeller, even though it is faster than the wind it experiences a velocity less than the speed. Let’s me explain it, when the propeller rotates a single point experiences like moving in the opposite direction, so relative it is moving less than the speed of the wind. Like the sail analysis the secrete is to change the direction of movimente, in this case doing the rotation.

  • Aka risking life for views 🙄

  • Could this be made into a boat with a water wheel under the boat? Or would there be too much drag?

    • @bill sheppard The turbine in water would be less efficient than the wheels, but that doesn't make it impossible, just more challenging. It might not go 2.8x faster than the wind, like the Blackbird did, but still faster. The bigger problem is hull drag, so you would need foils to lift it out of the water.

    • @bill sheppard Mark Drela, renowned expert in fluid dynamics, thinks otherwise: see his analysis (do an Internet search for Drela DDWFTTW). It would be a technological challenge, but it's doable.

    • No, because the whole thing depends on having a fixed ground reference, with wheels on the ground with zero wheel slip. A turbine in water would have 'waay too much slippage.

    • On foils with an efficient water turbine it could work.

  • I am in the process (as of right now) of installing a frikkin' huge fan on top my Mazda 3 sedan, even though trying to get into undercover carparks will be a pain, the cost effectiveness of a massive fan on top of my daily will negate this issue and save me some money on dinosaur fuel. Thank you for the inspiration.

    • Then just stow it when you go upwind! Should work.

  • Or maybe the speed of the wind in 4 meters above ground is higher than speed of the wind above 1 meter above ground? It needs more measure points.

  • It makes sense

  • Veritasium: I can go faster than the wind Me: Could I do this with light?

  • Actually, I didn’t like this video! The explanation was so hand-wavy it made me convinced this must be fake! But I couldn’t believe Veritasium could be complicit in such a fraud.. It took me an hour to figure out myself how this is indeed possible.. Basically: The wheels spin very fast propelled by energy from wind+the prop, but they only need to drive the prop. Also the analogy with sailboats is wrong and just adds a layer of confusion instead of explaining! Because it is not clear how this principle can be applied in a sail boat: yes it can travel very fast at an angle to the wind, but to chase the free-floating balloon the downwind component still has to be greater than the wind.. without wheels delivering power to the prop it’s difficult to see how the is possible. You would somehow have to make the sail work like the prop - pushing air back against the wind powered by the high speed of the boat across the wind. Perhaps this is possible as I now understand where the energy comes from. Still the explanations in the video were so hand-wavy I think it actually did a disservice..

    • "but to chase the free-floating balloon the downwind component still has to be greater than the wind." Yes and sailboats can do this.

  • Physics professors be like, *in very dumb accent* "uhhh actually, the windspeed in a natural environment such as the desert may fluctuate. This is obviously the explanation to the stringy thingy go backwards."

  • It does seem counter-intuitive. Theoretically, it makes sense and there is no violation of energy conservation. What is difficult to believe is that the impulse from the fan-action is great enough to cause an acceleration. I have a couple questions . . . 1. How much force is the fan action providing to the car once it exceeds the speed of the wind? I would think you would have that data set. 2. At what speed would would the drag from the relative wind (opposite direction now) balance the force from the fan action? Keep in mind that as the car, already faster than the wind, speeds up the fan speeds up meaning more thrust but so too does the drag increase. 2. Could this idea be re-tooled to make a prop sail boat? I'm envisioning an underwater prop too, taking on the role of the wheels that cause the air prop to turn in the opposite direction. I'm also thinking that since the initial drag is so much greater the critical speed would be much higher.

    • I don't think they measured the prop thrust during the runs. But I did some rough estimates on it for their NALSA record run at 28mph in 10mph wind, and it was 300-400N, most of which is canceled by the wheel-drag to turn the propeller. The aero-drag and rolling resistance are much smaller than those two opposing forces. This is similar to a tacking sailboat, where most of the sail-force is canceled by the keel-force, and only a small fraction remains for propulsion.

    • Mark Drela has done a pretty thorough analysis of the boat case. If you do an Internet search on Drela DDWFTTW you'll find it.

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  • It only looks like like you are going faster than wind straight but as you told in the video you are actually not going straight down because of the design of the wings it only looks like it.

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  • Imagine instead of a fan, there is a normal sized corkscrew, and in the air is an infinitely long cork. Imagine it's geared at the exact ratio where if you push the car on it's wheels, the corkscrew spins thru the cork. No friction, so once you get it spinning it goes forever, at constant velocity. Now, what happens if you push the cork forward at speed x? There is a bit of pressure on the corkscrew. Like a watermelon seed squeezed in your fingers. So the car goes a bit faster, the corkscrew spins a bit faster, and the pressure continues. So, there is constant force on the car, and it will accelerate.

  • Very cool.

  • I think it was fueled by white privilege. Has anyone gone there yet? Racial inequality, the difference moved the vehicle fasterr. Therefore, racism overcame the laws of physics and it is totally believable that 2 + 2 = 5 (sarcasm is even stronger than racism, btw)

  • "Even physics professors were arguing..." Do you know why they are called physics professors? Because they are not as smart as Rick and Neil, so they stuck being just physics professors. Rick and Neil are beyond that.

  • Wow. Mind blown.

  • The wind is a force. This force is pushing the entire vehicle, so the vehicle is pushing this force back. Now the vehicle is moving at same speed of the wind. The propeller is generating wind to the opposing direction, so the force of the propeller's wind is added to the force of the wind pushing it, giving more speed to the entire vehicle.

  • As a humble mechanical engineer, I find it odd that 'Physics Professors' dismiss the idea so easily using the principle of conservation of energy. It's quite simple: It's Not Perpetual Motion! You are not creating kinetic energy out of nothing. The source of energy is there, THE WIND! it's just about harnessing it properly to convert the huge energy in the bulk of moving air into a flimsy low mass item going faster. I guess these people also have difficulty explaining things like hydraulic jump or airfoil lift force. A perpetual motion device would be the same machine that you are riding, but without the wind. Here is a crazy idea for perpetual motion using the same machine: 1- Place that machine on a slope and let it run downhill 2- You will get some speed, now the wheels and the gears are running the fan 3- When the slope ends and you reach the flat road, your kinetic energy will run the fans and the fans run the vehicle. Voila, here comes perpetual motion Well that is obviously wrong, since the friction in the mechanical system and the air will eventually convert the whole energy into heat, and you will stop earlier than you think. The fan will actually work as a brake in this case. With the experiment you did, there is wind to compensate for (and even overcome) the friction. The blades' lift is also working. All they did was to make a set of sails that could direct the force in the right direction. Clever, but not magic. I even suspect that with proper design, you might even not need the gears. Maybe they are actually slowing you down? I would give it a try if I had a NOwine channel with almost 10M subscriber and didn't need to work for someone else as a design engineer :)

    • @Rick Cavallaro I guess that is what was being proven here, you are not bound by the wind speed, but by the amount of energy you can harest. After you harvested the energy, you might want to harnesss it to the wheels. Or, you might be able to just use the thrust and adjust its direction using an adjustable rack of blades. Then I assume you can just push the cart forward with no issues. Remember boats do not have wheels hence have to change direction frequenty to get the desired resultant vector. That is not the case with a cart. Again, I am just assuming stuff. Can't prove any of that. But still enjoy the discussion :)

    • @Mohsen Heravi Without any interface between wind and ground, you're just floating along with the wind as your new inertial reference. So if you can't make it work in no wind, you also can't make it go faster than the wind using only the wind (and no interface to the ground).

    • @Rick Cavallaro I believe you might not. With a clever design, you might be able to use the lift to push the cart forward just like a sail. I am not talikng about using the rotation of the blades, it's more about the wing lift and sail effect. Rotation might just be throwing us off and you might just need stationary blades with axis at an angle to wind. Remember the part of the video that shows the boat changing direction repeatedly and going faster than the wind? Although I have not done any calculations and might be completely wrong.

    • You may not need gears per-se, but you do need a means for coupling the blades to the ground to exploit the energy available at that interface.

  • Slowing down the air around the cart is why the cart can go faster than that local wind. That local wind, which is right around the cart, will not blow the streamer ahead anymore. It's being converted into mechanical energy, with some losses, and causing the cart to move closer to the wind that is some distance from the cart. You need a better way of measuring the speed of both the wind and the cart. I think you're on the right track, but I don't think this is conclusive yet. Perhaps placing the streamer at the rear instead of way out in front will give different results.

    • @Lassi Kinnunen 81 I know what the point is. The test is invalid.

    • the streamer was there just as a display and far enough from the prop. the point is that it's in different direction than the one on the ground. in the behind of the propeller you couldn't demo that point as per the explanation of why it works.

  • I love how Blackbird is made with bike parts

  • So this is interesting, but what I want to know is what can be done with the concept?

  • I think the comparison with a sail is misleading. The propeller should not be seeing as two sails, but as two rotating wings (they are actuals airfoils), like in an helicopter. The rotation motion means that there will always be relative wind to these wings. Because of that relative wind, a low pressure field is created ahead of the propeller and a high pressure field behind it. This difference of pressure create the lift force that will push the car faster than the wind. This is how actuals helicopters fly: they get the energy from a motor to rotate its wings which create a low pressure field above it, thus creating lift force, thus getting off the ground. The difference here are the source of power (instead of a motor the car is using the wind itself) and instead of going up, the car is going foward, which requires much less lift as you don't have to fight gravity. The explanation about the air being slowed down behind the car is perfect to demonstrate the energy conservation. All the kinect energy the car gets is being reduced from the air. As the speed goes up, the drag created by the structure will also increase, until it equals the lift foward. This is where you will find the car top speed.

    • @John Borton yeah, I actually haven't been watching it haha, but it's nice to know it. My point was not to opose a sail to a wing, but I tried to give more attention to the creation of lift when the air passes througout an airfoil. I believe the image of a sail can make people only think about the direct push of the wind and forget that there is some aerodynamics happening there. That's why I think it's misleading, but definetly not wrong.

    • If you think there is a difference between a sail on a broad reach and a wing on a broad reach, you haven't been watching the America's Cup (where at times they have literally replaced the sails with wings).

  • I cant be civil, Im Russian

  • 19:00 its called angular momentum && troll science! i loved the tube like water with 2 sailboats

  • Do this with solar sails

  • A gyro-copter generates LIFT on a rotating blade that is not connected to an engine. An airplane, sitting on a long conveyer belt, CAN take off even if the conveyer speed is geared to match the forward speed of the plane. No doubt there are loses in the 'chain drive' and on the wheel-ground contact but, as I have a degree in aeronautical engineering and know fluid flow theory, propeller and wing design, I do understand how this works. Once the windspeed is matched all you have to do is adjust the pitch of the propeller to get that extra bit of bite and you have just enough forward thrust to outpace the wind. This isn't a case of the prop driving the wheels, it's the wheels driving the prop. Airspeed and groundspeed are independent. I was able to 'slow flight' a Piper Cub so that I moved backwards (as viewed from the ground). According the the plane, I was going thru the air at 40 mph, headed W. But from the ground, I was tracking eastward (backwards) at 10 miles an hour. LOL Look, if you can do it in a sailboat in water (no matter which way the water is moving, or river), then you can do it in a ground based vehicle. This is just replacing sails with a propeller (which by its' very name, means it PROPELs you).

  • Well, in terms of pressure, the propeller pushes air back and increases the pressure behind the car, while this "bubble" of high-pressure is being pushed forward by the wind, so there you have: something similar to a rocket (riding a bubble of high pressure on the rocket exhaust). Then you can consider the effective force generated by this bubble as a function of the diameter of the propeller times the increase in pressure relative to ambient pressure of still air and voilá, a force pointing forward appears.

    • The notion that the cart produces a high pressure buffer or bubble that the tailwind can push on is a common misconception. The wind is not pushing this cart when it's above wind speed. The propeller is working on "new" air that is also at wind speed.

  • Being civil.

  • In the trademill model, there must be some glitch. I would say stored rotational energy. It should not go on long distance. Otherwise we gainig free energy.

    • @Deputy Dog You are also going forward on a trademill without any energy imputted? Please think before you write something.

    • It's not free. The treadmill is plugged in and using electrical energy, and transferring that energy to the car.

  • Instead of a static sail, this is a dynamic sail. Or more correctly, an aero dynamic sail. Literally.

  • Propeller is not perpendicular to real wind - only explanation I would take. Then torque force (from real wind) is going to wheels and move the car.

    • @Rick Cavallaro And I doubt thats true.

    • The wheels turn the propeller, not the other way around.

  • "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." What about the energy that builds up in the chains and machinery? The momentum? I mean if I would start to accelerate this machine, the acceleration would carry over its point of neutral energy level momentarily and the go below the point of neutral energy and only to repeat these motions until it balances out. What im trying to say, what if you had this machine moving in a constant speed of x meters a second, without the acceleration force, would it still go above the wind speed? I get a little pullback-car feeling here, even trough you only drag a pullback-car back a small amount, it goes a long distance, because of the momentum built up into its gears? Did not the acceleration of the vehicle make it temporarily go above the wind speed? Because should not something going faster than the wind, apply a force on that wind, making it also go faster? So if I filled the deserts with these machines, they would not only have a waste product of friction, sound and heat, but would also make the wind go faster, making themselves go faster, making the wind go faster... upsetting maxwell. I really can not digest this... Give me a few days.

    • Yes, because it steals the momentum of the wind behind it as it generates thrust.

  • So, is the answer to how it works as follows; 1) The vehicle acts as a sailing vessel until it reaches a critical speed OR wind speed (Whichever is less). 2) Once critical/wind speed is reached, the vehicle begins to operate as a propeller driven vehicle.

  • This machine is an example of aether engineering. It is not the wind that is moving the machine.

  • Do we have some explanation? On the moving belt I think it is going forward from rotational energy of propeler. On the ground it does not make sense to me, only from real wind, even when we going faster then wind. Otherwise, real wind would be useless there and I would speed up also without wind, just by pushing it by the car in the begining.

  • I love thought experiments like this. Trying to subvert the laws of thermodynamics to have something do something all people say cannot be done.

  • Well, Derek made a big mistake here. But I'm sure he will make a new cool video admitting and analyzing the mistake. This is a valuable lesson to all of us that we all make mistakes from time to time.

    • @John Borton I gave it a little more thought and now I feel like I see how this could work. So yeah I probably was wrong indeed. Man this thing is really counterintuitive. I'm really looking forward to the bet resolution video and I'm glad it wasn't me to challenge Derek on this bet!

    • @John Borton oh man you got me curious and excited. I really want to be proven wrong on the opinion I shared above. Did you already witness the experiment and was the independent judgement in favor of this apparatus working?

    • @SergTTL We certainly agree that Derek would take his lumps like a man if he were wrong. And I do have an advantage ... I know how it ends. :)

    • @John Borton I will like it either way. Even if this this thing does turn out to be working. Probably even more so. It's a win-win for me.

    • @SergTTL Excellent. Stay tuned (but you won't like it).

  • I have a sudden urge to construct one of these, although I would make several design changes that should improve the efficiency.

    • @John Borton Simply fixing some of the obvious issues like the unbalanced propeller will have a significant impact on efficiency.

    • I hereby volunteer to help you beat our record.

    • Please do. The NALSA ratified 2.8x wind speed world record is there for the taking and will be the perfect yardstick to measure your efficiency improvements against.

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  • Hear me out, I mean I may be stup, but can we do the same with sunlight? In space?

  • This is really inspiring! Could we regenerate enough power from water around a boat instead of regenerating it from wheels of this vehicle? So that for sailing downwind we could drop the traditional sails and employ a propeler?

  • 6:35 talking while its pretty windy. hahaha

  • I based my vehicle project in DT on this video

    • @Kar-Jun Thum we cannot make use of stored energy. That was one of the requirements for the record runs.

    • just it harnesses the energy using storage, like a solar panel

  • The gear ratio between the fan and the wheels...

    • The gears in no matter what ratio they are will only spin according to energy that being provided to it. So for example if the propeller is spinning once the wheels will spin in the that ratio but still as soon as the wind speed is matched there will be no energy to spin them beyond wind speed. Here we took the propeller in wind mill sort of situation. However, in the video it has been made clear the propeller works more like a fan.

  • That looks a lot of fun.

  • My brain is pain

  • Not new we got this in Holland

  • Somebody now do the same thing but with boats 🤔😊

  • free energy is here

  • I love when the armchair experts are proved wrong.

    • @Rick Cavallaro Yes those are the worst kind of armchair experts.

    • You mean armchair experts like UCLA physics professor Alexander Kusenko?

  • It’s like a cart from bad piggies

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  • Wow mind blown 🤯

  • Physics says no.

    • @eyytee I dunno eyytee. He made a pretty compelling argument. Can you point out the holes in it?

    • Physics is totally down with this.

  • +1 for accidentally proving the earth is flat (ish)

  • So what happens if you have more than 2 blades, would the increase in surface area add more top speed?

  • I would think due to the viscosity of the air you would have an inelastic collision between the air and sails as well as drag from the pre-frontal area and body shape of a typical sailing craft. The energy in the wind applying pressure arrives at a net force of zero at the speed of the wind due to the summation of these forces, but this equilibrium does not mean that energy in the wind is not sufficient to push that weight of an object faster given the exposed area that the wind pressure acts on. By changing the shape (in this case of the sail), you can reduce the drag that is limiting the speed. Since the sail is a propeller, its shape produces less drag than the force produced by the effective area that the wind applies pressure to. After matching speed with the wind, the net positive force cannot accelerate the craft faster to a much higher velocity due to the stickiness of the wind, but since it is connected via transmission the the wheels and the propeller can rotate to match the relative speed of the wind, this stickiness can be overcome while maintaining an energy balance. The air behind continues to apply pressure parallel to the direction of the craft while the energy from the drag up front can be converted to rotational energy, which is transferred to the wheels. It experiences less drag due to the energy conversion and the portion of the drag converted to kinetic energy is used to drive the wheels. The craft then accelerates until the friction and drag become too strong, leading to net zero force.

  • Its like kicking oneself forward in flowing water in the direction of the flow, isn't it?

  • I have a question for those, who get science more than me: isn't this similar concept to what theoretical builds of Star Trek's warp engine use? Because am prstty sure it is :D Anyway, this is absolutely amazing and I love it! Thanks for making science even more fun than it is itself.

    • @Jan-Willem Yes Yes, I am well aware of that ✌️ The warp engine is based on extreme gravitational fields which, according to the theory of gravitation particles (which we haven't discovered yet, but are theoreticaly possible), are used to propell the vehicle at speeds greater than c. This makes a "lower gravity trail" behind the ship, which reminded me of the concept mentioned in this video - the base concept seems similar, just different particles are the cause of movement.

    • While I am not sure how Star Trek's warp engines work, you have to remember that space is a vacuum. This means that the idea of using the energy from (air) particles in front of the vehicle would not be possible; fewer particles -> less energy, and when there are effectively 0 particles, the resulting energy would be effectively 0. So in space this concept would not hold at all.

  • So can you make same thing on the water?

  • this is alot simpler than it sound, it is just look at wrongly. engineer has been designing blade for planes and helicopters for decade, we have an entire science dedicate to getting more performance out of the blade without increasing it speed by adjusting its shape... clearly that must be doing something.

  • Out of interest, why was the rear wheelbase asymmetrical? Is it to do with the torque of the rotating prop?

    • Yes, it's because of the prop torque.

  • Just remember a child in Sweden putting a propeller on a car, in his sketch, and adults showing it and laughing... :-) Wonderful. I love your test.

    • Well that is why physics professors dismissed it. They thought it was that incorrect idea. It's also why I didn't watch this video for 3-weeks. I assumed the propeller would be driven from the front (not the wheels), and that this was a video to debunk that particular perpetual motion idea. I was suprised to see it was something different (that looks the same). Derek specifically pointed out that it's not a windmill (being driven by air from the front) but a fan driven by the wheels. The analogy with the boats was great, because instantly I thought there has to be some way to accomplish the same as tacking boats with other mechanisms, and this guy figured it out, nice.

  • Hi, im really impressed, there should be some tricky air currents around the propeller that could be an interesting challange for advanced airodynamic modeling software. The bad news: Here in Germany we lack such deserts..

  • Still not convinced...did you actually mesure the veichle speed and the wind speed or the floating string was the only evidence? Coldn't the fan just reduce the wind speed around the vichle and give wind a relative speed towards back, still the overall moving slower than the wind? Not saying it's fake, but it's so counter intuitive and this hipothesis would be way easier to accept...

    • @e c You're welcome. I have some animations which explain it on my channel.

    • I feared that someone did reliable measurements... So I'm now left with the task of trying to understand it... Thanks mate!

    • NALSA already did the proper measurements. Search for "NALSA downwind record"