Risking My Life To Settle A Physics Debate

6 milj. näkymät48 000

    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 FIblock 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: fiblock.infof... .

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

    Jack Goodman's FIblock 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

    Julkaistu 24 päivää sitten


    1. Veritasium

      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).

      1. Aryan Komati

        I'm mind blown

      2. Rick Cavallaro

        @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. :)

      3. Noguffay

        @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.

      4. Papa Legba

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

      5. Joeri sol

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

    2. Sadman Sam

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

    3. Draven Brewer

      The roasted velvet aesthetically chase because tiger synchronously drum down a fresh timer. stupendous, vivacious shovel

    4. Sheony

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

    5. Jan Novák

      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...

      1. Jan Novák

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

    6. Matias López

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

    7. Daniel Tupitza

      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!

    8. paulfreefall

      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.

    9. vbddfy euuyt

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

    10. E.I.P

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

      1. E.I.P

        @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.

      2. vbddfy euuyt

        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

    11. Techno Is Beautiful

      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

    12. Burton Schrader

      Thank you for this and other videos.

    13. Zanktus San

      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.

    14. David Amato Mantegari

      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.

    15. WunWeg WunDarWun

      Aka risking life for views 🙄

    16. light487

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

      1. coolaun

        @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.

      2. bill sheppard

        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.

      3. eyytee

        On foils with an efficient water turbine it could work.

    17. imma cabbage

      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.

      1. William Fahle

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

    18. pan klovatina

      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.

    19. Madison Filan

      It makes sense

    20. Simeon Murray

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

    21. ivalsar

      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..

      1. eyytee

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

    22. Peyton Conrady

      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."

    23. Mark Lenfestey

      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.

      1. eyytee

        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.

      2. coolaun

        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.

    24. Kristie Sullivan

      The ad airplane postsynaptically surround because eggplant logistically remind beside a stiff particle. screeching, cooing precipitation

    25. Sameer Rizwan

      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.

    26. Kyle Gray

      The poor stomach iteratively announce because soap compellingly stay apud a first norwegian. truthful, unhealthy net

    27. George

      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.

    28. Spencer Mac Gillivray

      Very cool.

    29. Badass Tutors

      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)

    30. Man Vs naM

      "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.

    31. watershed wonders1

      Wow. Mind blown.

    32. LucasCB

      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.

    33. Mohsen Heravi

      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 FIblock channel with almost 10M subscriber and didn't need to work for someone else as a design engineer :)

      1. Mohsen Heravi

        @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 :)

      2. Rick Cavallaro

        @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).

      3. Mohsen Heravi

        @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.

      4. Rick Cavallaro

        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.

    34. Alex T

      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.

      1. Lassi Kinnunen 81

        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.

    35. Pyro Sparkle

      I love how Blackbird is made with bike parts

      1. Deputy Dog

        Remind you of anyone?

    36. Torval T Haus

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

    37. Mateus Rocha

      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.

      1. Mateus Rocha

        @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.

      2. John Borton

        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).

    38. yunus YILMAZ

      I cant be civil, Im Russian

    39. Brandynette Damm

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

    40. AWESOM-O

      Do this with solar sails

    41. QuantumRift

      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).

    42. Rafael Heeren

      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.

      1. Rick Cavallaro

        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.

    43. Ilyes Hacahni

      Being civil.

    44. Dado Komar

      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.

      1. Deputy Dog

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

    45. Jack Odinsen

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

    46. Dado Komar

      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.

      1. Rick Cavallaro

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

    47. Washemo Amadah

      "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.

      1. ThatOneStopSign

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

    48. Robert Swick

      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.

    49. asollid

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

    50. Dado Komar

      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.

    51. Havoc Maverick

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

    52. SergTTL

      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.

      1. SergTTL

        @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!

      2. SergTTL

        @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?

      3. John Borton

        @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. :)

      4. SergTTL

        @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.

      5. John Borton

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

    53. Dustin Vanantwerp

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

      1. Dustin Vanantwerp

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

      2. Rick Cavallaro

        I hereby volunteer to help you beat our record.

      3. John Borton

        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.

    54. Rajat Roy

      Cognitive neurosciences approach. American flags elicit. New technologies construct. Sciences awaken. Agricultural economics lesson. Technical disciplines control. Ecological economics enhance. Lib labs attain. Liberal economics adopt. International forensics skill. Traditional economics arouse. Evolutionary economics conceive. Several labs encourage. Understandable technologies enact. Small flags compose. Experimental neurosciences approach. Traditional economics contribute. Human sciences engender. Industrial technologies assemble. Specific technologies emerge.

    55. Rajat Roy

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

    56. Pawel Kedzior

      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?

    57. Korey M

      6:35 talking while its pretty windy. hahaha

    58. Kar-Jun Thum

      I based my vehicle project in DT on this video

      1. Rick Cavallaro

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

      2. Kar-Jun Thum

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

    59. Jon Sia

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

      1. Pratham Tanwar

        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.

    60. disarchitected

      That looks a lot of fun.

    61. Ballsack69

      My brain is pain

    62. come y bebe la vida es breve!

      Not new we got this in Holland


      Somebody now do the same thing but with boats 🤔😊

    64. Zan bel

      free energy is here

    65. snarfbot

      I love when the armchair experts are proved wrong.

      1. snarfbot

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

      2. Rick Cavallaro

        You mean armchair experts like UCLA physics professor Alexander Kusenko?

    66. Tootking

      It’s like a cart from bad piggies

    67. Kevin Budzisch

      The mature july technically analyse because branch natively wipe besides a nutritious subway. inexpensive, panicky bridge

    68. Kevin Budzisch

      The heady door speculatively stuff because ocean intracellularly groan times a beneficial almanac. taboo, witty crayfish

    69. plebpunk

      Wow mind blown 🤯

    70. calivax

      Physics says no.

      1. Rick Cavallaro

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

      2. eyytee

        Physics is totally down with this.

    71. Leon Rai

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

    72. Bok Chuaka

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

    73. Dean White

      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.

    74. S.Vidhyardh Singh

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

    75. Filip Sochor

      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.

      1. Filip Sochor

        @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.

      2. Jan-Willem

        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.

    76. Рэй Чехов

      So can you make same thing on the water?

    77. lagrangewei

      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.

    78. stabarinde

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

      1. eyytee

        Yes, it's because of the prop torque.

    79. Martin Gustavsson

      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.

      1. Todd Hubers

        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.

    80. Urs Kinzelbach

      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..

    81. e c

      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...

      1. eyytee

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

      2. e c

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

      3. eyytee

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

    82. Alvise Sembenico

      Mind blowing, maybe at a higher speed than my mind itself.

    83. C: broski

      This car is literally the thing the goblins used for their race in the shimmering flats lol wtf

    84. spolo123

      Could they investigate the feasibility of a wind facing such chariot? Wouldn't that be totally impossible? Prove me wrong

    85. Dirk Anteunis

      Georgeos!!! Professor Lewin will love this !

    86. Jordan Fischer

      I immediately saw this guy and thought he was a flat earther. And then he said this: 8:06. *Wait, hold on a second...*

      1. Rick Cavallaro

        @Jordan Fischer I don't think anyone's pegged me for a flat earther before.

      2. Jordan Fischer

        hold on a second for two reasons: this guy's a genius, *and* he said "instead of a sphere" lol

    87. Nagaraju Chukkala

      Great video

    88. Anders Bodin

      There is no such law as conservation of speed, there is however conservation of energy/momentum. Momentum is mass times speed. by increasing the size of the aero-foil you deflect a bigger mass of air, and you gain more energy/momentum/lift without the wind speed having to increase through this deflection. Get a big enough aero-foil for the wight of your craft and you will be going faster than the wind. Physics professors should understand this.

      1. QuantumRift

        Sailboats can do it. SO can this vehicle. Simple aerodynamics.

    89. Suzanne Wilson

      The vehicle itself is the equivalent to the keel on a sailing boat. ie a resistance to the forward forces on the blades (Bernoulli effect)(assuming blades have profile of aircraft wings) Someone please correct me if I am wrong!

    90. Ben L

      If the explanation at the end is how the car manages to move faster than the wind, then isn't it already detached from the original debate about a boat? He's saying the large fans are generating that additional thrust needed to push the car forward faster than the wind by pushing some air molecules backwards. That's completely different than a sail boat's design.

      1. Rick Cavallaro

        It seems completely different, but it's actually aerodynamically identical to those two sailboats on a cylindrical Earth.

    91. Brian Baird

      Ok, I know there is a part of this video where the string and ribbon hanging on the front of the vehicle indicates he's going faster than the wind. I do not dispute this section of video. BUT here is what I believe happened: A gust of wind got him up to a good fast speed (but not faster than the gust), then the gust died away, leaving the car rolling along on it's own momentum. Since the wind gust has died, and the car is still rolling, of course it will now be moving faster than the wind. UNTIL IT COASTS TO A STOP. Also, if this thing can go faster than the air around it, why can't we just push it or pull it through still air so the wheels spin the prop and the resulting thrust keeps the thing running. Answer: that would be a perpetual motion machine---which does not and cannot exist. The only way I would believe this video is not a fake is if there is a chase vehicle off to the side of the prop car (so it won't interrupt the wind supply) and this vehicle has a very long, thin wand that goes up to the height of the propeller axle and releases a trail of smoke. Then we need a day with a steady wind and enough miles of level road to keep moving faster than the wind for several minutes. That way we rule out coasting.

      1. eyytee

        > "why can't we just push it or pull it through still air" Read the pinned comment. > "if there is a chase vehicle off to the side of the prop car" NALSA did that for the record runs. Google "NALSA downwind record" > "That way we rule out coasting." This was ruled out by the NALSA rules: No stored energy can be used for propulsion. The vehicle has to accelerate while being above current windspeed.

    92. Sanniv Bhaduri

      Even after the explanation, I still cannot wrap my head around how the energy in conserved? Till the moment the craft reaches the wind speed (the external force) it makes sense that the craft is accelerating. However, after reaching the wind speed, where is the power coming to spin the propellers faster than wind speed? As per explanation, the power after this point (for accelaration) is generated by the craft! If someone can explain further, it would be of much help!

      1. eyytee

        Where the power comes from depends on the reference frame you pick to do the analysis. But in any frame the velocity difference between air and ground (true wind) is being reduced.

      2. J Modified

        It is still slowing the wind relative to the ground when above windspeed. Energy lost there will balance the energy gained by the accelerated cart plus losses.

    93. Kris Hanna

      The zealous columnist covalently laugh because ease oceanographically alert versus a zealous llama. sore, nutty train

    94. Franklin Yao

      I dont understand how people dont get it LOL I mean the way you explained it, is so clear and even with an experiment XD

      1. Scott Reimers

        I think they did an excellent attempt to try and after a couple more hours of review trying to understand more fully I encountered somebody who pointed out that the rotation of the propeller creates a situation where the energy of the blowing wind against the swept area that could be used to push a heavier object is instead being able to be used to push a lighter object faster. I think the focus on the high pressure low pressure sail shape concept might perhaps be able to be expanded, but every way I try to contemplate doesn't quite make sense and I have to admit I don't know how it could be improved at this point.

      2. Franklin Yao

        @Scott Reimers well let's say is up to you, how would you do it so that the idea behind this could be presented better ?

      3. Scott Reimers

        I think the challenge some of us have is that the core argument sounds like it makes sense, but it's missing a major factor and intuitively the missing major factor drives us crazy. Propellers work through everything they described AND the concept of sweep. Near the center of rotation the propeller will be rotating slowly enough that it acts like a static sail and gets pushed faster than the wind, but the edges of the propeller it actually move fast enough in linear feet per second that they moves faster than the wind. The argument that they are taking energy from the air is very likely, but the method by which they are doing so is probably not well presented here. I'm guessing that if total airflow were measured as net "propeller-acceleration/minor-wind-deceleration" vs "propeller-deceleration/major-wind-deceleration" the likely effect is that for 60% of the swept surface area nearest the center of rotation you'd see the propeller being accelerated But for the 40% swept area furthest from the center of rotation, you'd see that propeller motion slowing the prop while "pushing against the air" and creating net vehicle acceleration.

    95. Don Omar Ramiro

      Now what about the gears? The fan could be a fan or a propeller, but with enought gears and little force reduction, they could drive against the wind?...

      1. eyytee

        They already went directly upwind at 2.1 windspeed with that cart.

    96. Student A Fake

      Rogue scientists.

      1. Rick Cavallaro

        Maybe free-range, but not rogue :)

    97. DumHed

      This is essentially a form of gearing between the input and output power to optimise the forces and speeds to the vehicle requirements. A couple of ways I think this can be compared to a "spinnaker going with the wind" (which is limited to below the wind speed, but can usually provide more than the required force): 1. Use the spinnaker to pull a vehicle up a hill at close to the wind speed, then roll down a hill at higher speed. This could average out well above the wind speed. 2. Have the spinnaker out in front of the vehicle on a long rope, and wind the rope in around the axle as the vehicle moves. It will travel faster than the wind until the rope runs out.