Risking My Life To Settle A Physics Debate

Veritasium

6mn visningar47 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

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    A HUGE thanks to Rick and Neil for letting me drive Blackbird. Check out Rick's SEprom 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: seprom.infof... .

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

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    References
    Jack Goodman's SEprom 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)

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    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

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    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

    Publicerades den 22 dagar sedan

    Kommentarer

    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. enochian seven

      Civility ya jerks,civility

    3. Maggie Hernandez

      The womanly idea timely exist because toast cytopathologically rain vice a deserted magician. windy, billowy dust

    4. David M

      I don't think you have to explain it. Just prove that it's possible. There are countless scientific discoveries where the discoverer did not fully understand what he/she accomplished. Let the physicists do the math.

    5. S1nwar

      im sorry Derek but your explanation "If we apply this power to the fan, it can create a force of F = P/V = 1200W / 2m/s = 600N" cant possibly be true because the force would tend towards infinity if the difference (vehicle speed - windspeed) approaches 0.

    6. Inshaf Ahmed

      🤔

    7. budrow1999

      So does that mean the prop is acting as a compressor second handedly to maintain air pressure?

    8. siddhanth ravichandran

      Idk why.... I keep imagining Charlie's voice (penguinz0) "SCIENCE SAID IT COULDNT BE DONE!!!!"

    9. Chetan Rajput

      How much faster it can possibly get ? What will be the bottleneck in that case ?

    10. unknown

      I won't push back. The vehicle is doing enough of that already :D Seriously, this is amazing. Thanks to all of you.

    11. brendy isabel santiago ullero

      The joyous grey aesthetically chop because business aboaly develop sans a male bagel. deafening, known relation

    12. L33Th1nK1ng

      But this time youre false. Bin von dir sehr Inspiriert, du machst eine tolle Arbeit und bringst uns alle weiter. Mit ispiration. Und genialer Wissenschaft. Aber es ist eine Optische Täuschung. It depends on potentional Energy, and in this case also Time. And a perpetuum Mobile is real, but the Energy to build some, is higher than it will produce.

    13. nickj384

      Your prop is on backwards in all of your animations

    14. Mikey Masticator

      This is nonsensical. If it is propelled in zero relative wind then it should work with no actual wind at all right?

      1. S1nwar

        a sailingboat can also travel as fast as the wind. does a boat work without wind :p? dont confuse yourself.

      2. Rick Cavallaro

        It can continue to maintain 2.8X wind speed in zero wind.

      3. eyytee

        "... it should work with no actual wind at all right?" Wrong. See the pinned comment.

    15. hunterssports

      Now we can use this type of concept on Sun Space Ship Sails to travel @2X the speed of light.

    16. Sandra Cash

      The common random intrestingly wink because fire pathophysiologically level like a overwrought diving. kindly, fuzzy musician

    17. Mark Freeman

      All these years and planes have had the props the wrong way round.

    18. Luobo Mu

      It's the same reason why a kite flies, isn't it? If you let go of a the line, the kite will immediately start falling to the ground.

    19. GetMoGaming

      My 2nd watch of the summary explanation and I have a complete moving demonstration in my mind. You have to think of it in an inertial frame of reference and keep in mind how the air is moving in relation to the ground.

    20. JsonKody

      this is realy amazing .. I love the thought process behind it and how genius it is :O

    21. David

      I wonder if it can make a plane fly faster then the tail wind?

    22. GetMoGaming

      I want a toy version of this.

    23. kaipirinha089

      Same explanation as sail boats going faster than the wind. The difference here is that you have two sailboats that each go at an angle to the speed of wind and in sum the vehicle goes exactly with the speed of win, pushed ahead by two angled sailboats.

    24. DualDesertEagle

      I kinda want a model of that thing now, complete with remote-controlled brakes, steering and prop pitch.

    25. Roy Plisko

      There is a clear difference between breaking the laws of physics and understanding how they are being applied. Lots of people with a casual understanding will think they are outsmarting an idea that is actually outsmarting them.

      1. John Borton

        ^^^^^ This.

    26. pengo

      You've create a true paradigm shift with this video. What was "obviously impossible" has become simply "obvious." Well done!

    27. MrStutz333

      Technically helicopters break the laws of physics too but here we are...

      1. John Borton

        @MrStutz333 // " I'll enjoy my "mythical fantasy" that i literally make a living off"// That's adorable.

      2. MrStutz333

        @John Borton Cool. I'll enjoy my "mythical fantasy" that i literally make a living off of and you can move on to stir the pot on someone else's post there, keyboard scientist lol

      3. John Borton

        @MrStutz333 Nonsense. Present your evidence. Until then, enjoy your mythical fantasy. It's your claim. Until supported (which you can't), I'm only put the energy into it and empty claim deserves.

      4. MrStutz333

        @John Borton I don't need to assert my claim with sufficient evidence until it has been challenged. It is a simple comment until a rebuttal is made, at which point a debate can begin. Also, i have been working on helicopters for 12 years. My claim is literally taught from day one. Helos are not supposed to fly according to the specifics of the Laws of Physics.

      5. John Borton

        @MrStutz333 Things asserted without evidence can be rejected equally.

    28. Chuzz Bot

      Looks like it wasn't just the wind that was high. Great show, great invention.

    29. Volo

      OOOOKAY, what is so special about this thing? They've been racing these crafts for at least a decade within Aeolus Racing annual competition. Actually the craft in the video would be considered junk by Aeolus Racing standards.

      1. eyytee

        The current Aeolus Racing record is 1.15 x windspeed going upwind. The Blackbird has a record of 2.1 x windspeed going directly upwind, and 2.8 x windpspeed going directly downwind. This video is specifically about going directly downwind faster than the wind, which no Aeolus Racer has ever done.

      2. John Borton

        Think of Aeolus as a series where there are a significant number of performance limiting rules (because there are). Think of the Blackbird as the 'open class' vehicle with no rules are imposed. The budget for the Blackbird was a tiny fraction of Aeolus and yet ... no comparison in performance.

      3. John Borton

        What's special about it is it absolutely spanks the Aeolus vehicles. Blackbird was ripping up over 2x the speed of the wind while Aeolus craft were in the 75% of ws range. Notice that it's the Blackbird that owns the records (and by a wide margin).

    30. Harshit Joshi

      Well we do have Dyson fanless fan somewhat based on the same thing... right?

    31. John Adams

      So could you do the same thing with a sail boat? Add a paddle wheel that powered a propeller?

      1. eyytee

        Yes, but a turbine rotor in the water might be more efficient than paddle wheels.

    32. Chuzz Bot

      You couldn't give the inventor a last name?

    33. O P

      The illustration of the sailboat sail used apparent wind from a slightly forward direction (tacking AGAINST the wind) whereas the prop had the wind from the back. So it does not feel like you can compare these two situations , right?

      1. O P

        @subductionzone you are right:)

      2. subductionzone

        @O P Look more carefully. The "wind" in that illustration is the apparent wind. The wind that one would feel as an observer on the sailboat. That is a combination of both the true wind and the "wind" caused by the boats motion.

      3. O P

        @subductionzone look at 7.05 - there the illustration is not downwind. I would argue that sailing against the wind, the the principle shown (similar to an airplane) works. But downwind, you do not use that principle. Hence, the illustration at 7.05 seems not appropriate. Agree?

      4. subductionzone

        If you look carefully the sailboat is also sailing downwind. With a high performance sailboat it is possible to tack back and forth downwind faster than the wind. In other words when sailing directly downwind the fastest course is not a straight line. If you look up iceboat racing, specifically DN class iceboats. They tend to run on course that consist of only two pylons. One directly downwind from the other. Pilots follow a diamond shaped course with the poles at two of the vertexes. On the downwind run an ice boat would obliterate someone sailing a sail boat on a straight downwind course.

    34. batuhan başpınar

      In summary, what will be understood is that the propeller is simultaneously pushing the vehicle while charging the wind since zero time. As the vehicle's speed increases, the wind transfers less power to the propeller, thus reducing the power stored in "t" time. The energy used to propel the vehicle from time zero continues until the total stored power is exhausted. A simple mechanism can be prepared to understand this situation: A strong wind flow is given to a triple propeller for 1 second and the flow is suddenly interrupted. As soon as the wind stops, the propeller is still spinning. This is because the propeller has stored the energy of the wind from the very beginning. I hope it was civil :D. Please correct me if I have given wrong information :). And sorry for my bad english too :-/.

      1. batuhan başpınar

        @eyytee K ty for info.

      2. eyytee

        " The energy used to propel the vehicle from time zero continues until the total stored power is exhausted." No, it doesn't use stored energy for propulsion.

    35. Manzoor Shah

      Great

    36. 1234 “90” 5678

      Sorry, but that looks like a huge doze of bullsh*t to me. At the top speed (speed of the wind) the rotor should change the direction of rotating to start sucking the air instead of being pushed by it, but it's immpossible to do with the wind comming from the back. Except we are using some motor inside the fan to force it.

      1. John Borton

        As noted in Derek's pinned post -- there are no motors. The rotor is never 'pushed' directly by the wind, but rather is driven to rotate against the wind by it's gearing to the wheels. And no, the rotor should never change direction -- it is geared to the wheels and turns at a fixed ratio to them.

    37. skiller_007

      so far as i still remember if you like wind surfing there are some manuvers which actually using the sail technic you showed which make it faster

    38. Melwill September

      This makes sense, so why were there people saying it is stupid, the explanation at the end of the video is good to explain it simply.

    39. oiuet souiu

      Flatearther be like, "see? told you Earth is not a ball". It's a cylinder, but the flat end of the cylinder.

    40. Im̶̧̲͇̂̇͂͒͒͊m̷̻̖͂͒̇̋͗̊͌̓̑̇Ωr†ΔL Z̴̙͖͚̗̜̜̍̓̓̕͠ΞN氣

      For the exercise: Take away the wind. And push this contraption (same as the wind) and it should keep going forever with no energy input.. This is a perpetual motion machine +. What they are doing is accelerating with the wind and the inertia helps it go faster than the wind due to acceleration/inertia physics (for a short time), it is not a machine that goes faster than the wind. It is inertia and any object will be able to do this

      1. eyytee

        " It is inertia ...." No, it cannot use inertia to accelerate.

      2. Rick Cavallaro

        @oiuet souiu >> There are flaws in this experiment. Wrong. >> I'm not a scientist Clearly.

      3. Rick Cavallaro

        >> it should keep going forever with no energy input.. Nope. >> This is a perpetual motion machine +. Nope. >> the inertia helps it go faster than the wind Nope. >> for a short time Wrong. >> it is not a machine that goes faster than the wind. Wrong. >> any object will be able to do this Wrong.

      4. oiuet souiu

        law of physics is a LAW. I'm not a scientist, but this is very trivial. There are flaws in this experiment. 1. To start the vehicle from 0, it already used so much wind power and con

    41. mxredbaron

      pushing against the wind isn't anything new, it's just being displayed differently here. well done.

    42. Felicia Moniq

      This is why we need women in science

    43. Noah Moss

      I spy a onewheel

    44. dotsync

      Seems like a vehicle that could be fitted with a little tech to be made autonomous and remote controlled for safer and more frequent experiments. Fascinating demonstrations for sure!

    45. Bon Bon

      Literally looks like something made in garry's mod

    46. Tao Zhang

      Now I wonder if this is possible with a version in the water using the same principle...

    47. zin yang

      Seems liike a simple "distributed" jetfan engine to be honest.

    48. Gertrude Elisa

      The loose toothpaste comparatively scold because linda climatologically tip modulo a abnormal oboe. careful, axiomatic sweets

    49. Phantom Knight Solaire

      Assuming the wheels didn't have friction. What stops this from accelerating indefinitely. I know this is impossible but how

    50. Alex Force

      This thing is made of 50 % spite and 50 % duck tape.

    51. Napi

      you should connect the propeller with a pedal powered foot

    52. Christine Bridges

      The steady prose supposedly scold because mouth outstandingly land circa a foregoing child. economic, miscreant apology

    53. upshot bwind

      Still way better and make more sense to work though not practical as a vehiclular solution but better than the hype vaporware of Elon's HYPERLOOP. Ya I said it.

    54. Anthony Bear

      Show me the experiment how you can show , Chicago skyline visible at 57 mi from Michigan coastline. Duplicate the The mirage that's supposed to be happening?

    55. Anthony Bear

      I want to see your gravity experiment? I want to see Bend water around the globe experiment? I want to see your experiment to show how an airplane that's in let's say Canada's whether there's only spending 200 mph cruises over to the equator we're spending 1,038 miles an hour, show me that experiment

    56. CJSuss

      It's like swimming down stream

    57. Julian Julian

      law of physics is a LAW. I'm not a scientist, but this is very trivial. There are flaws in this experiment. 1. To start the vehicle from 0, it already used so much wind power and convert it to kinetic energy to move that propeller. There's where you get the "extra" energy. So, it is not free. 2. Do you consider the elevation? 3. is the wind constant? If not, then you're just moving faster than the wind when it becomes weaker. And that's completely understandable

      1. Julian Julian

        @Rick Cavallaro What's your point? you want to have an argument based on fact? or do you want to just insult people? I did admit I'm not a scientist (as i should), do you think you are?

      2. Rick Cavallaro

        >> I'm not a scientist Clearly.

      3. Julian Julian

        @Craig S I did. And still, those three points stand. I've seen the design and the research. They lack those 3 things

      4. Craig S

        I thought the same thing, but then did some research of the data from about 10 years back. It doesn't break the laws of physics and is not free energy and it's not a trick It's just hard to understand the non obvious principal. You have to look at the old data and demonstrations to understand. Takes a lot of reading and googling.

    58. Ben Brown

      Now imagine the device with rare earth magnet frictionless hubs ... what kind of speeds could you get up to? And I'm sure the propellers could be tweaked for even greater efficiency to tack Against the Wind

      1. J Modified

        I think friction loss at the hubs is probably tiny compared to losses due to wind resistance at 2.8x wind speed. A full cockpit might help significantly. A larger diameter prop would probably help, but at some point the efficiency gained with size will be balanced out by added weight of the prop and the frame that holds it plus balance issues.

    59. Multiman40

      So it's creating a vacuum.

    60. jon b

      the beginning of the video and the animation with the cylinder earth and sailboats all made it seem like the prop was being used as a sail to drive the wheels. sort of confusing to make it that the wheels are actually driving a push prop.

      1. Rick Cavallaro

        It's supposed to be sort of confusing. That's what makes it a great brain teaser. But the wheels are in fact driving the propeller at all times.

    61. な だい

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    62. shaun mabey

      You are so high, look at you're eyes 😂

    63. gtr mjk

      The spotless earthquake frequently reply because liquor prospectively stitch until a homeless expert. itchy, nimble humor

    64. Vic R.

      The vehicle relies on wind shear, ie low down the wind goes slower due to ground friction than higher where the propeller is located. So when the vehicle gets up to the speed at the ribbon height, it droops down or switches direction while the prop keeps turning, generating power from the higher wind speed at it’s height. No free lunch!

      1. subductionzone

        No, it relies on the fact that wind blowing over a surface is a potential source of energy. After the wind passes through the rotator disc of the prop it is moving more slowly relative to the ground the energy that the wind loses goes into the cart.

    65. Severin .Wolf

      I wonder if the slower wind speeds behind the vehicle creates a vacuum, or lower pressure, that sucks air from the higher pressure in front.

    66. Christine Bridges

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    67. Gene Kim

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    68. Matt Martineau

      Could this apply to solar wind? Light? Hmmm... thinking, yes? tho... isn't lightspeed a hard limit?

    69. Blaze

      now that the muon accelerator exists our laws of physics are gone maybe more things like this exist

    70. Johan Zetterberg

      The air pushes on both sides of the propeller or sail

    71. J G-man

      The air colum the prop making is pushing the cart. Think of it as a 1stage rocket. Only 1 stage because the air pressure doesn't change no differnt nozzles needed

    72. Danny Darden

      So effectively there is a vacuum being produced on the headwind side of the fan which is pulling the cart forward. It would be the same thing as when you get in the vortex behind a semi truck on the interstate and you can reduce acceleration of your own vehicle yet the semi pulls you down the road behind it.

      1. subductionzone

        No the air that the propeller interacts with loses energy. That energy does into the cart. Just like a sailboat on a downwind reach. Does a sail make a vacuum in such a case?

    73. Jonathon Stillwell

      Wheels turn prop, prop pushes air back towards forward moving air. Absolutely logical. Great vid.

    74. Yannick Ramouillet

      Isn't this video older than just a few weeks !??? I have the impression i already have seen this, do am I right ?

    75. مهدی خ مقدم

      I just hear a sound looks like that a diesel motor gets out of fuel in 12:24 .why it should make sound look like this. it has no air compress system.

    76. Eric Ruhl

      What happens when you point it into the wind?

      1. subductionzone

        @Eric Ruhl No, the prop is rotating. That allows it to push back on the air. Or the air to push forwards on the prop. It is similar to a lever. The Blackbird in this configuration is only capable of going downwind. By the way, there are countless treadmill videos of carts on SEprom. The treadmill is a Galilean transformation of the cart on the road at windspeed, just as a wind tunnels can be used as a Galilean transformation of a wing in flight. There is at least one video of a person reversing his cart. It was not as efficient so he had to run it at higher speeds (that is the equivalent of a stronger wind) It still went up the treadmill or in other words Directly Downwind Faster Than The Wind.

      2. Eric Ruhl

        @subductionzone Nevermind, I think my mental model had the blade speed much lower than it is in reality.

      3. Eric Ruhl

        @subductionzone but by moving faster than the air, all force applied by the air is on the front of the vehicle, as if it were traveling up wind. At that point, it seems like the sailboat analogy should be flipped around, because as it is, sailboats are able to sail up wind by using the sail to generate force sideways, and using the rudder to redirect that force backwards, much like this vehicle is doing when it goes faster than the wind.

      4. subductionzone

        @Eric Ruhl No, it is just going faster than the wind. The prop merely extracts energy from the air. The wheels drive the prop, so the faster that the cart goes the faster that the prop spins. It is a feedback system. If there was no friction it would keep going faster and faster indefinitely, but in the real world friction is an increasing factor. It eventually keeps the cart from going any faster.

      5. Eric Ruhl

        @subductionzone but isn't that effectively what it's doing when it goes faster than the wind? I guess the way that it's geared to the wheels would have to change. Hrm... Maybe a 1/3 to 1/5 gear reduction to compensate for the lower land speed?

    77. Charles Majorson

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    78. Hugo Rechatin

      So is the cap speed when the air is left behind, still in reference to the ground, or would the fan just start blowing the air behind it at a headwind speed ?

      1. J Modified

        Yes, one absolute limit would be when you reduce the wind speed to zero in the column of air swept by the prop. The prop (or a prop actually capable of doing that in this configuration) would become highly inefficient long before that though.

    79. c64cosmin

      Is this the beginning of a real warp drive?

    80. Raminez Dery

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    81. kareybruner

      how is it any different than a prop on a boat, the air is essentially a fluid too so I don't see why it would be possible

      1. J Modified

        Yes, but the equivalent would be water/land, not water/air. So something that rides astride a canal with roadway on both sides and has a prop on a beam in the water. Water/air may be possible, but in that case you have a lot more losses.

    82. Rob Jarreau

      The merciful yellow apparently unpack because team hopefully punch on a necessary digital. wretched, willing suede

      1. sluggJB

        WTF? Your brain...watch video, Your brain on drugs...this comment!

    83. Pepeijndhoven

      before the video hitted to minutes i understood the clue, it's brilliant

    84. Scott Byars

      Wonderful!!! Fantastic!!! Funny how these so called scientist are so quick to doubt something new...

    85. :awesome:

      The Dyson dude gonna visit you

    86. Tony Higgins

      I really do love this channel.

    87. Eric Saumur

      Now apply this to the Alcubierre drive so that we can go faster than the speed of light in the direction that the universe is expanding. And then go for breakfast at Milliways.

    88. Pavlos Pavlou

      @Veritasium Build the same vehicle with 4 propellers with Carbon Frame and use a GearBox with 6 Gears. So when you have 20km/h Wind with the 6th GearBox can get up to 120km/h. :)

    89. Vo The Quyen

      The natural tank conspicuously slip because chess conservatively weigh among a unkempt wallaby. exciting exclusive, eight foot

    90. sevencolours

      The way the video was set up and presented, there is no pushback. When he said he expects pushback, he knew there will be virtually none.

      1. sevencolours

        @John Borton OK, give me the percentage. I'd say maybe 1%. If that's a lot, then you have a very strange understanding of "a lot".

      2. John Borton

        @sevencolours Never made that claim at all, but I have examined them all

      3. John Borton

        @sevencolours Given that I've read every comment, I have a much better idea as to the percentage of pushback than you do. If you were smart you wouldn't assume so much.

      4. sevencolours

        @John Borton The comments are overwhelmingly positive. You don't know anything about statistics. You made the noob mistake, claiming all comments must be examined.

      5. sevencolours

        @John Borton You don't know anything about data sets. In orders to see the percentage of push back comments, only a subset can be examined. If you were smart, you'd know that that.

    91. Matthew Simmons

      Think of it this way, wind energy is being converted into wheel energy right? As the vehicle approaches the same speed as the wind, the wind energy plateaus, but the wheel energy keeps on providing (by driving a propeller). This is because the wheel energy depends on the vehicles speed relative to the ground (which is always zero) whereas the wind energy depends on the vehicles speed relative to the wind. So it works by converting wind energy to another form of energy that can keep on providing a speed increase even after the wind energy no longer can.

      1. John Borton

        @Matthew Simmons Fair enough. ... not sure if you meant this one as worded either. // "whereas the wind energy depends on the vehicles speed relative to the wind."// The wind energy available to the Blackbird doesn't vary with vehicle speed -- that's what's unique about the design and what allows it to continue to accelerate even when the the airflow over the chassis is zero.

      2. Matthew Simmons

        @John Borton I should have worded it better. I meant that the ground is always zero. Meaning the delta V between ground and vehicle keeps growing unlike the delta V between the wind and vehicle.

      3. John Borton

        In operation, the vehicle's speed relative to the ground is most definitely not zero.

    92. Ernesto Guitian

      It may sound dumb but would this be considered infinite energy? Like would it just keep going

      1. Trueantitheist

        No because you still need the wind and it is powered by the sun which despite how long lasting it is does not by any means have infinite energy.

    93. Comms

      It needs more blades on the propeller

    94. steve poling

      So, when the vehicle is at wind-speed the prop acts like a wing spinning in stationary (relative to the vehicle) air. This lift pulls each prop blade forward and that force is translated to the mast of the vehicle. Gearing the wheels to the prop is just to get the prop spinning so the blades can start generating lift.

      1. John Borton

        Gearing the wheels to the prop provides the Blackbird the same kinematic constraint that the keel provides on a sailboat. Remove the keel on a sailboat and it merely drifts downwind at something less than windspeed. Same with the Blackbird. This constraint it required at all speeds.

    95. Cosmowerks tapes

      it would have been even more impressive to have it so the prop could be oriented at various angles, to allow different directions, and, see him turn instead of stop, and turn across the wind, and then, back at an angle into the wind, back towards where he started.

    96. RouVix

      Does this have any analogy to a helicopter falling without an engine? Just in the other direction

      1. John Borton

        Nope -- the Blackbird is utilizing a garden variety propeller and never autorotating.

    97. Gene Au

      Newton's mind is blown

    98. Szabo Robert Arpad

      Now it makes sense ... Love this kind of stuff... Bravo for the team ... Hello from Romania.