Should I tackle this subject?

greg, everything you produce is interesting. I will roll with the flow.

do it. Saw the video. the explanations ate partial and obscure. The msth and physics are trivial. Put it right!

I have followed this topic for years. Word of warning: where it goes, *endless* argument follows and people start throwing pocket protectors and scientific calculators at each other.

Make it, Greg. Given the choice between trusting a physicist or an engineer about a real world problem, I'd go with the engineer every time.

Yes, please.

I like it when you challenge so-called 'history channels' when they misrepresent well known events. Your video on the Wright Brothers is superb. However, challenging gimmicky physics claims gets into a whole morass of back and forth. The only real good challenge to the propeller car is if you could be on site, look at the inside and then drive it yourself. Dealing with this nonsense from a distance only creates more noise.

Per the suggestion I have sent the question to 3 of my Aero PhD friends ( 2 Stanford and one CalTech). It reminds me of a Movietone short from the twenties or thirties I saw of an actual "sailplane". A sand cart with a wing and a triangular sailboat sail on a tall mast. It charged down the beach under sail and lifted off. I don't think it showed it landing. I assume it was only able to fly by the inertia it built up rolling down the beach and must have landed as it started to drift with the wind losing the speed differential.

There's a pinned comment under the video that goes into depth about how it works, but I'm not sure if you can agree with it. I'm not saying he's right and you are wrong, and I'm not entirely buy into his explanation, but for the sake of information, from now on is a straight quote from the comment: 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).

Thinking about this more deeply, a speed faster than the wind might be achievable but could not be maintained unless the vehicle moved at an angle to it, so I think you ought to make a video.

No

Hi Greg, Veritasium has been called out multiple times for providing incorrect information, sometimes bordering on outright deception. So, please put out a correction. Veritasium's response should be entertaining.

If you're going to start challenging all the click bait bullshit on YouTube then the excellent content on your channel is going to get diluted very quickly.

Dear Greg, Please do. It is not at all far removed from aeronautical engineering and an interesting problem of vectors of motion and forces and of transmission. The interaction between one medium and another is also interesting. Dispite it being counterintuitive. It seems to me that it can be explained convincingly without being to complicated by doing the numbers and drawing the pictures, particularly the pictures (good pictures). Although maybe it's not for everyone of your audience. I've only watched the Veritasium video you mention and I must admit I havent done the homework on this, nor am I going to anytime soon. That would be a bit of work and setting up a good explanationation perhaps even more so. The sailboat analogy may be useful, although it would require a detailed and complete explanation of how it is analogous, or you will lose people. I haven't yet wrapped my head around it, so I would certainly be looking forward to your video to get the complete picture. I'm with Kilian Ortmann (a few comments back) on making it your own video and not to much of a rebuttal. It is in itself a very insightful physics and engineering problem with some interesting links to aviation.

Go for it. I know you'll do a great job.

I'd love to see such a response to Veritasium- this would not be the first time I've seen folks calling that channel out, especially when it seems to cover one 'new tech' company in particular.

I love it when you play the part of YouTube Police. There's not much money in it so nobody wants to do it but holy crap is it a valuable service. Go get 'em.

I have now watched the video. I don't quite know what your angle is on this but I am pretty sure what is happening. It is quite well known that a sail can move faster than the wind if it has a great enough angle to it. In the configuration that they have made with a propeller geared to drive the wheels, the propeller is the sail and it will be rotating faster than the wind is blowing; certainly at the periphery. This speed or energy is transmitted to the wheels which will propel the whole machine faster than the wind. It can be compared to a wind turbine generating power to propel a vehicle, but in this case the wind turbine is attached to the moving object [which is incidental], therefore I would be extremely surprised if it didn't exceed the velocity of the wind. I found Veritasium's understanding of it strange, which is unusual because he is pretty good as a rule. For what it is worth, in my view it is in complete harmony with the [laws of physics] but that means nothing, the laws of physics do not exist outside the domain of human thought. The universe has no concept of them.

I am sorry but I hadn't finished. I would like to respond to some of these videos myself but I am not a youtuber. Be aware of one thing though, the [air] has mass and a vehicle with a sail can certainly be propelled faster than the wind if configured appropriately. I have not seen this video so I leave it in your hands. I look forward to your reply though, if you decide to.

Yes, if you want to. I have watched some of his videos and while they are very informative, his emphasis is academic. Mathematics is not an understanding of anything, it is purely descriptive [a psychological apparatus which we use as a universal language of logic]. I hope that doesn't sound hifalutin, but there is nothing to fear from academia and it was/is the source of the resistance to the claim that the Wright Brothers created the first aircraft. The science of flight was well known, the task though, was a problem for engineering which necessitates a thorough understanding.

I think it would be an interesting video. That being said I do caution somewhat about straying from your area of expertise because that's a path many channels fall into which leads to a loss of credibility overall.

Nah, I wouldn't invest time in it Greg. I feel your time is better spent on your excellent regular content myself.

DO IT NOW…please

Definitely do it. You have the technical prowess to clarify the debate. Some strong visual graphics to accompany the analysis would be a worthwhile investment.

Do it.

Please do. There's way too many "engineering" channels on youtube with tons of subscribers and no depth, we need more channels like yours.

Do it. I'm a pilot and I race sailboats. A sloop with foresail and mainsail that including the space in between is managed like a slotted flap with both airfoils shaped for different conditions and points of sail.

I think this would be a great video. The one you did proving the Wright brothers is one of my favorites. Your response videos are something to look forward to. Please make this video.

Yes please do

If your channel did go there, a couple of suggestions, 1) Canvas the viewers for aerodynamics pHd s or similarly knowledgeable channel members and get their responses. 2). Add knowledgeable others who could provide succinct, logical, views on the subject. My input is rolling friction being what it is, this is certainly a claim that could be demolished quickly.

I watch Sail GP foiling yachts exceed wind speed all the time. I don't doubt it is possible but would like to know how.

I watched this a year or two ago and had the feeling that all was not revealed. And for that matter, the narrator was never very clear about what it was exactly that he was claiming. Just getting one physicist to say wow, "now i see how it makes sense" is not at all convincing. Much better would be two physicists who have decades of experience in say, wind turbine design, propeller design, etc. posed in opposition. Physicists are wrong very often. Especially when money, prestige, tenure, etc. are putting a thumb on the scale. It's absolutely crazy the things that physicists have been willing to say about climate change. When disagreements are censored they can and will say anything and while it they didn't censor anyone, they didn't have them on their video either. A one sided view is the definition of propaganda. Please do the video.

Please do. I used to rather like Veritasium, but over the years the channel has gotten very clickbait-y, and seems more and more like the guy is using the channel to lord his knowledge over other people instead of being a great science communicator (as he used to be). A better explanation of this effect would be fantastic, go for it!

Greg, I watch you channel because I like learning how people solve problems -- or don't. I would really like to hear what you have to say about how they are looking at this situation the wrong way, and thus not solving the problem they think they are. Plus, as long as you don't get sucked down a rabbit hole, legitimate controversy will help build your channel.

It's got a propellor - so go for it! Sailboats have been going upwind at faster than wind speed for a while, so it's obviously possible. I remember watching that video a while ago and it was too "breathless" for me...

I’m sure you would do a great job at explaining what’s actually going on, but taking the time to do so is totally up to you. I would love to see it, but ultimately, it’s your channel

I'd say no, only challenge in your swim lane.

The demonstration with the model and treadmill is false. If the wind over the treadmill proper is 10 and the treadmill platen is traveling at 10 while the surroundings are at 0, then the apparent wind is 20 because the wind is traveling over the treadmill platen at 20. In effect the treadmill platen is adding energy to the overall system. On the dry lake the "platen" is not moving in relation to the "base" (earth).

I’d love to hear your thoughts, Greg. I’m new to the topic, but find it interesting.

Well if you have enough efficiency to accelerate up to wind speed and the and wind speed decreases, at that point you will be going faster than the wind for a short time and the kinetic energy stored in the vehicle will continue to keep the vehicle faster than the wind for some time period. Therefore, if you start with a wind of 10 and the wind drops to 4, you would be going 2.5x the current lower wind speed. The question is for how long. The answer is hidden in this video since there is no object traveling with the wind at wind speed visible to compare the real wind to the vehicle speed. Now if you can make this happen with a lighter than air craft, you would be able to say the theory is plausible, but with a ground based vehicle you will always be working in a gust driven interaction. Take them on Greg.

I don't think it would be worth it from an angle pursuing these other channels, at least not the giant ones. However, I would be interested in a correct video about these cars. Maybe a good idea for a channel collaboration, maybe with one of the more physics oriented channels you are sure of so that you have both the physics legitimacy and your own

You have a talent for explaining complex technical/engineering related topics in a very clear and concise way without the need to "dumb them down" and that is exactly what's needed here. I think you could do a video like this very well, but I would prefer if you make it more of your own video, instead of just a focused rebuttal/debunking video.

I would be very interested in your analysis of this experiment.

I think many would be interested in your perspective, Greg. The subject isn't my cup of tea, however it is for many. I'd like to see you do a video, an honest appraisal, on Captain Eric "Winkle" Brown. I cannot praise the man's courage and accomplishments enough, nonetheless I do not believe he, alone, is the last word on all things aviation as the Brits (and many Anglophile Americans) seem to believe.

I'd like to see it. I'm familiar with turbine to propeller driven sailboats, the point being to sail directly into the wind. They've been around since the 1950's. I can't recall exactly where I first saw that, but there are other references on the Internet. I can't recall any similar attempts to sail directly downwind with such a device until you linked to Veritasium. A further check found this: https://www.youtube.com/watch?v=4pgDs50A-Yw&ab_channel=RickCavallaro and this: https://www.youtube.com/watch?v=X6oJpnSJyV8&ab_channel=RickCavallaro What I hadn't understood at first was that the wheel was powering the propeller, the opposite of what happens going upwind with a turbine to propeller vehicle. BTW, modern high speed catamarans and foilers do go faster than the wind downwind, but they do it at some angle to the wind. AC40"s, a 40 ' version of the AC75, polars show it going 44 knots in a 20 knot wind at 155 degrees. Polar: https://www.sail-world.com/photo/346441

Don't bother debunking, but do your own video if you like. There are so many bad channels that just spew.

Tough call for lowly me but I respect the things you do do and the things you don’t do.

I always enjoy your perspective on various topics. I would enjoy this as well.

I'd like to see it. Veritasium has always seemed a little too smug. I've noticed the same problems you have.

Derek is clearly a very smart guy and I appreciate his natural curiosity. But when you really know a subject, it's surprising what errors he let's seep through his "analysis." My domain is thermal imaging, night vision, etc. and his video on that was replete with errors, that could have easily been avoided. Left me scratching my head. So yes, by all means, please set the record straight with your customary data-driven and objective style. I look forward to seeing it. Thx. Skip

All content creators, scientific or otherwise, should be held to a high standard to prevent mis- or dis-information. Especially these days when it's everywhere on so many topics. If you can show that a creator needs to be corrected then I feel you should absolutely pursue it and make a video, which I think we all agree here will be straightforward to the point with facts to back it up.

In my opinion it is not worth trying to argue (point out their misinformation) with these people. If you want to do anything make an original, separate video on this or a related topic that distances your topic from their topics (i.e., don't even acknowledge that these people/videos exist). Always focus on your stand alone value proposition. I've noted when content creators get annoyed by other channels it just tends to not go well.

Go on. See how it goes.

I’d definitely be interested. This seems like a good marriage of the airplanes/automobiles this channel covers.

Do it! I'd love to hear about this thing regardless of whos right and wrong.

Yes! I'm still looking for an initiative understanding of that topic. And it's a fun Internet beef—why not?

I say go for it, if it's in the same area as the bomber mafia and the Wright Brothers.

I haven't ever really been much of a fan of the way Derek Muller explains things. He often goes about it in the most counterintuitive way possible, spending 15 minutes to do what most could get done in less than 5. He also loves to invoke unnecessarily complicated and counterintuitive mathematical concepts as part of the explanation. David Jones from the EEVblog did a similar response video with Derek's video on the speed of electricity. If you do decide to make a response video, just be comforted to know that you won't be the first person to make a Veritasium response video, nor will you likely be the last.

I'd love for ya to tackle it. I don't think it's arrogance either, honestly we need more folks that are technically grounded/knowledgeable that also will bring attention to something that's being intentionally or not dishonest in it's representation. I wonder how many other people have had a similar thought as you, but refrained from saying anything due to how daunting contradicting someone with that level of platform can be if it gets ugly. Or possibly they were shoo'ed away by those physicists you mentioned in your original post having made some sort of public comment on the thing. (Not to imply anything bad about Veritasium, they seem like they are fairly nice and even-keeled in their public relations, and I would like the knowledge to comment on anything deeper.)

I say no, there’s just way too much stuff out there to debunk. Stay with your original, rather than reactionary, content.

I’ve sailed sailboats ice boats, so I have a rudimentary understanding. This video could have been edited down to 5 minutes without all the “my life is in danger” BS. It looks to me like it’s trading volume for pressure. Please Greg, do a video on this!

Yes, a correct explanation would be excellent, especially if it can be done in under 11 minutes(?) I have to admit I'm too ignorant to see the flaw in Steve Mould's video, but that's why I watch you

Yes, but give the guys/gals who got it right without the clearest explanation some credit in it.

Greg: I'm a mechanical engineer working in academia at the end of a 50 year career in industry. I'm always in favor of an analysis/explanation based in experience and practical knowledge and supported by analytical treatment, as opposed to an academic treatment applied from the ivory tower without experience and practical understanding. The world always benefits from experience and practical knowledge. Go for it!

Please do. You do an excellent job explaining in depth with backups. Of course you may be grabbing a tiger by the tail...

This sounds great! I think you would have great insight, even if not a physicist. Ha. Have you seen the related video by Steve Mould on the torpedo that uses a similar approach? It is good. https://www.youtube.com/watch?v=qvtZIdSI1Yk

Now I'm so curious if course I want you to tackle this.

I would welcome your thoughts on this. The Veritasium channel has always seemed to me to engage in a kind of "gee whiz, isn't this neat!" approach to science journalism that I think is often misleading (though I admit my critique here is about the vibes; I am not here prepared to offer more substantive criticism). I say: make the video!

Greg, I have followed this thread and very much enjoyed Veritasium’s explanation of the issue. But, I really enjoy your channel and your explanations. If you think you have something to add to the discussion and the math or explanation to make it more understandable, then I would love to hear your explanation. I would watch the video and don’t think it would be a wasted effort. Of course it is different than what you normally cover so you have to decide if that’s where this channel is going.

I’d agree, provided the direction of the video is such that it is not particularly against the mentioned channel, yet provides correct enough information so it automatically implies those videos were misleading slash poorly communicated.

Yes please!

Yeah

Yes pse

Sounds interesting. I’d be interested in seeing you cover this

I’d be excited to hear what you have to teach me on this.

Yes, please