Hey that's pretty neat to learn about the alternating polarity creating a greater resistance. I didn't think of that. You could print a little cube grid that holds multiple magnets with opposing fields and probably get a much more impressive slow down when dropping it down a pipe.

Seeing your comments across a few different channels at the moment. Dont you have videos to make!!😊

@@UncleChopChop22 have and owe are two different words as per the dictionary.

If you thought about it for a minute, you would know this. Here's an important thought experiment: what if you replaced the ring of alternating magnets with an actual machined ring neodymium magnet concentric with the axle? How much torque would be transferred? Zero. The answer is zero. It would spin freely. Eddy currents form when there's a *change* in magnetic field, not just whenever there's a magnetic field. So the more changes there are, the more eddy currents form. The only limiting factor is when the magnets get so small that the changes in magnetic field don't bridge the gap from the magnets to the conductor.

Maybe the printable magnet company featured on SmarterEveryDay could create a tiny alternating pattern https://www.youtube.com/watch?v=IANBoybVApQ

@@Squancherino You people do understand that the efficiency asymptote this thing is approaching with more effective magnetic fields is identical to just gluing the two plates together, correct? There is literally zero benefit to this clutch? I feel like everyone is missing this fundamental concept.

The comparison shots of the falling weights was incredibly well done

Hmm... but copper is three times heavier than aluminum. If we consider that in the equation...(brain stops)

Right? It literally generated the graph.

@@operatorchakkoty4257 It makes sense on why it *looks* like a graph ... but then still "holy-shit" nevertheless

I loved how you could visually see the logarithmic, non-linear curve in that one test.

That was a brilliant, thoroughly well-thought and very well executed way to find out something is a not such a good idea. The effort put into this is admirable!

Just be careful of road man holes lifting up to stick with the magnet matrix

*manhole covers

not possible

They are magnetic but it would slow you down if anything

​@@Pooopersno shit!

Or the chain passing thru the magnetic fields developing a current and shocking you!

I'd love to see a return to this experiment with more designs and maybe some alterations with additional parts to see if this could be further built on as a viable drive method. The concept seems really awesome, and I'm sure there's got to be some utility in this somewhere.

would be cool to see how pedalling backwards while moving forwards would effect the braking power.

Yeah thought the same. Does not make any difference just pedalling backwards when trying to brake?

It will make a big difference. The speed of the magnets and copper disc relative to each other determines how much force they exert on each other. So at higher speed he exerts a lot of effort just to hold the pedals still, but at lower speed it should be possible to pedal backwards and therefore create enough force at the wheel to stop in a reasonable distance.

I mean the force was so strong it was basicly pushing his feet forward. Maybe peddling backwards wouldn't even be possible at higher speeds.

@@jackbauer2698 if you look into the world of fixed gear cycling, you find that people can break the traction of the rear tire and lock it by pulling up on the straps that they install on the pedals. The only thing preventing you from pedaling backwards is the traction of the rear tire.

It would either be enough resistance to break something on the bike, or open a rift in the fabric of reality...

I'm a physics professor and this whole project is incredible! That's one whole chapter of the textbook in a single short video!

That's why I regularly substitute lectures with YouTube videos - sometimes there is incredible stuff to find, that saves the student (me) hours of agony and self hatred. Hehe. Idk what these people do differently, maybe it's because they're closer to the point where they didn't understand it themselves than most professors are, but they sometimes have an incredible efficient way of teaching. (Helped me most with theoretical physics stuff)

@@braindecay9477 Personally I suspect it's just numbers. If there's hundreds of youtube videos explaining an idea, you're only likely to see the best ones, and the many many terrible videos just drop into obscurity. Whereas with your actual college course it's unlikely you have all the best professors for every subject. Although that does create an interesting idea. Imagine if you had access to lectures from hundreds of professors worldwide and your tuition went to the ones you watched the most.

Well I don't think most physics teachers have a small team, a budget that allows for cnc machining and 3d printing custom parts, and weeks/months to dedicate to creating a single 30 minute lesson (when would they do their marking?)

I just discovered your channel and I love it! Your editing, your ideas, your explanations — incredibly well done! Thank you so much and this is so cool

Magnetic coupling is very useful for underwater applications, where you want to disconnect the propeller from the internal electronics. Back when I was in highschool, we built an autonomous underwater vehicle and faced a real problem with isolating the propeller's entrance.

I think - The reason why flipping the center magnet works better is the field gets conentrated closer to the disk. Also the eddy current created by the first pair runs opposite to the one the second pair creates. The checkered pattern may be creating less field near the disk. Nice idea and nice video!!!! Really enjoyed!

Very good job on your thorough research and impressive fabrication skills! You essentially created the opposite of a magnetic braking system like on the Telma system. I drove heavy vehicles with a Telma and they work really well but they generate a lot of heat so you had to mind how much they had been applied.

Tom, Could you "theorhetically" have a variable number of magnets "working" at any given time? Which would allow a controlled amount of slippage (easier pedaling at lower speeds or on uphills). This experiment is simply brilliant !!! Thanks so much for doing this.

I guess the next step is to build a superconductor clutch to avoid the heat issues. That'll totally work.

A boring fixed gear can do that, too

Nah, he should just invent a room temperature superconductor instead. Seems simpler.

A supercunductor plate would cause it to be locked together lol. It would be almost impossible to slip it. That's essentially how magnetic levitation works.

@@rubiconnn but then it could be controlled. Connecting a grounded resistor to the superconducting plate would disturb the eddy currents, and provide momentary 100% slip. You could switch it on and off PWM style to tightly control slip. Now we just need room temeprature supeconductor. :(

Yeah that would induce instantaneous eddy currents of such proportion to effectively bolt it together, it would be an expensive, weighty and very cold cog.

Every time you have some different ideas, we see it implemented within seconds in the video. As an engineer, I know the pain anxiety of the challenge to go through implementing ,and the excitement during the test, and of course the joy when the idea works.

Fun and interesting idea! As I've understood permanent magnets, another downside is that they will lose their field strength continuously over time (through usage/wear). Don't know how much and how long it would take before it's noticeable though. AFAIK this is the reason why *higher tier* indoors training equipment such as ellipticals/crosstrainers use electromagnetic resistance instead of permanent magnets (or perhaps I'm misremembering and it's more because of better/smoother resistance adjustability, than it is to avoid permanent magnet wear?).

It’s because you can turn them off.

You can 'renergize' your magnets if you need to by applying a DC voltage to them.

Regarding "gears" you could use some kind of centrifugal force mechanism, that pushes counterweights out when you pedal faster, pulling the magnets in. Having the magnets closer to the rim will give you some leverage allowing for a lower "gear" when pedaling more slowly. This might be difficult to build and also difficult to control when riding, but on paper it should work

a variomatic from DAF. No magnets required.

You could probably play with the disc design and cut windows into it. This would potentially give you move controlled eddy currents. Another idea is the make the magnetic rotor smaller and offset the rotors axis relative to the stator. This allows the rotor to act as a magnetic gear.

First video I've seen of yours and I really enjoyed. I like the way you're passionate but not loud! You stick to the subject whilst allowing small tangents and your explanations are totally understandable! Great work!

The side by side comparisons are astonishing, it’s amazing to visualise the different behaviours induced by different configurations of magnets and weights

True. I just wished he had filmed them with his infrared camera, so that we also see the amount of heat loss

@@MrGustavier yeah true

@@MrGustavierYeah that would probably be really interesting, but I still think it’s good as it is of course

Tom is brilliant, I wouldn't be surprised at all if the heat generation turns out to be a huge positive for future project potential, surely this magnetic contactless set up could harness all sorts of free incidental energy

He could've used an off the shelf thread on 6 bolt brake adaptor for $10 instead of printing such a disc

absolutely impressive engineering by you ... makes me miss working as a Mechanical/Aerospace Engineer

Incredibly thorough and simple experiment. Well done, and that's a cool result 😊 Cheers for all your time and thought fella. That bearing is lovely 9:33 But not worth making a sprocket out of plastic, it's just too weak. Good reason why modern bikes have sprockets made from steel or even titanium at the high end 😉 Also, have to say too, if a bicycle is electric - regardless of power source - it would be ok to have a single drive like a car or motorbike does. Gears would be irrelevant. Single drive would be ok, and just attach a tidy throttle.

The thing that I would miss is the coasting ability. Sure going downhill and still pedaling would mean a somewhat constant speed instead of wearing down your breaks. But for that I think there is a better solution. You could reverse the design, so the magnets are constantly spinning and the copper plate is on the clutch. The magnets are placed low and due to the flying force, they fly outwards at a certain speed and only then engage with the plate. This way you break at a certain speed. I think this might work.

I was thinking that in a production run of something like this, you'd have a way to enable & disable the effect based on either environmental inputs or user control, so that coasting would still work.

I would've thought the lost energy could be used to charge a capacitor/battery. That energy could then be used to power a motor on the front wheel, controlled by a twist grip. Charging on the downhill sections and outputting on the uphill sections might level things out. Either way, it would be great nextvstep. Well done! 👏

That's a great idea. I think you could turn the copper disc into a copper coil, intern that could Supply electricity to a direct Drive DC motor. The faster you pedal the more electricity it would produce, therefore make you go faster. Then if you want to slow down just stop pedaling. Then there'd be no electricity produced yet the copper coil would still slow you down. GS

Very interesting design. I think some of the indoor training bikes use the same phenomenon to produce resistance.

The positioning of the weights at 7:44 is such a pleasing real-world representation of a log graph, I love it

might be a hyperbola

i tought the same !!! cool

​@@canteatpi or a root of some power. I think it's more likely to be a square root graph, due to the powers in the formulas for kinetic energy

@@mikhail_from_afar ты говоришь по русски? я учус, но это очень трудный язык :)

@@datbubby учусь*

This is a brilliant demonstration of how great ideas don't always pan out. I hope this video inspire a lot of viewers to consider engineering as a career.

I think it did pan out. If the copper disk is replaced with some coils like in a motor, you can improve efficiency greatly. This is a first design and there is lots of room for improvement.

excellent video as usual. i would have liked to have seen what would have happened with either a front derailer or even a similar magnet setup on the front as well as the back and how they would work together....

Great vid, really interesting concept! It could be worth trying to utilize electromagnets to give you the ability to increase or decrease resistance? Can have hand controls to adjust current etc..

Nice bit of work! I would imagine that the heat created in the disk would also be created in the magnets, so the plastic magnet housing will soon loose strength. This scheme would make a nice water heater driven by a windmill. Wrap copper pipe around the static magnets to cool them, and using a pair of rotating copper disks with water bled between them via a gland on the shaft to cool the disks. Could be a nice build! Thanks.

Could pedaling backwards help slow you down faster rather than staying still? This is a really cool project. I hope you think about revising it and coming up with other ways to improve it. What about going electromagnetic? Would that even work the same way as neodymium magnets?

As a bicycle mechanic over in Germany I gotta say, I really love your bike related videos. They give me great aspiration, sadly I lack the funding to copy your concepts for my own fun. But they make great talk in the break room!

In another life, I was a bike mechanic too. I probably enjoy as much these videos as you. Now that I’m doing more software and hardware, after building a few robots, it tickles me to try and build a braking system idea I had a long time ago!

as a bike mechanic in Germany, do you work on Rohloffs or other internal gearhubs. How do you like them? If this magnetic clutch/gear works, it would be fantastic!

I'm wondering if being able to vary the strength of the magnets (by making them tiny electromagnets) would make it a practical device. Sort of like gearing through magnetism. Probably not, but it's so tantalizingly almost useful.

By having Flux collector on each magnet of Faris metal you could greatly increase the magnetic strength of each magnet in the desired direction. If done correctly it could reduce the attraction to the chain.

Why not start a youtube channel with bike experimentation? It probably will pay for itself if done right... viel Glück!

That is an interesting take on a fixed gear bike! It is unfortunate heat waste cant be eliminated since this a side effect of how torque is transferred by :( But generally, as a bit atypical for a fixie rider to say - something about mechanical simplicity makes me wish this to work.

fantastic video. Couple of thoughts struck me, one of which might be useful. When I saw you spinning the copper disc, my first thought was that they use spinning as technique to allow the forming of copper and aluminium pans and bowls, so what effect would the RPMs you will experience do to a copper disc, especially as I assume (naively) that the disc will heat up with use (?) and the possibly useful one is would it be possible to use the switched magnet mechanism that you find on Dial test Indicator stands for when you set up runout on lathes etc. Could you use the rotating magnet mechanism used there to enable and disable totally the braking effect to get free wheeling. Keep up these fabulous and informative videos... Thanks

Another brilliantly composed and explained video. Magnetism is a very strange beast.

Ive always wanted to do something vaguely like this - have the pedals turn a generator and a motor turn the wheels (potentially having one on each wheel). Youve essentially combined the two sets of windings into one and eliminated the conductor between them. I was wondering how much energy that disk was soaking up. Good thing its copper!

The most amazing part is how well the plastic sprocket worked.

Tom again shows us not only how clever and creative he is, but also just how great YouTube can be with the right content providers!

Totally agree, YouTube at it’s best.

If my damned AWFUL home feed could learn this... I would be sooooo happy.

^^ I made a new account and seeded it with a Playlist of content types that I wanted and now my algorithm is much better than the old account. Probably a good idea to do this every few years to get a fresh look.

​@@DerrickBommarito replies are broken

you are very correct

Might be interesting to see what would happen if you drilled into the copper disc and installed more round magnets

Dang! This is interesting! I have designed and built prototype racecars in the past. I wonder if I can apply this on an engine, and eliminate the clutch. Perhaps use many more magnets on a type of release plate, a solid copper precision cut flywheel and make the magnets move closer and farther from the flywheel? My mind is racing. I'm going to give something like this a try! Thanks, one of the best vids I have seen in months!

I was very dubious at the start, thinking, “oh, yeah, another magnets perpetual motion scam”. . . but no. I learned a lot from this. . . an honest presentation. Nobody’s going to win the Tour de France with this setup (especially me, a 79-year old time triallist)😊 Well done, sir!

Очень четкая и красивая реализация. Сама идея может пригодиться для перемешивания агрессивных сред бесконтактным способом. А для велосипедов видимо проще соединить напрямую неодимовым магнитом... печально, что накат при этом потеряется)

I would love to see this project explored again, but with bike wheels that aren't spoked, but rigid body, like a 5-spoke carbon body wheel. You could also explore using a carbon or aluminum frame bike, and belt drive instead of chain drive, so you can eliminate the magnetic interference variables + reduce the weight of the bike.

As a retired engineer who cycles a lot, I enjoyed this immensely!

Finally you can ride with less efficiency !!

@@HK-fz5rn And more expense! It could be a government mandate!

Really nice! I love this creative engineering research! It seems like the definition of hobby at its best: achieve the least with the most amount of time, energy and money. 😁

I am speechless and you are a highly underrated engineer. I really loved the project.

An idea for optimizing the system I had would be to add steel rings to the sides of the magnet discs to increase the magnetic field strength

This is so cool. Totally impractical, but a great, fun eddy current demonstration with a few simple benchtop experiments to figure out the details.

If you utilize the spokes of the aluminum wheel that holds the magnets as a fan by tilting them to blow air over the copper disk, you could potentially see more efficiency! I would love to see this system attached to a combustion or electric motor and truly see the efficiency and effects! This clutch system could be amazing for vehicles powered by small engines! My hybrid powered bike's centrifugal clutch is acting up so if I could get my hands on a device like yours I could see it acting way more efficiently and maybe even improve the longevity of the engine!!!!!

The alternating magnets for stronger eddy currents was a great idea! You might want to look into the Halbach Array (a specific way of alternating magnets) that makes the field strength even higher. I think it might perform better than only alternating the magnets.

Exactly what I was Thinking. Also can't he put a steel plate on one side of the array to cancel the magnetic field so he won't have issues with the chain and spokes?

Also it makes magnetic field much stronger on one side (the clutch side) than on the other side (the chain side).

@@oodmboo If he made the diameter of the disks bigger he could fit more magnets in to give him the torque he needs to go uphill and it would also solve the spoke problem since the spokes are already sloped away from the magnets further out. Might run into torque issues breaking the disc though.

the steel plate (ie completing the magnetic circuit) is better than a halbach array unless you are extremely concerned with size and weight

@@5naxalotl Rotational inertia is certainly important, though I don't know how much.

Hello. This technique might work for a problem rim brake bicycles have, which is that in wet conditions it grinds off the aluminium from which the rim has been made. This could cost you a wheel set over a year or two (road bike training). I am thinking of holding the sink brush against the front wheel. A magnetic brake would be quite elegant ! Rolling to a full stop takes quite long. If you anticipate enough in advance on flat roads, not much braking force is needed to make an effective cost saving brake for the winter (unless you already have disk brakes I guess).

Wow, I learned so much watching this video! Very well explained, great visuals, cool experiment.

It would be cool to see this applied in an automotive application, such as replacing the fluid coupling of a torque converter in an automatic transmission, or in a rear differential housing as a sort of limited slip differential.

Considering he heated the disk with the tiny output of 8000 joules by 20c, it would be a really bad idea to use a torq converter using magnetic coupling like this. Unless you like slinging molten copper all over your car. Also copper (and all material) become less conductive the hotter they get, so your car would stop producing power at the wheels as the copper plate gets hotter and hotter unless you used some kind of cooling system, but at this point you're just throwing away power for a weird torq converter.

Thanks, Tom. Brilliant experiment and execution. Keep them coming.

An interesting experiment - I was watching this with my son, who did an engineering foundation at uni before his computer science degree, and I predicted the heat problem. Well done - it didn't work as well as you'd thought but it's a good experiment.

Hi Tom The checkerboard is only useful if you also want drag in the left-right direction.; generally the magnet diameter should be greater than the gap between facing magnets. More importantly, please look into "back irons" - these will easily improve the effectiveness by 2x or 3x and shall also eliminate the problem of the chain sticking to the magnets :)

Yes! I think this would probably double the performance at least. Mumetal is ideally suited for the job (which is why they use it in hard drive voice coils)

Would it not work better if there were magnets distributed around the disc ? (perhaps at pitch centres corresponding to say 9/10ths of the pitch of magnets, to get a sort of vernier effect). I guess the poles on the frame would want to be opposite polarity to those on the rotating disc. You'd want magnets both sides of the disc, to balance out the axial forces.

@@Gottenhimfella Quite a few drawbacks to your scheme - The damping (i.e. conversion of kinetic energy to heat) happens in the conductor, not in the magnet. A magnet shall store energy as potential energy (and then is mire like to demagnetize too, but that is a different story). So, to convert KE to heat, a conductive disc is essential. The added moving magnets shall add inertia to the rotor (non-issue in a bicycle, agreed) Second issue is that of axial (parallel to the axle of the wheel) force - rare-earth magnets of this size pull hard - a symmetric construction with two sets of fixed magnets and one moving conductor has no axial forces, and hence can be thin and slim.. to work-around this, perhaps 8/10th or 7/10th would be better. The third issue is cogging. Even with the Vernier, you would feel some. The advantage in your scheme (if I understand it correctly) is that you eliminate the air-gap on one side of the damper. The disadvantages that you have to pay as a price are, imo, not worthwhile (at least with my understanding of your described concept. Feel free to 3-d print a holder with 7-magnets and 10-magnets arranged in a circle and try twisting them against one another :) (without a conductor, it will feel more like a detent than a damper)

Im a student friction physics and an architect and engineer. Im very impressed at the out of the box concept for magnetic field clutching. Though i was initially sceptical about the blood, sweat, and muscles for propulsion, im absolutely godsmacked about the concept. Your an absolute genius. Your principle idea could have ground breaking effects in elevators, dumbwaiters, out of control frieght vehicles and airliners. Your concept could save thousand if not millions of lives. And do you worry about me, im no copyright poacher. Though a lot of others are. Best of luck

Great job, Tom. I always enjoy your videos.

A fabulous idea and great research project. Perhaps it just needs a lockup once you achieve a nominated speed. use the slip to get you moving, then ride in a physically connected arrangement.

Pretty cool. This will be amazing with room temperature superconductors. Until then I prefer it when the energy I put into the pedals gets transferred to movement efficiently.

Great experiment. I couldn’t help thinking though, didn’t we already have this in a traditional coaster brake. No worries about wearing out pads? Watched the whole video, very entertaining.

This channel was new to me. I was blown away by the concept, quality of the build, quality of the experimentation, and the quality of the video production. You, Sir, are really good at this!

He's a mechanical engineer

Completely agreed, very impressive testing and engineering

Check his railgun project

Seems like youtube as a whole is new to you...

With a heavy flywheel you could achieve better results by unwasted energy input. Great video!

Cool experiment. i love when people still show "failed" products. great learning experience for everyone and isn't really a failure but a collective learning experience instead.

What about increasing the diameter of the clutch? A smaller difference in rpm will still result in a comparatively larger difference in tangential speed. To reduce weight, you could hollow out the inside of the copper disk, and you could design the outer housing to redirect air into the metal parts to help with cooling. Not sure that would help. Also, I’m not sure about eddy currents, but is there any waste from eddy currents going into the rest of the copper disk, instead of being stuck in, and concentrated on, the area under the magnets? It seems to me like you might want to only make the area of the disk that will be under the magnets conducting, so the current doesn’t just dissipate into the rest of the disk. Finally, what about arranging the magnets in a halbach array? That way, most of the magnetic field gets concentrated into the disk, instead of half being wasted on the outside of the system? That would also help with the issue of the chain and spokes sticking, since you’d have less magnetic flux escaping the clutch.

I’d love to see you build a bicycle powered by a nitro RC engine (used in RC planes and cars) that has an RC engine powering a generator, which powers an electric motor in the hub. So essential an electric transmission, sorta like a diesel electric train. That, at least from my understanding would operate like a clutch of sorts. Idk I think it would be a neat project

Regardless of the final result, this is still an interesting project and informative video. Nice work.

Those calculations with the dropping weight videos were awesome, such an excellent visualization.that section was great!

oh yeah, you can literally see the non linear curve which was beautiful

Reminds me of Galileh!

This is the stuff that science is made of!

Absolutely fascinating Tom! Well done Mate!

It would be great to try it with electromagnets, to control the induced torque. You should be able to achieve the function of a clutch (0% lock-up with no current and progressive engagement through 100% lock-up)

You are much more analytical than I. I like trial and error. That said, I do something similar using neodymium magnets mounted on disks. I machine my disks out of plastic cutting boards using a lathe. I mount magnets about the flat circumference of the disk, then use either live steam or compressed air to spin it through a pick-up coil to generate electricity. I arrange the 1/2" magnets all facing the same direction (for d.c.) or facing n-s-n (for a.c.). I use both piston as well as turbine homemade engines. I build windmill-driven air compressors as well as small air engines as a hobby. Great fun! Thanks for your VERY ENTERTAINING channel.

Maybe for more braking force, try pedaling backwards to increase the difference in speed between magnets and copper. Cool video!!

Fun concept that actually works. Just something off about wanting an object to move via friction. Counterintuitive to moving object and speed. But there’s definitely something there. Incredible idea on its own merits.

I think you may have missed a trick. Putting an iron backing plate on both back sides of the magnets (ie facing opposite the copper disc) would give you two additional advantages. One being the flux would be more constrained and not grab the chain/spokes and the field facing the copper disc would be more intense. However the heat due to loss will definitely be more severe when the clutch starts slipping and will equally affect the magnets, which in your case, due to their size might have been a bit cooked too, but cooled faster due to less thermal mass. But in theory, the increase in efficiency would mean less slipping. Another factor is that neodymium magnets permanently lose their magnetism when heated to approximately 85deg C, which is why when these types of clutches are used in industrial applications, there is usually a significant liquid cooling system that either flows through the clutch components, or the clutch is immersed in it. They are very precise and consistent (repeatable) clutch designs that can absorb massive dynamic changes in force, so they are very useful in other applications, where longevity and smoothness are more important than efficiency in the force transfer. They are also used as brakes and dampers for similar reasons and also have more traditional lockup mechanisms and or clutches for greater efficiency when output (or input in the case of braking) has reached a certain speed. Obviously these are stupid expensive, mostly due to materials, proper matching of the specifications, and definitely being customised for the application, not to mention bulky, but sometimes they are worth it, to solve particularly difficult problems where traditional force coupling mechanisms don’t work as well. Anyway, sorry for being “that guy” at the party, great video and demonstration of a very useful and niche device!

I think you're the guy we very much needed on this party. Thank you.

Chain sticking is solved by using a rubber belt

Tom, this response is on the money. Ferrous materials will provide a much lower magnetic impedance than air, increasing the magnetic flux density experienced by the copper. So putting some of the outside faces of the magnet groups will improve performance. Again, on the money; watch out for heating and ideally turn that ferrous material into a heatsink for the magnets. Finally, milling a shallow pattern into the copper to sort of turn it into a centrifugal fan, (increasing air turbulence and heat transfer) may also extend the operating envelope. Mind you, it will always be lossy. Maybe it's more of a mobile cardio machine?

​@@pchandle c'mon peleton!

Electro mechatronics engineer here and were about to write pretty mich the same thing! However I disagree on the heat part... Yes the magnets suffer from higher temperatures but the heat is generated in the disk and not in the magnets. The suggested ferromagnetic parts to close the magnetic flux would alsobserve as additional radiators for the magnets to get rid of heat.

Cool idea, seems terrifying to ride. Any kind of obstruction could be very dangerous.

You could probably solve the attraction problem between magnets, chain and spokes by covering the outside of the magnets with a ferrous material, which would also increase the field density at the copper disk, because of the better magnetic conductance.

Im only at the 2:40 mark but the Al disc might still be better at breaking since its lower rotational inertia will allow it to slow down faster. Your test with the falling weights show that the copper disc resists changes in momentum more which for a break you want to reduce the momentum of the brake disc.

There is a bicycle trainer device called the Kinetic that has used this principle for decades. The resistance unit is hydraulic, that has a sealed chamber to prevent leaking. It’s hard to seal around a shaft, so they drive an impeller inside the sealed chamber with a magnetic clutch. My trainer is decades old still works great and no leaks.

Don't care that it didn't turn out to be a game-changer. You had an interesting idea and with a lot of thought and effort, you actually made it happen. And that's pretty amazing. :)

Your meticulous research and trials of materials and forces is truly impressive. Then to advise us that it didn't work as you had hoped shows your humility. Thanks for sharing this whole story.

The answer is seen in electromobile vehicles- Alternating current (in motor wire-windings) is far more efficient than permanent magnets only (which are also present in many EV motors). Also stopping power in EV regenerative/recuperative braking had same weakness as described in this video. But - with alternating current oposing the magnet rotation, it can be managed to fullstop in most current EV vehicles. Which translate to even not using normal friction brakes/pads at all = rusting. So this research is not completely wasted- it just needs to simulate EV motor = induce some current in copper disc (made from thousands of copper wires, insulated of course). And electronics with variable frequency of alternating current, made by using Gate-transistors. Of course it is not needed as you can buy such a bicycle now, but- exactly the same proces they do in Tesla, Mercedes factories/labs.

The very healthy and honest conclusion at the end nailed it. I´m glad someone has done this, because it was entertaining and informative to watch. Good luck for the next one.

Brilliant job! Following the same physical principle a torque converter could be made.

Reminds me of Buick's dynaflow transmission. Basically just a giant torque converter that burned up all your power as heat. You leave it in drive and it slips all the way up to highway speeds when it finally locks up. Wild engineering back in the day to reduce shifting interruptions.

This brings pedaling and braking into one functionality, further reducing the number of components of a bike.👀 Really looks like a tech that could catch on, in any other field even if not just cycling.

you know, theoretically, this could be applied to a motor vehicle using a similar idea. perhaps with a small amount of friction material with magnets embedded in it, using a thick aluminum flywheel and pressure plate. but this would have to have the ability to get up to speed using magnets before applying a clamping force to avoid wear on a soft material like aluminum. sort of like a lockup on a torque converter to avoid slipping as much as possible.

In home exercise bikes, a magnetic brake is sometimes used in the form of a set of fixed permanent magnets (or electric magnets in expensive devices), and a perforated metal disk (similar to an aluminum alloy) that rotates through an upshift pedals. The adjustment of the braking force is regulated by changing the distance of the magnets from the rotating disc. Excess heat is dissipated from the disk into the air by means of a small impeller with blades on the disk shaft. Thus, it turns out to achieve a fairly wide range of loads (from 50 watts to 1.5 kW) with modest dimensions of the device.

It's fine for a brake, where you are trying to convert energy to heat. That's not what you want for a transmission, where you want to waste zero.

Beautiful. My idea was to use gears to a flywheel placed in the triangle. Use axial magnets to generate electricity to regen your ebike. You control how hard you peddle, this goes to the flywheel between your legs and has a geared connection to the rear wheel. Add fancy battery management. Set top speeds for coasting, added goes to recharge or spin the flywheel faster, given the state of charge. Allows for bike stand secured stationary pedaling to recharge. Flywheel provides secondary storage and greater peak available power. Open whole industries worth of new markets. There are a stunning number of unique use cases that would create demand for various models. Building one is the only way to work out practicality & rideability. Since it does spin in line with the bike's center line the forces oughtn't really impact ridability. Then the math for how much the added storage can smooth out the drain off the battery while maximizing the regen to the point of significan stationary recharge with casual effort.

Absolutely loved the idea sir Stanton!! But I still can't help but wonder what it feels like but more so What happens if u pedal backward after gaining some momentum and how would That feel!?😮

Cool idea and nice mapping of the theory into the engineering of the parts

It might not compete with a chain drive, but it's definitely a great idea for a training bike 👏👏👏

Very cool video and idea! Speaking of important science projects, I've got an ion thruster that lifts its power supply against Earth's gravity! I had assumed that there would be a strong interest in it, but there isn't nearly as much as I had expected. Thank you for all the great scientific videos and unique project demonstrations!

Share a video.

What happens if you pedal backwards? Would that provide more braking force? How would the addition of an electrical current affect the resistance? Great videos! I really enjoy watching and learning such interesting concepts!

One of his tests demonstrates that the torque generated was proportional to the difference in RPM between the disc and the magnets, so yes, pedaling backward would increase this difference in speeds, and therefore produce more braking torque. The other question is interesting. The eddy currents that the magnets induce in the copper disc flow in a ring around the magnets, lagging behind the magnets because it takes some time for the current to die off once it's induced into a particular path. This is really how the torque is created - the ring of current induced by the magnets produces an opposite magnetic flux to that of the magnets, that's constantly trying to align itself with the magnets, so any rotation of the disc produces a "back torque" that opposes the motion. If you were to fit carbon brushes either ahead of or behind the magnets, current passed through the disc through these brushes will also produce a torque for similar reasons. You will have created a DC motor, but this would be very inefficient because the current you apply to the brushes would not just flow through the copper directly between the brushes, but also though many other paths that would not produce usable work. This could be improved by cutting slots radially at intervals around the disc, between the brushes, which would reduce the undesired currents without affecting the intended current path, but now you're getting closer to a conventional commutated DC motor. Which sounds like something interesting. However, if you look up radial flux brushless DC motor, you will find that this is very close to what is already being used for low-speed, high torque brushless motors.

Pedaling backwards does increase the braking resistance, because it means the sprocket RPM becomes 'negative' and the net RPM difference becomes larger. Regarding electrical current, the current in the disc is not DC but it's a localized AC current which moves along with the magnet's rotation. To get the disc to spin using electrical current, you need to apply a rotating magnetic field through a set of coils. In his experiment, the magnets are replacing the pole pairs of a motor.

thats what i was asking myself the whole vid too😭

@BrightBlueJim  Thanks for the response. I'm not an engineer and am not up to speed on the theory of DC motors. I know enough about electricity to be dangerous. My crude thought process was that an electrical current might increase the amount of torque that is being applied to the wheel from pedaling and provide a better braking action. Thanks again!

@@BrightBlueJim The homopolar generator designed by Michael Faraday was a similar design as well, very cool seeing how this is basically that but with no wires connected to it.

Thank you. This is pretty amazing. So happy you did this!

My man Tom here is the reincarnation of the inventor of modern bikes 😂. Seriously tho you are covering so many other topics while doing this 😊

I was already wondering how hot the disc got when you showed it 😄 - great project!

If you make a steel disc with slits between pairs as a backer for the magnets, it will drastically boost the efficiency of the magnets. The best is either turn Pair's into horse shoe magnets with as thin a gap as possible for the disc

Loved the science. Failed experiments are how we learn. Great stuff.

It's always so mesmerizing to witness eddy currents. I was playing with magnets and a copper pipe a while back and it's so so interesting to see it happen. The clutch idea is interesting, I could see this being useful in some kind of application that may get sudden changes of resistance, and it would save the output shaft of the motor. Rollercoaster brakes also work similarly to this.

Do not forget that Trains are fitted with induction breaks. No wear, and at high speeds to stationairy rails incredibly effective.

Roller coasters use this for emergency brakes.(obviously using a secondary brake so the train comes to a complete stop)

Thats one of the coolest projects ive seen on here! Great job.

You could probably make an electronic gear shift for this by adding a coil of wire instead of the copper disc and varying the resistance to change gears ( a low resistance would would be a low gear and a high resistance would be a high gear).

I bet you could brake pretty effectively if you pedals backwards at speed. Cool build!