I was curious how this thing works and asked Claude to visualize it -- mostly to see how good Fable is and I have to say, what it made was good enough for me to get a gist of it. Posted it here
Every plausibly cool electric car innovation leads me to the same thought: “5-10 years from now, the restomod potential will be wild once these come down in cost.” For this, I am imagining retrofitting a Pontiac Fiero to reduce as much weight as possible and see if extended flight becomes possible.
Thanks for sharing. I wish it was a bit more interactive especially when there are parameters, e.g. "Widen the disc and torque rises with diameter cubed" I wish there was a slider to see that effect and thus maybe why there might be a sweet spot.
Also I have "The Way Things Work" on my desk right now and can't help but wonder, could you adapt some of the pages of the book this way? It seems like exactly the kind of content that would benefit from such 3D (interactive) visual explainers.
Oof... well thanks for sharing but that's basically unusable for me. It neatly all packed in a 2MB file containing all assets, threejs, etc.
I assumed it's based on a three.js template due to the `Rendered live with three.js · Drag anywhere to orbit the model` kind of showcase but unfortunately that's not linked. I also imagine the 3D models are more that primitives (at least the arrows showcasing the flow) but I don't know where they came from, if that are also from a template or repository or if they are generated from a tube mesh.
So... I'm genuinely grateful that you took the time to share but I don't think I can do something with this except restarting from scratch, especially if it's one-shot.
I'd suggest, if you don't mind the extra effort, that you add a ReadMe.md in the repository to clarify how you did this, at least model name, version and prompt.
Yup, the visualization didn't help me understand the concept any more than plain text. Superficial in the way that you would expect from a system that has no real world reference for what it is creating.
To get something better I expect more than a one-shot is needed, and the knowledge to guide it in the right way.
Hundreds of examples of axial flux motors exist online. If you look at the visualization it shows the iron cores in a perpendicular orientation with the hub. This is correct, but loses so much of what makes these specific motors interesting. The angled nature of the grey cores and copper wrapping smoothes the transition between each magnetic field.
Basically it is a pretty version of a dumbed down partially incorrect answer. With a knowledgeable user it would be very good, but he has no idea he is wrong. I’m not sure what Dunning Kreguer with graphics should be called.
You don't. You didn't know before either. The difference is trust. How do you trust it as much as you do the hypothetical humans making such representations? That's up to you.
I think humans develop expertise and brand names and get called out when they make mistakes and if they are too wrong, their reputation is damaged.
This doesn’t seem to apply to AI for some reason. It keeps generating incorrect results after incorrect results, yet people continue to trust its output.
I am not an expert, but I do know some physics and I know how to read, and I’m pretty sure this is full of BS. Also it’s a really crappy visualization.
I wonder how developing electric motors compares to combustion engines. My hunch says that it’s the main reason the Chinese high-tech electronics industry was able to develop and iterate leading electric vehicles so fast. (Edit: My more clarified point is regarding the machinery required + place to accommodate them to work on electric motors vs. ICE metal parts and all the intermediary parts transfering power in the drivetrain. The shop in the video is smaller than many would imagine.)
When these hopefully go to the next generation Formula E cars, we’ll see some crazy improvements in cornering. The newest generation already has active 4WD. I imagine this can bring even better torque adjustment improvements.
The Chinese EV industry is actually lead by development of batteries, especially CATL. Along with the pack engineering, which is good old Mech.E stuff about heat transfer and physical strength.
Secondarily power electronics; at that scale, you can't just pick a bigger transistor and call it a day.
By comparison the motors seem to be a mostly solved problem, although I'm sure there's still some scope for power-to-weight engineering there, it's not as critical as the battery pack.
And is development of batteries (and better magnetics) not just chemical engineering and material science?
Motors might be a 'solved problem' - there might not be much innovation, Maxwell's laws aren't changing any time soon, but there will surely be a lot of incremental improvement - an early 1900s ICE is considerably worse than a 2000s ICE.
> n early 1900s ICE is considerably worse than a 2000s ICE.
But how much worse is a early 1900s electric motor from a modern one? I can't find data, but I suspect the first electric motor from the 1830s is more efficient than a modern ICE (even if we assume the ICE is built for efficiency, screw emissions). There is some room for improvement, but there isn't much difference between our best motors and perfection (a carnot cycle by contrast is as best much worse than perfection)
>I wonder how developing electric motors compares to combustion engines. My hunch says that it’s the main reason the Chinese high-tech electronics industry was able to develop and iterate leading electric vehicles so fast.
The talent had very little impact to be honest. The primary factor was a government looking 50 years down the road seeing that:
1. ICE engines have little to no long-term future in transportation.
2. global warming is a thing whether the right wing in the US likes it or not.
3. They were never going to overtake the West in ICE engines and had to attack from a different angle.
The US' lack of breakthroughs in EVs has little to do with technology or expertise and everything to do with an administration that is openly hostile towards EVs and renewable energy in general. For the rest of the planet, EVs becoming the primary form of transportation is just an obvious and logical conclusion, even if it takes us another 25-50 years to get there.
China saw it and decided to heavily incentivize and subsidize the rapid expansion of EVs both to fix the air quality issues in China and corner the market.
According to wikipedia[1] the first industrial steam engine (1712) was invented almost 100 years before the invention of the steam locomotive (1804), arguably its greatest evolutionary feat.
It would be awesome if they would implement a crude rule: no computers. You can use a computer to design the car--CAD/CAM/CAE are all fine--but no stored program computers are allowed in the race car. I think that would improve F1 tremendously.
> develop and iterate leading electric vehicles so fast.
How do you know this for a fact? Chinese press releases? You've driven one? Some auto blogger drove one?
After world war 2 Gorbachev or whoever visited the United States and during that trio visited a supermarket. He thought it was a facade, possibly, put on just for him, there's no way Americans are this prosperous (or whatever, this good at agriculture, farm equipment, etc)
Also do the race cars have 4 wheel drive, or all-wheel drive? I'm wagering all-wheel with "torque vectoring" and "Yaw control", like a Mitsubishi Lancer Evolution X.
I am somewhat confused at the intensity of pushback for the statement “leading electric vehicles.”
Chinese EVs are leading and that doesn’t necessarily mean being the best, most advanced vehicles. They are leading in value/pricing, and in many regions they are leading in sales.
BYD sells almost double the EV volume of Tesla globally as of December 2025. They are objectively leading in that respect.
I think the parent comment of yours made a good point (or at least adjacent to a good point) about China’s ability to enter the market: they can’t compete with 100 years of internal combustion engine development along with the vast parts supplier network of the West, but they can compete on battery chemistry, battery supply, motors, and the more vertically integrated EV space where automakers don’t need to depend on a huge network of parts suppliers like they did in the past.
I also think that a lot of pushback to the innovation that China is delivering is criticism that is stuck in the past. If you buy a Xiaomi car, it integrates perfectly with all your Xiaomi consumer devices. You can control your rice cooker or robot vacuum from your car’s integrated infotainment system. This type of approach was exactly what Apple was going to deliver before they abandoned their automotive project.
Or, you can buy a Mercedes and you’ll get a car with more precise handling and perfectly tuned driving characteristics. The infotainment system looks like Windows Vista.
Which side of the aisle do you think most consumers care about? I think most people buy into Xiaomi’s approach.
Semiofftopic but somehow I took offense at the Vista comparison. Aero Glass was peak UI design to me, and I'd certainly prefer it to modern paradigms like flat controls, or to stretch it even further, Corporate Memphis etc.
Curse you, Apple and Jony Ive. You only needed to tone skeuomorphism down not kill it.
I’m genuinely delighted that this reaction to that little phrase came up! It was definitely something of a half-joke on my part: the Mercedes infotainment system is very well-regarded, but it does not look “modern” compared to something like a Tesla, Rivian, or Xiaomi.
The hyperscreen from a physical hardware perspective looks strangely dated to me as well, depending on the specific car model.
I wouldnt be so harsh even with chinese combustion engines, its at this point a meme that is just copy pasted because everybody says so, but without actual experience. People dont understand how China is 3x bigger than Europe and 4x bigger than US, the scale of that market is absurd and competition numerous and fierce.
I've had MG suv rented recently with just gasoline engine and it was fine. This comes from long term bmw driver, they are not on the exactly same level, but light years ahead from similarly prices ie french vehicles. Handling was fine too, probably the biggest shock for me, this is where french, italian etc are losing me (bmw effect). And they cost 1/3 of bmw.
True, and on a similar wavelength, nobody seems to care that Kia/Hyundai engines are super mid.
Heck, nobody seems to care that Toyota engines/transmissions sound like a vacuum cleaner and have pretty mediocre NVH on models like the Corolla, but they buy those products for reliability and efficiency.
Listening to the heads of the American and European car companies say the same and driving in them in china. I know that is different than personally disassembling one and reviewing it, but I am not sure the incentive for the other companies to say they have inferior products, unless it was a play for subsidies or deregulation of some form.
Personally I feel that the rest of the world continues to dramatically under estimate China’s progress and technological advancement at our own peril. Is there fluff and are their lots of untrue claims, of course, but that is certainly not something they have a monopoly on.
A few years ago I built a few small ones in my home lab. They are extremely efficient. With the right setup, have insane torque, and don’t require a lot of energy to do it. The best part for me was that they are completely brushless by design and are easily to keep clean.
"In contrast to conventional radial flux motors, the electromagnetic flux in an axial flux motor runs parallel to the axis of rotation. The key components are arranged in a disc‑shaped layout: two rotors sandwich the stator from the left and right. This design enables an especially compact motor architecture, high power and torque density, and new freedoms in drivetrain packaging. In the new Mercedes‑AMG GT 4‑Door Coupe, the motor at the front axle is just under nine centimetres wide; the two motors at the rear axle each measure around eight centimetres in width. The three axial flux motors are integrated per axle into so‑called High Performance Electric Drive Units (HP.EDU), where they are combined with a compact input planetary gearbox in a single housing."
Really the kind of thing that should be earlier in an article about… that very thing the reader is wondering about, but maybe we arent the target audience?
Yes. If you have a laser printer, that windup sound you hear at the start of a job is the polygon mirror motor spinning up thousands of RPMs - those are PCB stator motors. As were VCR head motors.
"Advantages : A motor can be built upon any flat structure, such as a PCB, by adding coils and a bearing." https://en.wikipedia.org/wiki/Axial_flux_motor with image of "A miniature DC brushless axial motor used in a Digital Data Storage drive, showing the integration with PCB construction techniques."
It doesn't make that a good idea. Armature losses are proportional to torque squared - doesn't matter if it is radial or axial design. That's why all the EVs today have gear boxes with ratios like 13:1. Get rid of that gearbox and the steady-state losses go up with the square of that ratio. Then there are the issues of sprung mass, and where to put the mechanical brakes.
A very good YouTube video from Munroe Live (an engineering firm specializing in "design for manufacturing") explaining it: https://youtu.be/dCO633KE7RA "Axial Flux Motors Explained"
Visited Astrall Dynamics, a Chinese startup that builds quadrupeds with axial flux motors here in Shenzhen. Super cool to see the robots in actions, carrying 60kg of weight up over 20 flights of stairs quite rapidly. The high torque at the compact form factor was super impressive. As far as I understood they are more complex to manufacture, especially at scale.
> In contrast to conventional radial flux motors, the electromagnetic flux in an axial flux motor runs parallel to the axis of rotation. The key components are arranged in a disc‑shaped layout: two rotors sandwich the stator from the left and right. This design enables an especially compact motor architecture, high power and torque density, and new freedoms in drivetrain packaging. In the new Mercedes‑AMG GT 4‑Door Coupe, the motor at the front axle is just under nine centimetres wide; the two motors at the rear axle each measure around eight centimetres in width. The three axial flux motors are integrated per axle into so‑called High Performance Electric Drive Units (HP.EDU), where they are combined with a compact input planetary gearbox in a single housing.
For the AMG GT4 there will be 3 motors: two at the rear, and one at the front.
My interpretation (and my German's pretty lousy) is that each motor is combined with a gear system in a single package, and they're calling the overall package (motor plus gears) a High Performance Electric Drive Unit (HP.EDU).
The two rear motors will probably be independent, so no need for a mechanical rear diff (it'll be electronically controlled).
There's no mention of a front diff, so it's unknown whether that's built into the front HP.EDU or is a separate mechanical diff).
Kind of orthogonal. Traditional AWD and part-time 4WD systems are solutions to get power from a single motor to both the front and rear of a vehicle. AWD has a center differential to account for differences in front and rear driveshaft speeds when driving on high-traction surfaces. 4WD just locks the front and rear driveshaft rotation together, which is a simple and robust solution that only works on loose surfaces.
With separate front and rear electric motors, there's no center differential to worry about, and a sufficiently sophisticated motor control system can make it behave well on and off road.
I'm not sure that the traditional notion of traction control applies, given that there are three independent suppliers of power, so you don't necessarily need the mechanics of diffs and computer-controlled brakes to provide maximum traction.
What would it mean to "turn off" traction control in a car with independent motors per wheel? (OK this is a 3-motor/4-wheel scenario, but hypothetically…)
With software control and independent motors, we're likely to see increases in low-traction capability (for the right price-point and probably aimed at particular buyers)
“What“ might be a long answer, but why anyone might want one is to have increased torque density for the given volume and diameter. So they are thin motors where the generated flux is parallel to the shaft. And they are like the standard PMSMs where you apply the same driving algorithm from the inverter side to use them.
Most motors have N-S axis of magnets aligned tangential to the axis of rotation. Axial flux motors have N-S poles parallel to rotation. This allows motors to be thinner and wider as well as anyhow more lighter and sometimes easier made. Whether they make sense depends, it seems.
Consider the thousand or so comments at https://hn.algolia.com/?q=axial for more details. While it’s no substitute for a well-written comprehensive article, it certainly is a smorgasbord of answers.
> Mercedes-Benz subsidiary YASA (Yokeless and Segmented Armature) makes AFMs that have powered various concept (Jaguar C-X75), prototype, and racing vehicles. It was also used in the Koenigsegg Regera, the Ferrari SF90 Stradale and 296GTB, Lamborghini Revuelto, McLaren Artura and the Lola-Drayson.[9] The company is investigating the potential for placing motors inside wheels, given that AFM's low mass does not excessively increase a vehicle's unsprung mass.[10]
> In July 2025, YASA announced a prototype 550 kW (738 hp) 13.1 kg (29 lb) motor, equating to power density of 42 kW/kg, which the company claimed to be the highest ever achieved.[11] By contrast, the state of the art EV motor from Lucid Motors offers a 500 kW, 31.4-kg motor, or 16 kW/kg.[12]
> The first application of these motors will be in the High Performance Mercedes‑AMG GT 4-Touring Coupe.[14]
Thanks for posting this. Axial flux motors aren't some new sci-fi invention. We've had them in gadgets for a long time like in the floppy drive example. This is just one of the first industrial scale implementations of high-torque applications.
I would be careful about that video, it seems relatively "explaining this new amazing innovation that has no/negligible downsides (please invest in us)" rather than "explaining the practical pros & cons of this technology".
As far as I understand it's so small and lightweight you can put one on each wheel and remove brakes and still save weight (something something unsprung weight bad).
Very cool. Good to see more axial flux motors in the wild - will be interesting to see if they become the new standard in future. With smaller material costs the cost to manufacture at scale could actually become lower than radial
I expect radial will still dominate for at least another decade or so outside of premium performance focused cars. Radial has been battle-tested and proven. Axial still has a few more years to prove it's reliability in the field. Higher loads and stresses, tighter tolerances could make the axial motors less reliable overall especially at mass market trims. Mercedes is probably over-engineering for reliability and performance on the premium car
Radial is also "good enough" for most applications. The efficiency, form factor and weight improvements of axial is nice, but they aren't the limiting factor. Radial is already highly efficient, reasonably light and small. The real level for weight is the battery
I remember when YASA announced it and when MB bought them. Amazing technology and advancement in electric motor design. Good to see they somehow try to commercialize it.
An interesting part here is probably manufacturing and not the motor itself : going from a prototype to something you can mass produce reliably is often the hard part
Four years ago, when YASA's invention was discussed on HN, it attracted very little interest. Mercedes apparently saw more potential and decided to invest.
All motors are generators. It's only a matter of how you are creating the magnetic field with the stator windings.
In order to generate a higher regen, you'd have to somehow get more energy in the motor first... and since its only rated for 200kW, good ol' physics limits you, IF thats all the energy you put into the system.
If you roll it down a hill, or do something exotic like inverting the magnetic fields .... you can exceed the motor rating. But thats usually not recommended because the motor driver itself isnt rated to handle that power.
> can a car with 200kW propulsion have a 400kW regen
At the motor level it should be the same, in propulsion you’re converting current to torque and in regen you’re converting torque to current, with the same hardware. The high voltage wiring is the same and will set the same limit on current regardless of direction.
I believe bidirectional inverters are generally symmetrical as well, so that should not be a factor.
Which I reckon leaves two factors:
1. Battery C rates, afaik pretty much all chemistries have a higher discharge rate than charge rate, especially when trying to maintain them for a long time, so by that account regen power would at most be the same as propulsion (if the entire power train is sized for the battery’s charging rate).
2. Artificial limitations, obviously you could always artificially under-prop, though that seems unlikely outside of niche applications.
tldr: I don’t think so, except on a technicality (that you can artificially hobble propulsion).
How far fetched is the idea to use Super-Capacitors to take up the energy generated by braking and then slowly feeding it to the battery at a rate that it supports?
The energy density on super capacitors is pretty bad. If you imagine full power 200kW braking for 5 seconds that's 1 mega joule and at a best case 8 watt hours per liter you're going to need 35 liters minimum. Really you probably need to double that so you can float up and down and never fully saturate the capacitor as power inflow is going to drop as you get closer and closer to fully charged.
Am I reading you right that breaking power (that you want to regenerate in the system) >> speeding power? Obvious now I come to think of it, and still pretty nifty new thing learned if true!
Only slightly related but does anyone know anything about motors with magnetic bearings? As in, no contact or friction. I'm looking for a hardware project
There are fluid dynamic bearings which were used in VCRs and probably hard drives and definitely laser printer mirror motors - two sets of precise herringbone patterns cut into the ID of a bearing column and a tiny bit of oil that gets entrained between rotor shaft and that bearing column. As the motor speeds up the oil forms pressurized donuts. Only works at speed and generally only useful when there aren't side loads so applications are limited. Rolling element bearings are a quite developed technology and hard to beat in most applications.
Closest I can think of is flywheel "battery" storage tech many of which do have magnetic bearings and also some way to get power in and out of the flywheel so basically a motor. It's not exactly what you're looking for but there's prior art out there.
Probably not. A huge disadvantage of axial flux motors is they have a large number of poles, which means that they get less efficient at high speed because they require say 5x as much switching.
This makes them kind of unsuitable for power generation and really high power motors (despite their power density) where the main way you get more power is just to spin really fast.
The other disadvantage is they have such a low amount of material in them, that the stator overheats really easily. And the topology of the motor makes it really difficult to get the heat out efficiently, which again limits their maximum power.
For a century Germany's comparative advantage has been [mechanical] engineering. As a European I want (need?) Germany to succeed. Ergo: more of this, please.
Their advantage was mechanical engineering. They have historically not done well with electrical systems. So this is a change - hopefully for the better.
Electrical auxiliary stuff used to be and maybe still is a source of trouble. Power electronics should be fine, there's plenty of know-how available in the country, and with any luck, car companies won't have time to home-grow a mismanagement structure to fuck it up like they did with software.
Software and battery cells are the main challenges.
I am speculating but here might be reasons axial flux motors have advantage over radial flux motors:
1) torque: torque = applied force x length of the lever. Because the radial flux rotor must fit inside the stator, therefore radius << motor outside diameter. With the axial flux motor, the rotor is adjacent to the stator, therefore radius < motor outside diameter. Axial rotor radius > radial rotor radius.
2) space efficiency: in a radial flux motor you have 1 rotor, the coils arranged so that one end of the coil's magnetic field is useful to work on the rotor, the other end is not used. In an axial flux motor, (1) pancake rotor at each end of the coils, total (2) rotors, the coils can act on a rotor at each end. There is no free lunch here, to do useful work you still must provide more energy to the coil, but you can get the most from the space.
There must be someone here with a better handle on the electromagnetism, please correct me where I err.
Ah, another fantastic British innovator (YASA) having to realize its potential (and ultimately the downstream economic benefits of commercialisation) abroad.
Brought to you by the only country to have a space programme and abandon it.
Britain didn't abandon it's space programme. It abandoned a launch rocket programme though. That was over 50 years ago and the rocket was less capable and more expensive than alternatives at the time.
What alternatives? By your logic only one country should have a launch rocket. Thankfully that’s not a world we live in because that makes no sense. But I’m happy for you if you can be content with a space programme without a rocket, that’s a nice low bar to live with, you can basically never miss.
Did they have to? My impression is British companies sell out as soon as they can these days. Is this something that could be changed with policy? Does Germany incentivise running companies more? Or is this cultural, e.g. British people are more risk averse?
It's very difficult to raise late stage capital in the UK, especially for deep tech. We invent so much but our capital ecosystem is all tied up in land and our pensions providers don't want to know.
> UK is by far the best country to raise venture capital in Europe
For late stage? Continental Europe has its banks and industrial policy. America and China have their deep pockets. Scaling out of the UK is incredibly hard, doubly so post Brexit, that’s why they sell early.
I think continental Europe has nothing on the UK when it comes to banks and financial markets. The UK has the deepest pockets in Europe because it is a hub for global capital. Brexit does not seem to have made a difference:
UK has City of London that dwarfs the banks of continental Europe. we're talking big banks, Fintech, HFT, etc. When you deal with Austrian banks you realize they're 10-20 years behind the UK.
> and industrial policy
Continental Europe has a large but somewhat inefficient(compared to Asia) and heavily subsidized industrial policy, acting more a a jobs program for politicians chasing votes and state subsidies, that the UK gave up on during Thatcher(for better and worse), and stayed in the niche, low volume but highly important aerospace and defense parts that dwarfs that of continental Europe.
Ofc that also means the labor market in UK is very K-shaped. Highly paid skilled niche jobs in London and the university research centers, and then a wasteland everywhere else.
I think Germany has tax rules that make exits harder, whereas it's very easy in the UK to sell. If you have a more free market next to protective ones it makes sense that your IP is going to flow in that direction.
It’s cultural. It is not difficult to raise a lot of money in the UK. The problem is that the UK (government, investors, employees and employers) got so high on the margins of services and finance in the 90s, that it has never recovered from this all-consuming addiction. Everything else simply attracts no interest comparatively, economic diversification be damned.
I mean in EV's, a fancy expensive concept motor isn't going to help, autonomy should have been their direction 10 years ago, they are on the downward slope of their existence im afraid. Its the equivalent of Blockbuster adding a tape rewinding service to try and boost sales vs Netflix streaming.
That is also not guaranteed. VW (with its array of brands) leads the european BEV market by a lot. [1] (sorry I only found data for April 2026 right now but earlier months were similar)
One additional point of data. In Q1 of this year they delivered 200K BEV worldwide [2] while Tesla did 350k [3].
Calling that 10 years behind is not warranted in my opinion. I would agree to say competitive and challenged.
Never become dependent on doing hideously complicated things. You will eventually struggle to choose to do something more efficient, as the european auto industry is currently displaying. The car where thid motor will be used will, given current market sentiment, be a massive flop. Here they are showing off how complex the manufacturing process is. Surely we’d all be better off with simpler and cheaper processes.
This entire product is easier to build than the existing technology, has more simple tooling and will be simpler and cheaper.
Designing the manufacturing machinery is exactly what happens in any manufacturing process. Those robots are general purpose that have been adapted for the required tasks, that's a normal process.
Why would you build a motor that's twice as heavy with copper and much wider when you don't need to?
Efficiency and cost savings at scale usually involve an increase in complexity: in mass manufacturing, complexity is generally a fixed cost and so can be amortized over larger volumes.
By that logic we should all just be writing assembly manually. Screw hideously complicated higher level languages. Screw LLMs in particular, so complicated!
> Never become dependent on doing hideously complicated things
Is Mercedes stupid?
How did Carl Benz dare to do something as hideously complicated as building the first gasoline-powered car in history?
And why did they kept inventing complicated stuff that ended in all modern cars like ABS, adaptive cruise control, direct fuel injection, emergency brake assist, etc, etc?
Not all of those inventions are bad. But not all of them are coming from a place of necessity. All of them do increase complexity. My gripe with Mercedes is not that they are constantly pushing boundaries on what can be done with more tech. My main gripe is that the EVs they are building are essentially as complex as the ICE cars and follow largely the same design principles as the ICE cars. For instance, in the EQS, instead of applying engine breaking when the driver takes their foot off the pedal, they went to great lengths to _move the break pedal_ in proportion to the amount of engine breaking that is currently being applied as per the VCUs command. And yet the door cards on the EQS are not up to the standard of an S class.
My main gripe with MB is that they have this new technology that could simplify things and let them build a better product. Instead of building around it, they shove it in to their existing designs. I was expecting an electric S class to be more akin to a Lucid Air sans the teething problems of a new company. Instead, we get weak attempts at solving non issues.
And whilst they are certainly not in the market of producing affordable vehicles, I would hope that using EV tech they could create a better version of their existing fleet. I do not think anyone buying an A class cares about the 4 popper under the hood - losing it and simplifying radically, in my mind at least, would give them more budget and leeway to create a more compelling product.
> "instead of applying engine breaking when the driver takes their foot off the pedal, they went to great lengths to _move the break pedal_ in proportion to the amount of engine breaking that is currently being applied as per the VCUs command"
Regenerative braking slows the car more aggressively than an ICE where you take your foot of the gas, so the pedal change isn't putting on the brakes, it's communicating to a driver used to ICE that the car is slowing more than might be expected.
There may also be a sports-related reason for people who habitually left-foot brake.
It depends how much you draw from the motor/generator. One can modulate it as they want, whatever can't go into the battery due to chemistry or drive constraints can be disposed of as heat.
You clearly have never used a car like that. You develop muscle memory for where the pedal is - finding that the pedal is not where it used to be does not inspire much confidence.
Every other manufacturer has managed to control regen breaking via throttle modulation - even ICE hybrid cars have been doing that for ages.
I've used left-foot-braking in my (ICE-powered) daily driver for years.
Regenerative braking is very different to taking your foot off the accelerator in a conventional ICE car, it's much more powerful a stopping force than traditional engine-braking.
I understand the rationale for moving the pedal to illustrate the amount of "braking" force. I'll admit I'm not exactly a typical driver though.
I'd support that. It does feel unusual in most cars' cruise control that you can push the accelerator to three-quarters of its travel before you start to accelerate (e.g. if cruise control is at 50–60mph).
If you push the gas pedal, you'd expect to go faster, wouldn't you?
The equilibrium of "good enough vs technological simplicity" for cars was probably reached in the 1950s. Everything after that was more or less solving "non-issues" with ever-increasing complexity ;)
Great, they finally started mass-producing 19th century technology, let's cheer that! Nowadays, while Chinese and Americans are producing GPUs, AI and li-ion batteries, German high-tech is an engine invented by Faraday
Mercedes acquired Yasa (UK) couple of years ago and now getting up to the speed in the production.
Here is a nice video that explains axial flux motors with a factory visit
https://youtu.be/B2Hl4c1iZK0?si=VfDYARyuaPVj1nKm
They are so, so, small.
I was curious how this thing works and asked Claude to visualize it -- mostly to see how good Fable is and I have to say, what it made was good enough for me to get a gist of it. Posted it here
https://azimi.me/axial-flux-motor-explainer/
You made this with Fable? How many prompt? It is amazing.
Every plausibly cool electric car innovation leads me to the same thought: “5-10 years from now, the restomod potential will be wild once these come down in cost.” For this, I am imagining retrofitting a Pontiac Fiero to reduce as much weight as possible and see if extended flight becomes possible.
Can you elaborate a little on what you asked Claude to do here? This is a pretty impressive one-shot.
Thanks for sharing. I wish it was a bit more interactive especially when there are parameters, e.g. "Widen the disc and torque rises with diameter cubed" I wish there was a slider to see that effect and thus maybe why there might be a sweet spot.
Also I have "The Way Things Work" on my desk right now and can't help but wonder, could you adapt some of the pages of the book this way? It seems like exactly the kind of content that would benefit from such 3D (interactive) visual explainers.
Code is here https://github.com/mohsen1/axial-flux-motor-explainer
Feel free to steal! This was one shot with Claude Code. You can take it and adopt it to your need
Oof... well thanks for sharing but that's basically unusable for me. It neatly all packed in a 2MB file containing all assets, threejs, etc.
I assumed it's based on a three.js template due to the `Rendered live with three.js · Drag anywhere to orbit the model` kind of showcase but unfortunately that's not linked. I also imagine the 3D models are more that primitives (at least the arrows showcasing the flow) but I don't know where they came from, if that are also from a template or repository or if they are generated from a tube mesh.
So... I'm genuinely grateful that you took the time to share but I don't think I can do something with this except restarting from scratch, especially if it's one-shot.
I'd suggest, if you don't mind the extra effort, that you add a ReadMe.md in the repository to clarify how you did this, at least model name, version and prompt.
https://archive.org/details/TWTK_WIN
This viz is superficially neat, but hard to get info out of. It seems like a demo in a movie.
What did you like most about it?
Yup, the visualization didn't help me understand the concept any more than plain text. Superficial in the way that you would expect from a system that has no real world reference for what it is creating.
To get something better I expect more than a one-shot is needed, and the knowledge to guide it in the right way.
Honestly, I don't think this actually provided much above a paragraph of text.
The visuals didn't show much, and I learnt a lot more from one of the YouTube videos (https://www.youtube.com/watch?v=dCO633KE7RA) posted below.
It's neat that a whole interactive deck can be produced without effort. But it's just not very interesting.
what was the prompt for this, did you use a CAD/threejs skill or grab a model from somewhere?
The issue with this is, without an expert, how do I know I am getting an accurate representation?
Hundreds of examples of axial flux motors exist online. If you look at the visualization it shows the iron cores in a perpendicular orientation with the hub. This is correct, but loses so much of what makes these specific motors interesting. The angled nature of the grey cores and copper wrapping smoothes the transition between each magnetic field.
Basically it is a pretty version of a dumbed down partially incorrect answer. With a knowledgeable user it would be very good, but he has no idea he is wrong. I’m not sure what Dunning Kreguer with graphics should be called.
You don't. You didn't know before either. The difference is trust. How do you trust it as much as you do the hypothetical humans making such representations? That's up to you.
I think humans develop expertise and brand names and get called out when they make mistakes and if they are too wrong, their reputation is damaged.
This doesn’t seem to apply to AI for some reason. It keeps generating incorrect results after incorrect results, yet people continue to trust its output.
I don’t know what to make of this.
[delayed]
You first heard about this effect with the phrase "computer says no".
Tbh it did a pretty good job
I am not an expert, but I do know some physics and I know how to read, and I’m pretty sure this is full of BS. Also it’s a really crappy visualization.
That was a good video, and I also liked the Munro video that does a nice job of explaining how these work: https://www.youtube.com/watch?v=m507ryWhc6c
I wonder how developing electric motors compares to combustion engines. My hunch says that it’s the main reason the Chinese high-tech electronics industry was able to develop and iterate leading electric vehicles so fast. (Edit: My more clarified point is regarding the machinery required + place to accommodate them to work on electric motors vs. ICE metal parts and all the intermediary parts transfering power in the drivetrain. The shop in the video is smaller than many would imagine.)
When these hopefully go to the next generation Formula E cars, we’ll see some crazy improvements in cornering. The newest generation already has active 4WD. I imagine this can bring even better torque adjustment improvements.
The Chinese EV industry is actually lead by development of batteries, especially CATL. Along with the pack engineering, which is good old Mech.E stuff about heat transfer and physical strength.
Secondarily power electronics; at that scale, you can't just pick a bigger transistor and call it a day.
By comparison the motors seem to be a mostly solved problem, although I'm sure there's still some scope for power-to-weight engineering there, it's not as critical as the battery pack.
And is development of batteries (and better magnetics) not just chemical engineering and material science?
Motors might be a 'solved problem' - there might not be much innovation, Maxwell's laws aren't changing any time soon, but there will surely be a lot of incremental improvement - an early 1900s ICE is considerably worse than a 2000s ICE.
> n early 1900s ICE is considerably worse than a 2000s ICE.
But how much worse is a early 1900s electric motor from a modern one? I can't find data, but I suspect the first electric motor from the 1830s is more efficient than a modern ICE (even if we assume the ICE is built for efficiency, screw emissions). There is some room for improvement, but there isn't much difference between our best motors and perfection (a carnot cycle by contrast is as best much worse than perfection)
>I wonder how developing electric motors compares to combustion engines. My hunch says that it’s the main reason the Chinese high-tech electronics industry was able to develop and iterate leading electric vehicles so fast.
The talent had very little impact to be honest. The primary factor was a government looking 50 years down the road seeing that:
1. ICE engines have little to no long-term future in transportation.
2. global warming is a thing whether the right wing in the US likes it or not.
3. They were never going to overtake the West in ICE engines and had to attack from a different angle.
The US' lack of breakthroughs in EVs has little to do with technology or expertise and everything to do with an administration that is openly hostile towards EVs and renewable energy in general. For the rest of the planet, EVs becoming the primary form of transportation is just an obvious and logical conclusion, even if it takes us another 25-50 years to get there.
China saw it and decided to heavily incentivize and subsidize the rapid expansion of EVs both to fix the air quality issues in China and corner the market.
AFAIK Chinese electric cars used western motor drivetrains and often still do?
I'm not saying there isn't room for innovation but... Electric motors have been around for a century now already in many applications.
It's not like the Dawn of the steam engine
According to wikipedia[1] the first industrial steam engine (1712) was invented almost 100 years before the invention of the steam locomotive (1804), arguably its greatest evolutionary feat.
[1] https://en.wikipedia.org/wiki/History_of_the_steam_engine
The new season of Formula One feels (unfortunately) like Formula E!
In Formula E the drivers control engine behavior and regen. It is much better than F1 right now.
It would be awesome if they would implement a crude rule: no computers. You can use a computer to design the car--CAD/CAM/CAE are all fine--but no stored program computers are allowed in the race car. I think that would improve F1 tremendously.
> develop and iterate leading electric vehicles so fast.
How do you know this for a fact? Chinese press releases? You've driven one? Some auto blogger drove one?
After world war 2 Gorbachev or whoever visited the United States and during that trio visited a supermarket. He thought it was a facade, possibly, put on just for him, there's no way Americans are this prosperous (or whatever, this good at agriculture, farm equipment, etc)
Also do the race cars have 4 wheel drive, or all-wheel drive? I'm wagering all-wheel with "torque vectoring" and "Yaw control", like a Mitsubishi Lancer Evolution X.
I am somewhat confused at the intensity of pushback for the statement “leading electric vehicles.”
Chinese EVs are leading and that doesn’t necessarily mean being the best, most advanced vehicles. They are leading in value/pricing, and in many regions they are leading in sales.
BYD sells almost double the EV volume of Tesla globally as of December 2025. They are objectively leading in that respect.
I think the parent comment of yours made a good point (or at least adjacent to a good point) about China’s ability to enter the market: they can’t compete with 100 years of internal combustion engine development along with the vast parts supplier network of the West, but they can compete on battery chemistry, battery supply, motors, and the more vertically integrated EV space where automakers don’t need to depend on a huge network of parts suppliers like they did in the past.
I also think that a lot of pushback to the innovation that China is delivering is criticism that is stuck in the past. If you buy a Xiaomi car, it integrates perfectly with all your Xiaomi consumer devices. You can control your rice cooker or robot vacuum from your car’s integrated infotainment system. This type of approach was exactly what Apple was going to deliver before they abandoned their automotive project.
Or, you can buy a Mercedes and you’ll get a car with more precise handling and perfectly tuned driving characteristics. The infotainment system looks like Windows Vista.
Which side of the aisle do you think most consumers care about? I think most people buy into Xiaomi’s approach.
Semiofftopic but somehow I took offense at the Vista comparison. Aero Glass was peak UI design to me, and I'd certainly prefer it to modern paradigms like flat controls, or to stretch it even further, Corporate Memphis etc.
Curse you, Apple and Jony Ive. You only needed to tone skeuomorphism down not kill it.
I’m genuinely delighted that this reaction to that little phrase came up! It was definitely something of a half-joke on my part: the Mercedes infotainment system is very well-regarded, but it does not look “modern” compared to something like a Tesla, Rivian, or Xiaomi.
The hyperscreen from a physical hardware perspective looks strangely dated to me as well, depending on the specific car model.
I wouldnt be so harsh even with chinese combustion engines, its at this point a meme that is just copy pasted because everybody says so, but without actual experience. People dont understand how China is 3x bigger than Europe and 4x bigger than US, the scale of that market is absurd and competition numerous and fierce.
I've had MG suv rented recently with just gasoline engine and it was fine. This comes from long term bmw driver, they are not on the exactly same level, but light years ahead from similarly prices ie french vehicles. Handling was fine too, probably the biggest shock for me, this is where french, italian etc are losing me (bmw effect). And they cost 1/3 of bmw.
True, and on a similar wavelength, nobody seems to care that Kia/Hyundai engines are super mid.
Heck, nobody seems to care that Toyota engines/transmissions sound like a vacuum cleaner and have pretty mediocre NVH on models like the Corolla, but they buy those products for reliability and efficiency.
I think with xiaomi yu7 and Tesla killing the model S, the chinese are leading in everything when it comes to EVs.
Listening to the heads of the American and European car companies say the same and driving in them in china. I know that is different than personally disassembling one and reviewing it, but I am not sure the incentive for the other companies to say they have inferior products, unless it was a play for subsidies or deregulation of some form.
Personally I feel that the rest of the world continues to dramatically under estimate China’s progress and technological advancement at our own peril. Is there fluff and are their lots of untrue claims, of course, but that is certainly not something they have a monopoly on.
Aren't you getting your analogy backwards? American supermarkets have the same role in the story as Chinese cars.
A few years ago I built a few small ones in my home lab. They are extremely efficient. With the right setup, have insane torque, and don’t require a lot of energy to do it. The best part for me was that they are completely brushless by design and are easily to keep clean.
Came here for this, thank you for providing a link
Edit.... Video doesn't seem to explain very well either
It would have been awesome if that article had, at any point, explained what an electric axial flux motor was, and why anyone might want one.
Click "More" and scroll down:
"In contrast to conventional radial flux motors, the electromagnetic flux in an axial flux motor runs parallel to the axis of rotation. The key components are arranged in a disc‑shaped layout: two rotors sandwich the stator from the left and right. This design enables an especially compact motor architecture, high power and torque density, and new freedoms in drivetrain packaging. In the new Mercedes‑AMG GT 4‑Door Coupe, the motor at the front axle is just under nine centimetres wide; the two motors at the rear axle each measure around eight centimetres in width. The three axial flux motors are integrated per axle into so‑called High Performance Electric Drive Units (HP.EDU), where they are combined with a compact input planetary gearbox in a single housing."
Really the kind of thing that should be earlier in an article about… that very thing the reader is wondering about, but maybe we arent the target audience?
This is the same design that enables the PCB Stator Motors, right?
Yes. If you have a laser printer, that windup sound you hear at the start of a job is the polygon mirror motor spinning up thousands of RPMs - those are PCB stator motors. As were VCR head motors.
"Advantages : A motor can be built upon any flat structure, such as a PCB, by adding coils and a bearing." https://en.wikipedia.org/wiki/Axial_flux_motor with image of "A miniature DC brushless axial motor used in a Digital Data Storage drive, showing the integration with PCB construction techniques."
For some reason that reminds me of https://www.youtube.com/watch?v=aW2LvQUcwqc
> This design enables an especially compact motor architecture, high power and torque density, and new freedoms in drivetrain packaging.
Hand waving.
No, it means the motor is smaller and it can be put into the wheel
It doesn't make that a good idea. Armature losses are proportional to torque squared - doesn't matter if it is radial or axial design. That's why all the EVs today have gear boxes with ratios like 13:1. Get rid of that gearbox and the steady-state losses go up with the square of that ratio. Then there are the issues of sprung mass, and where to put the mechanical brakes.
aren't there other issues with having the motor in the wheels? Unsprung mass, plus the wheels can get pretty banged around?
A very good YouTube video from Munroe Live (an engineering firm specializing in "design for manufacturing") explaining it: https://youtu.be/dCO633KE7RA "Axial Flux Motors Explained"
Edit: a video from them on this particular YASA tech being discussed : https://youtu.be/m507ryWhc6c
Visited Astrall Dynamics, a Chinese startup that builds quadrupeds with axial flux motors here in Shenzhen. Super cool to see the robots in actions, carrying 60kg of weight up over 20 flights of stairs quite rapidly. The high torque at the compact form factor was super impressive. As far as I understood they are more complex to manufacture, especially at scale.
It's a bit buried, but it does:
> In contrast to conventional radial flux motors, the electromagnetic flux in an axial flux motor runs parallel to the axis of rotation. The key components are arranged in a disc‑shaped layout: two rotors sandwich the stator from the left and right. This design enables an especially compact motor architecture, high power and torque density, and new freedoms in drivetrain packaging. In the new Mercedes‑AMG GT 4‑Door Coupe, the motor at the front axle is just under nine centimetres wide; the two motors at the rear axle each measure around eight centimetres in width. The three axial flux motors are integrated per axle into so‑called High Performance Electric Drive Units (HP.EDU), where they are combined with a compact input planetary gearbox in a single housing.
> The three axial flux motors are integrated per axle
I wonder why they need tree motors per axle.
It's poorly worded. There aren't three motors per axle, there are three motors total: one on the front axle and two on the rear axle.
The translation's a little woolly.
For the AMG GT4 there will be 3 motors: two at the rear, and one at the front.
My interpretation (and my German's pretty lousy) is that each motor is combined with a gear system in a single package, and they're calling the overall package (motor plus gears) a High Performance Electric Drive Unit (HP.EDU).
The two rear motors will probably be independent, so no need for a mechanical rear diff (it'll be electronically controlled).
There's no mention of a front diff, so it's unknown whether that's built into the front HP.EDU or is a separate mechanical diff).
In terms of traction control, does this translate to something between "4WD" and "AWD"? Or is it orthogonal?
Kind of orthogonal. Traditional AWD and part-time 4WD systems are solutions to get power from a single motor to both the front and rear of a vehicle. AWD has a center differential to account for differences in front and rear driveshaft speeds when driving on high-traction surfaces. 4WD just locks the front and rear driveshaft rotation together, which is a simple and robust solution that only works on loose surfaces.
With separate front and rear electric motors, there's no center differential to worry about, and a sufficiently sophisticated motor control system can make it behave well on and off road.
I'm not sure that the traditional notion of traction control applies, given that there are three independent suppliers of power, so you don't necessarily need the mechanics of diffs and computer-controlled brakes to provide maximum traction.
What would it mean to "turn off" traction control in a car with independent motors per wheel? (OK this is a 3-motor/4-wheel scenario, but hypothetically…)
With software control and independent motors, we're likely to see increases in low-traction capability (for the right price-point and probably aimed at particular buyers)
I got the impression that there were three motors altogether and they were integrated with the axles.
“What“ might be a long answer, but why anyone might want one is to have increased torque density for the given volume and diameter. So they are thin motors where the generated flux is parallel to the shaft. And they are like the standard PMSMs where you apply the same driving algorithm from the inverter side to use them.
Here's a great Instructable on building one yourself, much better explanations in there.
https://www.instructables.com/Designing-and-Building-an-Axia...
It's basically the V8 of electric motors. Different topology results in better power to weight ratio. From the outside they look pancake shaped.
I want a V12 or V16, thank you very much.
I'd like a 600 HP 1.5l supercharged V16 - doesn't even need to be in a car, mainly just to listen to!
https://en.wikipedia.org/wiki/British_Racing_Motors_V16
Ok, me too now. But you can’t have that, so maybe you could settle for a high-reving V8 in a tunnel?
If the displacement isn’t measured in cubic meters, can you even call it an engine?
Bonus points if you have to heat that crap you call fuel before you inject it into the massive cylinder.
Then all you need is a good recording and decent headphones
A good recording and a sound system which can move the exact amount of air that the engine has moved, to be precise.
V5?
https://en.wikipedia.org/wiki/VR5_engine
We owned an vw inline 5 Passat (quantum in North America). Good engine and synchro awd.
Since they're relatively compact they will probably start stacking them. Like pancakes.
Stick two of them together on the same axle then.
Why do you need an axle?
Put the engine and its transmission to the wheel mounted next to each wheel.
No need for differentials etc, if they can work out a steering mechanism for each, then you've got 4WD with 4W steering.
In the video there's talk of how you can use them as regenerative braking as well, so have that as part of the wheel structure.
No axles, no differentials, independent suspension, electronically controlled power to each wheel, regenerative braking.
Gonna be a fun decade or more of innovation coming.
Wouldn't putting them in the wheel increase unsprung mass, which would degrade the feel of the car?
One in every wheel
Most motors have N-S axis of magnets aligned tangential to the axis of rotation. Axial flux motors have N-S poles parallel to rotation. This allows motors to be thinner and wider as well as anyhow more lighter and sometimes easier made. Whether they make sense depends, it seems.
This sounds straight out of an 89’s sci-fi flick. What time we get to live in!
Consider the thousand or so comments at https://hn.algolia.com/?q=axial for more details. While it’s no substitute for a well-written comprehensive article, it certainly is a smorgasbord of answers.
https://en.wikipedia.org/wiki/Axial_flux_motor
The automotive part is interesting:
https://en.wikipedia.org/wiki/Axial_flux_motor#Automotive
> Mercedes-Benz subsidiary YASA (Yokeless and Segmented Armature) makes AFMs that have powered various concept (Jaguar C-X75), prototype, and racing vehicles. It was also used in the Koenigsegg Regera, the Ferrari SF90 Stradale and 296GTB, Lamborghini Revuelto, McLaren Artura and the Lola-Drayson.[9] The company is investigating the potential for placing motors inside wheels, given that AFM's low mass does not excessively increase a vehicle's unsprung mass.[10]
> In July 2025, YASA announced a prototype 550 kW (738 hp) 13.1 kg (29 lb) motor, equating to power density of 42 kW/kg, which the company claimed to be the highest ever achieved.[11] By contrast, the state of the art EV motor from Lucid Motors offers a 500 kW, 31.4-kg motor, or 16 kW/kg.[12]
> The first application of these motors will be in the High Performance Mercedes‑AMG GT 4-Touring Coupe.[14]
Thanks for posting this. Axial flux motors aren't some new sci-fi invention. We've had them in gadgets for a long time like in the floppy drive example. This is just one of the first industrial scale implementations of high-torque applications.
> Axial flux motors aren't some new sci-fi invention
Indeed not. The first ever electric motor was an axial flux motor built by Michael Faraday in 1821. It's definitely not a new idea.
Here's a good video on it from my watch history: https://www.youtube.com/watch?v=dCO633KE7RA
This one gives a shorter more high level overview https://www.youtube.com/watch?v=B0CNZPenCb8
I would be careful about that video, it seems relatively "explaining this new amazing innovation that has no/negligible downsides (please invest in us)" rather than "explaining the practical pros & cons of this technology".
The AI voice is annoying, the content is as personal a a vanilla yogurt but the animation is clear.
Great video. I didn't know I was so interested in engine design before I watched it.
https://backtothefuture.fandom.com/wiki/Flux_capacitor .
As far as I understand it's so small and lightweight you can put one on each wheel and remove brakes and still save weight (something something unsprung weight bad).
Very cool. Good to see more axial flux motors in the wild - will be interesting to see if they become the new standard in future. With smaller material costs the cost to manufacture at scale could actually become lower than radial
I expect radial will still dominate for at least another decade or so outside of premium performance focused cars. Radial has been battle-tested and proven. Axial still has a few more years to prove it's reliability in the field. Higher loads and stresses, tighter tolerances could make the axial motors less reliable overall especially at mass market trims. Mercedes is probably over-engineering for reliability and performance on the premium car
Radial is also "good enough" for most applications. The efficiency, form factor and weight improvements of axial is nice, but they aren't the limiting factor. Radial is already highly efficient, reasonably light and small. The real level for weight is the battery
I remember when YASA announced it and when MB bought them. Amazing technology and advancement in electric motor design. Good to see they somehow try to commercialize it.
Seems like China is using them in buses already?
https://english.cas.cn/newsroom/cas-in-media/202606/t2026060...
This video explained to me what an axial flux motor is and how it's different to radial flux.
Amazing what materials science achieving to get this sort of power as well as the engineering and manufacturing.
https://www.youtube.com/watch?v=dCO633KE7RA
That is such a cool name!
An interesting part here is probably manufacturing and not the motor itself : going from a prototype to something you can mass produce reliably is often the hard part
Glad YASA's achievements are being realised but the UK really needs to get it act together so we can fully realise the next tech breakthough.
The main benefit here seems to be smaller and lighter for the same power output.
Roads? Where we're going we don't need roads.
It remains to produce the flux capacitor for time travel now :P
Four years ago, when YASA's invention was discussed on HN, it attracted very little interest. Mercedes apparently saw more potential and decided to invest.
https://news.ycombinator.com/item?id=31701133 Inside Yasa: how a British firm is revolutionising electric cars (2 points | 0 comments)
Tangential, how much regen can this system support?
For example, can a car with 200kW propulsion have a 400kW regen (Tesla has upto 65) and are cost effective like friction brakes?
All motors are generators. It's only a matter of how you are creating the magnetic field with the stator windings.
In order to generate a higher regen, you'd have to somehow get more energy in the motor first... and since its only rated for 200kW, good ol' physics limits you, IF thats all the energy you put into the system.
If you roll it down a hill, or do something exotic like inverting the magnetic fields .... you can exceed the motor rating. But thats usually not recommended because the motor driver itself isnt rated to handle that power.
Their founder/CTO discusses that here and their ability to match the braking power density of carbon ceramic brakes: https://youtu.be/B2Hl4c1iZK0?si=bCLQnfovjY7t-eYm&t=900
400kW regen is going to be a fairly alarming level of stopping for a normal vehicle. It's OK to leave emergencies to the friction brakes.
> can a car with 200kW propulsion have a 400kW regen
At the motor level it should be the same, in propulsion you’re converting current to torque and in regen you’re converting torque to current, with the same hardware. The high voltage wiring is the same and will set the same limit on current regardless of direction.
I believe bidirectional inverters are generally symmetrical as well, so that should not be a factor.
Which I reckon leaves two factors:
1. Battery C rates, afaik pretty much all chemistries have a higher discharge rate than charge rate, especially when trying to maintain them for a long time, so by that account regen power would at most be the same as propulsion (if the entire power train is sized for the battery’s charging rate).
2. Artificial limitations, obviously you could always artificially under-prop, though that seems unlikely outside of niche applications.
tldr: I don’t think so, except on a technicality (that you can artificially hobble propulsion).
How far fetched is the idea to use Super-Capacitors to take up the energy generated by braking and then slowly feeding it to the battery at a rate that it supports?
The energy density on super capacitors is pretty bad. If you imagine full power 200kW braking for 5 seconds that's 1 mega joule and at a best case 8 watt hours per liter you're going to need 35 liters minimum. Really you probably need to double that so you can float up and down and never fully saturate the capacitor as power inflow is going to drop as you get closer and closer to fully charged.
https://en.wikipedia.org/wiki/Supercapacitor
Am I reading you right that breaking power (that you want to regenerate in the system) >> speeding power? Obvious now I come to think of it, and still pretty nifty new thing learned if true!
Only slightly related but does anyone know anything about motors with magnetic bearings? As in, no contact or friction. I'm looking for a hardware project
There are fluid dynamic bearings which were used in VCRs and probably hard drives and definitely laser printer mirror motors - two sets of precise herringbone patterns cut into the ID of a bearing column and a tiny bit of oil that gets entrained between rotor shaft and that bearing column. As the motor speeds up the oil forms pressurized donuts. Only works at speed and generally only useful when there aren't side loads so applications are limited. Rolling element bearings are a quite developed technology and hard to beat in most applications.
Closest I can think of is flywheel "battery" storage tech many of which do have magnetic bearings and also some way to get power in and out of the flywheel so basically a motor. It's not exactly what you're looking for but there's prior art out there.
I think air bearings exist? Maybe some prior art to consider
Oh yeah tons. I'm not looking to invent just tinker
maglev but those do linear acceleration instead of rotational. seems tricky though for cars with such uneven surfaces.
I wonder if that is even possible since the whole point of the motor is an imbalance of magnetic forces.
According to Claude it requires active control. So complicated and only used in very niche applications.
Theoreticaly the rotor could float on top of the stator, although It it would have to be always on.
I would guess that hydro and other generator forms would benefit from this design as well?
Personally I’d love to see this make it’s way into power tools and CNC motors.
Probably not. A huge disadvantage of axial flux motors is they have a large number of poles, which means that they get less efficient at high speed because they require say 5x as much switching.
This makes them kind of unsuitable for power generation and really high power motors (despite their power density) where the main way you get more power is just to spin really fast.
The other disadvantage is they have such a low amount of material in them, that the stator overheats really easily. And the topology of the motor makes it really difficult to get the heat out efficiently, which again limits their maximum power.
For a century Germany's comparative advantage has been [mechanical] engineering. As a European I want (need?) Germany to succeed. Ergo: more of this, please.
Yasa is a British company, for the record.
Their advantage was mechanical engineering. They have historically not done well with electrical systems. So this is a change - hopefully for the better.
Electrical auxiliary stuff used to be and maybe still is a source of trouble. Power electronics should be fine, there's plenty of know-how available in the country, and with any luck, car companies won't have time to home-grow a mismanagement structure to fuck it up like they did with software.
Software and battery cells are the main challenges.
That's not quite right.
For example Siemens and Bosch are large enterprises specialised in industrial scale electrical machines and parts (among other fields).
Infineon was spun off from Siemens 25 years ago an plays an important role in chip manufacturing for automative systems.
Only if they could mass produce flux capacitor.
And reversed the polarity of the neutron flow.
That is one angry looking car.
I am speculating but here might be reasons axial flux motors have advantage over radial flux motors:
1) torque: torque = applied force x length of the lever. Because the radial flux rotor must fit inside the stator, therefore radius << motor outside diameter. With the axial flux motor, the rotor is adjacent to the stator, therefore radius < motor outside diameter. Axial rotor radius > radial rotor radius.
2) space efficiency: in a radial flux motor you have 1 rotor, the coils arranged so that one end of the coil's magnetic field is useful to work on the rotor, the other end is not used. In an axial flux motor, (1) pancake rotor at each end of the coils, total (2) rotors, the coils can act on a rotor at each end. There is no free lunch here, to do useful work you still must provide more energy to the coil, but you can get the most from the space.
There must be someone here with a better handle on the electromagnetism, please correct me where I err.
This is gonna be wild in a few years when these things are parted out the way tesla motors have been… Everything about these is crazy!
If you’re not caught up https://youtu.be/m507ryWhc6c?si=Hq3dfjXYxEIlYzeo
Ah, another fantastic British innovator (YASA) having to realize its potential (and ultimately the downstream economic benefits of commercialisation) abroad.
Brought to you by the only country to have a space programme and abandon it.
Britain didn't abandon it's space programme. It abandoned a launch rocket programme though. That was over 50 years ago and the rocket was less capable and more expensive than alternatives at the time.
What alternatives? By your logic only one country should have a launch rocket. Thankfully that’s not a world we live in because that makes no sense. But I’m happy for you if you can be content with a space programme without a rocket, that’s a nice low bar to live with, you can basically never miss.
> Brought to you by the only country to have a space programme and abandon it.
I mean, so did France; they both essentially folded theirs into ESA.
Did they have to? My impression is British companies sell out as soon as they can these days. Is this something that could be changed with policy? Does Germany incentivise running companies more? Or is this cultural, e.g. British people are more risk averse?
I suspect it has more to do with Germany’s industrial scale in the automotive space (as opposed to incentives or culture).
Yeah. Traditional car makers have enormous demand for EV innovations. Germany has more and bigger traditional car makers.
It's very difficult to raise late stage capital in the UK, especially for deep tech. We invent so much but our capital ecosystem is all tied up in land and our pensions providers don't want to know.
The UK is by far the best country to raise venture capital in Europe, and is the third largest market in the world after the US and China...
> UK is by far the best country to raise venture capital in Europe
For late stage? Continental Europe has its banks and industrial policy. America and China have their deep pockets. Scaling out of the UK is incredibly hard, doubly so post Brexit, that’s why they sell early.
I think continental Europe has nothing on the UK when it comes to banks and financial markets. The UK has the deepest pockets in Europe because it is a hub for global capital. Brexit does not seem to have made a difference:
https://www.uktech.news/funding/late-stage-funding-surges-as...
Regarding AI (since that's the hot thing of the day), but IMO indicator of where the money is:
https://digital-strategy.ec.europa.eu/en/library/funding-ai-...
[In the EU] "Most late-stage capital comes from the US and UK."
Now, regarding YASA, it isn't surprising that they were acquired by a car manufacturer. And, well, the UK has virtually none at this point...
>Continental Europe has its banks
UK has City of London that dwarfs the banks of continental Europe. we're talking big banks, Fintech, HFT, etc. When you deal with Austrian banks you realize they're 10-20 years behind the UK.
> and industrial policy
Continental Europe has a large but somewhat inefficient(compared to Asia) and heavily subsidized industrial policy, acting more a a jobs program for politicians chasing votes and state subsidies, that the UK gave up on during Thatcher(for better and worse), and stayed in the niche, low volume but highly important aerospace and defense parts that dwarfs that of continental Europe.
Ofc that also means the labor market in UK is very K-shaped. Highly paid skilled niche jobs in London and the university research centers, and then a wasteland everywhere else.
I think Germany has tax rules that make exits harder, whereas it's very easy in the UK to sell. If you have a more free market next to protective ones it makes sense that your IP is going to flow in that direction.
It’s cultural. It is not difficult to raise a lot of money in the UK. The problem is that the UK (government, investors, employees and employers) got so high on the margins of services and finance in the 90s, that it has never recovered from this all-consuming addiction. Everything else simply attracts no interest comparatively, economic diversification be damned.
10 years behind Tesla, they are doomed
Actually, 137 years behind Tesla ;)
https://spectrum.ieee.org/axial-flux-motor-yasa
My understanding is that all current Teslas use radial flux motors
... Eh? No. No current large-scale production car uses axial flux motors. You're talking concept cars, plus a few oddities like https://en.wikipedia.org/wiki/McLaren_Artura
I mean in EV's, a fancy expensive concept motor isn't going to help, autonomy should have been their direction 10 years ago, they are on the downward slope of their existence im afraid. Its the equivalent of Blockbuster adding a tape rewinding service to try and boost sales vs Netflix streaming.
That is also not guaranteed. VW (with its array of brands) leads the european BEV market by a lot. [1] (sorry I only found data for April 2026 right now but earlier months were similar)
One additional point of data. In Q1 of this year they delivered 200K BEV worldwide [2] while Tesla did 350k [3].
Calling that 10 years behind is not warranted in my opinion. I would agree to say competitive and challenged.
[1] https://cleantechnica.com/2026/06/01/europe-ev-sales-report-... [2] https://www.volkswagen-group.com/de/pressemitteilungen/volks... [3] https://ir.tesla.com/press-release/tesla-first-quarter-2026-...
Volume alone is a bad metric, Tesla makes profit on their EV's sales Mercedes makes a loss, not sustainable.
Never become dependent on doing hideously complicated things. You will eventually struggle to choose to do something more efficient, as the european auto industry is currently displaying. The car where thid motor will be used will, given current market sentiment, be a massive flop. Here they are showing off how complex the manufacturing process is. Surely we’d all be better off with simpler and cheaper processes.
This entire product is easier to build than the existing technology, has more simple tooling and will be simpler and cheaper.
Designing the manufacturing machinery is exactly what happens in any manufacturing process. Those robots are general purpose that have been adapted for the required tasks, that's a normal process.
Why would you build a motor that's twice as heavy with copper and much wider when you don't need to?
China is working on the same type of engine: https://interestingengineering.com/ai-robotics/chinese-axial...
Ye, and I’d wager China will put that motor into affordable vehicles first, not some BS AMG GT 4 door/4 seat hyper car.
Mercedes always brings their latest technologies to the highest tier of cars first. Almost every major innovation has first debuted on the S class
Efficiency and cost savings at scale usually involve an increase in complexity: in mass manufacturing, complexity is generally a fixed cost and so can be amortized over larger volumes.
He says, typing on one of the most hideously complicated things humanity has created.
A typical modern car is already hideously complicated and a different type of motor would not change this.
What is the current market sentiment? Share of EVs is slowly rising so having a good motor as important as ever.
By that logic we should all just be writing assembly manually. Screw hideously complicated higher level languages. Screw LLMs in particular, so complicated!
> Never become dependent on doing hideously complicated things
Is Mercedes stupid?
How did Carl Benz dare to do something as hideously complicated as building the first gasoline-powered car in history?
And why did they kept inventing complicated stuff that ended in all modern cars like ABS, adaptive cruise control, direct fuel injection, emergency brake assist, etc, etc?
Not all of those inventions are bad. But not all of them are coming from a place of necessity. All of them do increase complexity. My gripe with Mercedes is not that they are constantly pushing boundaries on what can be done with more tech. My main gripe is that the EVs they are building are essentially as complex as the ICE cars and follow largely the same design principles as the ICE cars. For instance, in the EQS, instead of applying engine breaking when the driver takes their foot off the pedal, they went to great lengths to _move the break pedal_ in proportion to the amount of engine breaking that is currently being applied as per the VCUs command. And yet the door cards on the EQS are not up to the standard of an S class.
My main gripe with MB is that they have this new technology that could simplify things and let them build a better product. Instead of building around it, they shove it in to their existing designs. I was expecting an electric S class to be more akin to a Lucid Air sans the teething problems of a new company. Instead, we get weak attempts at solving non issues.
And whilst they are certainly not in the market of producing affordable vehicles, I would hope that using EV tech they could create a better version of their existing fleet. I do not think anyone buying an A class cares about the 4 popper under the hood - losing it and simplifying radically, in my mind at least, would give them more budget and leeway to create a more compelling product.
There may also be a sports-related reason for people who habitually left-foot brake.
It depends how much you draw from the motor/generator. One can modulate it as they want, whatever can't go into the battery due to chemistry or drive constraints can be disposed of as heat.
You clearly have never used a car like that. You develop muscle memory for where the pedal is - finding that the pedal is not where it used to be does not inspire much confidence.
Every other manufacturer has managed to control regen breaking via throttle modulation - even ICE hybrid cars have been doing that for ages.
I've used left-foot-braking in my (ICE-powered) daily driver for years.
Regenerative braking is very different to taking your foot off the accelerator in a conventional ICE car, it's much more powerful a stopping force than traditional engine-braking.
I understand the rationale for moving the pedal to illustrate the amount of "braking" force. I'll admit I'm not exactly a typical driver though.
Why not move the gas pedal too, when using cruise control then?
If you push the gas pedal, you'd expect to go faster, wouldn't you?
The equilibrium of "good enough vs technological simplicity" for cars was probably reached in the 1950s. Everything after that was more or less solving "non-issues" with ever-increasing complexity ;)
And why had that cars be to be refueled in pharmacies?
https://de.wikipedia.org/wiki/Datei:Wiesloch_Stadtapotheke_E...
Great, they finally started mass-producing 19th century technology, let's cheer that! Nowadays, while Chinese and Americans are producing GPUs, AI and li-ion batteries, German high-tech is an engine invented by Faraday