5 ms·

YASA beats own power density record pushing electric motor to 59kW/kg benchmark

83 points by breve 1y ago

pinkmuffinere 1y ago
> The motor’s performance on the dyno has exceeded even our most optimistic simulations Not to take away from the exciting achievement, but I always found comments like this kindof unusual. Really, it exceeded even your _most optimistic_ simulations? If the high end of your simulated performance was below what you actually measured, I am worried that your simulation is seriously neglecting something. I used to work in decent depth with three phase bldc motors, so I feel I can say with some authority that these things _can_ be simulated, and while real world data is hard to exactly predict, getting something outside of the predicted range would generally be interpreted as a sign that your simulation isn't so good. But maybe this is just marketing-speak, and their simulations are actually totally fine.
- dmitrygr 1y ago
  +1 I suspect that the marketing guy's eyes glazed over when the engineers tried to explain confidence intervals to him. He demanded a simple figure. They gave him the median projected value to make him go away. The tested value was above median projection and thus you get this wordspew.
  - yunnpp 1y ago
    > Make him go away Spoken like a true engineer.
- jacquesm 1y ago
  > and while real world data is hard to exactly predict, getting something outside of the predicted range would generally be interpreted as a sign that your simulation isn't so good Either that, or your measurements are inaccurate.
  - metalman 1y ago
    or, yasa is moving very quickly,and as they are breaking new ground in power density, the numbers are ridonkulous,completly and utterly insane, 30lb's peak over 1000hp,just having the thing not vaporise itself is an achivement, and so there is no actual way to simulate that, outside of rocket motors, which is kind of where they are at. bet the tire guys are shaking there heads
    - jacquesm 1y ago
      Extraordinary claims and all that. Of course you can simulate it. If you are this surprised by the outcome of an experimental setup the first thing you should do is distrust the data. Figure out where the discrepancy is. Fix it, re-run the simulation and the experiment until the two are in agreement. Then publish. The normal scientific reflex is not to hit the marketing guy and say 'we've got a winner, go write it up'.
    - estimator7292 1y ago
      The point is that at this level, you shouldn't just let some engineers go wild on a physical prototype without simulating it first. You sort of have to simulate it before building the real thing or you're likely to waste a ton of time and money. If they did simulate this design and it exceeded their expectations so much, either something is wrong with the simulation or some engineer worked some voodoo magic into the very late prototype stages.
- bouchard 1y ago
  Depends if you make overly conservative assumptions in your modeling...
  - Dylan16807 1y ago
    If you have simulations with varying levels of optimism, but all of them were too conservative, then you screwed up.
    - bouchard 1y ago
      Meh, depends what's the goal. Exceeding predicted performance is not a screw up, it's just providing a minimum guaranteed performance aka playing it safe (under promise, over deliver). Also, we don't know by how much the most optimistic predicions were exceeded. Makes for nice marketing ;)
- watersb 1y ago
  > I used to work in decent depth with three phase bldc motors, so I feel I can say with some authority that these things _can_ be simulated If I take it literally versus hyperbole and excitement, could there be uncertainty coming from the drive train design choices, system integration details?
  - pinkmuffinere 1y ago
    Sure, but that sort of uncertainty should only increase the range of values you see out of the simulation. You could say “efficiency may range from 60% to 80%, so the output torque will range from X to Y”. If the real result is bigger than Y, something has gone wrong in your modeling or assumptions
    - yetihehe 1y ago
      > something has gone wrong in your modeling or assumptions Maybe they used a "all our previous tests showed 95% of efficiency compared to simulation, so let's multiply all our results, including top efficiency by this". Then their newest motor had 97% efficiency comparing to previous model.
- AdrianB1 1y ago
  Is constant power a lot easier to predict than short term peaks?
- Snoozus 1y ago
  I suspect they correctly simulated everything. Then on the test stand they turned the dial to 11 and saw a number higher than the simulations. Probably not reliable at that power level, but fine for a record announcement.
- ZiiS 1y ago
  Corpo speek for the CTO ignored our suggested safety margins and ran it at higher power then we had simulated, but it didn't melt.
abdullahkhalids 1y ago
Is there a chart or table somewhere for this benchmark, so one can compare the performance of many different available motors?
Animats 1y ago
"short-term peak rating" Short-term peak ratings for electric motors are always huge. You can put in higher voltages up to arc-over. More interesting is sustained output. 1 minute, 10 minutes, 1 hour, continuous duty. That's all about how well it can get rid of heat. That's why electric motors have a "temperature rise" number on the data plate. That's the steady-state temperature increase from a cold start when run continuously at rated power.
- pinkmuffinere 1y ago
  To be fair, in some applications the short-term peak rating is an important metric in its own right. For example, robotics applications frequently will have high peak load, but much lower steady state load. Eg, a jumping robot will briefly need a ton of force when pushing against the ground and when landing, but in the middle there it won't be applying such high loads. Likewise for bringing appendages up to speed, or accelerating a car to some speed, etc. edit: After looking at your account, I see you are John Nagle, and I worry that I am confidently-incorrect here, lol. I'll leave the comment as-is because it is still my genuine belief, but feel free to correct me if I'm totally off!
  - knob 1y ago
    I always remember the cool falling bodies animation Animats had in /.
  - Animats 1y ago
    There's a series of limitations on peak motor torque. Motors usually hit the thermal limits first, but here are some of the other limits: A big problem with older permanent magnet motors was that too much current could produce a field strong enough to demagnetize the magnets. Supposedly this is is less of an issue in the cobalt-neodymium magnet era, because the coercivity of those alloys is so high. Then there's finding a pulsed current source to power the windings. Ultracapacitors are good for that. Then there's finding big enough semiconductors to switch the thing. This, too, has become much easier. It's amazing how much current you can put through modern power MOSFETs. Then there are mechanical limitations. At some point, something is going to bend from sheer torque. At some point below that, the windings will distort a little on each cycle and wear out. Applications for this include railguns, catapults, and electrically launched rollercoasters. Interestingly, they're all linear motors. (I haven't looked at this since the 1990s. The components needed are now far better and more available. Mostly as a spinoff of the electric car industry.)
imoverclocked 1y ago
In the low-tens of kg, I have to wonder if we will just start mass-producing a single motor and just change the driving electronics for different vehicles/applications. Eg: De-rating this motor via driving electronics for aviation to only produce 200hp would be interesting for experimental designs.
- jacquesm 1y ago
  Then you could use a smaller motor which would be lighter (important for aviation) and likely cheaper.
  - imoverclocked 1y ago
    Looking at the whole system might reveal a different answer though.
    - jacquesm 1y ago
      Highly unlikely, but since you make the claim I think you also should present that whole system evidence. From what little I know as a once upon a time bit player in aviation I suspect that that will be a very hard sell. For instance: I know of an invention that will spin up the wheels of a landing aircraft just before touchdown. This saves on the wear of the tires (right now it is mostly the runway that spins them up, as a result of which you see these nice rubber deposits on the touchdown areas). But it would add a few kg to the weight of the wheels so it's a complete non-starter.
      - imoverclocked 1y ago
        Let's look at the marketplace for aviation piston engines. We still see the Lycoming IO360 [1] and its variants installed in aircraft today. For reference it was first produced in 1955. That's >70 year old tech which produces ~200 hp depending on the version. It's used in myriad designs because it's certified and well known. It weighs around 260 lbs. (very hand wavy calculation...) that means we are looking at roughly .76 hp/lb or 1.28 kW/kg. Compare that to 59kW/kg of the article. Right now, the engine is generally the most expensive as well as the heaviest component in GA aircraft. If you are developing a new airplane, you are often choosing a motor to build the craft around. You would be a fool to choose something that is not tested because (almost) nobody wants to fly a new plane with a new motor. I'm guessing that the cost of one of these axial flux motors is well below $70k. I'll guess $2k... just for ease of numbers. Our motor is now 46x lighter/hp and 1/35 of the cost. This means we have a lot more flexibility in our aircraft design and our budget for materials/components has gone up, or our market has gotten wider. The biggest hurdle now is to overcome the "unknown engine" which is possible when the exact motor has been mass-produced and mass-used in other sectors. By using this and not painting your design into a corner by relying on the absolute lightest motor you can get, you leave room for future designs in the same space. ie: you have set yourself up to produce the next Cessna 172. There are additional reasons to want a motor that is 200 hp or less which are written in FARs in the US and copied by other countries. Also, wanting a motor that is more than 200 hp is desirable for other use-cases. By having one motor that can fill both spaces you now have (waves hands) twice the reputation building power. Of course, there are other technical considerations such as energy storage/weight but the field is so wide that a book could be written on making comparisons. The technical landscape is also actively changing. [1] https://en.wikipedia.org/wiki/Lycoming_O-360 https://en.wikipedia.org/wiki/Lycoming_O-360
rcpt 1y ago
It's just amazing how over the past 10 years it's like the whole world rediscovered electricity.
- epistasis 1y ago
  What always shocked me were the number of tech-oriented people that were are not aware of the tremendous progress in lithium ion batteries. And not just in the cost, performance, and reduction in materials needed. Production capacity grows by 10x in a mere five years. We were at 1.2TWh of production in 2024, and will be at ~20TWh in 2030. When batteries are eventually recycled, they get recycled into a higher power capacity than went in because recovery of materials is high and gains in production are even higher. The global average cost of solar panels is $90/kW. With high tariffs, it's $150/kW in India and $270/kW in the US. Raising tariffs is something like 6 months of price drops. (Meanwhile installed, it costs $500-$3000 on residential properties...) Solar and storage are some of the most impressive technologies of the past century, and so many people are sleeping on the huge changes it will have.
  - AdrianB1 1y ago
    I think these days the solar panels and even batteries are quite cheap, but the equipment needed build a hybrid system for a house is still a mess. One can find the right inverter, but not a good match for the battery, the backup/switching system that needs to match, DC fuse boxes, especially for European systems that are 230V and sometimes 3-phase, the progress is not good enough even if the problem is simple enough.
  - stavros 1y ago
    And yet my VTC-6 are still the same capacity as five years ago :(
    - epistasis 1y ago
      hah, well it appears that the capacity may be part of the standardization for that?
AdrianB1 1y ago
The weight and form factor looks excellent for small propeller planes. Yes, batteries are heavy, but the lightweight of the motor makes room for more batteries. A typical Rotax 912 with accessories goes over 55 kg for 80 HP max and ~ 60 HP cruise. The 100 HP/75 HP version is around 65 kg. The same continuous power with this technology looks like a 5 kg motor and 60 kg of batteries for a direct replacement, if we consider the regular fuel tanks of 50-100 kg on some planes (I used to fly a plane that took 140 liters of fuel with a 100 HP Rotax, but it was modified) then there is enough battery for a flight school needs.
- plantain 1y ago
  The future is here - https://www.pipistrel-aircraft.com/products/velis-electro/ https://www.pipistrel-aircraft.com/products/velis-electro/ Seeing these pop up at a lot of flying schools for basic training.
- t43562 1y ago
  https://evolito.aero/electra-selects-evolito-to-supply-electric-engines/ https://evolito.aero/electra-selects-evolito-to-supply-elect... This is a spin-off company from YASA whose purpose is to supply them for aircraft together with other bits. The world speed record for electric aircraft is held by an aircraft with 3 YASA motors: https://www.youtube.com/watch?v=4hapBP-Cdis&t=418s&pp=0gcJCdcCDuyUWbzu https://www.youtube.com/watch?v=4hapBP-Cdis&t=418s&pp=0gcJCd...
aidenn0 1y ago
At what point can we just return to 1990s wheel sizes, add the motor to the wheel, and have the same unsprung mass as we have with today's gigantic wheels?
- bruce511 1y ago
  Putting the motor in the wheel does have some performance and space advantages. It is being done in some vehicles today. However it does have some limitations as well. For the "general case" it may not be ideal. Top of the list is protection. The motor is an expensive part, the wheel is an exposed part - bumping a curb for example could get expensive quickly. Cooling is also an issue. In-wheel motors suggest air cooling, whereas a bigger (single) motor can be liquid cooled. Currently in wheel motors end up being quite a bit more expensive (because 4 motors not 1). On paper, in-wheel motors save space, allow for concepts like "4 wheel drive with different lock", save weight and cleaner design (no drive shafts etc), but it's not clear that the end product is better for "every day" users.
- aitchnyu 1y ago
  I want rear wheel steering with 7m turning radius, 4m cars to have same cabin space as 4.5m ICE cars, seats in last row of a 3-row not constrained why wheel wells and axles as an Indian on congested roads. 160 HP is dangerous enough.
- thenewwazoo 1y ago
  As soon as the roads are as smooth as they were in the 90s. I have a pet theory that wheels have gotten huge partly in response to deteriorating roads - larger diameter means less leverage against the suspension when hitting defects. It’s the same reason dirt bikes have large front wheels.
  - qingcharles 1y ago
    The aspect ratio (sidewall height) of tires has decreased in a lot of vehicles though. They are driving around with low profile rubber bands on the rims. Looks cool, but not much fun in the potholed mid-west.
stx5 1y ago
Is this from a lab or a production unit? Because if it's just lab results, they don't really mean anything.
watersb 1y ago
Our Chevy Bolt EV has a real-time display of... something, a number in units of kW. I presume it's approximate instantaneous battery discharge rate. Anyhow, I rarely see more than 35 kW indicated for less than a minute at a time. So can I get my 59kW/kg to go, please? I will take two kilograms.
- aidenn0 1y ago
  FWIW: You have: 59kW You want: horsepower * 79.120303 / 0.012638981
jiehong 1y ago
Does that translate well in reverse? If the engine is spun to produce electricity, does that make it any different?
mrlonglong 1y ago
What amps and at what voltage did they push into the motor? These look small enough to use as the wheels. Just like that Audi that Will Smith drove in the film I, Robot.
kibwen 1y ago
> weighed 28.8 pounds, and achieved a peak power of 550 kilowatts How well does this scale down? Can I have a 550 watt motor that's 1/1000th the size and that weighs 0.0288 pounds? Would be nifty to have an e-bike without any visible motor.

83 points by breve 1y ago

> The motor’s performance on the dyno has exceeded even our most optimistic simulations Not to take away from the exciting achievement, but I always found comments like this kindof unusual. Really, it exceeded even your _most optimistic_ simulations? If the high end of your simulated performance was below what you actually measured, I am worried that your simulation is seriously neglecting something. I used to work in decent depth with three phase bldc motors, so I feel I can say with some authority that these things _can_ be simulated, and while real world data is hard to exactly predict, getting something outside of the predicted range would generally be interpreted as a sign that your simulation isn't so good. But maybe this is just marketing-speak, and their simulations are actually totally fine.

dmitrygr 1y ago
+1 I suspect that the marketing guy's eyes glazed over when the engineers tried to explain confidence intervals to him. He demanded a simple figure. They gave him the median projected value to make him go away. The tested value was above median projection and thus you get this wordspew.
- yunnpp 1y ago
  > Make him go away Spoken like a true engineer.
jacquesm 1y ago
> and while real world data is hard to exactly predict, getting something outside of the predicted range would generally be interpreted as a sign that your simulation isn't so good Either that, or your measurements are inaccurate.
- metalman 1y ago
  or, yasa is moving very quickly,and as they are breaking new ground in power density, the numbers are ridonkulous,completly and utterly insane, 30lb's peak over 1000hp,just having the thing not vaporise itself is an achivement, and so there is no actual way to simulate that, outside of rocket motors, which is kind of where they are at. bet the tire guys are shaking there heads
  - jacquesm 1y ago
    Extraordinary claims and all that. Of course you can simulate it. If you are this surprised by the outcome of an experimental setup the first thing you should do is distrust the data. Figure out where the discrepancy is. Fix it, re-run the simulation and the experiment until the two are in agreement. Then publish. The normal scientific reflex is not to hit the marketing guy and say 'we've got a winner, go write it up'.
  - estimator7292 1y ago
    The point is that at this level, you shouldn't just let some engineers go wild on a physical prototype without simulating it first. You sort of have to simulate it before building the real thing or you're likely to waste a ton of time and money. If they did simulate this design and it exceeded their expectations so much, either something is wrong with the simulation or some engineer worked some voodoo magic into the very late prototype stages.
bouchard 1y ago
Depends if you make overly conservative assumptions in your modeling...
- Dylan16807 1y ago
  If you have simulations with varying levels of optimism, but all of them were too conservative, then you screwed up.
  - bouchard 1y ago
    Meh, depends what's the goal. Exceeding predicted performance is not a screw up, it's just providing a minimum guaranteed performance aka playing it safe (under promise, over deliver). Also, we don't know by how much the most optimistic predicions were exceeded. Makes for nice marketing ;)
watersb 1y ago
> I used to work in decent depth with three phase bldc motors, so I feel I can say with some authority that these things _can_ be simulated If I take it literally versus hyperbole and excitement, could there be uncertainty coming from the drive train design choices, system integration details?
- pinkmuffinere 1y ago
  Sure, but that sort of uncertainty should only increase the range of values you see out of the simulation. You could say “efficiency may range from 60% to 80%, so the output torque will range from X to Y”. If the real result is bigger than Y, something has gone wrong in your modeling or assumptions
  - yetihehe 1y ago
    > something has gone wrong in your modeling or assumptions Maybe they used a "all our previous tests showed 95% of efficiency compared to simulation, so let's multiply all our results, including top efficiency by this". Then their newest motor had 97% efficiency comparing to previous model.
AdrianB1 1y ago
Is constant power a lot easier to predict than short term peaks?
Snoozus 1y ago
I suspect they correctly simulated everything. Then on the test stand they turned the dial to 11 and saw a number higher than the simulations. Probably not reliable at that power level, but fine for a record announcement.
ZiiS 1y ago
Corpo speek for the CTO ignored our suggested safety margins and ran it at higher power then we had simulated, but it didn't melt.

abdullahkhalids 1y ago

Is there a chart or table somewhere for this benchmark, so one can compare the performance of many different available motors?

Animats 1y ago

"short-term peak rating" Short-term peak ratings for electric motors are always huge. You can put in higher voltages up to arc-over. More interesting is sustained output. 1 minute, 10 minutes, 1 hour, continuous duty. That's all about how well it can get rid of heat. That's why electric motors have a "temperature rise" number on the data plate. That's the steady-state temperature increase from a cold start when run continuously at rated power.

pinkmuffinere 1y ago
To be fair, in some applications the short-term peak rating is an important metric in its own right. For example, robotics applications frequently will have high peak load, but much lower steady state load. Eg, a jumping robot will briefly need a ton of force when pushing against the ground and when landing, but in the middle there it won't be applying such high loads. Likewise for bringing appendages up to speed, or accelerating a car to some speed, etc. edit: After looking at your account, I see you are John Nagle, and I worry that I am confidently-incorrect here, lol. I'll leave the comment as-is because it is still my genuine belief, but feel free to correct me if I'm totally off!
- knob 1y ago
  I always remember the cool falling bodies animation Animats had in /.
- Animats 1y ago
  There's a series of limitations on peak motor torque. Motors usually hit the thermal limits first, but here are some of the other limits: A big problem with older permanent magnet motors was that too much current could produce a field strong enough to demagnetize the magnets. Supposedly this is is less of an issue in the cobalt-neodymium magnet era, because the coercivity of those alloys is so high. Then there's finding a pulsed current source to power the windings. Ultracapacitors are good for that. Then there's finding big enough semiconductors to switch the thing. This, too, has become much easier. It's amazing how much current you can put through modern power MOSFETs. Then there are mechanical limitations. At some point, something is going to bend from sheer torque. At some point below that, the windings will distort a little on each cycle and wear out. Applications for this include railguns, catapults, and electrically launched rollercoasters. Interestingly, they're all linear motors. (I haven't looked at this since the 1990s. The components needed are now far better and more available. Mostly as a spinoff of the electric car industry.)

imoverclocked 1y ago

In the low-tens of kg, I have to wonder if we will just start mass-producing a single motor and just change the driving electronics for different vehicles/applications. Eg: De-rating this motor via driving electronics for aviation to only produce 200hp would be interesting for experimental designs.

jacquesm 1y ago
Then you could use a smaller motor which would be lighter (important for aviation) and likely cheaper.
- imoverclocked 1y ago
  Looking at the whole system might reveal a different answer though.
  - jacquesm 1y ago
    Highly unlikely, but since you make the claim I think you also should present that whole system evidence. From what little I know as a once upon a time bit player in aviation I suspect that that will be a very hard sell. For instance: I know of an invention that will spin up the wheels of a landing aircraft just before touchdown. This saves on the wear of the tires (right now it is mostly the runway that spins them up, as a result of which you see these nice rubber deposits on the touchdown areas). But it would add a few kg to the weight of the wheels so it's a complete non-starter.
    - imoverclocked 1y ago
      Let's look at the marketplace for aviation piston engines. We still see the Lycoming IO360 [1] and its variants installed in aircraft today. For reference it was first produced in 1955. That's >70 year old tech which produces ~200 hp depending on the version. It's used in myriad designs because it's certified and well known. It weighs around 260 lbs. (very hand wavy calculation...) that means we are looking at roughly .76 hp/lb or 1.28 kW/kg. Compare that to 59kW/kg of the article. Right now, the engine is generally the most expensive as well as the heaviest component in GA aircraft. If you are developing a new airplane, you are often choosing a motor to build the craft around. You would be a fool to choose something that is not tested because (almost) nobody wants to fly a new plane with a new motor. I'm guessing that the cost of one of these axial flux motors is well below $70k. I'll guess $2k... just for ease of numbers. Our motor is now 46x lighter/hp and 1/35 of the cost. This means we have a lot more flexibility in our aircraft design and our budget for materials/components has gone up, or our market has gotten wider. The biggest hurdle now is to overcome the "unknown engine" which is possible when the exact motor has been mass-produced and mass-used in other sectors. By using this and not painting your design into a corner by relying on the absolute lightest motor you can get, you leave room for future designs in the same space. ie: you have set yourself up to produce the next Cessna 172. There are additional reasons to want a motor that is 200 hp or less which are written in FARs in the US and copied by other countries. Also, wanting a motor that is more than 200 hp is desirable for other use-cases. By having one motor that can fill both spaces you now have (waves hands) twice the reputation building power. Of course, there are other technical considerations such as energy storage/weight but the field is so wide that a book could be written on making comparisons. The technical landscape is also actively changing. [1] https://en.wikipedia.org/wiki/Lycoming_O-360 https://en.wikipedia.org/wiki/Lycoming_O-360

rcpt 1y ago

It's just amazing how over the past 10 years it's like the whole world rediscovered electricity.

epistasis 1y ago
What always shocked me were the number of tech-oriented people that were are not aware of the tremendous progress in lithium ion batteries. And not just in the cost, performance, and reduction in materials needed. Production capacity grows by 10x in a mere five years. We were at 1.2TWh of production in 2024, and will be at ~20TWh in 2030. When batteries are eventually recycled, they get recycled into a higher power capacity than went in because recovery of materials is high and gains in production are even higher. The global average cost of solar panels is $90/kW. With high tariffs, it's $150/kW in India and $270/kW in the US. Raising tariffs is something like 6 months of price drops. (Meanwhile installed, it costs $500-$3000 on residential properties...) Solar and storage are some of the most impressive technologies of the past century, and so many people are sleeping on the huge changes it will have.
- AdrianB1 1y ago
  I think these days the solar panels and even batteries are quite cheap, but the equipment needed build a hybrid system for a house is still a mess. One can find the right inverter, but not a good match for the battery, the backup/switching system that needs to match, DC fuse boxes, especially for European systems that are 230V and sometimes 3-phase, the progress is not good enough even if the problem is simple enough.
- stavros 1y ago
  And yet my VTC-6 are still the same capacity as five years ago :(
  - epistasis 1y ago
    hah, well it appears that the capacity may be part of the standardization for that?

AdrianB1 1y ago

The weight and form factor looks excellent for small propeller planes. Yes, batteries are heavy, but the lightweight of the motor makes room for more batteries. A typical Rotax 912 with accessories goes over 55 kg for 80 HP max and ~ 60 HP cruise. The 100 HP/75 HP version is around 65 kg. The same continuous power with this technology looks like a 5 kg motor and 60 kg of batteries for a direct replacement, if we consider the regular fuel tanks of 50-100 kg on some planes (I used to fly a plane that took 140 liters of fuel with a 100 HP Rotax, but it was modified) then there is enough battery for a flight school needs.

plantain 1y ago
The future is here - https://www.pipistrel-aircraft.com/products/velis-electro/ https://www.pipistrel-aircraft.com/products/velis-electro/ Seeing these pop up at a lot of flying schools for basic training.
t43562 1y ago
https://evolito.aero/electra-selects-evolito-to-supply-electric-engines/ https://evolito.aero/electra-selects-evolito-to-supply-elect... This is a spin-off company from YASA whose purpose is to supply them for aircraft together with other bits. The world speed record for electric aircraft is held by an aircraft with 3 YASA motors: https://www.youtube.com/watch?v=4hapBP-Cdis&t=418s&pp=0gcJCdcCDuyUWbzu https://www.youtube.com/watch?v=4hapBP-Cdis&t=418s&pp=0gcJCd...

aidenn0 1y ago

At what point can we just return to 1990s wheel sizes, add the motor to the wheel, and have the same unsprung mass as we have with today's gigantic wheels?

bruce511 1y ago
Putting the motor in the wheel does have some performance and space advantages. It is being done in some vehicles today. However it does have some limitations as well. For the "general case" it may not be ideal. Top of the list is protection. The motor is an expensive part, the wheel is an exposed part - bumping a curb for example could get expensive quickly. Cooling is also an issue. In-wheel motors suggest air cooling, whereas a bigger (single) motor can be liquid cooled. Currently in wheel motors end up being quite a bit more expensive (because 4 motors not 1). On paper, in-wheel motors save space, allow for concepts like "4 wheel drive with different lock", save weight and cleaner design (no drive shafts etc), but it's not clear that the end product is better for "every day" users.
aitchnyu 1y ago
I want rear wheel steering with 7m turning radius, 4m cars to have same cabin space as 4.5m ICE cars, seats in last row of a 3-row not constrained why wheel wells and axles as an Indian on congested roads. 160 HP is dangerous enough.
thenewwazoo 1y ago
As soon as the roads are as smooth as they were in the 90s. I have a pet theory that wheels have gotten huge partly in response to deteriorating roads - larger diameter means less leverage against the suspension when hitting defects. It’s the same reason dirt bikes have large front wheels.
- qingcharles 1y ago
  The aspect ratio (sidewall height) of tires has decreased in a lot of vehicles though. They are driving around with low profile rubber bands on the rims. Looks cool, but not much fun in the potholed mid-west.

stx5 1y ago

Is this from a lab or a production unit? Because if it's just lab results, they don't really mean anything.

watersb 1y ago

Our Chevy Bolt EV has a real-time display of... something, a number in units of kW. I presume it's approximate instantaneous battery discharge rate. Anyhow, I rarely see more than 35 kW indicated for less than a minute at a time. So can I get my 59kW/kg to go, please? I will take two kilograms.

aidenn0 1y ago
FWIW: You have: 59kW You want: horsepower * 79.120303 / 0.012638981

jiehong 1y ago

Does that translate well in reverse? If the engine is spun to produce electricity, does that make it any different?

mrlonglong 1y ago

What amps and at what voltage did they push into the motor? These look small enough to use as the wheels. Just like that Audi that Will Smith drove in the film I, Robot.

kibwen 1y ago

> weighed 28.8 pounds, and achieved a peak power of 550 kilowatts How well does this scale down? Can I have a 550 watt motor that's 1/1000th the size and that weighs 0.0288 pounds? Would be nifty to have an e-bike without any visible motor.