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Comment by lifeisstillgood | Hacker News Reader

One of the photos really brought something home to me. Where I would expect to see an axle or something to provide torque to wheels from the engine, there is just a yellow wire.

I know that's how electric cars work. But something about it in the racing car context just brings it home to me - electricity just works differently to all our other intuitions about the world. Factories used to have bands and axels taking power from one central steam engine to all corners of the building. And then they got redesigned once electricity came in.

I got a gut realisation from that photo that something similar is / has happened.

I like to emphasise using "boring tech" at work to avoid chasing too many rainbows. But sometimes there is a pot of gold and I need to remember that, else my factory will remain steam powered.

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The "instant" torque provided by electric motors compared to traditional IC/drivetrain systems is really sexy, but what is perhaps more useful is the vastly quicker power modulation that is possible with electric systems.

Electric cars can manage traction control so much more precisely that they can do seemingly impossible things. This snow climb comparison between various Audis - IC and electric, demonstrated that electric traction control could easily manage low friction scenarios which seem unimaginable. https://www.youtube.com/watch?v=HJRRvHlvhAI

Even in mid range tech this is true. My fricken KIA of all things (EV6) has AWD and a ‘snow mode’ that is fucking magic.

Climbing an iced over driveway on a hill in Utah on vacation while $90k big ass trucks were abandoned at the foot of the hill was awesome.

I’ve had some very high end 4x4’s in my time and none of them could climb, stop or accelerate like this $50k hot hatch.

The instant response to all 4 wheels being updated at kilohertz is a whole other paradigm.

> Factories used to have bands and axels taking power from one central steam engine to all corners of the building.

From my own experience: a popular home woodworker tool from the middle of the 20th century is a Shop Smith. It had a motor that you would couple to the various mounted attachments to run the lathe or the band saw or the table saw etc one tool at a time. I guess part of the appeal was certainly the size savings, but I have to think it was also only having to buy one electric motor. Life changingly good motors are now commodity parts, and artisanally crafted ones are setting acceleration world records. Cool time to be alive.

Tractors, still widely used today, as essentially a mobile version of this.

One of the main purposes of a tractor, compared to other farm vehicles, is that it has a power take-off [0] to enable the engine to drive other farm implements like combines.

[0]: https://en.wikipedia.org/wiki/Power_take-off

I've never actually thought about what a tractor actually is. I've seen them in use and could roughly describe one but its actual purpose or intent was unknown to me until now.

Easily one of the most dangerous bit of farm equipment. I’ve seen several people killed by getting their hand/arm in a PTO shaft.

You might be the only person on the planet who's witnessed several of those, if you mean first-hand.

They're still incredibly dangerous. Even with all the safety guards you've got 50-300hp being directed to a free-space shaft.

When we got a mower we went with a flail mower because we'd be mowing near neighbors and a bush hog(giant lawnmower blade style mower) will happily pick up a rock and send it with enough force to easily kill someone at a good distance. Flails tend to throw less things(which is why highway maintenance use them for mowing along the road).

Early tractor PTOs where especially, um, fun. No built-in overrunning clutch and no "live" PTO means the inertia of spinning implements could turn the PTO, and thus the drive wheels. Nothing like standing on the brakes while the tractor just...keeps going for a few feet.

Fortunately overrunning clutch attachments are cheap to add.

I'm a paramedic in a rural area. I didn't witness the initial events, only the aftermath.

that's actually a great point! In all of those cases the weight and breakdownability of having another motor in the tool attached to the tractor seems like a real hassle compared to a PTO.

Kind of. This team is specifically using hub motors, thus bypassing the need for traditional axles. Hub motors are notoriously inefficient, though, so you don’t see them in normal BEVs which typically mount the motors near the center of the axle (as part of an “e-axle”). Basically, this team’s car is purpose built only for acceleration and thus gets away with doing things you wouldn’t see in cars that need to maintain speed or drive efficiently. Great ingenuity by them!

They needn't be inefficient, as demonstrated by their use in the hyper efficient Lightyear0 solar powered car. But they do have plenty downsides [1].

[1] https://evcentral.com.au/why-dont-evs-have-four-in-wheel-mot...

YES

The use of hub motors is probably best when acceleration is paramount, but when handling starts to come into play (e.g., on road courses), it is likely best to bring the motors inboard and spend the extra weight and complexity of axles, as the unsprung weight outboard of the suspension is a serious detriment to handling.

> Factories used to have bands and axels taking power from one central steam engine to all corners of the building. And then they got redesigned once electricity came in.

Fascinating fact you might enjoy: many modern industrial facilities use compressed air to power many of the devices inside.

At a lot of Amazon facilities, a main compressor is somewhere on site keeping a large tank full. The compressed air is piped throughout the facility[0], and used to power a lot of moving parts in an open loop, making a distinctive 'hiss' sound[1] as the device moves and releases air. Not everything, certainly, but a lot of simple devices that need to move quickly and with some force.

It's all computer controlled and yes, electricity is a major part- but the driving force is coming from compressed air. And that's pretty neat.

[0] (Or so it was explained to me by the controls tech guys there)

[1] https://www.youtube.com/watch?v=Y5Hf08XrI_A (the first 30 seconds or so it's really noticeable).

Yeah, they've taken the "distribute mechanical work" part out of the process.

It's amazing that all those car cylinders going up and down (or technically, being forced up and down by tiny explosions) are transformed into work.

Rotary motion -> work has been part of humanity for a long time. I suppose in our space-bound future it won't be a big factor

Except as artificial gravity or pumps or geared robotic arms or automatic doors or … I think we’ll have rotary motion for some time to come.

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