Can we have more mechanical posts like this?
Behold The Hyundai Uni Wheel. Transportation May Never Be The Same
Submitted 11 months ago by floofloof@lemmy.ca to technology@lemmy.world
Comments
luthis@lemmy.nz 11 months ago
Maalus@lemmy.world 11 months ago
No, you need 555 posts about the shit that a billionaire said about stuff he knows nothing about
StereoTrespasser@lemmy.world 11 months ago
And then someone saying something about Linux
Joelk111@lemmy.world 11 months ago
On Monday I’m going to tell my boss to fuck off. He isn’t going to blackmail me into doing high quality work with money. Honestly, fuck off.
machinin@lemmy.world 11 months ago
Be the change you want to see!!
Mango@lemmy.world 10 months ago
A new mechanical motion is a seriously big deal and doesn’t happen often.
blanketswithsmallpox@lemmy.world 11 months ago
This requires educated users in their professions to read the news and share it to the public for free when not being paid.
XeroxCool@lemmy.world 11 months ago
There’s 2 significant inaccuracies in the article and 1 large oversight in the official video.
- Differentials are not one wheel drive. They can seem to drive only one wheel when spinning the wheels as one let’s loose and the other stays still, but it’s not driving one wheel. It’s still driving both. The problem is the free wheel is spinning at twice the speed indicated on the speedometer and the other is at 0. The driveshaft puts in a certain number of turns, the wheels, together, must add up to an equal output (multiplied by the gear ratio). If the car is going straight with full traction, then they turn the same. If you floor it in snow, one is probably spinning 40% over it’s share and the other 40% under. This is not unique to rwd either as fwd cars still very much have a functioning differential. To throw some numbers at it to help clarify the function, let’s say the engine is asking the wheels to spin at 30rpm each in a straight line. In a left turn, the right wheel travels further and needs to spin at 35rpm while the inner spins at 25rpm. It still adds up to 60rpm, same as a straight line. Mash it in the snow and it might be 60rpm in the left and 0nin the right or 0 in the left and 60 in the left. It could be 5/55, 40/20, or any other combo as long as it totals 60.
PS: differentials are irrelevant when the wheels aren’t connected to each other. Individual-motor wheels, as shown in the video, don’t need a diff. The non-drive wheels in a 2-wheel drive vehicle do not have a differential on the non-drive axle.
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Cv joints are not specific to fwd as nearly all modern rwd cars with independent rear suspensions have CV joints. I don’t know of any trucks still using U-joints either since big trucks are solid axle. Cv joints function the same as U joints. The difference is C.V. joints output constant velocity whereas U-joints (what you’ll see often under trucks on the driveshaft, two square C shaft ends with an X link between) have lopey output that gets worse with greater deflection angle. If you own a u-joint bit for your socket wrench, I invite you to play with it. Instead of a solid pinned X between the U ends, CVs have free-rolling balls that can roll inboard and outboard to maintain the link between the shaft’s cup and the wheel’s cone.
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The article is inaccurate but the video ignores this part, so I don’t fault The writer. The CV joints are said to be a poor design, yet, it ignores the part where the video reinstalls them at 4:20 and 5:10 for the front wheels. This mechanism does not allow angular deflection between the motor and hub, as it’s shown, without a CV joint. Lateral displacement, yes, but not angular - as in it can’t steer. This may be an overall improvement by reducing how often it needs to bend (only when steering), but it doesn’t eliminate it. And even then, the rear suspension is still designed to change camber as it changes ride height. Camber is the angle of the wheel as measured top to bottom, as in what you see from looking at the wheels from the front of the car. It keeps the wheels flat on the ground as you lean the car in a corner. You may see an overloaded car’s rear wheels look like /—\ as viewed from the rear or -–/ when hanging free on a lift.
Look, I’m not an engineer at Hyundai (or even a competitor) but this doesn’t quite pass the sniff test. Cool idea for sure, but it smells a little like marketing is clamoring for something edgy to display. Even as displayed, the motors and original reduces were already very compact and in close proximity to the wheels compared to a normal engine. The slightly reduced footprint of this uni wheel and slightly increased friction of a bunch of additional gears makes me think this is a fractional improvement in practice rather than a revolutionary improvement.
OhmsLawn@lemmy.world 11 months ago
I’d be concerned with the amount of unsprung weight this adds, too. You’re basically taking the transmission and adding that mass to the hub. Seems like it would be pretty crashy on rough surfaces.
XeroxCool@lemmy.world 11 months ago
I considered that but couldn’t make any conclusions. The driveshaft and sun gear are not added to the unsprung. I’d guess only half the weight of planets and carriers is added. It definitely adds the weight of the ring gear to both the unsprung mass.
I’m also curious how this affects rotational mass. So while every component spinning with the wheel from tire to motor shaft has rotational inertia, small-diameter components such as drive shafts have relatively little rotational inertia. Wheels and even brake discs have a lot more. I don’t have numbers obviously but I’m curious if the rotational mass of the ring gear ends up being detrimental compared to a heavier-weight lower-inertia cv setup.
BearOfaTime@lemm.ee 11 months ago
Yep.
Trucks used these as far back as pre-WWII. It a great solution for off road vehicles to gain clearance. At low speeds, even universal joints work fine for this setup, because the shaft rotates at 1/3 wheel speed, like a drives haft does going into a differential.
This puts a diff at each wheel.
agent_flounder@lemmy.world 11 months ago
I noticed they conveniently didn’t talk a lot about steering…
The claim of “one wheel drive” I think is meant to highlight what happens if traction is lost. It sounds like something I have heard on 4wd off-road forums. I agree the phrase “one wheel drive” is perhaps not a great way to explain the disadvantages of differentials vs limited slip differentials vs locking differentials vs individually driven wheels.
The idea of “one wheel drive” as I have seen it used, is that in a vehicle with one powered axle assembly (what we normally call 2wd-- either front or rear wheel drive) is that if you lose traction with either drive wheel, the vehicle no longer moves because all power is diverted to the slipping wheel.
If you have a limited slip differential, there is a limit to how much power is diverted to the slipping wheel. With a locking differential, you only stop moving if you lose traction to both drive wheels.
Anyway…
The design is really interesting.
You also bring up a good point about how camber changes with suspension position. Also the effective track width changes, such as with my 4Runner which has upper and lower control arms, a Double wishbone suspension. If the motor remains in a fixed position, the wheel will move onboard and outboard relative to the motor depending on suspension location.
I don’t quite get how these two effects are addressed with this new design. Or are the suggesting a different suspension technology that they didn’t discuss?
As for steering, I wonder if the design rotates the motor along with the wheel. In that case no CV is needed but I would guess there are some downsides to such a design.
I agree the video seems kind of… premature. The mechanism is cool but I don’t get the sense that its applications haven’t exactly been nailed down yet.
XeroxCool@lemmy.world 11 months ago
Individual motors on each wheel will still slip, just with half the power. So sure, it’s an improvement by an unrelated mechanism, but not having the wheels connected with a limited slip means it’ll still need a traction control system. And even still, the “half” power is a relative term because every car has a different output. That goes for not connecting left to right as much as it goes for front to back. So, not different than a traditional open diff or 2wd. There have been advances in brake-based traction control so they don’t just cut power and apply single brakes like the 00s, they can properly modulate pressure to get equal propulsion.
That’s a good point you’ve mentioned as well - the wheel will change distance to the motor as it goes through it’s motions. The only way to avoid that is to place the motor at the effective pivot point of the suspension which is, in a properly design suspension, inside the other wheel to mimic the level dynamics of a solid axle. That of course defeats the short halfshaft design direction. So something has to allow variation in distance. In the non-steer wheels, maybe this could be as simple as a telescoping spline drive. However, the video shows a small black joint at the same time stamps above on the rear and still has those normal-looking cv boots on the fronts.
Or maybe they’re ditching good handling and going with perfectly vertical suspension travel. Give it hard eco tires and it’ll slide before the suspension shows it’s flaws.
trash80@lemmy.dbzer0.com 11 months ago
This mechanism does not allow angular deflection between the motor and hub, as it’s shown, without a CV joint. Lateral displacement, yes, but not angular - as in it can’t steer.
The axis of the motor doesn’t need to be parallel to the axis of the wheel.
If the axis of the motor is vertical, you could use a ring and pinion gear to transfer the torque to the driveshaft running out to the wheel, and have the steering wheels pivot around the axis of the motor.
XeroxCool@lemmy.world 11 months ago
The steering wheels’ hubs rotate in two directions. The steering action rotates through a vertical axis while the typical suspension rotates in a front-to-back axis pinned approximately through the other side of the car. So unless they abandoned common suspension design to let tires lean in turns more than a reasonable amount, there needs to be an allowance for angular deflection. A pinion gear arrangement sounds like it would take up a lot of the space they’re trying to save but still not solve the multi-axis problem found at all 4 wheels. I’m trying to not take their video so literally but it’s not like it’s a dealership rep spouting incomplete info here
dubble_deee@lemmy.world 11 months ago
Unrelated comment, but holy shit I am a huge fan of the M8. So wild to see you on Lemmy, and this comment section is exactly what I’m here for.
BearOfaTime@lemm.ee 11 months ago
But you need a CV or Universal on that drive shaft to accommodate suspension travel (or steering if needed on that wheel).
barsoap@lemm.ee 11 months ago
With how small the motor is you could also pivot it alongside with the wheel, after all, something pivoting with the wheel doesn’t mean that it has to be unsprung.
ColeSloth@discuss.tchncs.de 11 months ago
- You are sort of correct about this, but it’s irrelevant since everyone moved onto limited slips decades ago.
As to the rest- you’re wrong. Sorry.
But the real reason this tech won’t be very important is because it’s a lot more complicated and expensive than a cheap ass cv joint and is minimally more efficient. I can buy both sides of my vehicle for like $80 and don’t have to worry about em again for ages. I think this new hyundai stuff could be reliable, but it’s going to be a lot more expensive.
Also, they look like they’d be noisy.
XeroxCool@lemmy.world 11 months ago
you’re wrong. Sorry.
No u. Bam, same level argument right there. Are you going to explain why or just throw out contrarian comments?
Cost will not be a limiting factor. Just about every feature on a 2023 car already costs more than a 1993 car’s version. Did adding a wheelspeed sensor, electronic 4-channel hydraulic brake actuator, and dedicated ecm programming cost too much to implement ABS? Did the complication of 40 sensors (100+ now) and a voodoo box of electronics cost too much to go efi instead of carbs? Did the price of disc brakes stop most cars from ditching rear drums? Did the cost of engineering and testing prevent manufacturers from implementing the following nearly-negligible aero improvements to eek out another 0.1% of fuel efficiency;
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aero strakes into mirror shells (prius, escape)
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relaminating roof spoilers into every hatchback/suv and even into every pickup bed
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Vortex generators on the top surface of tail lights (sonata, chr)
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Active grille shutters (fusion)
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Full underbody trays
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Chin spoilers (splitters) on just about every car to keep air out from underneath
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Hood beak splitters to keep grille air off the canopy (Volvo, accord)
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Short antennas/glass-embedded antennas to reduce antenna drag
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Front fender outlet vents to create laminar flow over the wheels (f150 2015+)
No, it didn’t.
And I’d be interested to hear why you think helical-cut gears will be “noisy”. I’m guessing you don’t know why reverse whines in certain cars but not the forward gears
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Joelk111@lemmy.world 11 months ago
Everyone moved onto limited slips decades ago.
Lol, what?
My RSX was made two decades ago in '03, so the newest that would be multiple decades old. It’s also a Type-S, the sporty model. It’s got an open diff.
My '93 Subaru Loyale, which is 3 decades old, has two open diffs, with a locking center diff. No limited slip.
My '04 (almost decades old) Crown Vic PI doesn’t have an limited slip. It was an option on Interceptors.
My '07 (not decades old) Volvo XC70 has no limited slip diffs. It uses the traction control to try to imitate them, but no actual limited slip differentials.
My partner’s '07 (still not decades old) Kia Spectra5 has an open diff.
The only car in my fleet that has a limited slip is my '02 Subaru Legacy Outback, and it was an option that the person who bought it new opted for.
If you go out and buy most cars today they’ll come with open differentials. The traction control system will likely try to compensate for this, but they do not have limited slip differentials.
BaroqueInMind@kbin.social 11 months ago
Now thar Hyundai has patented it, it will never become popular enough to impact the market and be standardized in more vehicles or change anything, similar to the Wankel engine.
psycho_driver@lemmy.world 11 months ago
similar to the Wankel engine
Was the Wankel engine really a step forward though? I’m a gearhead who does all his own car maintenance, up to and including engine swaps in the past and retro-modding bigger turbos and aftermarket fuel injection systems into my cars (Datsuns in the latter case). That being said, I only know the very basics about rotary engines. I’ve always admired the Mazda RX’s from afar.
Mazda, who by no means makes a bad gasoline engine, could never get a rotary motor to last well or to have anywhere near decent fuel economy. Also, the rotary design was tried for a while in at least refrigeration compressor applications, where it blew up there a lot more than the other types of compressors as well.
gens@programming.dev 11 months ago
Yea. They have worse efficiency. To get better efficiency from them you would need to run them hotter (afaik), and if you do that they would last even shorter.
It’s great if you want a smaller but still strong engine, but it’s not efficient and those seals are a big problem.
sunbeam60@lemmy.one 11 months ago
The argument is, though I’m not qualified to assess it, that Wankel engines are simpler, smaller, more power dense and, if allowed time to develop, would be an improvement on the traditional ICE. It’s very difficult to assess where we would have ended up and a little by the by, given we need to move away from burning fossil fuel.
That said, do check out LiquidPiston’s evolution of the Wankel engine. It does sort of look like they’ve solved a number of issues a traditional Wankel engine has.
Cethin@lemmy.zip 11 months ago
But capitalism creates innovation!!!
aidan@lemmy.world 11 months ago
Some people argue that intellectual property law is not free market capitalism, and is instead a regulation that benefits big business. I’m one of those people
tourist@lemmy.world 11 months ago
“Probably failed cuz they called it the wanker engine lmao. Now set aside another few milli for the copyright lawyers”
jimbo@lemmy.world 11 months ago
Indeed, nothing that is patented ever makes it to market…
trackindakraken@lemmy.whynotdrs.org 11 months ago
Did none of you watch the video? The article is crap, but the video explains it well.
Go back and watch the video, ya old codgers!
ZMonster@lemmy.world 11 months ago
I watched the video, but burying a good video under a trash article does not a good sauce make. OP should have just linked the fucking video.
PlutoniumAcid@lemmy.world 11 months ago
What a badly written article, wrongly explaining both the diff and the CV joint. That’s not what they do or how they work.
Snapz@lemmy.world 11 months ago
Yeah, skimmed and saw one of his other articles praising the cybertruck and realized this likely wasn’t a source worth absorbing.
cordlesslamp@lemmy.today 11 months ago
I DON’T want MORE space in the SAME sized cars.
I want the SAME space but in SMALLER sized cars.
The space we have now is FINE, and the car sizes are TOO BIG.
STOP MAKING BIGGER CARS!
AlijahTheMediocre@lemmy.world 11 months ago
If we could get standardized and interoperable electric car parts, that’d be great.
ICastFist@programming.dev 11 months ago
Imagine that XKCD competing standards comic here
itsnotits@lemmy.world 11 months ago
trying to sell* the idea
Mango@lemmy.world 10 months ago
You’re complaining like this doesn’t also mean the same space in smaller cars. Improvement is improvement.
nonfuinoncuro@lemm.ee 11 months ago
They have taken us for fools
danc4498@lemmy.world 11 months ago
Seems really cool. I will definitely not buy the first model vehicle to use this, though.
billwashere@lemmy.world 11 months ago
Surprisingly easy to understand video for a complex concept.
Death_Equity@lemmy.world 11 months ago
It is made by Hyundai, I wouldn’t touch anything close to cutting edge they make.
I can already see this tech holding a yard sale on the freeway after a pothole.
Trollception@lemmy.world 11 months ago
After owning a Hyundai I won’t touch anything made by Ford or Chevy again. This car has had literally nothing wrong with it for over 70k miles. Except routine maintenance like brakes, oil changes, air filter and tires.
ilovesatan@lemmy.world 11 months ago
The explaination of how differentials work was painfully wrong. An I lost confidence in this author’s ability to explain the topic.
elbarto777@lemmy.world 11 months ago
Ok. Care to elaborate, please?
towerful@programming.dev 11 months ago
…wikimedia.org/…/Around_the_Corner_(1937)_24fps_s…
Wiki to the rescue!
It’s a great video from 1937.How the automobile differential allows a vehicle to turn a corner while keeping the wheels from skidding. Reverse telecine & introduction edited out.
And the article has info as well …wikipedia.org/…/Differential_(mechanical_device)
Modern cars have “traction control”, which detects when a wheel turns more than the other wheel. If it turns too much more, it will engage a “diff lock” and lock the differential which makes each wheel turn with the same power/speed/energy as if the differential was just a solid axle.
The long & the short of it is that a differential is only “1 wheel drive” when the differential “thinks” (it’s not smart) it should put all the power into 1 wheel - which is when the cars computer locks the differential.
Bluetreefrog@lemmy.world 11 months ago
Came here to say this.
BearOfaTime@lemm.ee 11 months ago
It was sooooo wrong.
MonkderZweite@feddit.ch 11 months ago
So in short, this adds suspension directly to the wheel, at the cost of higher maintenance? That’s it?
Blue_Morpho@lemmy.world 11 months ago
It’s not suspension. It compacts down the differential and cv joint (linkage from the engine to the wheel).
Buddahriffic@lemmy.world 11 months ago
It compacts the whole drivetrain, from engine to the wheel. The space saving they were showing was mostly from the miniaturization and splitting of the motor.
orclev@lemmy.world 11 months ago
The one thing they don’t really talk about is how it turns. The animations show vertical movement almost exclusively. At one point in the video there is a far shot showing a car turning and it looks like they actually swivel the entire motor to keep it perpendicular to the wheel which if true is going to pretty heavily limit it’s turning angle and radius.
Magiccupcake@startrek.website 11 months ago
If you’re gonna go through all this trouble, why not put motors directly into the wheels? Then you can bypass the drivetrain all together and directly power the wheels.
x2XS2L0U@feddit.de 11 months ago
For the lazy people out there: www.youtube.com/watch?v=Nd6C0y8xc20
BearOfaTime@lemm.ee 11 months ago
Not a new idea, military trucks used reduction gear drives in the wheels before WWII.
One downside to doing this is adding unsprung weight.
epyon22@sh.itjust.works 11 months ago
I don’t understand how they are going to keep dust and dirt out of it. The point where the drive input goes in has so much movement.
Thorny_Insight@lemm.ee 11 months ago
I don’t get what this does or what’s the benefit. There’s still a cv-joint there. Otherwise the wheels can’t turn
hesusingthespiritbomb@lemmy.world 11 months ago
I cannot think of a car company I’d trust less to do this than Hyundai/Kia.
time_fo_that@lemmy.world 11 months ago
Article made it sound like only front wheel drive exists now and that only front wheel drive cars use CV joints lol.
trash80@lemmy.dbzer0.com 11 months ago
01189998819991197253@infosec.pub 11 months ago
Anyone remember the Hyundai debacle where the transmission gears stripped mid-drive? Yeah… I’m not trusting their gear-making ability (or lack thereof) with precision gears inside all of my wheels. Pass.
JustZ@lemmy.world 11 months ago
I was just learning about CVJ gearing the other day and was thinking cars should use it instead of fixed gear ratios. Very cool.
beerclue@lemmy.world 11 months ago
This is pretty cool!
But, in the video there is a quick flash of text that went away after 1s, 120km/h max speed?
ZMonster@lemmy.world 11 months ago
From a mechanical standpoint, the new bearing saves a nearly negligible amount of space. Splitting the motor up and moving it to the notoriously wasted wheel well space is what clears up the center of the frame. Still very cool. It’s basically a single output differential, which is already quite compact. No need to split the rotation for turning since the wheels rotation will no longer be mechanically linked.
KpntAutismus@lemmy.world 11 months ago
so the pretty much only upside compared to hub motors is less weight in the wheels, and comared to conventional drivetrain layouts there’s added complexity and slight extra interior space? i mean innovation is key, but i don’t quite see the upsides as much as the hyundai engineers.
Destraight@lemm.ee 11 months ago
So how does it handle potholes?
NeoNachtwaechter@lemmy.world 11 months ago
EV already have much smaller gearboxes, because they don’t need to shift.
Now they need 4 of them, not just 1.
Such a gain in weight :-)
dual_sport_dork@lemmy.world 11 months ago
Setting aside all of the already observed questions in the comments already about mechanical viability, i.e. how this assemblage is supposed to steer. The elephant in the room is whether or not this is equivalently economical to produce compared to an axle with a CV joint in it, and/or if it will acceptably reliable for roadgoing vehicle use, what with having a shitload more moving parts in there.
The animation shows the geartrain assembly in an open faced housing, which if that’s how it’s ultimately designed is going to mean that there is now no way to keep the gears in a bath of oil or transmission fluid like is presently done in traditional transmissions and differentials. And yes, even in CV joints which are packed with grease inside their rubber sealing boots. I’ll let you in on a big automotive industry secret: There’s a reason current transmissions and other geartrain devices are kept suspended in oil all the time. A big one. One that has to do with your transmission not glowing red hot by the time you make it to your destination, or converting itself into glitter within the first mile.
Even setting aside lubrication concerns – Maybe the thing is chock-a-block full of sealed ballraces or something, for all I know – the big open slot they depict for the axle to move up and down in is just begging for a stone, a stick, a stray bolt, or any other show-stopping piece of debris from getting in there and causing you to have a very expensive day. Ditto with the gap around the edge of the sun gear, which is going to need a bitchin’ huge mechanical seal on it at the minimum. If the solution is perhaps to put some kind of rubber boot over the opening that moves with the axle, it’s going to have to be ridiculously flexible and remain so even throughout all kinds of temperatures and operating environments. Cars, you know, being devices quite infamous for being operated outdoors in the weather and all.
I mean, I can’t imagine Hyundai’s engineers haven’t thought of this. But I wonder if this is one of those works-in-the-lab-and-test-track things, and they’re expecting someone else to figure out the viability challenges.
Semi-Hemi-Demigod@kbin.social 11 months ago
Another advantage of putting drivetrain components in the wheel is you can just swap them out easily rather than having to tear the engine bay apart. Really outstanding work!
Buffalox@lemmy.world 11 months ago
There needs to be more music in the background, and the narrator needs to speak with more enthusiasm about more needless details of how smaller makes it possible to use the space for something else. /s
Deceptichum@kbin.social 11 months ago
I know Hyundai is Korean and all, but this presentation style where the host pretends to be demonstrating a product "uh, wait a second . . . what if we" and is speaking almost like it's a personal conversation between the two of you is giving me huge Nintendo Direct vibes when they demonstrate unreleased games and play them for you.
Is this a common sort of business/sales presentation method in SEA?
MonkderZweite@feddit.ch 11 months ago
Can we please make touchscreens for neccessary functionality illegal, like using phones while driving?
Pulptastic@midwest.social 11 months ago
Yeah, buttons can be found without looking.
nexusband@lemmy.world 11 months ago
THE reason i got a Mazda…
RGB3x3@lemmy.world 11 months ago
I feel like not enough people realize how amazingly simple and tactile the rotating dial is for doing anything in a car. And especially the placement being down by your arm makes it so easy. I can feel where all those buttons are without taking my eyes off the road.
Haywire@lemm.ee 11 months ago
Also make them illegal in aircraft! And spacecraft! Seriously stupid.
CeeBee@lemmy.world 11 months ago
I vote for cheap PlayStation controllers.
echodot@feddit.uk 11 months ago
I suppose the advantage on aircraft and spacecraft is that they consolidate functions so you don’t have to have 90,000 switches in the cockpit, half of which you won’t ever need.
Anything you need to find in an emergency absolutely should be a physical switch but anything else can probably be a UI interface.
But in the car you need to keep your eyes on the road at all times, which isn’t so much of a requirement in the air.
sfgifz@lemmy.world 11 months ago
Salty Boeing
Pika@sh.itjust.works 11 months ago
So much this, it makes no sense for using a portable phone to be illegal while driving but yet my car stereo can be a full on entertainment system and require me to have zero feedback to change the channel or answer a call.
BilboBargains@lemmy.world 11 months ago
I’m pretty sure they are for safety critical controls, such as in an aircraft cockpit. In the automotive world, we like to keep it jazzy and smooth, like my romantic life.
Haywire@lemm.ee 11 months ago
They aren’t. Light ircraft now use touchscreens that you are supposed to use while bouncing around. They had a knob for a while but then it seemed touchscreens took over. With the knob you still had to look, it at least you didn’t have to aim at a bouncing spot on the screen.