In Micromouse (https://en.wikipedia.org/wiki/Micromouse) - a competition where autonomous devices solve a mouse maze - the fastest competitors are all using fans to increase traction (and thus speed).
radicalbyte, you're absolutely right that the use of fans in Micromouse increases the traction, and therefore the speed at which the maze is solved. Suction allows for impressive performances.
However, a small caveat that might be worth considering is that while the suction indeed increases speed, it might be more accurate to say that it primarily improves acceleration instead of car speed: The issue often lies with achieving rapid acceleration rather than with maintaining high speed. Even systems with relatively low traction can reach high speeds given enough time and distance, but the ability to accelerate quickly is crucial in competitions like Micromouse.
Something weird about this is that humans very often ascribe the sensation of d^ns/dt^n, to feeling d^n-1s/dt^n-1.
So people will say that something which accelerates quickly is 'fast'. Or they will say, when they feel themselves initially being pressed back into their seat as a plane starts its takeoff roll, that they are experiencing 'acceleration' when what they are experiencing is actually jerk.
The thing is, you can't actually feel motion at a constant speed - so the only thing that tells you you are acquiring speed is your body's experience of acceleration - so when you feel yourself accelerating, you associate that with speed. Likewise, your body also can't really tell the difference between constant acceleration and just... being at a different angle, and maybe a bit heavier than normal. So it's when you experience changes in the apparent direction of 'down' and the overall 'weight' you're feeling that you think 'oh, we're accelerating'.
My favorite way to get a sense of what acceleration, jerk and snap feel like is to focus on what happens when you're in a car that's braking hard. You're decelerating at a relatively constant rate while the brakes are applied - it feels as if 'down' is pointing slightly forward, meaning you'd be sliding off the seat if it weren't for your seatbelt holding you back. When the car finally stops though, there's a very abrupt change in acceleration - a 'jerk'. 'Down' switches to pointing straight down again, very quickly. You're pulled back into your seat. That's jerk. And specifically the sudden onset of that swing in what direction 'down' is pointing, and then its rapid disappearance is snap. Your body feels like it's being 'jerked' around when the car stops precisely because that motion has high snap - you experience a sudden high amount of jerk, then the jerk ends.
Well, if you're on a 2D plain, it's pretty easy to tell. If the solid plain is stationary to your motion, then the air is fast. If the solid plain is moving, then it's a little tricker to figure out.
Hmmm, from a Newtonian perspective I would have argued (or at least my personal impression is) the only thing we actually perceive is force (i.e. acceleration). All the situations you described are just (higher-order) changes of acceleration and even if you give them a name: At the end of the day, the only thing that matters to our bodies is the force.
Sure, but my argument is that you only really take note of changes in the acceleration you experience. Yes, your internal sense of ‘which way am I accelerating’ is the sensor you’re using (also ‘which way and how hard are my limbs being pulled’ and ‘how much force am I feeling in my joints and on the parts of my body that are touching the objects around me’) - but when those all indicate a generally constant vector with a magnitude close to 10m/s^2 your body just intuits that that direction is ‘up’. If that vector is changing your body figures you must be moving because ‘up’ normally doesn’t move.
So it’s changes in acceleration that create movement sensations, not acceleration itself.
Interesting thought but I'm not entirely convinced yet: 10m/s² down (along your body axis) is not the same as 10m/s² in any other direction. I would assume the body is perfectly able to distinguish between those.
Sure, but once you have speed you can use aerodynamics to get grip (e.g., F1 cars). So this is really only relevant if you need acceleration from low speed.
An issue with aero features (other than not producing their effects at low speed) is their ability to stall. Ground effect was especially dangerous (back when high-ground-effect designs were allowed) because if it stalls during a high speed corner (say from driving over a bump, like a kerb maybe) you can instantaneously lose a huge amount of downforce, which is obviously quite dangerous.
Exactly, thus you can simply integrate over a longer time span.
But if you want to increase the acceleration you need traction, your tyres need to be glued to the asphalt. Since you don't have aerodynamic pressure at those speeds you need to suck the vehicle to the ground.
Suddenly I remember a Top Gear episode where Nick Mason drops off his F1 (maybe it was a Ferrari Enzo?) at the test track, then his personal helicopter lands on the strip, picks him up, and flies him out of the scene, all while "Money" by Pink Floyd plays in the background.
I forgot about the book! Clarkson subtly-not-so-subtly promoting the book was such a riot. And to think that's not even close to the most ridiculous thing they did in the show's heyday.
Nick Mason has a pretty significant collection of cars. Back in the day he used to take his kids to school in his Ferrari 250 GTO. These days the car is so valuable I got the impression he has to call his insurance company to get permission to take it out on the road. Years ago he published a book called "Into the red" with some of his cars. The book had a companion CD of the engine noise made by a selection of the cars. They took each car to the track to record it.
From a Youtube interview with Gordon Murray I saw, the T.50 has fan-enhanced diffusers, the fan ingesting the boundary layer to prevent flow separation.
It's not able to produce extra downforce at zero speed.
The McMurtry Spéirling is more akin to this, with a 1.4s 0-60mph run.
These cars stem from the Formula Student, which since 2022 has re-allowed the previously forbidden "powered ground effect".
But this car has an upgraded battery and powertrain beyond what the rules allow and they maybe also use tire warmers and potentially rubber/glue on the launch surface/tires
Interesting. This is a Formula Student car, the european version of the Formula SAE. Powered ground effects were banned a long time ago in Formula SAE, but it seems like Formula Student does allow them.
Had the same thought, 0-100kmph in 3sec gives so much wheel spin.
Must be a whole lot of electronic trickery ever invented from launch control, traction control to power management plus the mechanical stuff sticky tyres, down force.
It amazes me how much faster we have got the last 6-7 years.
Racing rules are not generally updated because ground effect (powered or not) is a safety concern because losing traction through a corner suddenly when it fails can be catastrophic. This is why it was banned in F1 in the 80s, damage or getting lifted up and the car will suddenly fly off the track.
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.
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
> 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.
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'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.
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!
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)
I thought maybe this was a superficial tear-down but nope, it's a whole heckin teardown and measurement of components and relubing and cleaning and etc.
They pulled some type of rotary pump thingy out of that monster that ran the entire length of the engine. I'd never seen anything like that and had to look it up. It's a supercharger; a glorified air compressor. That air pump uses more HP than your average supercar.
bonkers is a good word. I've never enjoyed drag racing and top fuel cars are incredibly wasteful and yet, one has to admire and stand in awe at the engineering. Every single aspect of those cars is off the scale insane and then some.
They use spark plugs, driven by more amps than an arc welder. But the plugs melt away in just a few instants, the rest of the run the engine is dieseling from the extreme heat.
The supercharger alone takes so much power to turn that barely any car on the street could even run it.
The tires are quite something, watch slow motion videos.
I wonder if they'd go any faster if the rules allowed overhead cams!
Even though these cars have disastrous efficiency and need to be completely rebuilt after every run and have backwards rules that leave them using "ancient" technology, I can't help but be awed by the effectiveness of the sledgehammer approach.
Super capacitors are highly overrated by the general public. They really aren't that much better than lithium ion except for in a very narrow power/time bandwidth.
The comment I was responding to was lamenting the potentially slow speed of chemical reactions in batteries, so I recommended super capacitors specifically for the case where a higher rate of discharge is required. I agree lithium is potentially good enough there, I am merely speculating on solutions in the event that an ultra powerful vehicle really could exceed lithium’s capabilities.
As for the general public, I can’t say. I use super capacitors in the power system for my solar powered robot and I love them. Through that experience I have realized they have plenty of other applications.
Thinking out loud, but it's mostly power to weight ratio isn't it?
With batteries currently being less energy dense than fuel, can an electric car be faster?
Now there's more to the vehicles than just the energy supply, so I suppose if an electric car could harness battery power more efficiently (i.e. with less weight) than an ICE powered vehicle, it could be faster?
I was sure you made a typo and meant 10000 feet, instead of 1000. But after checking, yeah, it makes sense to make the track shorter to avoid the cars reaching even more insane speeds.
they've been playing this trick with top-fuel dragsters for decades - the "speed" was measured far before the end of the course. I think it was to keep the speeds below 300mph to help with track insurance.
I think hub motors like this are the future. Frees up space under the car for more battery. Removes the complexity of drive shafts and universal joints. Gives software full traction control. Reduces design time for new vehicles (just route a power and data cable to a wheel and you have a vehicle). Is the first step to all-electric braking.
The downside is more unsprung mass. But modern motors are getting lighter and lighter. And without a drive shaft, wheels could do crazy things like moving in and out to avoid potholes, or dynamically adjust camber to match the road you're on.
Modern motors get lighter in part because they can offer lower torque with a smaller rotor but compensate with higher rpm. That’s not possible for a hub motor
The hub motors on the car in the OP run at ~24k RPM (faster than any production electric car AFAIK) and have a multistage planetary gearbox for reduction.
Pretty much all top Formula Student cars now use hub motors. Mainly for packaging reasons. Putting the motor in the unused space in the wheel means you can make a smaller chassis and have more space for wings and underbody aero.
Torque is directly proportional to radius, all other factors being equal. There are practical limits on the strength of the magnetic force because you can only cram so many amps through a confined space, which is even more confined on a small motor.
It will still make high power at high RPMs, but you have to gear it down to convert that power into more torque at low speeds. A gearbox makes it not really a Hub Motor at all any more. Terminology aside, a gearbox also adds even more weight and complexity inside the wheel. For less weight and complexity you can use a half-shaft to the center of the vehicle and use whatever motor you want inboard.
I was wondering how this compared to motorcycles, and didn't realize that today's production motorcycles are not significantly faster than modern hypercars, the fastest motocycle clocking in at 2.2 seconds [1]
Ignoring the million dollar sports cars, other cars such as Porsche 911 turbo s from 2020 is 2.1s.[2].
I know, Tesla and Lucid, etc are also crazy fast, but I believe their quoted 0-60 times are all with a roll-out.
Cars designed for high speed will have a significant advantage over a motorcycle through capturing down forces to dramatically increase the amount of friction between the tires and the surface before losing grip and spinning out. Motorcycles can own the power to weight ratio category, but they can't use all that power because at that point the wheels just spin.
I found it super interesting when I learned that one of the biggest advances in maze solving races is that someone ended up putting a fan in their little "mouse" to push down so the wheels could get more traction.
Out of curiosity, what's the point of a driver in something like this besides to have a human in the vehicle adding weight? Are they doing much?
Serious & maybe very ignorant question.
- Edit - For clarification, my reason for asking was due to this occurring in less than 1 second. I don't understand what the driver does as I'm assuming they have no gears to shift or turns to make.
I assume it's because racing, as a sport, is a lot less interesting without the variable of a human with particular skills operating the vehicle. I doubt crowds would be as interested in watching cars race on autopilot, though it'd still be kind of cool, I guess.
> racing, as a sport, is a lot less interesting without the variable of a human with particular skills operating the vehicle.
If full self-driving gets much better, I think it could be fun to see this happen. It would be like a hackathon with teams swapping out and improving on strategies through laps. The qualifiers could happen on electric miniatures then the final round would get a full car to race on a track.
The racing formula this is from, Formula Student, actually has a driverless competition as part of it. It's pretty fun, but also harder than one would think, still.
Guinness world records are well defined and some are kinda arbitrary. In some sense, I'm sure the driver is there to satisfy the rules of the world record. In another sense, I'm sure they're there to have a load of fun, too.
> "To ensure strong traction right from the start, the AMZ team has developed a kind of vacuum cleaner that holds the vehicle down to the ground by suction."
Traction is now the limiting factor, so better acceleration results will be driven (hah) by better traction.
Traction has always been the limiting factor in automotive performance.
There is a reason why a Civic Type R set a faster time than exotic cars of early 2010s, and thats because modern street tire compounds are as grippy as slick racing tires from those years. And now, race tires have a static friction coefficient greater than 1, because when warmed up they actually glue themselves to the road.
These cars would appear to be utterly dependent on maintaining a very specific distance from the track for the ability to stay grounded. You imagine going into a curve at high speed and the slightest body roll or debris on the track that might kick the car up an inch or so would break the suction and send the car flipping like a pancake.
Something like that happened in the 1999 Le Mans to Mercedes[0]. It happened three times that race weekend before they decided to retire their last remaining car.
That is an issue with all ground-effect cars, not specific to fan cars, which is why they were banned, but that happened much later. The fan car was banned because it gave Brabham an unfair advantage and the other teams didn't like it.
Rather than teaching a separate utility, I would recommend qalc which has unit conversions built in :)
$ qalc -t 100km/h / 0.956s to gee
2.9629132 gees
(where -t is for terse mode; by default it expands unit abbreviations and adds parentheses so you see whether it did what you wanted)
The reason I recommend it is because it does so much more, I really love this utility since discovering it about a year ago. Example of using time notation combined with uncertainty and unit conversion:
What I meant to say is that, if one uses a featureful calculator like qalc, then you get unit conversion included without needing two separate utilities. Of course, if you've used a(n obscure) calculator for decades then it may be easier to learn to use a separate unit convertor instead
In my usage, GNU units appears to be more featureful than qalc. For example I noticed that qalc lacks many definitions that I often use, such as energy density (eg. "gasoline"), mass density (eg. "golddensity"), energy units (eg. "therm"), astronomy (eg. "earthradius", "solarmass"), etc. And GNU units works just fine as a calculator.
So, from my viewpoint, qalc is the "separate utility" that I don't need ;-)
i used this calculator[1]. Looks like 3.5 .
Just for fun...
Now, if we use the forces that air pilots can sustain for 2 seconds we're looking at about 0.35 seconds is around the limit. and 0.3 seconds would create about 11Gs enough to kill you (all according to quick googles of numbers.
If they can get a car to do 9Gs for 2 seconds we're looking at about 635Km/hr !!
I have watched a lot of car acceleration tests on YouTube (thanks COVID)... and the electric vehicles, especially the ones with artificial (vacuum) downforce) are approaching what seem like impossible limits.
For the lesser trained drivers, the acceleration forces experienced appear to temporarily affect some basic functions (like speaking).
However, these perhaps pale in comparison to the repeated acceleration and deceleration tests experienced by John Stapp - https://en.wikipedia.org/wiki/John_Stapp
I cannot find information about his 1-second speed (trap) number, but the Wikipedia article notes that on
"3 January 1955 says he accelerated to 632 mph (1,017 km/h) in five seconds and 2,800 feet (850 m), then coasted for half a second, then slowed to a stop in 1.4 seconds. It says the track was 3,500 feet (1,100 m) long."
On a related note in the sports car community its been interesting to watch Acceleration stop being a mark of a performance car. There is even a lot of chatter around this being the end of the supercar segment since there are family wagons that can now do 2 second 0-60 runs. On top of that the speed is now too much for anyone to reasonably use off a drag strip or circuit.
Now there is a huge emphasis on engagement, dynamics, and a bunch of vague "feelsomeness" as sports cars slowly become like horses.
We see this same sentiment in comments on this very website. Comments like "Straight line acceleration doesn't matter", for example.
Except, as a driver, I never accelerate in a tight curve. Once I got an EV, aggressive drivers were no longer able to block me from merging into traffic; if anything, I was able to easily get away from them if necessary.
I believe what we are seeing is car enthusiasm being pushed further into the long tail. Aesthetics, self-sufficiency through repair, exotics, etc, will always have a place, but speed off-track is over. ("Drive feel" is the new "gold cable connectors".)
Performance car /= sports car. Sports cars are light and nimble by definition. They are usually fast, but this is not a rule. There have always been sedans that are faster in a straight line than most sports cars. There have always been sports cars that are not very fast at all. None of this is new, and claiming otherwise is ahistorical. Even back in the '60s, a sports car enthusiast would have chosen an MGB over a much faster Camaro, because the MGB is a sports car and the Camaro is not.
Engagement, dynamics, and "feelsomeness" are not vague at all. Handling is the product of engineering. It is largely objective. Some cars really are easier to control than others. Some really do hold on better in the corners. Cars really do have more or less body roll and more or less oversteer. What "character" is best is a matter of opinion, but the car really does have that "character". The fact that something is hard to measure does not mean it doesn't exist.
Sports car fans mean exactly what they say: they value handling over acceleration. If they didn't mean it, they wouldn't buy sports cars.
You just said it's not a sports car. It's a sedan.
No one would dispute that it's a performance car. No one would dispute that it's very fast. But none of that matters here, because it weighs 5,000 lbs and has four doors. A Spitfire is not a muscle car, a Camaro is not a superbike, a 917 is not a performance sedan, and a Plaid is not a sports car.
You can, of course, use the word however you want. Words change meaning over time. But if you want to claim that sports car enthusiasts have moved the goal posts, you need to know where they were set in the first place. I am using the word in roughly the same way enthusiasts have always used it, and you are not.
Also, the Tesla Plaid is not the fastest sedan on the Nurburgring. It is the sixth fastest. Note that the top five times were set before Tesla's run.
Fine. At the time when it ran that time it was the fastest, and faster than practically every sports car ever made.
The nurburgring is about the most sports car track ever made. I don't really know how to measure anything about a car's sportiness other than its speed around the track generally agreed to be the most "Gran Turismo" style.
If you want your own personal gatekeeping standards for "true sports car", whatever. When batteries double in density in the next ten years, your gatekeeping will look even more ridiculous.
The ICE drivetrain is a zombie at this point that is surviving on inertia and the incompetence of legacy automakers.
All five sedans that beat the Model S around the Nürburgring drove their laps earlier. The Plaid has only ever been the sixth fastest sedan around the 'ring. Which is excellent, but not what you said.
>and faster than practically every sports car ever made.
It isn't. It loses even to the 2012 Nissan GT-R or 2007 911 GT2. It loses to any of the faster 911s by nearly a minute. It is faster than some sports cars, but not recent sports cars at a similar price.
How is it that the Plaid, despite being one of the fastest cars on the road in a straight line, loses quite badly to cars with half the power? Because there is much more to performance than just acceleration. The cars you disparage are dramatically better in the corners than the Plaid.
>The nurburgring is about the most sports car track ever made.
I don't quite know what this means, but I don't think it's true. The use of the 'ring as a benchmark is often criticized because it rewards power over handling. A track that specifically tests handling would be slower and twistier. This is not sour grapes; people have been saying this for decades.
> Now there is a huge emphasis on engagement, dynamics, and a bunch of vague "feelsomeness" as sports cars slowly become like horses.
I think this is mostly just the experience of people who only started caring about performance cars when EVs started being competitive. Porsche people (and many others) have been ranting about the engagement and driving dynamics for 50 years now. There are decades of arguments on forums about handling, 50/50 weight ratios, understeer and oversteer, shifter feel, track times, etc. in addition to arguing about straight line acceleration.
EV people feel like those things are just excuses because previously they only digested mainstream auto news which puts a massive emphasis on straight line acceleration.
This has been an age old debate -- if you read the comment closely it was saying that supercars were defined by acceleration and handling, but now acceleration is no longer their forte. You could always get a sports car like a P-car if you wanted handling.
Don't think everything is just defined by this one issue, it goes way back, but Electric has now killed the first half of a supercar
> if you read the comment closely it was saying that supercars were defined by acceleration and handling
> sports car community
> as sports cars slowly become like horses
can you see how I might have been confused that the comment was about sports cars?
> supercars were defined by acceleration and handling, but now acceleration is no longer their forte.
I would argue that their forte is (usually) being fast around a track, and that acceleration and handling are just aspects of a complete system, subject to engineering tradeoffs like anything else. When we evaluate through that lens, ICE/hybrid supercars are doing just fine.
Acceleration was never really the top metric for super cars. It was more performance at high speeds, with high end cars like the Bugatti Chiron Supersport 300+ going up to 489 kmph (that is a lot in case you wonder). Part of the super car segment will go electric, that is for sure, but I do not see the end of the super car. Look at luxury watches. They are booming despite a Casio GShock with Multiband beating the shit out of them in terms of accuracy.
Super car segment is well below Bugatti. Thats a 2.5 million dollar car. Super cars are between 150k usedish and a million. Plus a lot of other vague definitions. Most people say call the 911 the dividing line of a supercar and top of the sports car range.
In general this segment is dying off, chasis are being reused for 10+ years in the market, tons and tons of special edition and reissues. most of the new work is being done in the Hypercar segment which is almost just a nonsensical money-fight space. And they were, for the most part, defined by speed in the public eye. If you wanted feelsome-ness you just go a Cayman or a Lotus.
I stand corrected, the Bugatti is a hypercar. It's a bit embarrassing considering that I was in the workshop where they make the Bugatti engines just a few weeks ago. Awesome experience btw, seems to be part of the standard factory tour at Volkswagen Salzgitter currently.
Indeed. It's a case of "my favorite kind of car isn't the best performing anymore, but I refuse to accept that, so I'm going to change the definition of performance instead."
Pretty much what is destroying the notion of 'sports car' and 'supercar' Enthusaists don't want to admit a family SUV can now blow them away on the road or the track -- so you have to fallback on things like 'feelsome'. its a huge sore spot in the community
The maths doesn't check out. A 9 second quarter mile is an average of well under 1g.
It is like lying on a bed except with less gravity than usual.
Of course it's not linear, but it's very unlikely to be more than 2g at any time. People can comfortably handle well over that in that direction of acceleration
It's *roughly* the gravitational acceleration at the surface of an Olympic-size swimming pool of electron-degenerate matter from a white dwarf star. Hope this helps!
(Note: the swimming pool has collapsed under its own weight and is now a sphere).
A white dwarf's density is apparently around 1e9 kg/m³. Olympic swimming pools at 50m*25m*2m * 1e9kg/m³ would have a weight of 2.5e12 kg. As a sphere, the radius is (solving: volume_of_sphere = 4/3×π×radius³)
Gravitational acceleration (for a point mass) is: the gravitational constant, multiplied by the mass, divided by the radius squared, and we want the result in Earth gravities:
$ qalc G * 2.5e12kg / 8.4194515² m² to gee
(newtonian_constant * ((2.5 * (10^12)) * kilogram)) / ((8.4194515^2) * (meter^2)) =
approx. 0.24 gee
You're only one order of magnitude off — if this is correct, which I am really not sure about!
What I'm even less sure how to calculate is whether an 8-meter sphere can be that heavy. Uranium is ~2e4 kg/m³, but under its own gravity, things shrink until they reach black hole status (infinite smallness; perceived size coming from its event horizon). Basically I'd want to turn the above 1e9kg/m³ into an unknown, but what's the formula for mass given your specified radius and gravitational acceleration? TBD
I'm really curious if this was just a few words strung together and it happened to come out to within one order of magnitude by pure coincidence, or if (how) you calculated this!
Very cool, but also kind of impressive that a Tesla manages this in ~2.5 seconds while doing all the other stuff a production car does. What time would a Tesla get if you stripped out all the extra weight? (seats, glass, electronics, roof, etc. etc.)
I'm pretty sure a Tesla spends most of its 2.5 seconds traction limited. Ie. if you could fit gearwheels and drive on a toothed road, I think a stock tesla could accelerate faster.
Or burn, or cost three times the price! Most components used in Teslas are not made to run so intensively, wether it is the wheels, the motors, the battery, the brakes, ... they most likely limit the acceleration to prevent bad things.
True, but this car has low 300s HP, no torque mentioned that I saw. The Tesla is over 1K HP and torques. The Teslas, for road cars, are pretty stunning for acceleration. Agreed that it's not going to reach this level of 0-100 performance, but it sounds like it can get shockingly close.
I've driven Porsches on the track, and the Tesla Model S Ludicrous loaner I had for a few days is startlingly fast. Fast enough that I decided I was glad I didn't get one.
This thing has a power to weight ratio of close to 2 HP per kg. That is beyond insane, and if they didn't have active suction that is essentially doubling the grip, this thing would just be fast at converting rubber into smoke.
Just to put in perspective how ridiculous it is, the equivalent would be if the Tesla was close to 5000 HP and could produce 5000 lbs of suction downforce at standstill.
>"All of mythen’s components, from the printed circuit boards (PCBs) to the chassis and the battery, were developed by the students themselves and optimised for their function. Thanks to the use of lightweight carbon and aluminium honeycomb, the race car weighs in at only around 140 kilos (309 pounds)."
Never knew about Aluminum Honeycomb -- before reading this article...
Aluminium Honeycomb - CEL Components - As core material, aluminium honeycomb is used in sandwich panels and it is utilised in: floors, roofs, doors, partitions, facades, working surfaces for automatic machines, laser jet cutting and for all products which require an optimal stiffness-to-weight-ratio."
>"Aluminium honeycomb is highly desirable due to its incredibly high strength-to-weight ratio and is applicable wherever lightness and strength are required."
So, very interesting!
Another material of the future, no doubt!
(I bet it works great as an electrical ground and/or antenna, too!)
I am curious what sort of physical preparation the driver (Kate Maggetti) did to train for these runs, if any? Surprisingly the average g-force is just under 3 g.
From my FSAE days, she is likely the lightest engineer on the team. It was standard for the lightest team member to do the acceleration runs. The car is about 300lbs so it makes a difference.
Not sure but it's fairly mild compared to what I think is the fastest accelerating car, Sammy Miller's Vanishing point which I think recorded 26g. They had some failsafe to stop the car if he passed out on that one. (car doing a 3.22 quarter https://youtu.be/7QC6tymIvKA?t=213)
3g for less than a second is really not to that much. Most people can easily withstand 3g sustained for minutes with (almost) no preparation. Just don't forget to breathe and maybe contract your leg muscles a bit. Many can go up to 7g sustained with half a day of training.
I find the suspension design to be really interesting. It seems like the front wheels and the rear wheels each share a single coilover and they use hydraulic cylinders at each wheel to transmit the force. I'm sure this saves a lot of weight but I'm interested in how the suspension dynamics are changed by two independent wheels sharing the same spring and damper.
Do any other vehicles do this? Are there are any other applications where it would make sense?
This is actually fairly common in Formula Student cars. They often use decoupled heave/roll suspension systems, where one spring/damper is for the heave of the entire axle and another one for the roll on the axle. It has some advantages over separate springs, but I'd have to ask our suspension guys.
The graphics in this article show its function fairly well, but don't explain the calculations either
Isn't the go-kart suspension still somewhat competitive, though? I'd heard of teams that have suspension travel for passing tech and then jack up the rates afterward.
Yes, or maybe more accurately - we are the American equivalent of Formula SAE Germany. The German teams are significantly more advanced and better funded, with some of the teams running custom built electric inhub motors (something that's unheard of here in the US)
I am currently on San Jose States Formula SAE team - we merged our electric and combustion teams last year to go all electric since it's where the stiffest competition exists.
If we could secure sponsorships we'd love to take our car to Germany!
Formula Student Germany has been leading the rules for the electric and driverless since their inception. There is a meeting every few years at the FSG event to align some rules for the different global student competitions. There was one this year again. (Source: I'm in the timekeeping team/organisation, to the driverless cars: please stop destroying our gear)
I didn't know San Jose State had enough money to run an team like this.
Unless I'm mistaken, aren't Formula teams expensive? the cars get rebuilt often, I imagine its no different with electric (less to rebuild, perhaps, but anything mechanical would need to be)
I was thinking the same. It is interesting to think of different fuel modalities. Liquid fuels seem to have a throughput advantage for now. The article doesn't seem go into electrical depth. From the pictures, it looks like they are powering all four wheels at the hub.
A top fuel dragster accelerates from a standstill to 100 mph (160.9 km/h) in as little as 0.8 seconds (less than one third the time required by a production Porsche 911 Turbo to reach 60 mph (96.6 km/h))[1] and can exceed 297 mph (478.0 km/h) in just 660 feet (201.2 m). This subjects the driver to an average acceleration of about 4.0 g0 (39 m/s2) over the duration of the race and with a peak of over 5.6 g0 (55 m/s2).
.....the what now? Have you watched any drag strip racing, like, ever? Cars regularly go up in flames. The suggestion that normal ICE cars would be allowed over EVs for "safety" is actively hilarious.
Yeah.. if people think the prospect of a lithium fire is going to scare drag strips into banning them, even under 'false' pretenses, they haven't spent any time at a drag strip.
Most drag strips are run by volunteers or extremely small hobbyist tracks and have almost no regard for safety. Basically if the driver is wearing a helmet (and a fire suit at more formal places) you can run it. To compete they'll often require roll cages but most pulls are just against the clock so on many nights they let any random joe schmo pull up and get a time.
The crowd often line the lanes behind small concrete barriers and people are usually welcome in the staging area and right up next to the burnout boxes..
Drag racers used to use hydrazine which would slowly convert into a contact explosive when mixed with gasoline. The exhaust flames were green. If the carburetor and fuel tank was not purged fast enough after a race the engine, carb, and/or fuel tank would explode and sometimes kill people. I doubt drag racers or venues are scared of lithium.
As someone who grew up racing go karts and still enjoys motor sports (mostly F1), the problem I have with e-racing is the lack of sound. The winding noise they make just isn't adequate and really puts me off to the racing.
https://www.roadandtrack.com/motorsports/a32350/jim-hall-cha...
Still neat stuff.
Race sanctioning bodies will need to update their rules or these will just be one off bragging rights.