Humans have a need for speed, and students from the Academic Motorsports Club Zurich (AMZ) have set a new acceleration record for an electric vehicle with a 0 to 100 km/h (0 to 62 mph) time of 0.956 seconds.
The mythen features four custom electric hub motors with a total output of 240 kW and a vehicle weight of 140 kg (309 lb) thanks to the use of carbon fiber and aluminum honeycomb. The car was able to get up to speed over only 12.3 m (40 ft)! As with many student design team projects, every component was hand built and designed to optimize the power to weight ratio of the vehicle.
The students from ETH Zurich and Lucerne University of Applied Sciences and Arts were excited to regain the record from the team at the University of Stuttgart, having previously held the title in 2014 and 2016. We suspect that they will find any European EV maker’s engineering department excited for the chance to hire them come graduation.
If you want to go fast at a smaller scale, checkout 3D printing RC car wheels for speed, and if you’d rather ride the rails at an accelerated rate, here’s an article on high speed rail.
For reference, the acceleration due to gravity produces a 0-100km/h time of 2.83s. So this thing is approaching 3g on a level, straight line.
The sensor on the car measured a max of 3.81 g.
Probably very close to zero velocity – that downforce fan offers gobs of grip, and motor torque is highest near zero.
This is the future of hypercars driving 0-60 times down well below 2 seconds – fans!
That’s going to be very uncomfortable for anyone with weak stomach.
It’s going to be uncomfortable for *anyone.* A weak stomach just makes it messy. :V
I wonder if these runs are long enough for a somatogravic illusion to show up (i.e. your vestibular system tricks you into thinking you’re going straight up).
Those tires must have amazing coefficient of friction to produce that kind of force.
The forced-air ground effect helps a lot, but still: they produce about double the friction of an ordinary road tire. Sticky rubber. I wonder how long they last.
this one isn’t quite as fast to 100, but close enough and it goes around corners like on rails, https://en.wikipedia.org/wiki/McMurtry_Sp%C3%A9irling
In the video, they mention their ground effect system (the obvious portion of which is the large panels between the tires) roughly doubles their normal force.
It doesn’t do that at a standstill, however. Still need some wicked sticky tires. In the photos they look like somebody dropped a ball of gum on the beach:
https://ethz.ch/en/news-and-events/eth-news/news/2023/09/from-zero-to-one-hundred-in-0-956-seconds/_jcr_content/wide_content/slideshow_copy/images/image6.imageformat.slideshow.1388371058.jpg
It uses an active ground effect system: so it works at standstill too. You can see this if you watch carefully you can see the fans and how it pulls down the car at the start of the acceleration.
Seriously, this was my first thought.
To me that’s even more interesting than the actual car, yet the people who set these records never seem to talk about it.
Going fast is just a problem of enough motor and battery, but the do you get 2 units of stick out of a tire with one unit of gravity?
See my reply to OP. They give the answer in the linked video.
Also, top fuel dragsters regular get even more launch acceleration without any ground effects at all (those big wings don’t kick in till you get some serious airflow)
Magic tires indeed.
And track prep, which is basically glue in the launching area.
The rear tyres on those dragsters though are something else – run effectively under-inflated, and the sheer magnitude of torque being driven into them at launch causes them to bulge out increasing their surface area before they actually expand at higher speeds of the run. Their lifespan is essentially 1-2 miles so just a few runs at best.
According to the video, ground effects almost doubles the downforce. Assuming the young lady driver with clothes and safety equipment is 101 pounds, the total mass is 410 pounds. Assuming the effective area of the ground effects is 10 square feet, that implies less than 41 pounds per square foot = 0.28 psi = 0.019 atmospheres.
Good traction requires both good tires and good pavement. A quick internet search suggests that top fuel dragsters can get a coefficient of friction of 5 in the burnout area and roughly 2 otherwise. The Swiss team didn’t use a burnout so 2 is a good estimate if the rubber is very sticky. Burnouts are very tough on tires, so at least they can expect more than the 10 runs of a dragster.
The tires get heated up to make them more sticky. You can see the tire heating mats in the video. The team uses Hoosier racing tires, with different softness and stickiness. Actually the sticky ones are useful to ‘clean’ the race track as all the small stones/etc stick to the tire :-).
So, assuming the driver is 60 kg, the kinetic energy of the car will be 75 kJ at 100 km/h after one second.
Even at the end of the run, the (traction-limited) wheel power is still only 145 kW.
The stated motor (output) power is 240 kW.
That’s 95 kW lost along the way: something in the drivetrain is warming up very quickly.
And they don’t state the downforce fan power, but that’s gotta suck a few kW too.
I’ll bet the batteries are being asked for over 400 kW peak. Pretty impressive for something you can fit in that weight budget.
Things get exciting when you inch closer to measuring your car in megawatts.
Is that the traction-limited wheel power for one driven wheel, or all driven wheels?
There’s no evidence of breaking traction in the video – neither the screech of a skid nor visible rubber left on the pavement. The only sound I heard was the whine that might have come from gears or the motor. I suspect the motor controller was carefully calibrated to not break traction, rather than to deliver maximum power. In other words, if they were willing to risk a spinout, they could have gone faster.
Interesting, now we start talking about torque delivery strategies to maximize traction or ‘bite’.
I’ve heard of inline 3 cyl motorcycles having a lopsided torque delivery with periods of no torque, this lets the tires bite and then the torque comes back on. Also heard of a v8 firing one bank in order, then switching and firing the other bank, might help traction.
As for this, its smooth delivery, so not sure if they can pulse the power or just rely on the tires being massively sticky.
I don’t know how this team is doing it, but I do know from work with old-fashioned racecars that you anticipate that the wheels doing the acceleration are going to be slipping a little at your desired operating point, either in cornering, braking, or speeding up. If you have the sensor and computation bandwidth, you can optimize your amount of slip.
rubber tires transfer maximum force with something like 10% slip
I felt this in my neck
Germany produces this and it’s rad and setting records.
Reminded me of this and headline begs not to mock it:
https://hackaday.com/2023/01/17/the-first-afghan-sports-car-has-an-engine-you-shouldnt-mock/
the ETH is in Switzerland not Germany.
“custom electric hub motors”
CNC spindle derived motors ?
Faster Than EJ Potter?
https://thekneeslider.com/e-j-potter-and-the-super-slot-car/