Tesla was first to patent a primitive axial-flux electric motor—Nikola Tesla, that is, way back in 1889. It would be 126 years before the concept found its way to a car, the 1,500-horsepower (1,103 kilowatt), US $1.9 million, Koenigsegg Regera hybrid, in 2015. Even today, nearly all the world’s EVs and hybrids rely on relatively inefficient, easy-to-manufacture radial-flux motors.
Yet the latest electrified revolution is underway, led by YASA. Founded in the U.K. by Tim Woolmer in 2009, a spin-off from his Oxford PhD project, the company’s pioneering axial-flux motors are powering hybrid supercars from a Who’s Who of makers: Ferrari, Lamborghini, McLaren and Koenigsegg. Those include the Ferrari 296 Speciale and Lamborghini Temerario that I recently drove in Italy.
Boosted by these power-dense electric machines, these racy Italians carved up roads in Emilia-Romagna like hunks of prosciutto di Parma. The Temerario’s gasoline V-8 revs to a stratospheric 10,000 rpm, higher than any production supercar. Still not enough: The Temerario also integrates three YASA motors. A pair on the front axle deliver all-wheel-drive traction and a peak 294 horsepower (216 kilowatts). A total of 907 hybrid horsepower (667 kilowatts) sends the Temerario to a blistering 343 kph (213 mph) top speed. The electric motors ably fill any gaps in gasoline acceleration and finesse the handling with torque-vectoring , the electrified front wheels helping to catapult the Lamborghini out of corners with ridiculous ease.
With their compact design and superior power-to-weight ratio, these motors are setting records on land, sea and air. The world’s fastest electric plane, the Rolls-Royce Spirit of Innovation, integrated three YASA motors for its propeller, sending it to a record 559.9 kph (345.4 mph) top speed. Applying tech from its Formula E racing program, Jaguar used YASA motors to set a maritime electric speed record of 142.6 kph (886 mph) in England’s Lake District in 2018 (that record has since been broken).
Claimed Power Density is Three Times Tesla’s Best
In August, YASA’s motors helped the Mercedes-AMG GT XX prototype set dozens of EV endurance records. Cruising around Italy’s Nardo circuit at a sustained 186 mph (300 kph), the roughly 1,000-kilowatt (1,360 horsepower) Mercedes EV drove about 5,300 kilometers per day. In 7.5 days, it traveled 40,075 kilometers (24,902 miles), the exact equivalent of the earth’s circumference. That time included stops for charging, at 850 kilowatts.
Mercedes F1 driver George Russell stands next to a Mercedes AMG GT XX during its record-setting endurance run this past August. Powered by three YASA axial-flux motors, the concept EV drove the equivalent of the earth’s circumference in 7.5 days, at a near-steady 300 kph. A production version of the car could be a competitor for the Porsche Taycan. Mercedes-Benz
Mercedes bought YASA outright in 2021. Daimler, Mercedes’ corporate parent, is retrofitting a factory in Berlin to build up to 100,000 YASA motors a year, for the next logical step: The motors will power mass-produced EVs for the first time, specifically from AMG, Mercedes’ formidable high-performance division.
The company recently unveiled its latest motor, and its stats are eye-opening: The axial-flux prototype generates a peak 750 kilowatts, or 1,005 horsepower, as tested on a dynamometer. The motor can output a continuous 350-400 kilowatts (469-536 horsepower). Yet the unit weighs just 12.7 kilograms (27.9 pounds). Woolmer says the resulting power density of 59 kilowatts per kilogram is an unofficial world record for an electric motor, and about three times that of leading radial-flux designs, including Tesla’s.
“And this isn’t a concept on a screen — it’s running, right now, on the dynos,” Woolmer says. “We’ve built an electric motor that’s significantly more power-dense than anything before it, all with scalable materials and processes.”
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