A 28-pound motor makes 1,000 hp — and Britain had to watch Germany build it

The motor, and why it matters

Mercedes-Benz began large-scale production of its axial-flux electric motor at the Berlin-Marienfelde plant in June 2026 — seven production lines across roughly 30,000 m² in three halls. The technology came from YASA, the Oxford-born specialist Mercedes acquired in 2021.

The numbers are the reason engineers care. An axial-flux ("pancake") motor routes magnetic flux parallel to the shaft instead of radially, which collapses the package. YASA's second-generation unit weighs just 12.7 kg (28 lb) and produces 750 kW — over 1,005 hp — a power density of 59 kW/kg, up from 42 kW/kg in the prior prototype. The front-axle motor in the AMG GT 4-Door Coupé is under nine centimetres wide and spins past 15,000 rpm; three of them together produce a 0–100 km/h of 2.1 seconds. As the thread's most grounded comment noted, "The main benefit here seems to be smaller and lighter for the same power output."

The thread's wound: invented in Britain, built in Germany

The top comment wasn't about torque. It was about industrial policy, and it stung:

"Ah, another fantastic British innovator (YASA) having to realize its potential … abroad. Brought to you by the only country to have a space programme and abandon it." — throwaway132448

Someone who'd been around for the original news supplied the receipt — the idea was on HN years ago and nobody blinked:

"Four years ago, when YASA's invention was discussed on HN, it attracted very little interest. Mercedes apparently saw more potential and decided to invest." — the author of Hyvector

The contrarian: complexity is a trap, not a moat

The most interesting dissent argued the whole bet is backwards — that celebrating a fiendishly complex process is how legacy automakers lose:

"Never become dependent on doing hideously complicated things. You will eventually struggle to choose to do something more efficient, as the european auto industry is currently displaying. … Surely we'd all be better off with simpler and cheaper processes." — eptcyka

A more measured engineer mapped the actual risk: axial-flux is unproven at mass-market scale, with "Higher loads and stresses, tighter tolerances" that "could make the axial motors less reliable," while radial stays "good enough" for most cars for another decade. The blunt bear case needed only nine words: "10 years behind Tesla, they are doomed."

The criticism Mercedes earned: explain your own product

One high-karma reader landed a fair hit on the press release itself: "It would have been awesome if that article had, at any point, explained what an electric axial flux motor was, and why anyone might want one." That's the gap this story sits in — a genuine engineering milestone, wrapped in a launch that assumed you already knew why a 28-pound motor making four-figure horsepower is a big deal. The reason it's a big deal: less unsprung mass and a tiny package mean the motor stops being the thing you design the car around. Whether Mercedes can make that reliable at volume — and whether the UK keeps exporting the next one — are the open questions the thread actually cared about.