British electric motor specialist YASA has once again redefined the technological limits of power density in high-performance electric propulsion. The company’s latest axial flux prototype motor has achieved an extraordinary 59 kW/kg power density — marking an unprecedented leap in electric motor engineering.
Earlier this summer, YASA reached an unofficial record of 42 kW/kg when its 13.1 kg motor delivered a peak output of 550 kW (738 bhp). Now, with a refined 12.7 kg version tested on a more powerful dynamometer, the development team has recorded a short‑term peak power of 750 kW (>1,000 bhp). This represents a 40% performance improvement compared to the previous prototype and sets a new benchmark that pushes the boundaries of axial flux technology.
Beyond headline peak figures, YASA projects a continuous power capability between 350 kW and 400 kW (469–536 bhp), reinforcing the prototype’s viability for high‑performance automotive applications. The motor’s compact and lightweight design uses no exotic materials, relying instead on advanced thermal management, precision electromagnetic optimization, and an innovative structural layout to achieve exceptional efficiency and scalability.
Developed and manufactured at YASA’s Oxford Innovation Centre with support from the UK’s Advanced Propulsion Centre, the prototype represents a tangible step forward in electrified propulsion technology. Unlike theoretical models or digital simulations, this is a fully functional test unit currently undergoing extensive validation cycles on the dynamometer.
Tim Woolmer, YASA’s founder and Chief Technical Officer, described the achievement as a significant validation of the company’s next‑generation axial flux architecture:
“Achieving a 750 kW short-term rating at 59 kW/kg demonstrates what focused engineering innovation can deliver. This motor is running today — not just existing on a screen — and it shows the potential of scalable materials and manufacturing processes to transform high-performance electrification.”
YASA’s breakthrough underscores the continuing evolution of axial flux designs toward higher specific power density, compact size, and manufacturability — parameters crucial for future supercars, aerospace, and performance EV applications. The company’s test program will now focus on endurance validation, system integration studies, and scaling the technology for production-ready variants.
