Tiny electric motor can produce more than 1,000 horsepower

Original Article ↗ Hacker News Discussion ↗

Better link and units discussion

  • Many prefer the original YASA press release over the clickbait article, as it has specs, test data, and context.
  • Long subthread on whether to express power density as kW/kg vs W/g. Consensus: kW/kg is standard because kg and kW are SI base units in this context and communicate scale better, even if W/g is mathematically equivalent.
  • Side debates on aspect ratios, “silly” composite units, and metric vs imperial quirks (e.g., kilograms as base unit).

Power density and impact on EVs

  • The motor’s 59 kW/kg (≈750 kW peak, ~350–400 kW continuous at ~13 kg) is seen as a major power-density milestone.
  • Enthusiastic takes: weight savings compound across the vehicle (smaller battery, lighter structure, smaller brakes), particularly valuable for performance cars, light EVs, and aircraft.
  • Skeptical takes: in mainstream EVs the battery dominates mass; shaving ~30–70 kg of motor weight on a 1.6–2.0 ton car is only a few percent and won’t be a “game changer” for range. Batteries remain the bottleneck.

Hub motors, unsprung weight, and layouts

  • Big discussion on whether these are intended as in-wheel (hub) motors. Some assume yes due to pancake shape; others note YASA’s current use is inboard on axles.
  • Unsprung weight is a recurring concern: adding heavy hub motors hurts ride and handling, especially for performance vehicles.
  • Still, high power density could make multi-motor layouts (one per wheel, no differentials) more attractive, enabling better torque vectoring and possibly smaller brake systems.

Cooling, efficiency, and engineering tradeoffs

  • Commenters question how such a small unit sheds heat at hundreds of kW; YASA’s own info mentions direct oil cooling and very high efficiency as prerequisites for this density.
  • Some note peak power claims can be gamed by very short pulses; continuous ratings (350–400 kW) are seen as the more meaningful figure.
  • Axial-flux advantages (shorter flux paths, high torque) are acknowledged, but manufacturing complexity, bearing loads, and SMC losses at low frequency are cited as challenges.

Other applications and economics

  • Suggested use cases: electric flight (especially short-range or high-payload), drones, motorcycles, e-bikes, robotics, nose-wheel taxi motors for airliners, high-end hybrids, and race vehicles.
  • Questions remain about scaling the design down (for bikes/tools) or up (for ships/generators), and about actual efficiency vs conventional motors.
  • Some lament that such electromechanical innovations attract modest investment compared to software/AI, and note that YASA’s ownership by Mercedes may limit broad availability.