Found this in my e-mail and sounds interesting. Source: https://www.automotive-iq.com/electrics-electronics/articles/can-modern-e-motors-dispel-power-density-concerns?utm_campaign=AUIQ NL 2018 Week 49&utm_medium=email&utm_source=internalemail&MAC=AUIQ1-OM79Y2X|1-E3QCWCD&elqContactId=13876107&disc=&elqCampId=36891 Magnax, a Belgian startup, claims its direct drive motor has a peak power density of 15 kW/kg, with a continuous rating of around 7.5 kW/kg. To put this in context - a BMW S1000RR superbike has a lightweight motor producing a relatively modest 2.7 kW/kg. According to Magnax this impressive output is as a result of the direct drive axial flux design that uses a stator disc sandwiched between two rotor discs with small air gaps in between. Among the several advantages that yokeless axial flux motors have over the more common radial flux design, are a shorter flux path and magnets positioned further away from the axis, leading to greater efficiency and leverage. . . . I need more technical details but this looks interesting. The two, exterior rotors have a lot of area exposed for cooling and are in motion. The sandwiched stator is doing double duty, both sides, versus the single side of traditional motors. So liquid cooling could easily handle the heat load. Now if it could just have high-temperature, superconductor coils ... High temperature, superconductors operate at liquid nitrogen temperatures. But because of their low resistance, they don't generate heat like typical coils. It would be cheaper to run a solid-state or even gas-based cooling system than have to dump the heat of normal stators. Bob Wilson
