“…Even for the relatively small X-57, Falck et al [62] found that the air-cooled motors will reach its temperature limits during climb, which would constrain the climb rate. However, Tallerico et al [63], showed that an efficiency of >96% could be achieved for the X-57 motors with cooling provided only with the flow from the propeller wake travelling over the outer mould line of the nacelle in which the motor is embedded.…”