Since the new motor delivers its record-setting performance at rotational speeds of just 2,500 revolutions per minute, it can drive propellers directly, without the use of a transmission. “This innovation will make it possible to build series hybrid-electric aircraft with four or more seats,”
Read more at: http://phys.org/news/2015-04-world-record-electric-motor-aircraft.html#jCp
http://phys.org/news/2015-04-world-record-electric-motor-aircraft.html