US Patent 10150567 Rotor systems for rotorcraft

A rotor system for a rotorcraft includes a first rotor assembly defining a rotation axis, a second rotor assembly offset from the first rotor assembly along the rotation axis, and a drive system connected to the first and second rotor assemblies. The drive system includes a first electric motor disposed along the rotation axis and operably connected to the first rotor assembly, and a second electric motor disposed along the rotation axis and operably connected to the second rotor assembly to rotate the second rotor assembly about the rotation axis independent of rotation of the first rotor assembly about the rotation axis.