Rotor assembly connectable to rotor hub and having pitch control

A co-axial rotary wing aircraft, comprising:

• a first rotor hub configured to spin about a central axis in a first direction;
• a first torsional pitch member extending away from the central axis and coupled to the first rotor hub at a first position such that the first torsional pitch member does not hinge about the first rotor hub, wherein the first torsional pitch member includes a first curvilinear channel and a second curvilinear channel each having a front side and a back side, wherein the first curvilinear channel and the second curvilinear channel are disposed adjacent to each other, such that the back side of the first curvilinear channel faces the back side of the second curvilinear channel;
• a first blade coupled to the first rotor hub and associated with a first pitch angle;
• a first torque tube coupled to the first torsional pitch member such that a portion of the first torque tube surrounds the first torsional pitch member;
• a second rotor hub configured to spin about the central axis in a second direction that is opposite the first direction;
• a second torsional pitch member extending away from the central axis and coupled to the second rotor hub at a second position such that the second torsional pitch member does not hinge about the second rotor hub;
• a second blade coupled to the second rotor hub and associated with a second pitch angle;
• and
• a second torque tube coupled to the second torsional pitch member such that a portion of the second torque tube surrounds the second torsional pitch member.

A method of controlling a co-axial rotary wing aircraft, the method comprising:

• controlling, by a pitch control member, a pitch input to a pitch horn, the pitch horn being coupled to a rotor assembly including:
• a rotor hub configured to rotate about a center axis;
• a blade defining a pitch angle and comprising:
• a torsional pitch member coupled to the rotor hub, wherein the torsional pitch member includes a first curvilinear channel and a second curvilinear channel each having a front side and a back side, wherein the first curvilinear channel and the second curvilinear channel are disposed adjacent to each other, such that the back side of the first curvilinear channel faces the back side of the second curvilinear channel;
• a torque tube coupled to the torsional pitch member, wherein the torsional pitch member extends away from the center axis through a portion of the torque tube;
• and
• a blade spar coupled to the torque tube.