An aircraft is provided including an airframe, an extending tail, a counter-rotating, coaxial main rotor assembly having an upper rotor assembly and a lower rotor assembly, and a translational thrust system including a propeller positioned at the extending tail. The translational thrust system is configured to provide translational thrust to the airframe when the aircraft is in a non-autorotation state and to generate power when in an autorotation state. A gearbox interconnects the propeller and the main rotor assembly to drive the main rotor assembly and the translational thrust system in the non-autorotation state. When the aircraft is in autorotation, the power generated by the propeller drives rotation of the main rotor assembly via the gearbox.