An aircraft includes an airframe having an extending tail, a counter rotating, coaxial main rotor assembly disposed at the airframe including an upper rotor assembly and a lower rotor assembly, and a translational thrust system positioned at the extending tail and providing translational thrust to the airframe; The aircraft is configured to operate at an altitude of over 20,000 feet and at an airspeed of greater than 200 knots.

An aircraft is provided including an airframe, an extending tail, and a counter rotating, coaxial main rotor assembly including an upper rotor assembly and a lower rotor assembly. The upper rotor assembly and the lower rotor assembly each include a plurality of blades. A translational thrust system is positioned at the extending tail and provides translational thrust to the airframe. The plurality of blades of the main rotor assembly extend beyond a nose of the aircraft by about 13 inches.

An aircraft includes an airframe having an extending tail, and a counter rotating, coaxial main rotor assembly located at the airframe including an upper rotor assembly and a lower rotor assembly. A translational thrust system is positioned at the extending tail and providing translational thrust to the airframe. An active vibration control (AVC) system is located and the airframe and includes a plurality of AVC actuators configured to generate forces to dampen aircraft component vibration, and an AVC controller configured to transmit control signals to the plurality of AVC actuators thereby triggering force generation by the plurality of AVC actuators. A method of damping vibration of an aircraft includes receiving a vibration signal at an AVC controller, communicating a control signal from the AVC controller to a plurality of AVC actuators, generating a force at the AVC actuators, and damping vibration of the aircraft via the generated force.

An aircraft is provided and includes an airframe, an extending tail, a counter rotating, coaxial main rotor assembly including an upper rotor assembly and a lower rotor assembly, a translational thrust system positioned at the extending tail, the translational thrust system providing translational thrust to the airframe, at least one sensor and at least one inertial measurement unit (IMU) to sense current flight conditions of the aircraft, an interface to execute controls of a main rotor assembly in accordance with control commands and at least one flight control computer (FCC) to issue the control commands. The at least one FCC includes a central processing unit (CPU) and a memory having logic and executable instructions stored thereon, which, when executed, cause the CPU to issue the control commands based on the current flight conditions and a result of an execution of the logic for the current flight conditions.

A method of controlling a rotary wing aircraft includes accelerating the aircraft in a fore direction independently of cyclic control of the main rotor and pitch of the aircraft.

An aircraft is provided including an airframe, an extending tail, and a counter rotating, coaxial main rotor assembly including an upper rotor assembly with a plurality of blades rotating in a first plane and a lower rotor assembly with a plurality of blades rotating in a second plane, each of the blades having a root end, a midpoint, and a tip end. A translational thrust system positioned at the extending tail, the translational thrust system providing translational thrust to the airframe. The blades of the upper rotor assembly and the blades of the lower rotor assembly are indexed to improve tip end clearance between pairs of tip ends in the crossing plane as the tip ends move in respective first and second sinusoidal paths.

An aircraft is provided including an airframe, an extending tail, and a counter rotating, coaxial main rotor assembly including an upper rotor assembly with an upper blade and a lower rotor assembly with a lower blade. A first antenna in one of upper blade and the lower blade, and a second antenna in the other of the upper blade and the lower blade. An oscillator to apply an excitation signal to the first antenna. A blade proximity monitor to monitor a magnitude of the excitation signal and an output signal from the second antenna to determine a distance between the upper blade and the lower blade.

A bottom abutment device for a rotor having a plurality of lift assemblies. The bottom abutment device comprises at least one abutment track per lift assembly. The bottom abutment device comprises a plate with a ring and one branch per lift assembly. The bottom abutment device has a plurality of supports, each support including fastener means for fastening to a rotary member of the rotor, each support extending in part in an opening in a branch, the supports giving the plate a restricted degree of freedom to move in translation, the supports giving the plate at least one restricted degree of freedom to move in rotation about the axis of symmetry.

A rotor for a rotorcraft, the rotor having a plurality of lift assemblies, together with a flapping abutment mechanism for each lift assembly. Each abutment mechanism has a projection secured to a lift assembly with an abutment end provided with an inner face and an outer face, and at least one pivotally-mounted lever extending longitudinally from a flyweight to a hook. The hook is provided with two walls in elevation and a bottom wall forming a periphery that defines the groove, a first wall in elevation having an upper bearing zone for blocking the inner face and a second wall in elevation including a lower bearing zone for blocking the outer face.

A rotor assembly includes a yoke operably associated with a rotor blade. The yoke includes a first device and a second device that attach the rotor blade to the yoke. The first device is configured to allow transverse movement of the rotor blade about a chord axis and rotational movement about a pitch-change axis. The second device is configured to allow rotational movement of the rotor blade solely about the pitch-change axis. The method includes rotating rotor assembly about a first plane of rotation, while retaining a relatively stiff out-of-plane rotation and a relatively soft in-plane rotation during flight.