The present invention includes a span-balance pocket in a surface of a rotor blade, the span-balance pocket including an inboard surface and an outboard surface; and one or more weights disposed in the span-balance pocket to span-balance the rotor blade; and at least one of one or more retention devices to retain the one or more weights against the outboard surface of the span-balance pocket or the span-balance pocket is machined or molded into a tip block of the rotor blade.

A system and method for measuring, or otherwise determining pitch length adjustments to a pitch link coupled to a rotor blade in a rotorcraft includes vertical track adjustment indicators machined onto an exterior of the tube of the pitch link and a vertical reference indicator machined onto an exterior of the upper or the lower rod of the pitch link. A metric of a pitch length adjustment can be determined by tracking or counting how many track adjustment indicators pass the reference indicator while the tube of the pitch link is being turned in either direction for increasing or decreasing the pitch length. The track adjustment indicators can be relied upon to track one or a series of adjustments for tracking a rotor blade installed in a rotor assembly.

An aircraft includes an airframe having an empennage, a counter rotating, coaxial main rotor assembly located at the airframe including an upper rotor assembly and a lower rotor assembly, and a translational thrust system positioned at the empennage and providing translational thrust to the airframe. At least two control surfaces located at the empennage are independently operable via commands from one or more flight control computers. A method of operating an aircraft includes transmitting a first signal from one or more flight control computers to a first control surface located at a first lateral side of a translational thrust system, and actuating the first control surface to a first position via the first signal. A second signal is transmitted to a second control surface located at a second lateral side opposite the first lateral side, and the second control surface is actuated to a second position via the second signal.

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. A flight control computer is configured to control a main rotor rotational speed of the upper and the lower rotor assemblies of the main rotor assembly as a function of airspeed of the aircraft. A method of operating an aircraft includes retrieving a threshold main rotor rotational speed of the dual coaxial main rotor assembly and calculating an actual main rotor rotational speed according to an environment of the aircraft. The actual main rotor rotational speed is maintained to remain at or below the threshold main rotor speed according to an airspeed of the aircraft.

The present invention includes a balancing system that includes a weight box, mounted substantially within the rotor-blade spar, flush with a rotor-blade spar outer surface, operably accessible from a rotor-blade tip, and retained within the rotor-blade spar by a weight-box retention pin, one or more weight-box contact surfaces bonded to a rotor-blade-spar inner surface, or a weight-box lip providing a bearing contact with an edge of a spar rotor-blade spar cutout; and a weight package attached to the weight box, the weight package including a weight-box cover, two or more weight guide-rods attached to the weight-box cover, wherein one of the two or more weight guide-rods is positioned forward of a pitch change axis or center of twist and wherein one of the two weight guide-rods is positioned aft of the pitch change axis or center of twist, and one or more balance weights mounted on the weight guide-rods.

In one embodiment, a rotor blade may comprise a blade body, a spar structure, and a blade nose. The blade body may comprise a skin, wherein the skin is configured to form an airfoil shape, and wherein the airfoil shape comprises an inboard end, an outboard end, a leading edge, and a trailing edge. The spar structure may comprise a first spar cap and a second spar cap, wherein the first spar cap is coupled to an upper portion of the skin, and wherein the second spar cap is coupled to a lower portion of the skin. The blade nose may comprise a cavity, wherein the cavity is configured to house a plurality of modular weights at a plurality of radial blade locations, wherein the plurality of radial blade locations comprises a range of locations between the inboard end and the outboard end.

A rotor blade is provided that includes an airfoil extending spanwise from a base to a tip. The airfoil extends longitudinally (e.g., chordwise) from a leading edge to a trailing edge. The airfoil extends laterally between a first side and a second side. The airfoil includes a body and a weight. The body includes a plurality of body layers. Each of the body layers includes fiber reinforcement within a body thermoplastic matrix. The weight includes a weight layer embedded within the body. The weight layer includes metal powder within a weight thermoplastic matrix.

A rotorcraft has a rotor blade having a spar comprising an internal space. A weight system is disposed within the spar and the weight system includes a weight tray having an open top, a weight guide rod connected to the weight tray. The weight guide rod extends in a spanwise direction through an interior of the weight tray and a weight is disposed on the weight guide rod and vertically captured by at least one side wall of the weight tray. The weight guide rod is insertable into the weight tray from a location above the weight tray to restrict longitudinal movement of the weight guide rod relative to the weight tray.

A rotorcraft has a rotor blade having a spar comprising an internal space. A weight system is disposed within the spar and the weight system includes a weight tray having an open top, a weight guide rod connected to the weight tray. The weight guide rod extends in a spanwise direction through an interior of the weight tray and a weight is disposed on the weight guide rod and vertically captured by at least one side wall of the weight tray. The weight guide rod is insertable into the weight tray from a location above the weight tray to restrict longitudinal movement of the weight guide rod relative to the weight tray.

A blade tracking system including a detector having one or more sensors to detect radiation from at least one field of view of the detector, the one or more sensors generating signals based on changes in incident radiation to the one or more sensors as a rotor blade passes the field of view, and a processor to determine a pass time for the rotor blade to pass through the at least one field of view based on the generated signals.