Abstract: An aircraft includes an airframe, an extending tail, a counter rotating, coaxial main rotor assembly including an upper rotor assembly and a lower rotor assembly, and a translational thrust system positioned at the extending tail. The translational thrust system provides translational thrust to the airframe. An upper hub fairing is positioned at the upper rotor assembly. A lower hub fairing is positioned at the lower rotor assembly. A shaft fairing is disposed between the upper hub fairing and the lower hub fairing. The upper hub fairing is substantially sealed to the shaft fairing and the lower hub fairing is substantially sealed to the shaft fairing.

Abstract: A main rotor blade assembly for a rotary wing aircraft is provided including a main rotor blade root region, a main rotor blade inboard region arranged outboard of said main rotor blade root region, a main rotor blade main region arranged outboard of said main rotor blade inboard region, and a main rotor blade tip region arranged outboard of said main rotor blade main region. At least one of chord, twist, sweep, airfoil shape, and thickness/chord of the main rotor blade assembly has been optimized to achieve balanced high speed forward flight and hover relative to both efficiency and high thrust capability.

Abstract: An aircraft includes an airframe, an extending tail, a counter rotating, coaxial main rotor assembly including an upper rotor assembly and a lower rotor assembly, and a translational thrust system positioned at the extending tail. The translational thrust system provides translational thrust to the airframe. An upper hub fairing is positioned at the upper rotor assembly. A lower hub fairing is positioned at the lower rotor assembly. A shaft fairing is disposed between the upper hub fairing and the lower hub fairing. The upper hub fairing is substantially sealed to the shaft fairing and the lower hub fairing is substantially sealed to the shaft fairing.

Abstract: A main rotor blade assembly for a rotary wing aircraft is provided including a main rotor blade root region, a main rotor blade inboard region arranged outboard of said main rotor blade root region, a main rotor blade main region arranged outboard of said main rotor blade inboard region, and a main rotor blade tip region arranged outboard of said main rotor blade main region. At least one of chord, twist, sweep, airfoil shape, and thickness/chord of the main rotor blade assembly has been optimized to achieve balanced high speed forward flight and hover relative to both efficiency and high thrust capability.

Abstract: An aircraft 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; an upper hub fairing positioned at the upper rotor assembly; a lower hub fairing positioned at the lower rotor assembly; and a shaft fairing disposed between the upper hub fairing and the lower hub fairing; wherein a geometry of at least one of the upper hub fairing and the lower hub fairing progressively blends from a circle to a series of curved elliptical surfaces in an inboard direction.

Abstract: A stationary ground tube for use in an aircraft rotor fairing includes a first cylindrical portion including a first bore aligned along a longitudinal axis, the cylindrical body portion having a tubular body from a first end to a second end; and a second cylindrical portion coupled to the first cylindrical portion, the second cylindrical portion including a second bore aligned along the longitudinal axis. The second cylindrical portion is coupled to the aircraft rotor fairing via at least one attachment device.

Abstract: A stationary ground tube for use in an aircraft rotor fairing includes a first cylindrical portion including a first bore aligned along a longitudinal axis, the cylindrical body portion having a tubular body from a first end to a second end; and a second cylindrical portion coupled to the first cylindrical portion, the second cylindrical portion including a second bore aligned along the longitudinal axis. The second cylindrical portion is coupled to the aircraft rotor fairing via at least one attachment device.

Abstract: A main rotor blade incorporating a rotor blade tip region having a tip chord and a tip taper such that the ratio of the main rotor blade chord to the tip chord is approximately 0.30. The tip taper ratio preferably providing an approximately 28% area of reduction in said outer 10% of said blade span. The tip region preferably further including a hover optimized high lift airfoil and a tip sweep that reaches a constant value of approximately 30 degrees along the quarter chord line.

Abstract: A mounting arrangement (100) for a Variable Diameter Rotor blade assembly (16) having an outer blade segment telescopically mounting to a torque tube member (24), and connecting means (70) for transferring centrifugal loads of the outer blade segment (22) to a rotor hub assembly (18). The outer blade segment (22) includes a spar member (30) having a longitudinal axis (26) and defining an internal channel (62) for accepting the torque tube member (24) and the connecting means (70). The mounting arrangement (100) couples the connecting means (70) to the spar member (30) and includes a restraint surface (86) formed within the spar member (30) and a restraint assembly (68) disposed in combination therewith. The restraint surface (86) is disposed inboard of the tip end (90) of the spar member (30) and in a plane oriented transversely of the longitudinal axis (26).

Abstract: A rotor blade subassembly for a rotor assembly having ducted, coaxial counter-rotating rotors includes a flexbeam, an integrated torque tube/spar member, and an aerodynamic fairing or rotor blade. The flexbeam is a laminated composite structure that reacts centrifugal loads and a majority of the bending loads of the rotor assembly. The flexbeam has a spanwise predetermined linear twist so that the pretwisted flexbeam is unstrained during specified forward flight conditions. The integrated torque tube/spar member is formed as a continuous, filament wound tubular composite structure having high torsional and bending stiffness that provides a continuous torsional load path and facilitates load coupling between the rotor blade and the pretwisted flexbeam. The spar segment of the functions as the primary structural member of the rotor blade subassembly and, is operative to react all bending, torsional, shear, and centrifugal dynamic loads of the rotor assembly.