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 foldable rotor blade assembly includes a first section including a connector assembly including a plurality of through holes and a second section including a connector having a plurality of openings. The connector is receivable within a hollow interior of the first section. A plurality of fasteners insertable within the plurality of through holes and the plurality of openings. A fold assembly is operably coupled to both the first section and the second section. The fold assembly defines a blade fold axis about which the second section is rotatable to transform the rotor blade assembly between a normal configuration when the connector is received within the hollow interior of the first section, and a folded configuration when the connector has rotated outside of the hollow interior of the first section.

Abstract: A fairing system, includes a hub fairing and a fixed fairing, such as a shaft fairing or a pylon fairing, both arranged about a rotation axis. A gap is defined between the hub fairing and the fixed fairing, and a seal assembly is axially interposed between the hub fairing and the fixed fairing. The fixed fairing and the hub fairing are both removably mounted to the seal assembly such that either or both of the fairings can be dismounted from the seal assembly without disturbing the seal assembly to provide access to components disposed within the fairing.

Abstract: A foldable rotor blade assembly includes a first section including a connector assembly including a plurality of through holes and a second section including a connector having a plurality of openings. The connector is receivable within a hollow interior of the first section. A plurality of fasteners insertable within the plurality of through holes and the plurality of openings. A fold assembly is operably coupled to both the first section and the second section. The fold assembly defines a blade fold axis about which the second section is rotatable to transform the rotor blade assembly between a normal configuration when the connector is received within the hollow interior of the first section, and a folded configuration when the connector has rotated outside of the hollow interior of the first section.

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 fairing system, includes a hub fairing and a fixed fairing, such as a shaft fairing or a pylon fairing, both arranged about a rotation axis. A gap is defined between the hub fairing and the fixed fairing, and a seal assembly is axially interposed between the hub fairing and the fixed fairing. The fixed fairing and the hub fairing are both removably mounted to the seal assembly such that either or both of the fairings can be dismounted from the seal assembly without disturbing the seal assembly to provide access to components disposed within the fairing.

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: 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.