Abstract: A coupling system is described that allows users to avoid having to manipulate two tools at the same time while reaching around to both sides of the coupled components. A lock plate can rest above one or more holes passing through (and for joining together) the components. A blade pin with a partially hollow cylinder can be inserted through holes in the lock plate and at least partially through the holes. A blade bolt can be inserted into the holes and the cylinder from the other side. The blade bolt can comprise an o-ring that engages with an inner diameter of a portion of the cylinder and holds the parts together with an interference fit. A portion of the bolt can extend through the top of the holes, and a washer and nut can be attached to or about a threaded portion of the bolt. During each state of installation a user will not have to reach to both sides of the system while manipulating multiple tools.

Abstract: A system for monitoring of elastomeric bearings is described. A pattern or shape can be applied to a joint comprising elastomeric material. A camera can be disposed such that it can capture photographs or video of the pattern and how it deforms under torque and other stresses. Actual deformation of the shape/pattern can be compared to an expected deformation to gauge levels of degradation of the elastomeric material or other joint components.

Abstract: A system for monitoring of elastomeric bearings is described. A pattern or shape can be applied to a joint comprising elastomeric material. A camera can be disposed such that it can capture photographs or video of the pattern and how it deforms under torque and other stresses. Actual deformation of the shape/pattern can be compared to an expected deformation to gauge levels of degradation of the elastomeric material or other joint components.

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 attachment assembly for coupling a rotary blade to a hub includes a hollow shear pin, a nut cap, and a tensioning fastener. The hollow shear pin defines an attachment axis. The nut cap abuts the shear pin along the attachment axis. The tensioning fastener is seated within the shear pin, is threadably engaged to the nut cap, and has an axial length that is smaller than an axial length of the shear pin to fix a rotary blade to a rotor assembly within a profile of the rotary blade.

Abstract: An attachment assembly for coupling a rotary blade to a hub includes a hollow shear pin, a nut cap, and a tensioning fastener. The hollow shear pin defines an attachment axis. The nut cap abuts the shear pin along the attachment axis. The tensioning fastener is seated within the shear pin, is threadably engaged to the nut cap, and has an axial length that is smaller than an axial length of the shear pin to fix a rotary blade to a rotor assembly within a profile of the rotary blade.

Abstract: An aircraft includes an airframe and a rotary component rotatably connected to the airframe by way of a plain bearing. The rotary component is part of a rotorcraft control system. The plain bearing includes an inner member rotatably engaged in at least two axes of rotation to an outer member. The inner member has a coefficient of thermal expansion (CTE) substantially less than that of the outer member.

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 and a rotary component rotatably connected to the airframe by way of a plain bearing. The rotary component is part of a rotorcraft control system. The plain bearing includes an inner member rotatably engaged in at least two axes of rotation to an outer member. The inner member has a coefficient of thermal expansion (CTE) substantially less than that of the outer member.

Abstract: A helicopter rotor blade includes a structural composite skin defining a cavity therein; a composite spar disposed within the cavity and adhesively bonded to the skin, a portion of the spar exhibiting a C-shape in cross section; and a foam core disposed within the cavity and adhesively bonded to the skin. The structural composite skin forms an external, closed box structure configured to transmit mechanical loads encountered by the rotor blade.

Abstract: A rotor yoke includes a blade attachment portion, a mast attachment portion, and an intermediate portion extending between the blade attachment portion and the mast attachment portion. The intermediate portion, the blade attachment portion, and the mast attachment portion define an optional inner edge, such that the inner edge, if present, defines an opening. The rotor yoke further includes a peripheral, outer edge extending about the blade attachment portion, the intermediate portion, and the mast attachment portion. At least one of the outer edge and the inner edge, if present, includes a reduced thickness portion exhibiting a thickness that is less than a thickness of an adjacent portion of the rotor yoke.

Abstract: A helicopter rotor blade includes a structural composite skin defining a cavity therein; a composite spar disposed within the cavity and adhesively bonded to the skin, a portion of the spar exhibiting a C-shape in cross section; and a foam core disposed within the cavity and adhesively bonded to the skin. The structural composite skin forms an external, closed box structure configured to transmit mechanical loads encountered by the rotor blade.

Abstract: A rotor yoke includes a blade attachment portion, a mast attachment portion, and an intermediate portion extending between the blade attachment portion and the mast attachment portion. The intermediate portion, the blade attachment portion, and the mast attachment portion define an optional inner edge, such that the inner edge, if present, defines an opening. The rotor yoke further includes a peripheral, outer edge extending about the blade attachment portion, the intermediate portion, and the mast attachment portion. At least one of the outer edge and the inner edge, if present, includes a reduced thickness portion exhibiting a thickness that is less than a thickness of an adjacent portion of the rotor yoke.