Abstract: One aspect of a method of manufacturing a honeycomb core includes positioning a first thermoplastic columnar cell adjacent a second thermoplastic columnar cell, modifying a thermoplastic property of the first thermoplastic columnar cell, wherein the modified thermoplastic property permits joining a circumferential surface of the first thermoplastic columnar cell to a circumferential surface of the second thermoplastic columnar cell. The method also includes joining the circumferential surface of the first thermoplastic columnar cell having the modified thermoplastic property to the circumferential surface of the second thermoplastic columnar cell resulting in the honeycomb core.

Abstract: A method for calculating torque through a rotor mast of a propulsion system of a tiltrotor aircraft includes receiving the torque being applied through a quill shaft of the rotorcraft. The quill shaft is located between a fixed gearbox and a spindle gearbox, and the spindle gearbox is rotatable about a conversion access. The torque through the rotor mast is determined by using the torque through the quill shaft and the efficiency loss value between the quill shaft and the rotor mast.

Abstract: Some examples of rotating shaft damping with electro-rheological fluid can be implemented as a method. At least a portion of a circumferential surface area of a portion of a rotorcraft rotating shaft is surrounded with multiple hollow members. Each hollow member includes an electro-rheological fluid having a viscosity that changes based on an electric field applied to the electro-rheological fluid. A vibration of the rotorcraft rotating shaft is controlled by changing the viscosity of the electro-rheological fluid in response to the electric field applied to the electro-rheological fluid.

Abstract: According to one embodiment, a bearing is situated between a pitch link and a swashplate or a hub. The bearing comprises an outer housing having a first opening therethrough, an intermediate housing adjacent the housing inside the first opening and having a second opening therethrough, and an inner housing adjacent the intermediate housing inside the second opening and having a third opening therethrough. The inner housing comprising a first inner surface and a second inner surface defining the third opening. A first member is adjacent the first inner surface inside the third opening having a fourth opening therethrough. A second member is adjacent the second inner surface inside the third opening having a fifth opening therethrough coaxial with the fourth opening.

Abstract: An adapter is configured to hold a loose tube fiber cable and is mountable into a fusion splicer. The adapter includes a clamp base having a first and second grooves, each groove having a centerline, a width and a depth. The depth of the second groove is greater than the depth of the first groove, such that a shoulder is formed between the first and second grooves. The centerlines of the grooves align. This allows for the loose tube fiber cable or splice-on connector to be properly positioned within the grooves. The first groove is V-shaped. The second groove may be V-shaped, U-shaped or square-shaped. A clamp cover seats on the clamp base. The clamp cover has a compressible pad which, when the clamp cover is placed into a facing relationship with the clamp base, the pad aligns with the first groove.

Abstract: A quill shaft is configured for transferring torque and accepting misalignments between a fixed gearbox and a rotatable spindle gearbox in a propulsion system of a tiltrotor aircraft, the quill shaft includes a first splined portion configured for coupling to an output gear of the fixed gearbox, and a second splined portion configured for coupling to an input gear of the spindle gearbox. The spindle gearbox includes a rotor mast associated therewith, the spindle gearbox being rotatable so that the tiltrotor aircraft can selectively operate in a helicopter mode and airplane mode.

Abstract: A battery heater system for a battery used in cold weather operations and methods for using the battery heater system are described. Embodiments of the battery heater system may incorporate a heater switch with an indicator, a timer circuit, a controller, a voltage meter, a temperature transducer, and a heating element. In some methods of using the device, the battery powers the heating element for a fixed cycle time based on the time to discharge the battery at a cold-soaked temperature. In other methods of using the device, the battery powers the heating element for a varying cycle time as necessary to discharge the battery to a discharge cut-off voltage value. In other methods of using the device, the heating element is operated using a duty cycle that is varied based on the battery temperature.

Abstract: A rotor blade system includes a first hub assembly having a first set of rotor blades and rotatably attached to a rotor mast, a second hub assembly having a second set of rotor blades and rotatably attached to the rotor mast, the second hub assembly being positioned at a space relative to the first hub assembly, a torque splitter device engaged with both the first hub assembly and the second hub assembly, and a locking device operably associated with the torque splitter device. The method includes rotating the first hub relative to the second hub via the torque splitter until the first set of rotor blades align with the second set of rotor blade about a common horizontal axis.

Abstract: A tiltrotor aircraft includes a fuselage, a wing member extending from the fuselage, an engine disposed relative to the wing member and a proprotor mechanically coupled to the engine. The proprotor includes a plurality of proprotor blade assemblies each including a spar and a sheath extending spanwise along the spar forming the leading edge of the proprotor blade assembly. The spar has a root section, a main section and a tip section. The spar has a generally oval cross section at radial stations along the main section and a first edge having a structural bias relative to a generally oppositely disposed second edge at the radial stations along the main section.

Abstract: A method for making a composite-metal hybrid shaft for a rotorcraft includes providing a tubular metal member that has an internal surface defining a space therein, preparing a composite member using a curing tool, curing the composite member, creating a cured composite member, expanding the metal member with heat, placing the cured composite member into the space defined by the internal surface of the expanded metal member, and allowing the expanded metal member to cool.

Abstract: A method of assisting in rotor speed control in a rotorcraft can include measuring a rotor speed with a sensor; detecting a droop in the rotor speed beyond a lower droop limit; and commanding a decrease in collective in response to the rotor speed drooping beyond the lower droop limit. A system of assisting in rotor speed control in a rotorcraft, the system can include: a computer having a control law, the control law operable to generate a decrease collective command to an actuator in response to a rotor speed decreasing below a lower droop limit; wherein the lower droop limit is below a normal lower rotor speed range.

Abstract: A tiltrotor aircraft includes a fuselage, a wing member extending from the fuselage, an engine disposed relative to the wing member, a rotor hub assembly mechanically coupled to the engine and a plurality of proprotor blade assemblies rotatably mounted to the rotor hub assembly and operable for beamwise folding relative thereto. The proprotor blade assemblies each including a spar and a sheath extending spanwise along a leading edge of the spar. The spar has a root section, a main section and a tip section. The spar has a generally oval cross section at radial stations along the main section of the spar with the root section of the spar forming an integral tang assembly operable for coupling the spar to the rotor hub assembly.

Abstract: In one example embodiment, a valve can include a piston configured to open the valve when a first force is greater than a second force, a biasing member that pushes against the piston and exerts a substantial portion of the first force against the piston, and a material that exerts a substantial portion of the second force against the piston, wherein the material changes from a solid to a liquid at an approximate, predetermined temperature, the change of the material from solid to liquid decreases the second force and allows the piston to move and open the valve.

Abstract: Systems, methods and non-transitory computer readable storage medium are provided for task-based health data monitoring relating to aircraft components of aircraft within an aircraft fleet. One method includes establishing a review item with a first data review state to create a review task relating to health data of an aircraft component, generating images relating to the review item for display on a display device, retaining the review item for monitoring responsive to receiving user input changing the first data review state of the review item to a second data review state, receiving new health data relating to the aircraft component and automatically resetting the review item from the second data review state to the first data review state responsive to receiving the new health data to create a new review task.

Abstract: A composite core includes a plurality of tubes, each the plurality of tubes comprising a plurality of fibers disposed in a polymeric matrix. Adjacent tubes of the plurality of tubes are adhesively bonded to one another along sides of the adjacent tubes. A method of making a composite core includes the steps of providing a plurality of tubes, each of the plurality of tubes including a plurality of fibers disposed in a polymeric matrix, and adhesively bonding adjacent tubes of the plurality of tubes along sides of the adjacent tubes. A method of making a composite core such that a removable band is included in the core, the removable band being configured to be removable through a procedure subsequent to the cure of the composite core, thereby producing gaps in the core.

Abstract: An aircraft rotor assembly has a central hub and a plurality of rotor blades coupled to the hub for rotation with the hub about an axis, each blade having a Lock number of approximately 5 or greater. A lead-lag pivot for each blade is formed by a flexure coupling the associated blade to the hub. Each pivot is a radial distance from the axis and allows for in-plane lead-lag motion of the associated blade relative to the hub, each pivot allowing for in-plane motion from a neutral position of at least 1 degree in each of the lead and lag directions. Elastic deformation of the flexure produces a biasing force for biasing the associated blade toward the neutral position, and the biasing force is selected to achieve a first in-plane frequency of greater than 1/rev for each blade.

Abstract: A mounting assembly is provided for mounting a sheave roller to a ladder-type cable tray. The cable cables can be laid on the cable tray for routing through a building. The mounting assembly includes first and second housing parts which are moveable relative to each other. The housing parts are attached to respective rungs of the cable tray. A lock prevents the relative movement of the housing parts relative to each other once the mounting assembly is engaged with the cable tray. The sheave roller is rotatably attached to the one housing part. This quickly and easily installs the sheave roller on the cable tray.

Abstract: A propulsion system for a tiltrotor aircraft includes an engine supported by the airframe and a fixed gearbox operably coupled to the engine. Inboard and outboard pedestals are supported by the airframe and positioned above the wing. A pylon assembly is rotatably coupled between the inboard and outboard pedestals. The pylon assembly includes a spindle gearbox having an input gear, a mast operably coupled to the input gear and a proprotor assembly operable to rotate with the mast. The spindle gearbox is rotatable about a conversion axis to selectively operate the tiltrotor aircraft between helicopter and airplane modes. A common shaft, rotatable about the conversion axis, is configured to transfer torque from an output gear of the fixed gearbox to an input gear of the spindle gearbox. Each of the inboard and outboard pedestals includes a spherical bearing providing a self-aligning coupling with the pylon assembly.

Abstract: According to one embodiment, a method for determining a position of a rotor blade includes receiving a plurality of measurements from a plurality of magneto-resistive sensors and determining a position of the at least one magnet based on the received plurality of measurements. In this example, one of the plurality of magneto-resistive sensors and the at least one magnet moves with a rotor blade.

Abstract: A motor vehicle operating fluid container is made of thermoplastic. The container is composed of two shells forming a substantially closed hollow body. A first shell forms an upper base of the container, and a second shell forms a lower base of the container. The container includes at least one line which is designed as an integral part of a container wall over at least one sub-length, where the line is designed as a channel which runs in the container wall over said sub-length. The channel has an open trough-shaped profiled cross-section which forms a part of the line cross-section, and the channel is closed by at least one cover which complements the trough-shaped profiled cross-section so as to form a closed cross-section.