Abstract: An aircraft and method to control flat yawing turns of the aircraft while maintaining a constant vector heading across a ground surface. The aircraft includes a control system in data communication with a model, a lateral control architecture, a longitudinal control architecture, and an initialization command logic. The model decouples the directional movement of the aircraft into a lateral equation of motion and a longitudinal equation of motion. The lateral control architecture utilizes the lateral equation of motion to control the aircraft in the lateral direction, while the longitudinal control architecture utilizes the longitudinal equation of motion to control the aircraft in the longitudinal direction. The initialization command logic selectively activates the lateral control architecture and the longitudinal control architecture.

Abstract: According to one embodiment, a helicopter rotor system has a bearing disposed between the drive train and the rotor blade. The bearing comprises an elastomeric material, a housing member coupled to the elastomeric material, and an anti-rotation member coupled to the housing member opposite the elastomeric material. A bearing mount is coupled to the grip and comprises a first opening configured to receive the anti-rotation member of the bearing. The first opening is defined at least in part by a first surface that receives the anti-rotation member and prevents the anti-rotation member from completing a rotation within the first opening.

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: An internal stiffening member of varying configurations in which the stiffening elements support the skin using a compression-only load path is disclosed. A rib can be inserted into an assembled structural box beam, and a filler material can be used to fill any gaps between the slip-in rib and the interior surface of the structural box beam. The filler material is preferably an expandable material, such as an expandable foam-type material. However, in situations where a slip-in rib forms a primary structural rib, the filler material is preferably a structural adhesive or liquid shim material. A solid adhesive or filler would not crush under the clamping forces from fasteners or bolts at localized fitting attachments.

Abstract: A regeneration energy shunt system utilizes a module to monitor the power bus voltage and can divert excess regeneration energy to a resistor array to dissipate the excess regeneration energy. The module can monitor the state of charge of an energy storage device to ascertain when excess regeneration energy condition exists. The resistor array can include a plurality of resistors. The module can ascertain the number of resistors needed dissipate the excess regeneration energy and selectively direct the excess regeneration energy to the required number of resistors. The module can dynamically switch which resistors are used to dissipate the excess regeneration energy and can thereby even out the loading across the resistors. The module can ascertain a state of health of the individual resistors and remove unhealthy resistors from service, report the state of health of the resistors, and initiate changes in operation based thereon.

Abstract: A compression-molded part has a conductive layer embedded in the part during molding of the part. The conductive layer is generally adjacent an outer surface of the part and is preferably formed from a mesh, a foil, a pulled screen, or multiple layers of conductive elements. The part is preferably optimized for use on the exterior of an aircraft for lightning-strike or EMI protection or for use as an antenna. Methods for forming the panels of the invention include placing the conductive layer against a mold surface of a compression mold, then forming the compression-molded part with the conductive layer embedded in the part.

Abstract: A dual frequency damper includes a liquid inertia vibration eliminator (LIVE) portion and a fluid damper portion. LIVE portion and fluid damper portion operate in series and function so that dual frequency damper is optimized in both stiffness and damping at multiple frequencies. LIVE portion acts as a frequency dependent switch to selectively cause low frequency oscillatory forces to be treated primarily by the high spring rate and high damping rate characteristics of the fluid damper portion, and also to select high frequency oscillatory forces to be primarily treated by the low spring rate and low damping rate characteristics of the LIVE unit portion.

Abstract: A feathering, flapping and rotor loads indicator for use in a rotorcraft includes a calculation unit configured to calculate (a) a current temperature of a bearing of the rotor assembly using a first calculation model, (b) a projected temperature of the bearing using the first calculation model and (c) a load exerted on a selected component of the rotor assembly using a second calculation model, the first and second calculation models adapted to calculate, respectively, the projected and the current temperatures of the bearing and the load exerted on the selected component based on flight control parameters; and a display unit configured to display on a common scale a movable indicator, the movable indicator being driven by the highest value between the projected temperature of the bearing and the load exerted on the selected component. The display unit displays another movable indicator driven by the current temperature of the bearing.

Abstract: A rotary aircraft exhaust system having an engine, an exhaust member in gaseous communication with the engine, and a longitudinally compressible bellow seal in sealing contact with both the engine and the exhaust member. The bellow seal is configured to provide a gaseous seal between the engine and the exhaust member while also allowing the exhaust member to move in the transverse, longitudinal, and pivoting directions relative to the engine.

Abstract: According to one embodiment, an aircraft gearbox lubrication system includes a lubricant source containing a nanodiamond lubricant, a pump, and a dispenser. The nanodiamond lubricant comprises a base lubricant and a nanodiamond additive. The pump is in fluid communication with the lubricant source and is configured to provide a flow of the lubricant from the lubricant source. The dispenser is in fluid communication with the reservoir and configured to allow the nanodiamond lubricant to flow from the pump onto a component in a gearbox at a predetermined rate.

Abstract: A method and apparatus for reconfiguring flight control of an aircraft during a failure while the aircraft is flying. The method and apparatus provide a control law that is software-implemented and configured to automatically send flight control data to a mixing/mapping matrix. The method and apparatus also provide a reconfiguration management tool configured to communicate with the mixing/mapping matrix in order to safely transfer authority from a failed actuator to a back-up actuator. The method and apparatus also provide a sensor management tool for providing input to the reconfiguration management tool in order to smooth any transient conditions that may occur during reconfiguration. The method and apparatus provide for a way of smoothing any possible transient situation that might otherwise occur by employment of a fader, the fader being used to gradually convert positioning of failed actuators and positioning of reconfigured actuators.

Abstract: An alternative system for damping the dutch roll mode in an aircraft is provided using roll control surfaces. Classical yaw dampers for the dutch roll mode utilize the yaw control surfaces such as a rudder to dampen the dutch roll mode oscillations. An alternative damper is described that utilizes roll control surfaces such as spoilers or ailerons to dampen the dutch roll mode.

Abstract: The landing gear system for an aircraft includes a shock strut assembly that is coupled to the airframe with a universal joint. A tire member is mounted to the shock strut assembly. The landing gear system also includes a drag brace assembly coupled to an airframe of the aircraft with a spindle, the spindle being rotatable about a spindle axis. A radius rod is rotatably coupled to the airframe of the aircraft. The radius rod and the shock strut assembly are retractable about a retraction rotation axis. Further, the spindle axis has a common intersection point with the centerline axis and the retraction rotation axis. The orientation of the spindle axis causes a translation of the tire member to have a longitudinal component during a compression of the shock strut assembly.

Abstract: According to one embodiment, a radial fluid device comprises a cylinder block, a first plurality of pistons, a second plurality of pistons, a first cam, a second cam, and a coupling device. Each of the first plurality of pistons are slidably received within a different one of a first plurality of radially extending cylinders. Each of the second plurality of pistons are slidably received within a different one of a second plurality of radially extending cylinders. The first cam is disposed about the first plurality of radially extending cylinders. The second cam is disposed about the second plurality of radially extending cylinders. The coupling device is operable to couple the cylinder block to a cylinder block of a second radial fluid device.

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 elastomeric bearing adjacent the housing inside the first opening and having a second opening therethrough, and an inner housing adjacent the elastomeric bearing 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: According to one embodiment, a radial fluid device comprises a cylinder block, a first plurality of pistons including a first piston, and a second plurality of pistons including a second piston. Each of the first plurality of pistons are slidably received within a different one of a first plurality of radially extending cylinders. Each of the second plurality of pistons are slidably received within a different one of a second plurality of radially extending cylinders. The second piston is configurable to begin its stroke at a different time relative to the first piston within the first cylinder pair.

Abstract: According to one embodiment, a radial fluid device comprises a cylinder block, a first plurality of pistons, a second plurality of pistons, a first cam, a second cam, and a cam rotation device. Each of the first plurality of pistons are slidably received within a different one of a first plurality of radially extending cylinders. Each of the second plurality of pistons are slidably received within a different one of a second plurality of radially extending cylinders. The first cam is disposed about the first plurality of radially extending cylinders. The second cam is disposed about the second plurality of radially extending cylinders. The cam rotation device is coupled to the first cam and the second cam. The cam rotation device is operable to rotate the first cam in a first direction and the second cam in a second direction.

Abstract: A lightweight skid shoe assembly comprises a body of wear resistant, non-metallic or partially metallic material; and a structure coupling mechanism; wherein the body prevents friction-related damage to the structure. Another lightweight skid shoe assembly comprises a body of wear resistant, non-metallic or partially metallic material selected from the group consisting of: a polyamide or polyimide impregnated carbon fiber layup, a peek or PEI injection mold with carbon fiber, compression molded carbon fiber or fiberglass, a resin infusion with carbon fiber preform fabric, a fiber reinforced thermoset, acetal resin, machined acetal or thermoplastic, thermosetting plastic, or a metal-matrix composite; wherein the body prevents friction-related damage to a structure.

Abstract: A motion capture environment includes a plurality of sensor-trackers for tracking physical locations of a plurality of tracked objects relating to a first simulation within the motion capture environment and for tracking physical locations of a plurality of tracked objects relating to a second simulation, which is different from the first simulation, within the motion capture environment and one or more computers collectively operable to generate a first virtual reality environment corresponding to the first simulation and a second virtual reality environment corresponding to the second simulation.