Abstract: A system and method for preventing a maximum asymmetric condition between pylon tilt angles due to a degraded pylon in a fly-by-wire tiltrotor aircraft during transitions between airplane mode and helicopter mode includes a conversion system for imparting movement on a right and left pylon. A flight control computer is operatively connected to a set of transducers for measuring pylon angles. The flight control computer is further connected to a set of actuators which are attached to each pylon. The flight control computer receives flight dynamics input from the set of transducers and/or the pilot and sends pylon command to the set of actuators. The conversion system measures the difference between the pylon angles during the transition and provides a pylon command adjustment if the difference exceeds a preset threshold.

Abstract: An exemplary liquid tank level measurement system includes a tank having a wall, an accelerometer attached to the wall and configured to measure a vibration in the wall, and an instrument electronically connected to the accelerometer, the instrument configured to communicate a liquid level condition responsive to a vibration measurement received from the accelerometer.

Abstract: An aircraft includes a variable-speed gearbox. The variable-speed gearbox includes a low-speed gear train and a high-speed gear train, each gear train of which is configured to selectively provide torque from an engine of the aircraft to a proprotor. The variable-speed gearbox also includes a hydraulic system configured to provide torque to the proprotor. The hydraulic system includes a hydraulic pump driven by the engine of the tiltrotor aircraft and a variable-displacement motor driven by a hydraulic fluid from the hydraulic pump.

Abstract: The present invention includes methods of preparing a composite structure comprising: placing a first ply of a fibrous material with a curable material on a layup tool; adding one or more additional plies on the first ply, wherein each of the one or more additional plies has a perimeter that is different in size around the perimeter than a previous ply to form a taper; and curing the composite structure, wherein the curable material is selected to minimize, limit, control, or eliminate the outflow of the curable material along the perimeter of the composite structure during the curing step.

Abstract: The present invention includes a balancing system that includes a weight box, mounted substantially within the rotor-blade spar, flush with a rotor-blade spar outer surface, operably accessible from a rotor-blade tip, and retained within the rotor-blade spar by a weight-box retention pin, one or more weight-box contact surfaces bonded to a rotor-blade-spar inner surface, or a weight-box lip providing a bearing contact with an edge of a spar rotor-blade spar cutout; and a weight package attached to the weight box, the weight package including a weight-box cover, two or more weight guide-rods attached to the weight-box cover, wherein one of the two or more weight guide-rods is positioned forward of a pitch change axis or center of twist and wherein one of the two weight guide-rods is positioned aft of the pitch change axis or center of twist, and one or more balance weights mounted on the weight guide-rods.

Abstract: A system and method for providing supplemental power includes: a motor-generator or a hydraulic pump-motor configured to attach to a transmission of an engine, a controller connected to the motor-generator or the hydraulic pump-motor, and a battery system or a hydraulic accumulator coupled to the motor-generator or the hydraulic pump-motor, respectively. During normal operation of the engine, the engine drives the transmission to rotate rotor blades connected to the transmission, and the motor-generator or the hydraulic pump-motor draws an energy from the transmission and store the energy in the battery system or the hydraulic accumulator, respectively. Upon a manual and/or an automatic control by the controller, the battery system or the hydraulic accumulator discharges the energy to the motor-generator or the hydraulic pump-motor, respectively, and the motor-generator or the hydraulic pump-motor provides the supplemental power to drive the transmission to rotate the rotor blades.

Abstract: A method of selectively preventing flapping of a rotor hub includes providing a flapping lock proximate to a rotor hub and shaft assembly and moving the flapping lock from an unlocked position to a locked position, the flapping lock operable in the locked position to prevent at least some flapping movement of the rotor hub relative to the shaft, the flapping lock operable in the unlocked position to allow the at least some flapping movement of the rotor hub relative to the shaft.

Abstract: An exemplary passive oil system includes a reservoir housing configured in operation to rotate around a rotational axis, the reservoir housing defining a reservoir between a top wall, a bottom wall, innermost side, and an outer sidewall; and an outlet positioned adjacent the outer sidewall to discharge a lubrication fluid contained in the reservoir in response to the reservoir housing rotating around the rotational axis.

Abstract: The present invention includes a passive hub flapping lock including stop wedges; frames coupled to the stop wedges; rods coupled to the frames, and each rod comprising a bracket; lever arms, each lever arm rotatably coupled to a pivot and coupled at a first lever arm end to one of the rods at the bracket of the rod; weight sets, each weight set coupled to a second lever arm end; and pivot torsion springs, each pivot torsion spring positioned at a pivot and biased to hold the flapping lock in an engaged position when stationary or at a rotational speed below a specified rotational speed; wherein the flapping lock is in an engaged position below the specified rotational speed and in a disengaged position above the specified rotational speed and the weight sets move outward, rotating the lever arms.

Abstract: A light weight hybrid torque transfer joint trunnion has an integral metal hub spline fitting oriented on a center axis. This integral metal hub spline fitting may be made of steel, aluminum, titanium, or the like and may be generally cylindrical. The integral metal hub spline fitting defines an integral central internally-splined mast or driveshaft coupling opening centered about the center axis. A composite material body centrally retains, and is cured to, the metal hub spline fitting. Torque transfer joint link attachment pins extend from the composite material body and are rigidly linked to the metal hub spline fitting. In an example constant-velocity joint, a plurality of pivoting linkages may each be rotatably coupled to the torque transfer joint link attachment pins, and each of the plurality of pivoting linkages may, in turn be secured to a rotor yoke configured to mount a plurality of rotorcraft blades.

Abstract: A hybrid power system for a vertical takeoff and landing (“VTOL”) aircraft including a first power source operable to provide a power output for at least a forward flight mode; and a second power source configured to provide a high specific power output for an altitude adjustment flight mode, the second power source including an auxiliary gas generator coupled to a turbine and a drive system. In other aspects, there is provided a VTOL aircraft and methods for providing power to a VTOL aircraft.

Abstract: The present invention includes a system, method and kit for preventing or reducing water penetration of a gearbox, the system including: a fan or impeller coupled to the gearbox; and a hub coupled to the fan and shaped to provide a labyrinth seal that prevents or reduces water penetration into the gearbox.

Abstract: An embodiment of the present invention provides a blocking door that is pivotally disposed on a fixed nacelle of a tiltrotor aircraft for pivoting between a stowed position when a proprotor pylon is in the substantially horizontal position and a protective blocking position in front of the proprotor pylon when the proprotor pylon is positioned in the non-horizontal position. In other aspects, there is provided a blocking door and a method of reducing infrared and/or radar signatures of rotorcraft with a rotatable proprotor.

Abstract: In some examples, an aircraft comprises a motorized module. The motorized module comprises a motor and a first coil. The motor is to operate equipment onboard the aircraft and generates vibrations during operation. The first coil is operable to wirelessly transmit power to a separate module onboard the aircraft based on electromagnetic induction between the first coil and a second coil in a separate module, and wirelessly transfer data with the separate module via the second coil based on the electromagnetic induction, the data being associated with the motor. A gap separates the motorized module and the separate module. The gap isolates the separate module from the vibrations.

Abstract: A door system for a nacelle of a tiltrotor aircraft, the nacelle including a movable proprotor housing rotatable relative to a fixed portion of the nacelle from a forward flight mode to a vertical flight mode and a proprotor gearbox door connected to the movable proprotor housing and pivotably coupled to the fixed portion. The door system including a linkage to pivotably couple the door and the fixed portion of the nacelle; a track assembly mounted to the movable proprotor housing; and a door roller mechanism connected to the proprotor gearbox door. The door roller mechanism traverses the track assembly during rotation of the movable proprotor housing.

Abstract: A method for defining a threshold stress curve utilized in fatigue and/or damage tolerance analysis, the method including conducting a direct test method on a plurality of specimens with a notch to generate raw data, the notch in each of the specimens having a notch dimension; determining a plurality of analyzed data points based upon the raw data; determining a regression line based upon the plurality of data points, the regression line including an exponential portion and a power law portion; and connecting the exponential portion and the power law portion of the regression line to form a threshold stress curve based on the regression line.

Abstract: The present invention includes a rotor-blade span-balancing system, including a span-balance pocket in a surface of a rotor blade; a cover operably configured to cover the span-balance pocket, wherein the cover is operably configured to be substantially flush with the surface of the rotor blade surface when covering the span-balance pocket, and wherein the cover includes a cover boss for reacting centrifugal force of the cover into the rotor blade; and one or more span-balance weights attached to the cover to span-balance the rotor blade.

Abstract: A strut assembly for a vibration isolation device is disclosed, comprising a piston spindle; a first elastomeric member and a second elastomeric member bonded to the piston spindle and in contact with an upper housing and a lower housing, respectively; a first strut support and a second strut support attached to or integral with the upper housing and the lower housing, respectively; a first strut spindle and the second strut support configured to be placed in the first strut support and the second strut support, respectively; and one or more removable struts configured to be engaged to the first strut spindle and to the second strut spindle, wherein at least one of the first or second strut spindles is removable such that the one or more struts can be replaced without breaking a bonding of the first elastomeric member, the second elastomeric member, or both.

Abstract: A device to verify main rotor swashplate positioning includes an inner surface of a first section and a gradient surface of a second section. The gradient surface of the second section may have a plurality of graduation indications. In one implementation, the inner surface of the first section at least partially defines a travel arc that is parallel to and concentric with the inner surface. In such an implementation, the device may be configured to move along the travel arc as it rotates about a collective sleeve to contact a swashplate lug.

Abstract: An inboard beam includes a body having an upper flange and a lower flange coupled thereto. The upper flange includes a first upper inboard aperture and an upper outboard aperture formed therein. The lower flange includes a first lower inboard aperture and a lower outboard aperture formed therein. An upper beam fitting is coupled to the upper flange and lower beam fitting is coupled to the lower flange. The upper beam fitting includes a first upper inboard post. The upper beam fitting includes an upper outboard post extending parallel to the inboard post. The lower beam fitting includes a first lower inboard post. The lower beam fitting includes a lower outboard post extending parallel to the lower inboard post.