Abstract: A hydraulic actuator has a lower cylinder comprising a lower cylinder extension area and a lower cylinder retraction area, an upper cylinder comprising an upper cylinder extension area and an upper cylinder retraction area, and an actuator shaft. The actuator shaft has a lower cylinder piston disposed in the lower cylinder, an upper cylinder piston disposed in the upper cylinder, a lower shaft connecting the lower cylinder piston to the upper cylinder piston, and an upper shaft extending from the upper cylinder piston and at least partially externally from the upper cylinder. At least one of fluid flow of the lower cylinder matches fluid flow of the upper cylinder and (1) an internal diameter of the lower cylinder is not equal to the an internal diameter of the upper cylinder and (2) a diameter of the lower shaft is not equal to a diameter of the upper shaft.

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: 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 movable ballast system for an aircraft includes first and second ballast docks secured to the aircraft. The first ballast dock includes a first housing and a first ballast tray secured within the first housing. The first ballast tray includes a plurality of channels. The second ballast dock is positioned aft of a CG of the aircraft and includes a second housing and a second ballast tray secured within the second housing. The second ballast tray includes a plurality of channels. The movable ballast system includes a plurality of movable ballasts, each movable ballast of the plurality of movable ballasts being configured to fit within at least one channel of each of the plurality of channels of the first and second ballast trays.

Abstract: An aggregate-removal method includes placing a metallic article in a tank of fluid, a piece of aggregate being lodged in a feature of the metallic article, and treating the metallic article with sound waves to dislodge the lodged aggregate from the metallic article. An aggregate-identification method includes applying a fluorescent penetrant solution to a metallic article, exposing the metallic article to UV light, and identifying fluorescing aggregate lodged in a feature of the metallic article.

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: 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 exemplary pitch lock for a tiltrotor aircraft to enable and disable a pitching degree of freedom of a rotor blade assembly includes a first tab coupled to a blade stop assembly, the first tab having a first ramp surface, a second tab coupled to a blade cuff, the second tab having a second ramp surface, a hasp having a central opening to receive the first and the second tab and rollers rotatably coupled to the hasp on opposite sides of the central opening, where the rollers engage the first and second ramp surfaces and retain the first and the second tabs in the central opening.

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 of displacing rotors of an aircraft between a hover mode and an aircraft mode includes rotating a spindle drivingly connected to the rotors about a spindle axis to displace the rotors between the hover and aircraft modes until a component displaceable with the spindle abuts against a downstop of the aircraft and applies a load against the downstop. The method includes passively maintaining the component against the downstop to maintain the load applied against the downstop. An aircraft is also disclosed.

Abstract: A drivetrain for an aircraft includes an engine, a driveshaft receiving rotational energy from the engine and a gearbox including a planetary gear system receiving rotational energy from the driveshaft. The planetary gear system includes a sun gear, planet gears, a ring gear and an integral carrier forming flexured carrier posts. Each flexured carrier post supports a respective one of the planet gears and has a fixed proximal end and a cantilevered distal end. The planetary gear system includes flexured roller races, each having a fixed end and a cantilevered end. The fixed end of each flexured roller race is coupled to the cantilevered distal end of a respective flexured carrier post. The planet gears engage with the flexured roller races to rotate about the flexured carrier posts. The cantilevered ends of the flexured roller races experience cantilevered motion to absorb loads from the planet gears.

Abstract: An aircraft includes a wing and a rotor pod mounted to the wing. The rotor pod includes a body having a forward end and an aft end. A propeller is mounted to the body of the rotor pod at the forward end. A control surface is mounted to the body of the rotor pod between the forward and aft ends and extends outwardly from the body. The control surface is displaceable relative to the body between a first control configuration and a second control configuration to control an attitude of the aircraft. The control surface in the first control configuration is closer to the propeller than the control surface in the second control configuration.

Abstract: There is provided a method and a system for finite element (FE) analysis of a composite structure comprising plies arranged according to a stacking sequence and layers of bonding agent. Each layer of bonding agent interconnects two adjacent plies. In-plane properties and out-of-plane properties of the composite structure are received. An FE model of the composite structure is generated by representing the plies by two-dimensional (2D) elements configured to be arranged according to the stacking sequence, representing the layers of bonding agent by three-dimensional (3D) elements, each 3D element configured to interconnect two adjacent 2D elements, and associating the in-plane properties with the 2D elements and the out-of-plane properties with the 3D elements. An FE analysis of the FE model is performed to predict delamination of the composite structure.

Abstract: A rotorcraft having pusher propeller generated power during autorotations. The rotorcraft has an engine powered mode and an autorotation mode. The rotorcraft includes an engine and a drivetrain configured to receive torque and rotational energy from the engine in the engine powered mode. A main rotor system is coupled to the drivetrain and is rotatable to generate lift and forward thrust for the rotorcraft in the engine powered mode. A pusher propeller is coupled to the drivetrain and is rotatable to generate forward thrust for the rotorcraft in the engine powered mode. In the autorotation mode, the pusher propeller is aerodynamically driven responsive to airflow therethrough and the drivetrain is configured to receive torque and rotational energy from the pusher propeller, thereby providing power to the main rotor system.

Abstract: An autonomous cargo delivery aircraft operable to transition between thrust-borne lift in a VTOL orientation and wing-borne lift in a biplane orientation. The aircraft includes a fuselage having an aerodynamic shape with a leading edge, a trailing edge and first and second sides. First and second wings are coupled to the fuselage proximate the first and second sides, respectively. A distributed thrust array includes a first pair of propulsion assemblies coupled to the first wing and a second pair of propulsion assemblies coupled to the second wing. A flight control system is operably associated with the distributed thrust array and configured to independently control each of the propulsion assemblies. The first side of the fuselage includes a door configured to provide access to a cargo bay disposed within the fuselage from an exterior of the aircraft with a predetermined clearance relative to the first pair of propulsion assemblies.

Abstract: A tension-torsion strap, for example for a rotor aircraft, including a continuous length of carbon fiber tow arranged in multiple loops to form an elongated member extending between opposing ends and a flexible cover encasing the carbon fiber tow.

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: A tiltrotor assembly has a central hub with a plurality of rotor blades extending therefrom and is configured to rotate about a mast axis to generate lift in a hover position. The central hub is configured to rotate about a tilt axis between the hover position and a forward-flight position such that rotation about the mast axis generates forward thrust. The central hub is surrounded by a segmented duct that includes a thin rotatable inner ring and a wide fixed outer ring. The inner ring is configured to rotate with the central hub about the tilt axis leaving the wide outer ring in a generally horizontal position.

Abstract: An example of an emergency lubrication system for an aircraft includes a lubricant tank configured to supply a lubricant to a gearbox of the aircraft, a tube coupled between the lubricant tank and the gearbox and comprising a check ball disposed within the tube, a first lubricant line coupled to the tube and a first inlet of the gearbox, and a second lubricant line coupled to the tube and a second inlet of the gearbox.