Abstract: A lockout system for an aircraft having a rotor assembly. The lockout system includes a drive shaft coupled to and rotatable with the rotor assembly, a nonrotating airframe structure disposed proximate the drive shaft and a lock assembly having first and second lock members. The first lock member is rotatable with the drive shaft and includes a plurality of bearing assemblies. The second lock member is coupled to the nonrotating airframe structure and includes a cradle having a plurality of asymmetric slots each with a leading ramp and a trailing stop. The lock assembly has a disengaged position in which rotation of the drive shaft is allowed and an engaged position in which each of the bearing assemblies is seated within one of the asymmetric slots to prevent rotation of the drive shaft. The lock assembly is actuatable between the engaged and disengaged positions.

Abstract: A lockout system for an aircraft having a rotor assembly. The lockout system includes a drive shaft coupled to and rotatable with the rotor assembly, a nonrotating airframe structure disposed proximate the drive shaft and a lock assembly having first and second lock members. The first lock member is rotatable with the drive shaft and includes a plurality of bearing assemblies. The second lock member is coupled to the nonrotating airframe structure and includes a cradle having a plurality of asymmetric slots each with a leading ramp and a trailing stop. The lock assembly has a disengaged position in which rotation of the drive shaft is allowed and an engaged position in which each of the bearing assemblies is seated within one of the asymmetric slots to prevent rotation of the drive shaft. The lock assembly is actuatable between the engaged and disengaged positions.

Abstract: A rotor mast including an outer member defining a channel therethrough and an inner member disposed in the channel through the outer member, wherein the inner member is configured to apply a compressive force to the outer member.

Abstract: A clutch has an inner race, an outer race spaced from the inner race and forming a radial cavity between the races, and a plurality of sprags disposed in the radial cavity. The sprags have a different coefficient of thermal expansion (CTE) from the inner race, the outer race, or both races, and a sprag cage retains the sprags at a uniform spacing within the radial cavity. When the clutch is at a first temperature, a gap exists between the sprags and the inner race, between the sprags and the outer race, or between the sprags and both races, and the clutch is disengaged. When the clutch is at a second temperature the sprags are in contact with both the races, and the clutch is engaged.

Abstract: A clutch has an inner race, an outer race spaced from the inner race and forming a radial cavity between the races, and a plurality of sprags disposed in the radial cavity. The sprags have a different coefficient of thermal expansion (CTE) from the inner race, the outer race, or both races, and a sprag cage retains the sprags at a uniform spacing within the radial cavity. When the clutch is at a first temperature, a gap exists between the sprags and the inner race, between the sprags and the outer race, or between the sprags and both races, and the clutch is disengaged. When the clutch is at a second temperature the sprags are in contact with both the races, and the clutch is engaged.

Abstract: A sprag clutch has an inner race, an outer race, and a radial cavity between the races. A plurality of sprags are disposed in the radial cavity, and each sprag is configured to rotate about an axis of rotation that is perpendicular to its longitudinal axis. A sprag cage retains each of the plurality of sprags at a uniform spacing within the radial cavity, and a plurality of actuators are positioned to exert or withdraw a force upon a corresponding sprag.

Abstract: An example of a ceramic bearing system includes a shaft comprising two radially extending shoulders that define a channel therebetween, a first tolerance ring disposed in the channel of the shaft, and a bearing assembly comprising a ceramic bearing. The bearing assembly is positioned around the first tolerance ring and has an axial length that is longer than an axial length of the first tolerance ring.

Abstract: A powertrain for a rotorcraft includes first and second engines and a transmission system that includes a main rotor gearbox, a first freewheeling unit coupling the first engine to the main rotor gearbox and a second freewheeling unit coupling the second engine to the main rotor gearbox. The first freewheeling unit has a driving configuration and a bypass configuration. In a preflight configuration of the rotorcraft, the first engine provides power to at least one auxiliary component with the first freewheeling unit in the bypass configuration while the second engine provides power to the main rotor. In a flight configuration of the rotorcraft, the first engine provides power to the main rotor with the first freewheeling unit in the driving configuration while the second engine also provides power to the main rotor.

Abstract: A powertrain for a rotorcraft includes first and second engines and a transmission system that includes a main rotor gearbox, a first freewheeling unit coupling the first engine to the main rotor gearbox and a second freewheeling unit coupling the second engine to the main rotor gearbox. The first freewheeling unit has a driving configuration and a bypass configuration. In a preflight configuration of the rotorcraft, the first engine provides power to at least one auxiliary component with the first freewheeling unit in the bypass configuration while the second engine provides power to the main rotor. In a flight configuration of the rotorcraft, the first engine provides power to the main rotor with the first freewheeling unit in the driving configuration while the second engine also provides power to the main rotor.

Abstract: A rotor mast including an outer member defining a channel therethrough and an inner member disposed in the channel through the outer member, wherein the inner member is configured to apply a compressive force to the outer member.

Abstract: A rotor assembly has a composite driveshaft extending between a transmission and a yoke for providing torque from the transmission to the yoke to cause rotation of the yoke and a plurality of rotor blade assemblies attached thereto. The rotor hub also has a composite static mast coupled to the yoke and a frame. The static mast being configured to carry the lift and thrust forces from the yoke to the frame.

Abstract: A hybrid composite reinforced ring gear minimizing radial deformation during high RPM conditions includes a composite backing secured to a metal rim. In use, at operating temperature the composite backing contracts while the metal rim expands thus creating a compressive stress on the metal rim and significantly reduces radial deformation due to centrifugal forces as compared to an all steel ring gear.

Abstract: A method includes forming a mask that defines a masked area and an unmasked area on a front side of a substrate, and implanting a buried layer corresponding to the unmasked area on the front side of the substrate. The method also includes forming an epitaxial layer having a back side on the front side of the substrate and on a front side of the buried layer, and creating an opening into a back side of the substrate up to a back side of the epitaxial layer and a back side of the one or portions of the buried layer.

Abstract: A rotor assembly has a composite driveshaft extending between a transmission and a yoke for providing torque from the transmission to the yoke to cause rotation of the yoke and a plurality of rotor blade assemblies attached thereto. The rotor hub also has a composite static mast coupled to the yoke and a frame. The static mast being configured to carry the lift and thrust forces from the yoke to the frame.

Abstract: A hybrid composite reinforced ring gear minimizing radial deformation during high RPM conditions includes a composite backing secured to a metal rim. In use, at operating temperature the composite backing contracts while the metal rim expands thus creating a compressive stress on the metal rim and significantly reduces radial deformation due to centrifugal forces as compared to an all steel ring gear.

Abstract: A method includes forming a mask that defines a masked area and an unmasked area on a front side of a substrate, and implanting a buried layer corresponding to the unmasked area on the front side of the substrate. The method also includes forming an epitaxial layer having a back side on the front side of the substrate and on a front side of the buried layer, and creating an opening into a back side of the substrate up to a back side of the epitaxial layer and a back side of the one or portions of the buried layer.

Abstract: A pressure sensor having a diaphragm having a boss with a pattern. The diaphragm having a boss may be regarded as a bossed diaphragm. The bossed diaphragm may have higher sensitivity than a flat plate diaphragm having the same area as the bossed diaphragm. The bossed diaphragm may incorporate a simple cross pattern that can further improve the sensitivity and linearity of a pressure response of the diaphragm at low pressures. Reduction of sharp edges and corners of the boss and its legs around the periphery of the diaphragm may reduce high stress points and thus increase the burst pressure rating of the bossed diaphragm.

Abstract: A sensor assembly includes a first wafer having a cavity formed therein and a second wafer bonded relative to the first wafer to form a diaphragm over the cavity. A trench is formed in the second wafer in or around the diaphragm and the trench may be filled with an isolating material to help thermally and/or electrically isolate the diaphragm. The diaphragm may support one or more sense elements. The sensor assembly may be used a flow sensor, a pressure sensor, a temperature sensor, and/or any other suitable sensor, as desired.

Abstract: A pressure sensor having a diaphragm having a boss with a pattern. The diaphragm having a boss may be regarded as a bossed diaphragm. The bossed diaphragm may have higher sensitivity than a flat plate diaphragm having the same area as the bossed diaphragm. The bossed diaphragm may incorporate a simple cross pattern that can further improve the sensitivity and linearity of a pressure response of the diaphragm at low pressures. Reduction of sharp edges and corners of the boss and its legs around the periphery of the diaphragm may reduce high stress points and thus increase the burst pressure rating of the bossed diaphragm.

Abstract: A sensor assembly includes a first wafer having a cavity formed therein and a second wafer bonded relative to the first wafer to form a diaphragm over the cavity. A trench is formed in the second wafer in or around the diaphragm and the trench may be filled with an isolating material to help thermally and/or electrically isolate the diaphragm. The diaphragm may support one or more sense elements. The sensor assembly may be used a flow sensor, a pressure sensor, a temperature sensor, and/or any other suitable sensor, as desired.