Abstract: A gear train includes a first gear having teeth meshed with teeth of a second gear. Each tooth of the first gear includes a coast side and a drive side opposed to the coast side. The drive side has a pressure angle that is greater than that of the coast side. The gear train can be part of a powertrain system for a rotorcraft, and can replace a traditional gear train in a retrofit or new build. The first gear is a planet gear and the second gear is a ring gear wherein the planet gear and ring gear are in a planetary gear train configuration.

Abstract: A vibration damping device is configured to reduce vibration that causes lateral flexing of an elongated member that extends along a centerline. The device includes a split sleeve co-extending with and disposed about the elongated member, and a spring that extends about the sleeve and exerts a force that biases the sleeve radially inward.

Abstract: A gearbox for a rotary wing aircraft including a sump, a primary lubricant reservoir fluidically connected to the sump, one or more primary lubricant jets fluidically connected to the primary lubricant reservoir, an auxiliary lubricant reservoir fluidically connected to the sump, one or more auxiliary lubricant jets fluidically connected to the auxiliary lubricant reservoir, and at least one valve selectively fluidically connecting the sump and the primary lubricant reservoir based on a first lubricant pressure and the sump and the auxiliary lubricant reservoir based on a second lubricant pressure at the at least one valve.

Abstract: A vibration control assembly for an aircraft including a housing operatively coupled to the aircraft. Also included is a cage disposed within an interior region of the housing, the cage rotatable within the housing about a first axis. Further included is a gyroscope wheel disposed within the cage and rotatable about a second axis other than the first axis, wherein a controllable moment is imposed on the aircraft upon rotation of the gyroscope wheel to counter vibratory moments produced by the vehicle.

Abstract: A hanger bearing assembly for a shaft assembly includes a plurality of bearing elements arranged around a circumference of a shaft assembly, each bearing element having a bearing element diameter. A bearing inner race is positioned between the plurality of bearing elements and the shaft assembly and extends circumferentially about the shaft assembly. The bearing inner race includes an outer wall interactive with the plurality of bearing elements. The outer wall has a linear profile extending in an axial direction. A bearing outer race is positioned radially outboard of the plurality of bearing elements and extends circumferentially about the shaft assembly. The bearing outer race includes an inner surface interactive with the plurality of bearing elements and having a curvilinear inner surface profile extending in the axial direction.

Abstract: A gearbox oil cooling assembly for a gearbox driving a drive shaft having a drive shaft coupling. The assembly includes a heat exchanger to receive and cool an oil from the gearbox and having an inlet. Also included is an impeller axially disposed between the heat exchanger and the drive shaft coupling, wherein the impeller is operatively coupled to, and rotated by, the drive shaft operatively coupled to the drive shaft coupling. Further included is an exhaust duct operatively coupled to the heat exchanger and disposed radially outwardly around the impeller and defining an airflow pathway through which air passes through the inlet, the impeller and through the exhaust duct according to the rotation of the impeller to cool the oil in the heat exchanger.

Abstract: A fluid level sensor for determining an amount of first fluid in a system is provided including a first substantially transparent sight glass mounted outside and fluidly coupled to a portion of the system. A level of first fluid in the first sight glass is indicative of the amount of first fluid in the system. A second substantially transparent sight glass has an independent closed loop containing a second fluid. The second sight glass is positioned adjacent outside the system. A plane of the second sight glass is arranged adjacent to a pivot point of the first fluid within the system. A level of second fluid in the second sight glass is indicative of the amount of first fluid corresponding to normal operation of the system. A comparison of the level of first fluid in the first sight glass and the level of second fluid in the second sight glass indicates if the amount of first fluid in the system requires adjustment.

Abstract: An impeller retention apparatus is provided. The impeller retention apparatus includes a bearing element, a rotatable gear shaft rotatably supported within an outer body by the bearing element, an impeller disposed about and coupled to the rotatable gear shaft to rotate with the rotatable gear shaft, a preload spacer and a flexible coupling. The preload spacer is disposed along the rotatable gear shaft between the impeller and the bearing element and includes a forward preload spacer end abutting an aft end of the bearing element, an aft preload spacer end abutting a forward face of the impeller and an elastic element that biases the impeller away from the bearing element in an axial direction along the rotatable gear shaft. The flexible coupling is coupled to the rotatable gear shaft such that the outer body and the flexible coupling cooperatively define an annulus from which the impeller receives an airflow.

Abstract: A rotor apparatus is provided and includes a first rotor shaft disposed to rotatably support a first rotor, a second rotor shaft disposed to rotatably support a second rotor and first and second bearing elements disposed to support the first rotor shaft within the second rotor shaft and to pre-load the first rotor shaft in one of tension and compression and the second rotor shaft in the other one of tension and compression.

Abstract: A brake disc of a rotor brake is provided including a generally cylindrical body having a first planar surface, a second, opposite planar surface, and a central opening extending there through. A plurality of first connection members extend generally outwardly from the first planar surface. The first connection members are generally equidistantly spaced about a diameter of the first planar surface. A plurality of second connection members extend generally outwardly from the second planar surface. The second connection members are generally equidistantly spaced about a diameter of the second planar surface.

Abstract: A connection between a first component and a second component is provided including a first hole formed in a portion of the first component and a second hole formed in a portion of the second component. The second hole is aligned with the first hole. A pin includes a through hole having a pin hole diameter. The pin extends through a portion of the first hole and into a first portion of the second hole. The pin is configured to absorb a shear load applied to the connection. A bolt extends through the second hole and the pin such that a clearance fit is formed between the bolt and the pin. The bolt is configured to absorb an axial load applied to the connection. A nut connected to the free end of the bolt limits movement of the bolt relative to the first and second component.

Abstract: An impeller retention apparatus is provided and includes a bearing element, a rotatable shaft, which is rotatably supported within an outer body by the bearing element, an impeller disposed about and coupled to the shaft to rotate with the shaft and a preload spacer disposed along the shaft between the impeller and the bearing element, the preload spacer comprising an elastic element which biases the impeller away from the bearing element in an axial direction along the shaft.

Abstract: A torque limiting device includes a first portion connected to a first rotatable component. The first portion has a flange extending radially outward therefrom. A second portion includes a plurality of pre-loaded axial springs and is coupled to a second rotatable component. The second portion is arranged adjacent opposing surfaces of the flange. The second portion is configured to apply a biasing force to the flange to selectively couple the first rotatable component and the second rotatable component.

Abstract: A connection between a first component and a second component is provided including a first hole formed in a portion of the first component and a second hole formed in a portion of the second component. The second hole is aligned with the first hole. A pin includes a through hole having a pin hole diameter. The pin extends through a portion of the first hole and into a first portion of the second hole. The pin is configured to absorb a shear load applied to the connection. A bolt extends through the second hole and the pin such that a clearance fit is formed between the bolt and the pin. The bolt is configured to absorb an axial load applied to the connection. A nut connected to the free end of the bolt limits movement of the bolt relative to the first and second component.

Abstract: A brake disc of a rotor brake is provided including a generally cylindrical body having a first planar surface, a second, opposite planar surface, and a central opening extending there through. A plurality of first connection members extend generally outwardly from the first planar surface. The first connection members are generally equidistantly spaced about a diameter of the first planar surface. A plurality of second connection members extend generally outwardly from the second planar surface. The second connection members are generally equidistantly spaced about a diameter of the second planar surface.

Abstract: A fluid level sensor for determining an amount of first fluid in a system is provided including a first substantially transparent sight glass mounted outside and fluidly coupled to a portion of the system. A level of first fluid in the first sight glass is indicative of the amount of first fluid in the system. A second substantially transparent sight glass has an independent closed loop containing a second fluid. The second sight glass is positioned adjacent outside the system. A plane of the second sight glass is arranged adjacent to a pivot point of the first fluid within the system. A level of second fluid in the second sight glass is indicative of the amount of first fluid corresponding to normal operation of the system. A comparison of the level of first fluid in the first sight glass and the level of second fluid in the second sight glass indicates if the amount of first fluid in the system requires adjustment.

Abstract: A device for limiting torque between a first rotatable component and a second rotatable component is provided including a first portion connected to the first component. The first portion has a flange extending radially outwardly therefrom. A second portion includes at least one biasing mechanism configured to provide a biasing force. The second portion is coupled to the second component and is arranged adjacent opposing surfaces of the flange. The second portion is configured to apply the biasing force to the flange to selectively coupled the first component and the second component.

Abstract: A split torque gearbox system provides a multiple path, three stage power gear train that transmits torque from a high-speed engine to a low speed output shaft, while providing equal gear load distribution with a floating pinion in the second stage of reduction. The number of the split modules in the gearbox depends on gearbox configuration, number of high speed input shafts, and transmitted power. The split modules are located around a last stage output gear that combines power from each module and transmits the power to an output such as a main rotor system.

Abstract: A lubrication system includes an external pump system which pumps air out of the housing and develop negative pressure therein in response to a loss of lubrication condition. The negative pressure operates as an air lock to minimize or prevent lubricating oil loss from the housing while an internal lubrication system continues to distribute lubricating oil—which although now increasing in temperature—still operates to lubricate the gearbox components. For further ballistic tolerance, the housing is a compound housing that reduces or closes the penetration and further minimizes lubricating oil and negative pressure loss. The housing may be still further hardened by an armor layer.

Abstract: A split torque gearbox system provides a multiple path, three stage power gear train that transmits torque from a high-speed engine to a low speed output shaft, while providing equal gear load distribution with a floating pinion in the second stage of reduction. The number of the split modules in the gearbox depends on gearbox configuration, number of high speed input shafts, and transmitted power. The split modules are located around a last stage output gear that combines power from each module and transmits the power to an output such as a main rotor system.