Abstract: A transmission gearbox for a rotary-wing aircraft includes a main gearbox and a variable speed gearbox in meshing engagement with the main rotor gearbox. The variable speed gearbox permits at least two different RPMs for the main rotor system without disengaging the engine(s) or changing engine RPMs. The variable speed gearbox includes a clutch, preferably a multi-plate clutch, and a freewheel unit for each engine. A gear path drives the main gearbox in a “high rotor speed mode” when the clutch is engaged to drive the main rotor system at high rotor rpm for hover flight profile. A reduced gear path drives the main gearbox in a “low rotor speed mode” when the clutch is disengaged and power is transferred through the freewheel unit, to drive the main rotor system at lower rotor rpm for high speed flight. The variable speed gearbox may be configured for a tail drive system that operates at a continuous speed, a tail drive system that changes speed with the main rotor shaft or for no tail drive system.

Abstract: A multi-path split torque gearbox system provides a multiple of three stage torque split power gear trains modules that each transmits torque from a high-speed engine to a main rotor shaft (36). The first stage bevel gear arrangement (30,32) provides a compact packaging arrangement that facilitates various engine mounting locations in all axes. At the second stage, quill shaft assemblies (40) provide equal load balance. At the third stage, each quill shaft assembly includes a multiple of pinion gears (48) in meshing engagement with the final output gear (28). Each torque split modules transfer the power from the high speed input shaft into a multiple of meshing engagements with the final output gear to provide significant torque transfer desired in a single rotor heavy lift rotary wing aircraft embodiment within a compact housing package.

Abstract: A transmission gearbox for a rotary-wing aircraft includes a main gearbox and a variable speed gearbox in meshing engagement with the main rotor gearbox. The variable speed gearbox permits at least two different RPMs for the main rotor system without disengaging the engine(s) or changing engine RPMs. The variable speed gearbox includes a clutch, preferably a multi-plate clutch, and a freewheel unit for each engine. A gear path drives the main gearbox in a “high rotor speed mode” when the clutch is engaged to drive the main rotor system at high rotor rpm for hover flight profile. A reduced gear path drives the main gearbox in a “low rotor speed mode” when the clutch is disengaged and power is transferred through the freewheel unit, to drive the main rotor system at lower rotor rpm for high speed flight. The variable speed gearbox may be configured for a tail drive system that operates at a continuous speed, a tail drive system that changes speed with the main rotor shaft or for no tail drive 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 gearbox of a rotary-wing aircraft includes at least one variable speed system which optimizes the main rotor speed for different flight regimes such as a hover flight profile and a high speed cruise flight profile for any rotary wing aircraft while maintaining an independently variable tail rotor speed.

Abstract: A transmission gearbox for a rotary-wing aircraft includes a main gearbox and a variable speed gearbox in meshing engagement with the main rotor gearbox. The variable speed gearbox permits at least two different RPMs for the main rotor system without disengaging the engine(s) or changing engine RPMs. The variable speed gearbox includes a clutch, preferably a multi-plate clutch, and a freewheel unit for each engine. A gear path drives the main gearbox in a “high rotor speed mode” when the clutch is engaged to drive the main rotor system at high rotor rpm for hover flight profile. A reduced gear path drives the main gearbox in a “low rotor speed mode” when the clutch is disengaged and power is transferred through the freewheel unit, to drive the main rotor system at lower rotor rpm for high speed flight. The variable speed gearbox may be configured for a tail drive system that operates at a continuous speed, a tail drive system that changes speed with the main rotor shaft or for no tail drive system.

Abstract: A multi-path split torque gearbox system provides a multiple of three stage torque split power gear trains modules that each transmits torque from a high-speed engine to a main rotor shaft (36). The first stage bevel gear arrangement (30,32) provides a compact packaging arrangement that facilitates various engine mounting locations in all axes. At the second stage, quill shaft assemblies (40) provide equal load balance. At the third stage, each quill shaft assembly includes a multiple of pinion gears (48) in meshing engagement with the final output gear (28). Each torque split modules transfer the power from the high speed input shaft into a multiple of meshing engagements with the final output gear to provide significant torque transfer desired in a single rotor heavy lift rotary wing aircraft embodiment within a compact housing package.

Abstract: A gearbox of a rotary-wing aircraft includes at least one variable speed system which optimizes the main rotor speed for different flight regimes such as a hover flight profile and a high speed cruise flight profile for any rotary wing aircraft while maintaining an independently variable tail rotor speed.

Abstract: A gearbox of a rotary-wing aircraft includes at least one variable speed system which optimizes the main rotor speed for different flight regimes such as a hover flight profile and a high speed cruise flight profile for any rotary wing aircraft while maintaining an independently variable tail rotor speed.

Abstract: A gearbox of a high speed compound rotary-wing aircraft includes a main module, an input module and a translational thrust module. The input module receives power from the engines to drive a dual, contra-rotating, coaxial main rotor system and a translational thrust system which provides significant translational thrust generally parallel to an aircraft longitudinal axis. Each of a multiple of engine drives the input module such that power is distributed to the main module and the translational thrust module. The gearbox provides a lightweight solution, since each module need only transmit a required fraction of available engines power.

Abstract: A transmission gearbox for a rotary-wing aircraft includes a main gearbox and a variable speed gearbox in meshing engagement with the main rotor gearbox. The variable speed gearbox permits at least two different RPMs for the main rotor system without disengaging the engine(s) or changing engine RPMs. The variable speed gearbox includes a clutch, preferably a multi-plate clutch, and a freewheel unit for each engine. A gear path drives the main gearbox in a “high rotor speed mode” when the clutch is engaged to drive the main rotor system at high rotor rpm for hover flight profile. A reduced gear path drives the main gearbox in a “low rotor speed mode” when the clutch is disengaged and power is transferred through the freewheel unit, to drive the main rotor system at lower rotor rpm for high speed flight. The variable speed gearbox may be configured for a tail drive system that operates at a continuous speed, a tail drive system that changes speed with the main rotor shaft or for no tail drive system.

Abstract: A transmission gearbox for a rotary-wing aircraft includes a main gearbox and a variable speed gearbox in meshing engagement with the main rotor gearbox. The variable speed gearbox permits at least two different RPMs for the main rotor system without disengaging the engine(s) or changing engine RPMs. The variable speed gearbox includes a clutch, preferably a multi-plate clutch, and a freewheel unit for each engine. A gear path drives the main gearbox in a “high rotor speed mode” when the clutch is engaged to drive the main rotor system at high rotor rpm for hover flight profile. A reduced gear path drives the main gearbox in a “low rotor speed mode” when the clutch is disengaged and power is transferred through the freewheel unit, to drive the main rotor system at lower rotor rpm for high speed flight. The variable speed gearbox may be configured for a tail drive system that operates at a continuous speed, a tail drive system that changes speed with the main rotor shaft or for no tail drive system.

Abstract: A gearbox of a rotary-wing aircraft includes at least one variable speed system which optimizes the main rotor speed for different flight regimes such as a hover flight profile and a high speed cruise flight profile for any rotary wing aircraft while maintaining an independently variable tail rotor speed.

Abstract: A drive system for a high speed rotary-wing aircraft includes a combiner gearbox in meshing engagement with a main gearbox. The combiner gearbox is driven by one or more engines such that a main rotor system and a translational thrust system are driven thereby. The engine drives the combiner gearbox and thus the main gearbox through an overrunning clutch. The drive system permits the main rotor system RPM to be controlled by offloading power to the translational thrust system during a high speed flight profile.

Abstract: A transmission gearbox for a rotary-wing aircraft includes a main gearbox and a variable speed gearbox in meshing engagement with the main rotor gearbox. The variable speed gearbox permits at least two different RPMs for the main rotor system without disengaging the engine(s) or changing engine RPMs. The variable speed gearbox includes a clutch, preferably a multi-plate clutch, and a freewheel unit for each engine. A gear path drives the main gearbox in a “high rotor speed mode” when the clutch is engaged to drive the main rotor system at high rotor rpm for hover flight profile. A reduced gear path drives the main gearbox in a “low rotor speed mode” when the clutch is disengaged and power is transferred through the freewheel unit, to drive the main rotor system at lower rotor rpm for high speed flight. The variable speed gearbox may be configured for a tail drive system that operates at a continuous speed, a tail drive system that changes speed with the main rotor shaft or for no tail drive system.

Abstract: A gearbox of a high speed compound rotary-wing aircraft includes a main module, an input module and a translational thrust module. The input module receives power from the engines to drive a dual, contra-rotating, coaxial main rotor system and a translational thrust system which provides significant translational thrust generally parallel to an aircraft longitudinal axis. Each of a multiple of engine drives the input module such that power is distributed to the main module and the translational thrust module. The gearbox provides a lightweight solution, since each module need only transmit a required fraction of available engines power.

Abstract: A split torque gearbox having multiple input shafts. Each input shaft is connected to two face gears. Each face gear is connected to two quill shafts, one is coaxially mounted and the second is not coaxially mounted. Of the two quill shafts, one is positioned on a first side of an output stage and a second quill shaft is located on a second side of the output stage and the quill shafts are connected thereto. The output stage is connected to a main shaft.

Abstract: A split torque gearbox having multiple input shafts. Each input shaft is connected to two face gears. Each face gear is connected to two quill shafts, one is coaxially mounted and the second is not coaxially mounted. Of the two quill shafts, one is positioned on a first side of an output stage and a second quill shaft is located on a second side of the output stage and the quill shafts are connected thereto. The output stage is connected to a main shaft.

Abstract: A powerplant system for a vehicle such as a hybrid UAV includes a miniature gas turbine engine and a gearbox assembly. The engine is mounted to the gearbox assembly through a support structure which provides for pivotal movement of the engine relative thereto. The input gear is engaged with two gears such that the pivoted engine arrangement permits the input gear to float until gear loads between the input gear and the first and second gear are balanced. Regardless of the gear teeth errors or gearbox shaft misalignments the input gear will float and split the torque between the two gears.

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.