Abstract: A differential gearbox assembly for a turbine engine having a fan shaft and a drive shaft. The differential gearbox assembly includes an epicyclic gear assembly coupling the fan shaft to the drive shaft. The epicyclic gear assembly includes a sun gear, a planet gear constrained by a planet carrier, and a ring gear. The sun gear is coupled to the drive shaft and the planet carrier is coupled to the fan shaft. The sun gear, the planet gear, and the ring gear all rotate about the drive shaft. The differential gearbox assembly includes an electric machine assembly that includes an input coupled to the epicyclic gear assembly. The electric machine assembly provides mechanical power to the fan shaft through the epicyclic gear assembly.

Abstract: A turbomachine engine includes a fan section having a fan shaft, and a core engine having one or more compressor sections, one or more turbine sections that includes a power turbine, and a combustion chamber in flow communication with the compressor sections and turbine sections. The turbomachine engine includes a low-speed shaft coupled to the power turbine and having a midshaft that extends from a forward bearing to an aft bearing. The low-speed shaft is characterized by a midshaft rating (MSR) between two hundred (ft/sec)1/2 and three hundred (ft/sec)1/2. The low-speed shaft has a redline speed between fifty and two hundred fifty feet per second (ft/sec). The turbomachine engine includes a gearbox assembly that couples the fan shaft to the low-speed shaft and characterized by a gearbox assembly mode less than 95% of a midshaft mode of the midshaft or greater than 105% of the midshaft mode.

Abstract: A gear assembly for use with a turbomachine comprises a sun gear, a plurality of planet gear layshafts that each support a first stage planet gear and a second stage planet gear, and a ring gear. The sun gear is configured to rotate about a longitudinal centerline of the gear assembly, and the plurality of planet gear layshafts comprise an interior passage that receives one or more lubrication supply lines.

Abstract: A differential gearbox assembly for a turbine engine having a fan shaft and a drive shaft. The differential gearbox assembly includes an epicyclic gear assembly coupling the fan shaft to the drive shaft. The epicyclic gear assembly includes a sun gear, a planet gear constrained by a planet carrier, and a ring gear. The sun gear is coupled to the drive shaft and the planet carrier is coupled to the fan shaft. The sun gear, the planet gear, and the ring gear all rotate about the drive shaft. The differential gearbox assembly includes an electric machine assembly that includes an input coupled to the epicyclic gear assembly. The electric machine assembly provides mechanical power to the fan shaft through the epicyclic gear assembly.

Abstract: A gearbox assembly includes a first gear and a second gear. The first gear includes a plurality of first gear teeth. The second gear includes a plurality of second gear teeth. The plurality of first gear teeth and the plurality of second gear teeth mesh with each other as the first gear and the second gear rotate. A profile shape of at least one first gear tooth of the first gear is characterized by a total profile modification between 66 micrometers and 120 micrometers.

Abstract: A turbomachine engine can include a fan assembly, a vane assembly, a core engine, and a gearbox. The fan assembly can include a plurality of fan blades. The vane assembly can include a plurality of vanes, and the vanes can, in some instances, be disposed aft of the fan blades. The core engine can include one or more compressor sections and one or more turbine sections. The gearbox includes an input and an output. The input is coupled to the one or more turbine sections of the core engine and comprises a first rotational speed, the output is coupled to the fan assembly and has a second rotational speed. A gear ratio of the first rotational speed to the second rotational speed is within a range of 4.1-11.0, and a gearbox oil flow rate at an inlet of the gearbox within a range of 5-25 gallons per minute at a max takeoff condition.

Abstract: A gear assembly for use with a turbomachine comprises a sun gear, a plurality of planet gears, and a ring gear. The gear assembly is connected to an input shaft and an output shaft. The sun gear is configured to rotate about a longitudinal centerline of the gear assembly, and is driven by the input shaft. A component of the gear assembly drives the output shaft. The gear assembly further comprises an output shaft reversal mechanism configured to reverse the rotational direction of the output shaft.

Abstract: A gearbox assembly includes a gearbox and a gutter for collecting a gearbox lubricant scavenge flow from the gearbox. The gutter is characterized by a lubricant extraction volume ratio between 0.01 and 0.3, inclusive of the endpoints. A gas turbine engine includes the gearbox assembly.

Abstract: A differential gearbox assembly for a turbine engine having a fan shaft and a drive shaft. The differential gearbox assembly includes an epicyclic gear assembly coupling the fan shaft to the drive shaft. The epicyclic gear assembly includes a sun gear, a planet gear constrained by a planet carrier, and a ring gear. The sun gear is coupled to the drive shaft and the planet carrier is coupled to the fan shaft. The sun gear, the planet gear, and the ring gear all rotate about the drive shaft. The differential gearbox assembly includes an electric machine assembly that includes an input coupled to the epicyclic gear assembly. The electric machine assembly provides mechanical power to the fan shaft through the epicyclic gear assembly.

Abstract: Methods for treating steel, along with the resulting treated steel, are provided. The method may comprise: nitriding a carburized Ferrium steel component such that the Ferrium steel component has a surface portion with a nitrogen content that is greater than 0% to about 5% by weight. Nitriding the Ferrium steel component may increase the surface hardness of the Ferrium steel. The surface portion may have a nitrogen content of about 0.05% to about 0.5% by weight.

Abstract: A gearbox assembly includes a gear assembly that includes a planet gear, a pin disposed within the planet gear, a first sensor, and a second sensor. The first sensor is disposed within the pin and is configured to produce a signal indicative of a strain of the pin. The second sensor is disposed within the pin and is configured to produce a signal indicative of a vibration of the pin. Another gearbox assembly includes a gear assembly including a planet gear, a pin disposed within the planet gear, and a strain sensor. The strain sensor is disposed within the pin and is configured to produce a signal indicative of a strain of the pin. The strain sensor is located within the pin at a circumferential location of the pin that is opposite to a location of a force acting on the pin when the planet gear rotates about the pin.

Abstract: A turbomachine engine includes a fan section having a fan shaft, and a core engine having one or more compressor sections, one or more turbine sections that includes a power turbine, and a combustion chamber in flow communication with the compressor sections and turbine sections. The turbomachine engine includes a low-speed shaft coupled to the power turbine and having a midshaft that extends from a forward bearing to an aft bearing. The low-speed shaft is characterized by a midshaft rating (MSR) between two hundred (ft/sec)1/2 and three hundred (ft/sec)1/2. The low-speed shaft has a redline speed between fifty and two hundred fifty feet per second (ft/sec). The turbomachine engine includes a gearbox assembly that couples the fan shaft to the low-speed shaft and characterized by a gearbox assembly mode less than 95% of a midshaft mode of the midshaft or greater than 105% of the midshaft mode.

Abstract: A turbomachine engine can include a fan assembly, a vane assembly, a core engine, a gearbox, and a gearbox efficiency rating. The fan assembly can include a plurality of fan blades. The vane assembly can include a plurality of vanes, and the vanes can, in some instances, be disposed aft of the fan blades. The core engine can include one or more compressor sections and one or more turbine sections. The gearbox includes an input and an output. The input is coupled to the one or more turbine sections of the core engine and comprises a first rotational speed, the output is coupled to the fan assembly and has a second rotational speed, and a gear ratio of the first rotational speed to the second rotational speed is within a range of 4.1-14.0. The gearbox efficiency rating is 0.10-1.8.

Abstract: A mounting assembly for a gearbox assembly of a gas turbine engine includes at least one mounting member configured to mount a gear of the gearbox assembly to a component of the gas turbine engine, the at least one mounting member characterized by a lateral impedance parameter, a bending impedance parameter, and a torsional impedance parameter. A gas turbine engine includes the mounting assembly. The at least one mounting member may be a flex mount, a fan frame, or a flex coupling.

Abstract: A turbomachine engine can include a fan assembly, a vane assembly, a core engine, a gearbox, and an overall engine efficiency rating. The fan assembly can include a plurality of fan blades. The vane assembly can include a plurality of vanes, and the vanes can, in some instances, be disposed aft of the fan blades. The core engine can include a low-pressure turbine. The gearbox includes an input and an output. The input of the gearbox is coupled to the low-pressure turbine of the core engine and comprises a first rotational speed, the output of the gearbox is coupled to the fan assembly and has a second rotational speed, and a gear ratio of the first rotational speed to the second rotational speed is within a range of 2.0-4.0. The overall engine efficiency rating is greater than or equal to 0.35GR1.5 and less than or equal to 0.7GR1.5.

Abstract: A gear assembly comprises a plurality of planet gear layshafts that have an outer surface having a plurality of gear surfaces and a surface having one or more bearing surfaces. The one or more bearing surfaces of the surfaces of the planet gear layshafts have a first case hardening depth and a first nitriding hardness depth. The gear surfaces of the outer surface of the planet gear layshafts have a second case hardening depth.

Abstract: A turbomachine engine can include a fan assembly, a vane assembly, a core engine, a gearbox, and an overall engine efficiency rating. The fan assembly can include a plurality of fan blades. The vane assembly can include a plurality of vanes, and the vanes can, in some instances, be disposed aft of the fan blades. The core engine can include a low-pressure turbine. The gearbox includes an input and an output. The input of the gearbox is coupled to the low-pressure turbine of the core engine and comprises a first rotational speed, the output of the gearbox is coupled to the fan assembly and has a second rotational speed, and a gear ratio of the first rotational speed to the second rotational speed is within a range of 3.2-4.0. The overall engine efficiency rating is within a range of 0.57-8.0.

Abstract: A turbomachine engine can include a fan assembly, a vane assembly, a core engine, a gearbox, and an overall engine efficiency rating. The fan assembly can include a plurality of fan blades. The vane assembly can include a plurality of vanes, and the vanes can, in some instances, be disposed aft of the fan blades. The core engine can include a low-pressure turbine. The gearbox includes an input and an output. The input of the gearbox is coupled to the low-pressure turbine of the core engine and comprises a first rotational speed, the output of the gearbox is coupled to the fan assembly and has a second rotational speed, and a gear ratio of the first rotational speed to the second rotational speed is within a range of 3.2-4.0. The overall engine efficiency rating is within a range of 0.57-8.0.

Abstract: A turbomachine engine can include a fan assembly, a pitch change mechanism, a vane assembly, a core engine, a gearbox, and a gearbox efficiency rating. The fan assembly can include a plurality of fan blades. The pitch change mechanism can be coupled to the fan assembly. The vane assembly can include a plurality of vanes. The core engine can include one or more compressor sections and one or more turbine sections. The gearbox includes an input and an output. The input is coupled to the one or more turbine sections of the core engine and comprises a first rotational speed, the output is coupled to the fan assembly and has a second rotational speed, and a gear ratio of the first rotational speed to the second rotational speed is within a range of 4.1-14.0. The gearbox efficiency rating is 0.10-1.8.

Abstract: A turbomachine engine includes a fan section having a fan shaft, and a core engine having one or more compressor sections, one or more turbine sections that includes a power turbine, and a combustion chamber in flow communication with the compressor sections and turbine sections. The turbomachine engine includes a low-speed shaft coupled to the power turbine and having a midshaft that extends from a forward bearing to an aft bearing. The low-speed shaft is characterized by a midshaft rating (MSR) between two hundred (ft/sec)½ and three hundred (ft/sec)½. The low-speed shaft has a redline speed between fifty and two hundred fifty feet per second (ft/sec). The turbomachine engine includes a gearbox assembly that couples the fan shaft to the low-speed shaft and characterized by a gearbox assembly mode less than 95% of a midshaft mode of the midshaft or greater than 105% of the midshaft mode.