Abstract: A turbofan engine includes a turbo-engine, a fan, and a double gearbox assembly. The turbo-engine includes a compressor section, a turbine section, and a combustor in fluid communication with the compressor section and the turbine section. The turbine section includes a low-pressure turbine having a low-pressure shaft and a plurality of low-pressure turbine stages. The fan has a fan shaft drivingly coupled to the low-pressure shaft through the double gearbox assembly. The double gearbox assembly includes a first stage gear assembly coupled to the low-pressure shaft and an interstage shaft, a second stage gear assembly coupled 100 to the interstage shaft, and an output shaft coupled to the fan shaft.

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 turbofan engine for an aircraft includes a fan and a fan actuation system. The fan has a plurality of fan blades coupled to a fan shaft having one or more fan bearings. The fan blades are rotatable about a pitch axis. The fan actuation system is disposed within a fan hub and includes one or more actuators for rotating the fan blades about the pitch axis and one or more radial thrust bearings. The fan actuation system is characterized by a fan actuation system length envelope in a range from 8.5 to 24 and given by N FB × D FT L AXIAL × ( R TB N FB ) . NFB is a number of the fan blades, DFT is a fan tip diameter of the fan blades, RTB is a thrust bearing radius of the radial thrust bearings, and LAXIAL is an axial length from a fan hub tip to the fan bearings.

Abstract: An engine system for an aircraft includes a first turbofan engine and a second turbofan engine. The first turbofan engine includes a first low-pressure shaft, a first fan having a first fan shaft, and a counterclockwise gearbox assembly. The first fan shaft is drivingly coupled to the first low-pressure shaft through the counterclockwise gearbox assembly. The first low-pressure shaft rotates in a counterclockwise direction. The first fan shaft rotates in the counterclockwise direction such that the first fan rotates in the counterclockwise direction. The second turbofan engine includes a second low-pressure shaft, a second fan having a second fan shaft, and a clockwise gearbox assembly. The second fan shaft is drivingly coupled to the second low-pressure shaft through the clockwise gearbox assembly. The second low-pressure shaft rotates in the counterclockwise direction. The second fan shaft rotates in a clockwise direction such that the second fan rotates in the clockwise direction.

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: An aircraft engine component (100) may include a wall (200) comprising an aluminum alloy and/or a magnesium alloy, and a protective coating (108) covering the wall (200). The protective coating (108) may include a prime layer (206), a silicone elastomer layer (208), and an abrasion resistant layer (210). The prime layer (206) may at least partially cover a surface (202) of the wall (200). The prime layer (206) may include a silane coupling agent and an organic titanate. The silicone elastomer layer (208) may at least partially cover the prime layer (206). The silicone elastomer layer (208) may include one or more filler materials dispersed in a matrix of cross-linked silicone polymers. The abrasion resistant layer (210) may at least partially cover the silicone elastomer layer (208). The abrasion resistant layer (210) may include a fiber-reinforced elastomeric material.

Abstract: An engine assembly defining an axial direction (A) and including a gearbox, an engine core including at least one rotor, and a flexible coupling shaft having a first end and a second end along the axial direction (A). The first end of the flexible coupling shaft is connected to the engine core and the second end of the flexible coupling shaft is connected to the gearbox. A damper system is positioned at the second end of the flexible coupling shaft. The damper system is configured to reduce vibrations to the flexible coupling shaft during operation of the engine assembly.

Abstract: An aircraft engine component (100) may include a wall (200) comprising an aluminum alloy and/or a magnesium alloy, and a protective coating (108) covering the wall (200). The protective coating (108) may include a prime layer (206), a silicone elastomer layer (208), and an abrasion resistant layer (210). The prime layer (206) may at least partially cover a surface (202) of the wall (200). The prime layer (206) may include a silane coupling agent and an organic titanate. The silicone elastomer layer (208) may at least partially cover the prime layer (206). The silicone elastomer layer (208) may include one or more filler materials dispersed in a matrix of cross-linked silicone polymers. The abrasion resistant layer (210) may at least partially cover the silicone elastomer layer (208). The abrasion resistant layer (210) may include a fiber-reinforced elastomeric material.

Abstract: An engine assembly defining an axial direction (A) and including a gearbox, an engine core including at least one rotor, and a flexible coupling shaft having a first end and a second end along the axial direction (A). The first end of the flexible coupling shaft is connected to the engine core and the second end of the flexible coupling shaft is connected to the gearbox. A damper system is positioned at the second end of the flexible coupling shaft. The damper system is configured to reduce vibrations to the flexible coupling shaft during operation of the engine assembly.