Abstract: An apparatus has a first member, a shaft rotatable relative to the first member about an axis, and a seal system. The seal system has: a seal carried by the first member and having a seal face; and a seat carried by the shaft and having a seat face in sliding sealing engagement with the seal face. The seal system is a dry face seal system. The seat further includes a section having: an outer diameter surface encircled by the seal; and a rim.

Abstract: An apparatus has a first member, a shaft rotatable relative to the first member about an axis, and a seal system. The seal system has: a seal carried by the first member and having a seal face; and a seat carried by the shaft and having a seat face in sliding sealing engagement with the seal face. The seal system is a dry face seal system. The seat further includes a section having: an outer diameter surface encircled by the seal; and a rim.

Abstract: A gas turbine engine includes a fan drive turbine driving a fan rotor through a main gear reduction. A primary lubricant system supplies lubricant to the main gear reduction. An auxiliary oil pump supplies oil to the main gear reduction. An auxiliary pump epicyclic gear train drives the auxiliary pump when the fan rotor is rotating in either direction. The main gear reduction is separate from the auxiliary pump epicyclic gear train.

Abstract: A gear reduction includes a sun gear that engages a plurality of planet gears mounted on a carrier. The planet gears are engaged with a ring gear. The ring gear is fixed against rotation such that rotation of the sun gear causes rotation of the planet gears to cause rotation of the carrier. There are spray bars positioned circumferentially between adjacent ones of the planet gears. The spray bars have jet openings, such that lubricant can be passed directly onto teeth on the sun gear. One of the side faces has a plurality of windows such that oil can be scavenged. There are side surfaces between plurality of windows that do not have an opening. A gas turbine engine and a spray bar are also disclosed.

Abstract: A gear reduction includes a sun gear that engages a plurality of planet gears mounted on a carrier. The planet gears are engaged with a ring gear. The ring gear is fixed against rotation such that rotation of the sun gear causes rotation of the planet gears to cause rotation of the carrier. There are spray bars positioned circumferentially between adjacent ones of the planet gears. The spray bars have jet openings, such that lubricant can be passed directly onto teeth on the sun gear. One of the side faces has a plurality of windows such that oil can be scavenged. There are side surfaces between plurality of windows that do not have an opening. A gas turbine engine and a spray bar are also disclosed.

Abstract: An apparatus has a first member, a shaft rotatable relative to the first member about an axis, and a seal system. The seal system has: a seal carried by the first member and having a seal face; and a seat carried by the shaft and having a seat face in sliding sealing engagement with the seal face. The seal system is a dry face seal system. The seat further includes a section having: an outer diameter surface encircled by the seal; and a rim.

Abstract: An apparatus has a first member, a shaft rotatable relative to the first member about an axis, and a seal system. The seal system has: a seal carried by the first member and having a seal face; and a seat carried by the shaft and having a seat face in sliding sealing engagement with the seal face. The seal system is a dry face seal system. The seat further includes a section having: an outer diameter surface encircled by the seal; and a rim.

Abstract: A damping apparatus includes a first sidewall defining a centerline axis, a second sidewall disposed coaxial with the first sidewall, a main cavity defined between the first sidewall and the second sidewall, and a damping material disposed in the main cavity.

Abstract: A gear reduction includes a sun gear that engages a plurality of planet gears mounted on a carrier. The planet gears are engaged with a ring gear. The ring gear is fixed against rotation such that rotation of the sun gear causes rotation of the planet gears to cause rotation of the carrier. There are spray bars positioned circumferentially between adjacent ones of the planet gears. The spray bars have jet openings, such that lubricant can be passed directly onto teeth on the sun gear. One of the side faces has a plurality of windows such that oil can be scavenged. There are side surfaces between plurality of windows that do not have an opening. A gas turbine engine and a spray bar are also disclosed.

Abstract: An engine includes a spool including a turbine, a second spool including a second turbine, a fan, and a fan drive gear system. A tower shaft is engaged to the spool. A second tower shaft is engaged to the second spool. A superposition gear system includes a plurality of intermediate gears engaged to the sun gear and supported in a carrier and a ring gear circumscribing the intermediate gears. The tower shaft drives the sun gear. An oil pump is driven by the carrier and supplies oil to the fan drive gear system from an oil tank through a first pickup at a first end of the oil tank and a second pickup at a second, opposite end of the oil tank. A shuttle valve at a suction side of the oil pump selectively allows oil to be supplied by one of the first and second pickup.

Abstract: A seal assembly for a gas turbine engine according to an example of the present disclosure includes, among other things, a rotatable shaft defining a longitudinal axis, and a bearing housing extending along the longitudinal axis to define a bearing compartment. The bearing housing has a first seal land defined along an inner diameter of the bearing housing, a seal carrier fixedly attached to an outer periphery of the shaft, and a seal member extending outwardly from the seal carrier. The seal member defines a plurality of helical grooves facing radially outward to establish a first sealing relationship with the first seal land, and each one of the helical grooves has a major component extending in an axial direction relative to the longitudinal axis. A method of sealing for a gas turbine engine is also disclosed.

Abstract: A turbofan engine includes a first spool including a first turbine and a second spool including a second turbine. A superposition gear system includes a plurality of intermediate gears engaged to a sun gear and supported in a carrier and a ring gear circumscribing the intermediate gears. A second tower shaft is engaged to drive the sun gear. A starter is selectively coupled to the sun gear through a starter clutch. A first electric motor and a second electric motor are coupled to the superposition gear system and are operable to input power into a corresponding one of the first and second spools.

Abstract: A power extraction system for a gas turbine engine may comprise a low spool transmission and a low spool accessory gearbox. The low spool accessory gearbox may comprise a generator and a dual clutch transmission. The dual clutch transmission may be coupled between the low spool transmission and the generator.

Abstract: A gas turbine engine including a low speed spool including a low pressure compressor, a low speed output gear disposed on the low speed spool, a high speed spool including a high pressure compressor, a high speed output gear disposed on the high speed spool, a first tower shaft engaged to the low speed spool at the low speed output gear, a second tower shaft engaged to the high speed spool at the high speed output gear, and a superposition gearbox. The gas turbine engine further including a ring gear shaft coupled to drive the ring gear, a ring gear shaft drive gear. A low speed spool drive train gear ratio is between 0.5 to 2.0, the low speed spool drive train gear ratio being measured from the low speed output gear to the ring gear shaft drive gear.

Abstract: A filtration system is disclosed. In various embodiments, the filtration system includes a fine mesh filter configured for disposition within a chamber and defining a first volume, the first volume in fluid communication with a main exit conduit; and a coarse mesh filter configured for disposition within the chamber and at least partially surrounding the fine mesh filter, the coarse mesh filter and the fine mesh filter defining a second volume, the second volume in fluid communication with a first bypass valve, the coarse mesh filter and the chamber defining a third volume, the third volume in fluid communication with a second bypass valve.

Abstract: An engine includes a spool including a turbine, a second spool including a second turbine, a fan, and a fan drive gear system. A tower shaft is engaged to the spool. A second tower shaft is engaged to the second spool. A superposition gear system includes a plurality of intermediate gears engaged to the sun gear and supported in a carrier and a ring gear circumscribing the intermediate gears. The tower shaft drives the sun gear. An oil pump is driven by the carrier and supplies oil to the fan drive gear system from an oil tank through a first pickup at a first end of the oil tank and a second pickup at a second, opposite end of the oil tank. A shuttle valve at a suction side of the oil pump selectively allows oil to be supplied by one of the first and second pickup.

Abstract: A gas turbine engine includes a fan drive turbine driving a fan rotor through a main gear reduction. A primary lubricant system supplies lubricant to the main gear reduction. An auxiliary oil pump supplies oil to the main gear reduction. An auxiliary pump epicyclic gear train drives the auxiliary pump when the fan rotor is rotating in either direction. The main gear reduction is separate from the auxiliary pump epicyclic gear train.

Abstract: A power extraction system for a gas turbine engine may comprise a low spool transmission and a low spool accessory gearbox. The low spool accessory gearbox may comprise a generator and a dual clutch transmission. The dual clutch transmission may be coupled between the low spool transmission and the generator.

Abstract: A damping apparatus includes a first sidewall defining a centerline axis, a second sidewall disposed coaxial with the first sidewall, a main cavity defined between the first sidewall and the second sidewall, and a damping material disposed in the main cavity.

Abstract: A gas turbine engine includes a fan drive turbine driving a fan rotor through a main gear reduction. A primary lubricant system supplies lubricant to the main gear reduction. An auxiliary oil pump supplies oil to the main gear reduction. An auxiliary pump epicyclic gear train drives the auxiliary pump when the fan rotor is rotating in either direction. The main gear reduction is separate from the auxiliary pump epicyclic gear train.