Abstract: A ram air turbine (RAT) restow system includes an actuator assembly with a piston interposed between an upper fluid compartment and a lower fluid compartment. The actuator assembly is configured to selectively move the piston between a deployed position and a stowed position. A hydraulic restow circuit is interposed between the actuator assembly and a hydraulic fluid system that is configured to output fluid. The hydraulic restow circuit includes a restow valve configured to operate in a first position that establishes a first fluid path to deliver the fluid to the upper fluid compartment and a second position that establishes a second fluid path to deliver the fluid to the lower fluid compartment.

Abstract: An engine system can include an engine having an engine shaft and a transmission that can include an input shaft connected to the engine shaft to rotate with the engine shaft, one or more rotating gears configured to rotate relative to the input shaft, and a synchromesh configured to selectively engage each of the one or more rotating gears to the input shaft. Transmission can include a second shaft comprising a clutch configured to selectively engage the one or more rotating gears to the second shaft to cause the second shaft to rotate with the one or more rotating gears.

Abstract: A turbomachine dual spool transmission system can include a transmission assembly configured to connect to a combination output of a dual spool differential at a transmission input to be driven by the combination output to turn a transmission output. The transmission assembly can be configured to provide a first output gear ratio in a first state and a second output gear ratio in a second state. The system can include the dual spool differential. The dual spool differential can include a gear assembly configured to combine a low pressure spool input and a high pressure spool input into a combination output to provide an output speed range smaller than a low pressure speed range alone.

Abstract: A ram air turbine release system including a turbine defining a rotational axis including at least one notch therein for receiving a plunger to prevent rotation of the turbine mechanically by moving between a first position and a second position, and a first bearing system contacting at least a portion of an outer surface of the plunger configured to reduce friction produced when the plunder moves between the first positon and the second position.

Abstract: A toggle assembly includes a first joint member having a first lug and a second lug, a second joint member, and a third joint member. The second joint member has a first arm that receives a first rolling element, a second arm that receives a second rolling element, a third arm, and a fourth arm. The second joint member is pivotally connected to the first joint member via a first pin that extends through the first lug, the first rolling element, the second rolling element, and the second lug. The third joint member has a third lug and a fourth lug disposed opposite the third lug. The third joint member is pivotally connected to the second joint member via a cross rod pin that extends through the third lug, the third arm and the fourth arm.

Abstract: A hydraulic control valve includes a sleeve with actuator and biasing member ends and a spool with first and second lands. The sleeve defines a bore extending along a spool movement axis, a source port proximate the stow solenoid end and in communication with the bore, and a supply port between the source port and the biasing end. The spool is slidably disposed within the bore, is movable along the spool movement axis between first and second positions, fluidly separates the source port from the supply port in the first position, and allows the bore to fluidly couple the source port with the supply port in the second position. The first land extends circumferentially about the spool and has a first land length, the second land extending circumferentially about the spool and has a second land length, and the first land length is larger than the second land length.

Abstract: A turbomachine dual spool differential can include a gear assembly configured to combine a low pressure spool input and a high pressure spool input into a combination output to provide an output speed range smaller than a low pressure spool speed range alone. The gear assembly can include a ring gear, a sun gear, and a plurality of planetary gears disposed between the sun gear and the ring gear and meshed with the sun gear and the ring gear. The planetary gears can be rotationally connected to a carrier.

Abstract: A multispeed turbomachine transmission can include an input shaft and a plurality of input shaft gears disposed on the input shaft. The transmission can include one or more clutch shafts, one or more clutch shaft input gears disposed on the one or more clutch shafts, each meshed with at least one of the plurality of input shaft gears, at least one clutch shaft output gear mounted to each clutch shaft, a clutch connected to each clutch shaft and configured to selectively connect the one or more clutch shaft input gears to the at least one clutch shaft output gear. The transmission can include an output shaft and at least one output shaft gear connected to the output shaft and meshed with the at least one clutch shaft output gear.

Abstract: A system for axially retaining two coaxial components includes an inner component having an annular compression groove formed in a radially outer surface thereof, an outer component having an annular engagement groove formed in a radially inner surface thereof, and a split retaining ring installed in the annular compression groove of the inner component, wherein the split retaining ring is adapted for movement between a radially compressed condition to facilitate axial engagement of the inner component within the outer component and a radially expanded condition to facilitate radial engagement of the split retaining ring in the annular engagement groove of the outer component, so that the inner and outer components are axially locked together.

Abstract: A hydraulic clutch assembly can include a shaft defining a shaft channel, one or more hydraulic ports defined through the shaft, and one or more lubrication holes defined through the shaft. A porting manifold can be disposed at least partially within the shaft channel. The porting manifold can include a control pressure path in fluid communication with the one or more hydraulic ports and a lubrication flow path in fluid communication with the one or more lubrication holes. The control pressure path and the lubrication path can be fluidly isolated in the porting manifold.

Abstract: A wet clutch assembly can include a clutch pack having a plurality of friction members attached to a first clutch housing and a plurality of separator members attached to a second clutch housing. The friction members and the separator members can be configured to be selectively contacted to each other to engage the first housing member to the second housing member. The clutch pack can be in fluid communication with a lubrication source such that a lubrication flow can flow to the friction members and the separator members to remove heat and/or debris therefrom.

Abstract: A turbomachine dual spool transmission system can include a transmission assembly configured to connect to a combination output of a dual spool differential at a transmission input to be driven by the combination output to turn a transmission output. The transmission assembly can be configured to provide a first output gear ratio in a first state and a second output gear ratio in a second state. The system can include the dual spool differential. The dual spool differential can include a gear assembly configured to combine a low pressure spool input and a high pressure spool input into a combination output to provide an output speed range smaller than a low pressure speed range alone.

Abstract: A ram air turbine release system including a turbine defining a rotational axis including at least one notch therein for receiving a plunger to prevent rotation of the turbine mechanically by moving between a first position and a second position, and a first bearing system contacting at least a portion of an outer surface of the plunger configured to reduce friction produced when the plunder moves between the first positon and the second position.

Abstract: A turbomachine dual spool transmission system can include a transmission assembly configured to connect to a combination output of a dual spool differential at a transmission input to be driven by the combination output to turn a transmission output. The transmission assembly can be configured to provide a first output gear ratio in a first state and a second output gear ratio in a second state. The system can include the dual spool differential. The dual spool differential can include a gear assembly configured to combine a low pressure spool input and a high pressure spool input into a combination output to provide an output speed range smaller than a low pressure speed range alone.

Abstract: A retaining ring configured to retain a shaft to a sleeve to fix the shaft rotationally and axially to the sleeve can include a first portion configured to install around the shaft and within the sleeve. The first portion can include one or more first curved sections and at least one first portion flat. The retaining ring can include a second portion configured to install around the shaft and moveable relative to the first portion, the second portion comprising one or more second curved sections and at least one second portion flat. The first portion flat can be defined between a plurality of the first curved sections, and wherein the second portion flat can be defined between a plurality of the second curved sections, for example.

Abstract: A ram air turbine (RAT) restow system includes an actuator assembly with a piston interposed between an upper fluid compartment and a lower fluid compartment. The actuator assembly is configured to selectively move the piston between a deployed position and a stowed position. A hydraulic restow circuit is interposed between the actuator assembly and a hydraulic fluid system that is configured to output fluid. The hydraulic restow circuit includes a restow valve configured to operate in a first position that establishes a first fluid path to deliver the fluid to the upper fluid compartment and a second position that establishes a second fluid path to deliver the fluid to the lower fluid compartment.

Abstract: A hydraulic control valve includes a sleeve with actuator and biasing member ends and a spool with first and second lands. The sleeve defines a bore extending along a spool movement axis, a source port proximate the stow solenoid end and in communication with the bore, and a supply port between the source port and the biasing end. The spool is slidably disposed within the bore, is movable along the spool movement axis between first and second positions, fluidly separates the source port from the supply port in the first position, and allows the bore to fluidly couple the source port with the supply port in the second position. The first land extends circumferentially about the spool and has a first land length, the second land extending circumferentially about the spool and has a second land length, and the first land length is larger than the second land length.

Abstract: Disclosed is a transmission, including: an input shaft; an output shaft; a gear system connected between the input shaft and the output shaft, the gear system including: a first epicyclical gear set that includes a first ring gear coupled to the input shaft, a first sun gear, a first planetary gear set, and a first planetary carrier connected to the first planetary gear set; and a second epicyclical gear set that includes a second ring gear, a second sun gear, a second planetary gear set, and a second planetary carrier connected to the second planetary gear set, wherein: the input shaft is coupled to the first ring gear and the second planetary carrier; and the first planetary carrier is coupled to the second ring gear; and clutches that engage the first epicyclical gear set and the second epicyclical gear set, the clutches shifting the transmission to generate overlapping transmission speeds.

Abstract: A ram air turbine (RAT) can include a housing and a turbine shaft configured to connect to one or more turbine blades and be turned by the one or more blades. The turbine shaft can be disposed in the housing to rotate relative to the housing along a rotational axis. The RAT can include a first bearing and a second bearing mounted between the turbine shaft and the housing to allow the turbine shaft to rotate relative to the housing. The RAT can include a whirl reduction system configured to dampen or eliminate whirl around the rotational axis.

Abstract: A ram air turbine (RAT) actuator piston can include a body defining a piston structure having an inner cavity. The piston can include one or more damping holes axially defined through the body to the inner cavity and a lock rod hole defined axially through the body to the inner cavity. The lock rod hole can have a larger flow area than one or more of the one or more damping holes. The lock rod hole can be configured to receive a lock rod of a RAT actuator to at least partially block flow through the lock rod hole when the lock rod is in a locked position. The one or more damping holes can be configured to allow flow through the damping holes in the locked position to allow the RAT actuator piston to move within the RAT actuator in the locked position to dissipate vibratory loads.