Abstract: A ram air turbine (RAT) stowing system includes a closed loop hydraulic circuit configured to hold a quantity of a hydraulic fluid to be utilized only by the RAT stowing system and a RAT actuator disposed in fluid communication with the closed loop hydraulic circuit. A pump system is connected to the hydraulic circuit to selectively pump the hydraulic fluid to a stow reservoir portion of the RAT actuator to move the RAT actuator from a deployed position to a stowed position. A control valve is connected to the hydraulic circuit between the RAT actuator and the pump to selectively allow the hydraulic fluid to be drained from the stow reservoir portion of the RAT actuator in a drain state and to allow the hydraulic fluid to be pumped into the stow reservoir portion of the RAT actuator in a pump state.

Abstract: A ram air turbine (RAT) stowing system includes a closed loop hydraulic circuit configured to hold a quantity of a hydraulic fluid to be utilized only by the RAT stowing system and a RAT actuator disposed in fluid communication with the closed loop hydraulic circuit. A pump system is connected to the hydraulic circuit to selectively pump the hydraulic fluid to a stow reservoir portion of the RAT actuator to move the RAT actuator from a deployed position to a stowed position. A control valve is connected to the hydraulic circuit between the RAT actuator and the pump to selectively allow the hydraulic fluid to be drained from the stow reservoir portion of the RAT actuator in a drain state and to allow the hydraulic fluid to be pumped into the stow reservoir portion of the RAT actuator in a pump state.

Abstract: A ram air turbine with a turbine assembly and a power train, the turbine assembly only coupling to the entire power train upon reaching a desired rotational speed of the turbine assembly, the ram air turbine having a clutch mechanism, the engagement of which couples the turbine assembly to at least a portion of the power train, and a speed control mechanism that engages the clutch mechanism only when the turbine assembly attains at least the desired rotational speed.

Abstract: A hydraulic system for a ram air turbine includes a hydraulic pump having a high pressure fluid outlet port, a housing, a pivot post arranged to pass through the housing and defining a mechanical pivot relative to the housing about an axis, a transfer tube positioned between the high pressure fluid outlet port of the hydraulic pump and a port in the housing for the high pressure fluid outlet path, and seal elements positioned at or near opposite ends of the transfer tube. A fluid inlet path and a high pressure fluid outlet path pass through the housing and the pivot post. The transfer tube has a crowned end.

Abstract: A ram air turbine with a turbine assembly and a power train, the turbine assembly only coupling to the entire power train upon reaching a desired rotational speed of the turbine assembly, the ram air turbine having a clutch mechanism, the engagement of which couples the turbine assembly to at least a portion of the power train, and a speed control mechanism that engages the clutch mechanism only when the turbine assembly attains at least the desired rotational speed.

Abstract: A hydraulic system for a ram air turbine includes a hydraulic pump having a high pressure fluid outlet port, a housing, a pivot post arranged to pass through the housing and defining a mechanical pivot relative to the housing about an axis, a transfer tube positioned between the high pressure fluid outlet port of the hydraulic pump and a port in the housing for the high pressure fluid outlet path, and seal elements positioned at or near opposite ends of the transfer tube. A fluid inlet path and a high pressure fluid outlet path pass through the housing and the pivot post. The transfer tube has a crowned end.

Abstract: An auxiliary hydraulic power generation system includes a first spool including a turbine. A fan is coupled to the first spool, the fan operable to drive the first spool in a windmill condition in which the turbine fails to provide rotational drive to the fan. An auxiliary variable displacement hydraulic pump is selectively driven by the first spool in the windmill condition to augment a hydraulic power source.

Abstract: A hydraulic differential with a variable displacement hydraulic unit of the axial piston type, a fixed displacement hydraulic unit of the axial piston type, a stationary housing for mounting the hydraulic units, an input shaft for coupling to a variable speed power source and an output shaft for coupling to a constant speed load, comprises: a wobbler and a port plate for the variable displacement hydraulic unit coupled to the stationary housing; an axial block and piston set for the variable displacement hydraulic unit, a port plate for the fixed displacement hydraulic unit and a wobbler for the fixed displacement hydraulic unit coupled to the input shaft; and an axial block and piston set for the fixed displacement hydraulic unit coupled to the output shaft; wherein the variable displacement hydraulic unit port plate and the fixed displacement hydraulic unit port plate couple together through a circumferential interface to minimise hydraulic thrust forces developed by the hydraulic unit.

Abstract: A hydraulic differential with a variable displacement hydraulic unit of the axial piston type, a fixed displacement hydraulic unit of the axial piston type, a stationary housing for mounting the hydraulic units, an input shaft for coupling to a variable speed power source and an output shaft for coupling to a constant speed load, comprises: a wobbler and a port plate for the variable displacement hydraulic unit coupled to the stationary housing; an axial block and piston set for the variable displacement hydraulic unit, a port plate for the fixed displacement hydraulic unit and a wobbler for the fixed displacement hydraulic unit coupled to the input shaft; and an axial block and piston set for the fixed displacement hydraulic unit coupled to the output shaft; wherein the variable displacement hydraulic unit port plate and the fixed displacement hydraulic unit port plate couple together through a circumferential interface to minimise hydraulic thrust forces developed by the hydraulic unit.

Abstract: A starter-generator for an aircraft engine comprises a dynamoelectric machine alternatively operable as a motor or as a generator, having a rotor. A support motor is coupled to the dynamoelectric machine to assist the machine. A torque converter selectively couples and decouples the rotor to the engine, coupling the rotor to the engine at some point when dynamoelectric machine is operated as a motor. A constant speed transmission has an input adapted to be connected to the engine and an output to be connected to the rotor. The unit provides a desired speed relation between input and output. The engine may be started by the dynamoelectric machine when operated as a motor through a first power train including the torque converter and may drive the dynamoelectric machine as a generator through a second power train including the constant speed transmission.

Abstract: A starter-generator for an aircraft engine comprises a variable dynamoelectric machine alternatively operable as a motor or as a generator, having a rotor. A support motor is coupled to the variable dynamoelectric machine to assist the machine. A torque converter selectively couples and decouples the rotor to the engine, coupling the rotor to the engine at some point when the dynamoelectric machine is operated as a motor. The engine may be started by the dynamoelectric machine when operated as a motor through a first power train including the torque converter and may drive the dynamoelectric machine as a generator through a second power train.

Abstract: Cavitation in axial piston motors (20) caused to act as a pump by an aiding load (28), and the related difficulty of loss of hydrostatic film (52), and tipping or hammering of motor slippers (64), can be reduced by a method which includes the step of recirculating hydraulic fluid from the supply port (18) of the motor (20) to the return port (30) of the motor (20) upon the occurrence of an aiding load (28).