Abstract: The presently disclosed embodiments utilize an ice separator vessel to trap ice particles in a non-homogeneous ice/fuel mixture flowing in a fuel system. A source of heat, such as heated fuel provided to the ice separator vessel, is used to melt at least a portion of the ice particles so that they do not enter the fuel system downstream of the ice separator vessel.

Abstract: An auxiliary power unit (APU) generator system for an APU can include a doubly-fed induction generator (DFIG) configured to be operatively connected to an APU to be turned by an APU and to have an output frequency that is a function of an excitation frequency and an APU speed. The system can include a generator control module configured to control the excitation frequency to the DFIG to output a substantially constant frequency with changing APU speed to supply the substantially constant frequency to a load.

Abstract: The presently disclosed embodiments utilize an ice separator vessel to trap ice particles in a non-homogeneous ice/fuel mixture flowing in a fuel system. A source of heat, such as heated fuel provided to the ice separator vessel, is used to melt at least a portion of the ice particles so that they do not enter the fuel system downstream of the ice separator vessel.

Abstract: A power supply arrangement (PSA) for an aircraft having an electrical system and an environmental control system (ECS) operatively connected to a cabin of the aircraft, the PSA has: at least one propelling engine; a secondary power unit (SPU) having a rotary engine, at least one generator in driving engagement with the rotary engine and operatively connectable to the electrical system of the aircraft, and at least one load compressor operatively connected to the rotary engine and pneumatically connected to a pneumatic circuit connectable to the ECS of the aircraft, the PSA having a propelling configuration in which the at least one propelling engine and the SPU are both powered and a hotel configuration in which the at least one propelling engine is unpowered while the SPU is powered, the pneumatic circuit pneumatically disconnected from the at least one propelling engine in both of the hotel and propelling configurations.

Abstract: An engine assembly for an aircraft, including an internal combustion engine having a liquid coolant system in fluid communication with a heat exchanger, an exhaust duct in fluid communication with air passages of the heat exchanger, a fan in fluid communication with the exhaust duct for driving a cooling air flow through the air passages of the heat exchanger and into the exhaust duct, and an intermediate duct in fluid communication with an exhaust of the engine and having an outlet positioned within the exhaust duct downstream of the fan and upstream of the outlet of the exhaust duct. The outlet of the intermediate duct is spaced inwardly from a peripheral wall of the exhaust duct. The engine assembly may be configured as an auxiliary power unit. A method of discharging air and exhaust gases in an auxiliary power unit having an internal combustion engine is also discussed.

Abstract: An aircraft system includes a component configured to operate with a minimum power demand. The aircraft system also includes an auxiliary power unit including an engine. The auxiliary power unit is configured to power the component and to operate the engine in a plurality of operating modes including a power mode and a standby mode. The auxiliary power unit generates a first power output at least equal to the minimum power demand during the power mode. The auxiliary power unit generates a second power output less than the minimum power demand during the standby mode.

Abstract: An auxiliary power unit assembly for an aircraft, including an engine assembly including an internal combustion engine, a first duct in fluid communication with an inlet of the internal combustion engine and configured to be in fluid communication with an environment of the aircraft, and a second duct configured to be in fluid communication with the environment. The second duct may be in fluid communication with an inlet of a compressor drivable by the internal combustion engine or with a compartment receiving the engine assembly. A filter extends across the first duct. The filter is removable from the first duct through an opening in a wall of the first duct, the opening accessible from an exterior of the engine assembly.

Abstract: An inlet assembly for an auxiliary power unit for an aircraft, including a particle separator and a plenum having first and second inlets. A first duct configured to deliver air to an engine of the auxiliary power unit is in fluid communication with an outlet of the plenum. A second duct configured to deliver air to a compartment containing the auxiliary power unit is in fluid communication with the outlet of the plenum. The assembly is selectively configurable between a first configuration where the plenum is in fluid communication with the environment of the aircraft through the second inlet and through the particle separator, and a second configuration where the plenum is in fluid communication with the environment of the aircraft through the first inlet independently of the particle separator. An auxiliary power unit assembly and a method of feeding air to an auxiliary power unit assembly are also discussed.

Abstract: An inlet assembly for an auxiliary power unit for an aircraft, including a duct configured to provide fluid communication from an environment of the aircraft to an inlet of an engine of the auxiliary power unit, and a filter received in and extending across the duct. The filter includes a first filter portion permeable to air, positioned across only part of the duct and defining a transverse edge in the duct; a second filter portion permeable to air and extending from the transverse edge to an end downstream of the transverse edge, and a collection member impermeable to water. The collection member extends between the downstream end and a duct wall. The first and second filter portions are non-parallel and the second filter portion and the collection member are non-parallel. An auxiliary power unit assembly and a method of feeding air to an internal combustion engine are also discussed.

Abstract: An engine assembly for an aircraft, including an internal combustion engine having a liquid coolant system in fluid communication with a heat exchanger, an exhaust duct in fluid communication with air passages of the heat exchanger, a fan in fluid communication with the exhaust duct for driving a cooling air flow through the air passages of the heat exchanger and into the exhaust duct, and an intermediate duct in fluid communication with an exhaust of the engine and having an outlet positioned within the exhaust duct downstream of the fan and upstream of the outlet of the exhaust duct. The outlet of the intermediate duct is spaced inwardly from a peripheral wall of the exhaust duct. The engine assembly may be configured as an auxiliary power unit. A method of discharging air and exhaust gases in an auxiliary power unit having an internal combustion engine is also discussed.

Abstract: An auxiliary power unit for an aircraft includes a turbine engine. An inlet includes an opening and a passageway between the opening and the turbine engine. An acoustic splitter is supported within the passageway for attenuating noise within the inlet. An inlet door is movable between a closed position and a fully open position. A portion of the inlet door aligns with a part of the passageway in at least a first position and divides the passageway to deflect ice and noise in at least a second position. An air inlet and a method are also disclosed.

Abstract: An engine assembly for an aircraft, including an internal combustion engine having a liquid coolant system in fluid communication with a heat exchanger, an exhaust duct in fluid communication with air passages of the heat exchanger, a fan in fluid communication with the exhaust duct for driving a cooling air flow through the air passages of the heat exchanger and into the exhaust duct, and an intermediate duct in fluid communication with an exhaust of the engine and having an outlet positioned within the exhaust duct downstream of the fan and upstream of the outlet of the exhaust duct. The outlet of the intermediate duct is spaced inwardly from a peripheral wall of the exhaust duct. The engine assembly may be configured as an auxiliary power unit. A method of discharging air and exhaust gases in an auxiliary power unit having an internal combustion engine is also discussed.

Abstract: Systems and methods of monitoring health of rotating engine components are provided. The systems and methods may receive a measurement from a speed sensor, detect the measurement from the speed sensor indicates a vibration of an engine, determine the vibration of the engine persisted for a predetermined duration, and signal the vibration of the engine is detected.

Abstract: Herein provided are methods and systems for detecting blockage of an inlet of gas turbine engine. An oil temperature measurement of the engine and an ambient temperature measurement is obtained. The oil temperature measurement is compared to a threshold based on the ambient temperature measurement. Blockage of the inlet of the engine is detected when the oil temperature measurement exceeds the threshold.

Abstract: A turbine retention device is made by forming a bullet having a cylindrical geometry, forming a wing, coupling the wing to the bullet with a proximal portion of the wing along an axial length of the bullet, and coupling a mounting bracket to a distal end of the wing.

Abstract: A technique for mounting a turbine retention device is provided. The technique comprises forming openings in a diffuser, aligning a mounting bracket with the openings, and installing fasteners through the openings and the mounting bracket. A turbine retention device mounted to a diffuser may is also provided. The turbine retention device may comprise a bullet, wings coupled to the bullet, mounting brackets coupled to the wings, and fasteners disposed through the mounting brackets and openings formed in the diffuser.

Abstract: An inlet assembly for an auxiliary power unit for an aircraft, including a particle separator and a plenum having first and second inlets. A first duct configured to deliver air to an engine of the auxiliary power unit is in fluid communication with an outlet of the plenum. A second duct configured to deliver air to a compartment containing the auxiliary power unit is in fluid communication with the outlet of the plenum. The assembly is selectively configurable between a first configuration where the plenum is in fluid communication with the environment of the aircraft through the second inlet and through the particle separator, and a second configuration where the plenum is in fluid communication with the environment of the aircraft through the first inlet independently of the particle separator. An auxiliary power unit assembly and a method of feeding air to an auxiliary power unit assembly are also discussed.

Abstract: An auxiliary power unit assembly for an aircraft, including an engine assembly including an internal combustion engine, a first duct in fluid communication with an inlet of the internal combustion engine and configured to be in fluid communication with an environment of the aircraft, and a second duct configured to be in fluid communication with the environment. The second duct may be in fluid communication with an inlet of a compressor drivable by the internal combustion engine or with a compartment receiving the engine assembly. A filter extends across the first duct. The filter is removable from the first duct through an opening in a wall of the first duct, the opening accessible from an exterior of the engine assembly.

Abstract: An inlet assembly for an auxiliary power unit for an aircraft, including a duct configured to provide fluid communication from an environment of the aircraft to an inlet of an engine of the auxiliary power unit, and a filter received in and extending across the duct. The filter includes a first filter portion permeable to air, positioned across only part of the duct and defining a transverse edge in the duct; a second filter portion permeable to air and extending from the transverse edge to an end downstream of the transverse edge, and a collection member impermeable to water. The collection member extends between the downstream end and a duct wall. The first and second filter portions are non-parallel and the second filter portion and the collection member are non-parallel. An auxiliary power unit assembly and a method of feeding air to an internal combustion engine are also discussed.

Abstract: According to one aspect of the present invention, a preloaded hybrid duplex bearing assembly is disclosed. A hybrid duplex ball bearing assembly includes a forward bearing, an aft bearing, and a preload spring, the preload spring disposed adjacent the aft bearing and configured to apply an axial force to push the aft bearing toward the forward bearing, where the forward bearing and aft bearing share an inner race. The forward bearing and the aft bearing are angular contact bearings each including a contact angle, and the contact angles of the forward bearing and the aft bearing converge at a point within the bearing assembly. In one embodiment, the aft bearing is not radially loaded and carries only the axial force of the preload spring. In at least one embodiment, the forward bearing forms a radial clearance fit with the aft bearing such that the aft bearing carries no radial load.