Abstract: According to one aspect, a resolver-to-digital converter includes a first filter configured to receive a first delta-sigma modulated resolver input. A second filter is configured to receive a second delta-sigma modulated resolver input. A summing junction is configured to output a difference between a scaled output of the first filter and a scaled output of the second filter. A controller is configured to generate a controller output based on a product of a demodulator and an output of the summing junction. An integrator is configured to generate an estimated position based on the controller output. The resolver-to-digital converter also includes a compensator configured to generate a compensated estimated position based on the controller output and a compensation offset delay adjustment.

Abstract: A blade shank assembly for an aircraft propeller blade includes a blade shank; and a split blade retention race encircling the blade shank, the split blade retention race comprising two sections separated by two splits, the two splits being perpendicular to a race surface of the split blade retention race, wherein the split blade retention race comprises: an inner chamfer located between a surface of the split blade retention race that is adjacent to the blade shank and a split surface of the split blade retention race at each of the two splits; and an outer chamfer located between the race surface of the split blade retention race and the split surface at each of the two splits.

Abstract: A generator system includes a generator having a stationary portion and a rotating portion. The generator includes an exciter field winding disposed on the stationary portion. A first channel includes a first main field winding and a first main field power converter disposed on a rotating portion. The first main field power converter selectively delivers voltage from the exciter winding to the first main field winding. A second channel includes a second main field winding and a second main field power converter disposed on the rotating portion. The second main field power converter selectively delivers voltage from the exciter winding to the second main field winding. A generator control unit is connected to the first channel and the second channel. The generator control unit monitors an output voltage at each of the first channel and the second channel and generates the first and second control signals based on the output voltage.

Abstract: A generator system includes a generator having a stationary portion and a rotating portion. An exciter field winding and a main armature winding are disposed on the stationary portion. An exciter armature winding and a main field winding are disposed on the rotating portion. A frequency demodulator is configured to extract a frequency modulated control signal from the exciter armature winding and to demodulate the frequency modulated control signal to generate a demodulated control signal. The generator includes a main field rotating power converter to selectively control current in the main field winding in response to the demodulated command signal. The generator system includes a generator control unit in electrical communication with the generator to monitor the output voltage at the main armature winding and to output an exciter current including the frequency modulated control signal to the exciter field winding based on the output voltage.

Abstract: A mixer has an internal bore with an inlet to a chamber, and an outlet at an opposed end/A duct is connected to receive a recirculated air flow. The duct communicates air into the chamber through recirculating air ports such that the recirculating air can mix with the air from the inlet. The mixer housing has a cockpit outlet for delivering air to a second outlet, with the cockpit output being located axially upstream from the recirculating air ports. An isolator is mounted at an outer periphery of the mixer housing, and has flat sides on each of two circumferentially spaced sides. A belly band is bolted to an outer periphery of the mixer housing and to flat sides of the isolator.

Abstract: A heat exchanger assembly for an inert gas system includes a ram air inlet flange, a ram air outlet flange, and a core coupled to the ram air inlet flange and the ram air outlet flange. The core includes a fin assembly having a plurality of hot layers and ram air layers. The hot layers have an effective hot flow length, the ram air layers have an effective cold flow length, and the fin assembly has a no flow length. A ratio of the effective hot flow length to the effective cold flow length is between 9.23 and 10.32. A ratio of the no flow length to the cold flow length is between 21.86 and 25.23.

Abstract: A temperature-compensated pressure sensor system includes a pressure sensing element, a temperature sensing device, and a temperature compensation network. The pressure sensing element provides a first voltage output representative of a sensed pressure value. The temperature sensing device provides a second voltage output representative of a sensed temperature value. The temperature compensation network is connected to receive the first voltage output provided by the pressure sensing element and the second voltage output provided by the temperature sensing device. The temperature compensation network provides a temperature compensated voltage representative of sensed pressure, wherein the second voltage output passively biases the temperature compensation network.

Abstract: A propeller blade includes a foam core, a structural layer formed of multiple layers that surrounds at least a portion of the foam core and at least one section of fibers formed separately from the structural layer located between two of the multiple layers.

Abstract: A first inlet port extends radially through a valve sleeve into an internal bore. A first outlet port extends radially outwardly through an outer periphery of the valve sleeve. A second inlet port on an opposed side of the first outlet port from the first inlet port, extends radially through a wall of the valve sleeve. A valve spool is received in the internal bore and has a first channel at an outer peripheral surface selectively communicating the first inlet port to the first outlet port. The valve spool has a second channel at the outer peripheral surface that communicates the second inlet port to an axial vent formed in an internal surface of the valve sleeve. The axial vent extends axially to communicate the second channel to the first outlet port. A pumping system is also disclosed.

Abstract: In one featured embodiment, a spring assembly for a valve comprises a spring, a spring seat including a cup-shaped portion for seating one end of the spring, and a ball received within a recess formed within the cup-shaped portion of the spring seat. The ball is defined by a ball diameter. A disc prevents the ball from contacting a piston. The disc is defined by an outer diameter and includes a center opening defined by an inner diameter. A ratio of the inner diameter to the ball diameter is between 0.60 and 0.65.

Abstract: In one featured embodiment, a sleeve for a valve includes a sleeve body surrounding a center axis and defined by an overall length extending from a first end to a second end. The sleeve body has a central bore extending from the first end to the second end. The central bore has a first surface portion comprising a piston contact surface that is defined by a first inner diameter, wherein the piston contact surface is configured to slide against a piston to be received within the central bore. In one example, a ratio of the overall length to the first inner diameter is between 3.51 and 3.63.

Abstract: An electronics enclosure has a blower and diffuser received within an enclosure. Electronic components are also received within the enclosure. The blower diffuser is positioned in contact with at least one of the electronic components. A shroud surrounds the blower diffuser and the at least one electronic component, and is spaced from an outer surface of the at least one electronic component. An opening is formed through the shroud, such that air can be driven within the shroud from the blower diffuser, and across at least one electronic component, and then outwardly of the opening. A heat exchanger is positioned in the path of air leaving the opening.

Abstract: A compressor rotor compresses and delivers compressed air across a turbine rotor. The turbine rotor is connected to the compressor rotor such that rotation of the turbine rotor drives the compressor rotor. A shaft is connected to rotate with the turbine rotor and the compressor rotor. A thrust bearing is provided by a member extending perpendicular and radially outwardly of the shaft. The member rotates with the shaft and faces a first housing wall. A hollow chamber is formed on an opposed side of the first housing wall. A cooling air path supplies air across a thrust bearing surface, and between the member and the first housing wall. The first housing wall has a communication hole for communicating cooling air from the cooling air path into the hollow cavity to drive air within the hollow chamber. Also, a housing incorporating the communication hole is disclosed.

Abstract: A journal bearing for a generator idler gear assembly which includes an impregnated carbon body that has an inner diameter and an outer diameter that provides a bearing thickness. The body includes a height, wherein outer diameter to inner diameter provides a first ratio of approximately 1.3-1.5 and the inner diameter to height provides a second ratio of approximately 1.5-1.9.

Abstract: A disclosed connector assembly for a refrigerant system mounted within an aircraft includes a metal seal disposed within a seal bore of a connector and compressed against a seal face of a nipple secured to the connector by a threaded member. The connector includes a seal bore that receives the metal seal with the inner portion of the seal bore open to the bore. In one example, the connector and nut are formed from aluminum and the nipple is formed from stainless steel and includes an aluminum coating applied to surfaces in contact with the metal seal and the connector.

Abstract: A power system for an aircraft includes a solid oxide fuel cell system which generates electric power for the aircraft and an exhaust stream; and a heat exchanger for transferring heat from the exhaust stream of the solid oxide fuel cell to a heat requiring system or component of the aircraft. The heat can be transferred to fuel for the primary engine of the aircraft. Further, the same fuel can be used to power both the primary engine and the SOFC. A heat exchanger is positioned to cool reformate before feeding to the fuel cell. SOFC exhaust is treated and used as inerting gas. Finally, oxidant to the SOFC can be obtained from the aircraft cabin, or exterior, or both.

Abstract: A method for joining a cast metal material blade ring and a metal material hub structure into a turbine rotor. One of the blade ring and the hub structure is mounted in a holder and the other is mounted in a rotation holder for being rotated. At least one of these mountings is heated, and then they are pressed together with a selected force while rotating to weld the ring interior wall and the disk side to form the assembled structure.

Abstract: A method of installing the terminal block assembly onto a generator includes the step of providing a terminal block with multiple terminal studs. Protrusions that are integral with the terminal block are aligned with corresponding bores in a generator housing. The terminal block is mounted on the generator housing with the protrusions received in the bores. A terminal lead assembly is inserted through the protrusion, and a terminal pad of the terminal lead assembly is arranged over the terminal stud. A terminal lug is fastened to the terminal stud. A terminal cover is secured to the terminal block over the terminal with a boss of the terminal block received in a corresponding recess of the terminal cover.

Abstract: A starting/generating system includes a rotor portion and a stator portion. The stator portion is connected to a DC power source during starting operations and to a DC load during generating operations, and includes a DC link having a first and second DC link bus, a DC link capacitor connected between the DC link buses, and an inverter/rectifier that converts AC power to DC power and vice versa. A switching device is connected in series on the first DC link bus and is controlled by a controller that turns the switching device On and Off to provide various functionality to the starting/generating system.

Abstract: A blade profile section for an air turbine starter includes an airfoil which defines an airfoil profile section through a leading edge and a trailing edge. The airfoil profile section is defined by a set of X-coordinates and Z-coordinates defined in any of Table I, Table II, Table III or Table IV scaled by a desired factor. The X-coordinate is the tangential direction, and the Z-coordinate is a radial direction between an airfoil root and an airfoil tip.