An auxiliary power unit (APU) oil quantity indication system and method provides a stable and accurate oil quantity indication during startup, mission duration and shutdown. The system determines a gulp value at various stages of operation, which is combined with a raw oil quantity indication to provide an indicated oil quantity.

An engine starting system for a gas turbine engine is provided, the engine starting system comprising: a gas turbine engine including rotational components comprising an engine compressor, an engine turbine, and a rotor shaft operably connecting the engine turbine to the engine compressor, wherein each rotational component is configured to rotate when any one of the rotational components is rotated; an electro-pneumatic starter operably connected to at least one of the rotational components, the electro-pneumatic starter being configured to rotate the rotational components; an electric drive motor operably connected to the electro-pneumatic starter, the electric drive motor being configured to rotate the rotational components through the electro-pneumatic starter; and a motor controller in electronic communication with the electric drive motor, the motor controller being configured to command the electric drive motor to rotate the rotational components at a selected angular velocity for a selected period of time.

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.

A method for generating electric power for a rocket system includes burning a primary solid propellant grain to create a primary high pressure gas for providing thrust to the rocket, opening a first valve to divert a portion of the high pressure gas to an auxiliary solid propellant grain for igniting the auxiliary solid propellant grain, wherein the auxiliary solid propellant grain is disposed in a housing separate from the primary solid propellant grain, and burning the auxiliary solid propellant grain to create an auxiliary high pressure gas for turning a turbine. The method further includes driving a generator with the turbine and generating an electric power with the generator.

Devices and methods for fabrication of a multiscale porous high-temperature heat exchanger for high-temperature and high-pressure applications are disclosed. The heat exchanger can include a core with macrochannels formed in a checkerboard pattern to facilitate alternative flow of working fluid having hot and cold temperatures between adjacent macrochannels. Each macrochannel can include a two-dimensional microchannel array that further distributes flow throughout the heat exchanger to enhance heat transfer and mechanical strength without significant pressure drop penalty. The heat exchanger can further include a header integrated therewith to distribute working fluid flowing through the heat exchanger through the outlets such that it flows evenly therethrough. Methods of fabricating heat exchangers of this nature are also disclosed.

A heat exchanger system includes a core structure with an oil flow path configured to receive an oil flow. The heat exchanger system also includes a fuel flow path included in the core structure and configured to receive a fuel flow. The fuel flow path is coupled to the oil flow path to allow the fuel flow to receive heat from the oil flow in the oil flow path. Also, the heat exchanger system includes a supplemental airflow path defined at least partly by the core structure and configured to receive a supplemental airflow that receives heat from at least one of the oil flow and the fuel flow.

A fan and compressor housing for an air cycle machine includes a fan inlet disposed around a center axis of the housing and having a fan inlet mounting flange, a compressor outlet having a compressor outlet mounting flange, and a compressor inlet having a compressor inlet mounting flange. The fan inlet mounting flange has a pinhole disposed thereon configured to receive a pin from a fan inlet diffuser housing and a fan inlet counterbore configured to receive a mating component from the fan inlet diffuser housing. The compressor outlet mounting flange has a compressor outlet counterbore configured to receive a first mating component from a condenser/reheater. The compressor inlet mounting flange has a compressor inlet counterbore configured to receive a second mating component from the condenser/reheater.

A gas turbine engine includes a core cowl and a core contained within the core cowl. The core includes a compressor in fluid communication with a downstream combustor and a downstream turbine, the compressor including a compressor bleed port, wherein an undercowl space is defined between the core cowl and the core. The gas turbine engine further includes a cooling duct disposed at least partially in the undercowl space and having an inlet and an outlet, wherein the cooling duct is in fluid communication with a source of cooling air and is further in fluid communication with the compressor bleed port; a valve assembly including at least one valve disposed in the cooling duct; and a cooling blower disposed within the engine and operable to move an air flow from the inlet of the cooling duct towards the outlet of the cooling duct and through the compressor bleed port.

A gas turbine engine for an aircraft comprising an engine core and including a bypass channel which radially surrounds the engine core at least in part is described. A core shaft is operatively connected to an engine accessory gearbox, which is arranged between the engine core and the bypass channel, by means of a radial shaft of a drive train. An electric machine is provided which is designed to start the gas turbine engine during motor operation and to generate electrical energy during alternator operation. The electric machine is arranged coaxially with the core shaft and connected thereto for conjoint rotation. Alternatively, the electric machine can be arranged radially outside the bypass channel and can be operatively connected to the core shaft by means of the radial shaft, wherein a rotor of the electric machine is arranged coaxially with the radial shaft and connected thereto for conjoint rotation.

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.