A power management system for a multi engine rotorcraft having a main rotor system with a main rotor speed. The power management system includes a first engine that provides a first power input to the main rotor system. A second engine selectively provides a second power input to the main rotor system. The second engine has at least a zero power input state and a positive power input state. A power anticipation system is configured to provide the first engine with a power adjustment signal in anticipation of a power input state change of the second engine during flight. The power adjustment signal causes the first engine to adjust the first power input to maintain the main rotor speed within a predetermined rotor speed threshold range during the power input state change of the second engine.

A gas turbine engine for an aircraft, comprises a high-pressure (HP) spool comprising an HP compressor and a first electric machine driven by an HP turbine, the first electric machine having a first maximum output power; a low-pressure (LP) spool comprising an LP compressor and a second electric machine driven by an LP turbine, the second electric machine having a second maximum output power; and an engine controller configured to identify a condition to the effect that the LP turbine is operating in an unchoked regime, and, in response to an electrical power demand being between zero and the first maximum output power, only extracting electrical power from the first electric machine to meet the electrical power demand.

A gas turbine engine for an aircraft, comprises a high-pressure (HP) spool comprising an HP compressor and a first electric machine driven by an HP turbine, the first electric machine having a first maximum output power; a low-pressure (LP) spool comprising an LP compressor and a second electric machine driven by an LP turbine, the second electric machine having a second maximum output power; and an engine controller configured to identify a condition to the effect that the LP turbine is operating in an unchoked regime, and, in response to an electrical power demand being between zero and the first maximum output power, only extracting electrical power from the first electric machine to meet the electrical power demand.

A fuel power transfer system for an engine may include a cryogenic fuel supply, a fuel pump in fluid communication with the cryogenic fuel supply, a multi-position valve in fluid communication with the fuel pump and a combustion chamber of the engine, a fuel turbine operatively coupled to the fuel pump and having a primary discharge port in fluid communication with the combustion chamber, a primary heat exchanger in fluid communication between the multi-position valve and the fuel turbine, and a gearbox operatively coupled to the fuel turbine and the fuel pump and configured to transfer power from the fuel turbine to the engine.

A gas turbine engine includes a main compressor section, a combustor, and a main turbine section. A fuel pump delivers fuel to the combustor. A tap taps air compressed by the main compressor section, and is connected for delivering the tapped air through a first heat exchanger and to a boost compressor. Air downstream of the boost compressor is connected to cool a component. Driving compressed air is connected to be delivered to a power turbine. The power turbine is connected to drive both the boost compressor and the fuel pump.

A gas turbine engine includes a main compressor section, a combustor, and a main turbine section. A fuel pump delivers fuel to the combustor. A tap taps air compressed by the main compressor section, and is connected for delivering the tapped air through a first heat exchanger and to a boost compressor. Air downstream of the boost compressor is connected to cool a component. Driving compressed air is connected to be delivered to a power turbine. The power turbine is connected to drive both the boost compressor and the fuel pump.

A jet engine is provided which can efficiently pressurize fuel. A jet engine 2 includes a pump 110 that heats fuel, a heating conduit 120 that heats the pressurized fuel, a fuel turbine 130 that provides mechanical power to the pump, and an electric rotating machine 140. When a given condition is not satisfied, the electric rotating machine 140 provides mechanical power to the fuel turbine 130. When the given condition is satisfied, the fuel that has passed through the heating conduit 120 before combustion flows into the fuel turbine 130 to provide mechanical power to the fuel turbine 130.

A jet engine is provided which can efficiently pressurize fuel. A jet engine 2 includes a pump 110 that heats fuel, a heating conduit 120 that heats the pressurized fuel, a fuel turbine 130 that provides mechanical power to the pump, and an electric rotating machine 140. When a given condition is not satisfied, the electric rotating machine 140 provides mechanical power to the fuel turbine 130. When the given condition is satisfied, the fuel that has passed through the heating conduit 120 before combustion flows into the fuel turbine 130 to provide mechanical power to the fuel turbine 130.

An aspect includes a dirt mitigation system for a gas turbine engine. The dirt mitigation system includes a plurality of bleeds of the gas turbine engine and a control system configured to determine a particulate ingestion estimate indicative of dirt ingested in the gas turbine engine. The control system is further configured to determine one or more operating parameters of the gas turbine engine and alter a bleed control schedule of the gas turbine engine to purge at least a portion of the dirt ingested in the gas turbine engine through one or more of the bleeds of the gas turbine engine based on the particulate ingestion estimate and the one or more operating parameters.

An aspect includes a dirt mitigation system for a gas turbine engine. The dirt mitigation system includes a plurality of bleeds of the gas turbine engine and a control system configured to determine a particulate ingestion estimate indicative of dirt ingested in the gas turbine engine. The control system is further configured to determine one or more operating parameters of the gas turbine engine and alter a bleed control schedule of the gas turbine engine to purge at least a portion of the dirt ingested in the gas turbine engine through one or more of the bleeds of the gas turbine engine based on the particulate ingestion estimate and the one or more operating parameters.