A method of operating an environmental control system of an aircraft includes providing a first medium to the environmental control system including a compressor and a turbine, wherein the first medium is provided to the compressor and the turbine sequentially and extracting work from a second medium provided to a power turbine operably coupled to the compressor to drive the compressor. In a first mode of operation, the first medium to be provided to a downstream load is output from the turbine, in a second mode of operation, at least a portion of the first medium to be provided to a downstream load bypasses the turbine, and in a third mode of operation, at least a portion of the first medium output from the compressor is provided to the power turbine.

An environmental control system of an aircraft includes a compressing device including a compressor and a turbine configured to receive a flow of first medium sequentially and a second turbine arranged in fluid communication with an outlet of the compressor. The second turbine is configured to receive a flow of second medium distinct from the first medium. A dehumidification system is arranged in fluid communication with the turbine, a first bypass valve is configured to divert at least a portion of the flow of the first medium output from the compressor around the turbine, and a second bypass valve configured to divert at least a portion of the flow of first medium output from the compressor to the second turbine.

Systems and methods for conditioning a fluid using bleed air from a bypass duct of a turbofan engine are disclosed. In one embodiment, such system comprises a heat exchanger configured to facilitate heat transfer between a flow of bleed air from the bypass duct of the turbofan engine and the fluid, and a fluid-driven fluid propeller configured to drive the bleed air through the heat exchanger.

An environmental control system includes a plurality of inlets for receiving a plurality of mediums including a first medium and a second medium and an outlet for delivering a conditioned flow of the second medium to one or more loads of the aircraft. A ram air circuit includes a ram air shell having at least one heat exchanger positioned therein and a compressing device is arranged in fluid communication with the ram air circuit and the outlet. The compressing device includes a compressor and at least one turbine operably coupled via a shaft. The environmental control system is operable in a first mode and a second mode. In the second mode, a pressure of the second medium output from the compressor is equal to the pressure of the second medium provided to the outlet.

One example includes an aircraft retrofit system to provide a retrofitted aircraft from an original aircraft. The system includes a plurality of multi-axis vectoring nozzles configured to replace a respective plurality of original nozzles of a respective plurality of original engines of the original aircraft and empennage of the original aircraft, such that the retrofitted aircraft includes no empennage. The system also includes retrofit electronics for controlling the plurality of multi-axis vectoring nozzles to provide yaw control of the retrofitted aircraft.

A system includes a manifold, a power unit, and a throttle valve. The manifold is configured to receive cabin discharge air from a cabin. The cabin discharge air includes cabin discharge air from a waste region of the cabin. The auxiliary power unit is fluidically coupled to the manifold and configured to draw cabin discharge air from the manifold. The throttle valve is configured to control flow of cabin discharge air from the manifold to the power unit. A method includes receiving a pressure measurement for the manifold and a pressure setpoint for the manifold representing a predetermined flow of cabin discharge air from the cabin to the manifold. The method includes determining and outputting, based on the pressure measurement and the pressure setpoint, a control signal for at least one manifold inlet configured to control flow of cabin discharge air from the cabin to the manifold.

Auxiliary power systems, aircraft including the same, and related methods. An auxiliary power system comprises an auxiliary power unit (APU) controller and an APU with an air intake, a powerhead, and a load compressor stage. The load compressor stage includes a flow regulator assembly, a load compressor, and a bleed air temperature (BAT) sensor for generating a BAT signal. The APU controller regulates a flow rate of a load compressor airflow through the load compressor based on the BAT signal. A method of utilizing an auxiliary power system includes compressing a load compressor airflow to generate a bleed air flow, measuring the BAT with a BAT sensor, generating a BAT signal based on the BAT, transmitting the BAT signal to an APU controller, generating a flow regulator command with the APU controller, transmitting the flow regulator command to a flow regulator assembly, and controlling a flow regulator assembly.

A method for managing the offtake of power produced by an auxiliary power unit of an aircraft. The method comprises a step of calculating a maximum capacity for offtake of mechanical power that the auxiliary power unit can provide to the aircraft, a step of determining an actual offtake of mechanical power taken off by a first mechanical power offtake system of the auxiliary power unit, a step of comparing the maximum capacity for offtake of mechanical power and the actual offtake of mechanical power, a step of optimizing the offtake of mechanical power which step, based on the comparison of the maximum capacity for offtake of mechanical power and the actual offtake of mechanical power, determines at least one corrective action. A device for managing the offtake of power produced by an auxiliary power unit of an aircraft and an aircraft including such a device are provided.

An auxiliary power system for an airplane includes at least one fuel cell unit each with at least one fuel cell, a voltage output, a fuel intake and an outlet for reaction products, a fuel tank that is couplable with the fuel intake of the fuel cell unit, at least one compressor unit with an air intake and air outlet and an electric motor, which is couplable with a voltage output of the at least one fuel cell unit and, by way of a shaft, with the at least one compressor unit. At least the at least one fuel cell unit, the compressor unit and the electric motor are interconnected to yield a coherent unit, which continuously provides electrical power and pressurized air.

An operating method of a vehicle cabin air supply device comprising taking fresh air from outside the cabin, diverting the fresh air to an air exhaust during an exhaust duration period after starting the air supply device, before injecting the fresh air into the cabin, such that the fresh air injected in the cabin after the exhaust duration period minimizes unpleasant odors in the cabin. A vehicle cabin air supply device and an aircraft comprising such a device is also provided.