An aircraft propulsion system with a drag reduction portion adapted to reduce skin friction on at least a portion of the external surface of an aircraft. The drag reduction portion may include an inlet to ingest airflow. The aircraft may also have an internally cooled electric motor adapted for use in an aerial vehicle. The motor may have its stator towards the center and have an external rotor. The rotor structure may be air cooled and may be a complex structure with an internal lattice adapted for airflow. The stator structure may be liquid cooled and may be a complex structure with an internal lattice adapted for liquid to flow through. A fluid pump may pump a liquid coolant through non-rotating portions of the motor stator and then through heat exchangers cooled in part by air which has flowed through the rotating portions of the motor rotor. The drag reduction portion and the cooled electric motor portion may share the same inlet.

Methods, apparatus, systems, and articles of manufacture are to control air flow separation of an engine. An example turbofan includes a nacelle having an outer lip surface, an inner lip surface, a first opening and a second opening, the first opening coupled to a first region forward of a fan of the turbofan, the second opening coupled to a second region aft of the fan, the nacelle including a first pressure sensor coupled to the outer lip surface, a second pressure sensor coupled to the inner lip surface, and an actuator, and a conduit coupled to the actuator, the conduit configured to have a first end and a second end, the first end coupled to the first opening, the second end coupled to the second opening.

Methods, apparatus, systems, and articles of manufacture are disclosed to detect air flow separation of an engine. An example apparatus includes hardware, and memory including instructions that, when executed, cause the hardware to at least determine an inlet flow separation parameter based on a first pressure value from a first pressure sensor included in a nacelle of a turbofan and a second pressure value from a second pressure sensor included in the nacelle, determine a severity level parameter based on the inlet flow separation parameter, the severity level parameter based on a difference between the first pressure value and the second pressure value, and adjust a contribution of airflow from aft of a fan of the turbofan based on the severity level parameter.

A hybrid electric gas turbine propulsion system may comprise: a first propulsion system, a second propulsion system, and a third propulsion system. The first propulsion system may comprise a first fan, a first turbine, a first compressor, and a first electric motor, the first fan operably coupled to the first turbine and the first compressor by a first shaft, the first shaft coupled to the first electric motor, the first shaft configured to be disposed radially inward of a fuselage of an aircraft. The second propulsion system and the third propulsion system may be in accordance with the first propulsion system. The hybrid electric gas turbine propulsion system may be symmetric about a vertical plane extending through a neutral aerodynamic axis.

An aircraft engine nacelle for coupling to a wing of an aircraft is disclosed having a fore end, and an aft end that is immoveable relative to the fore end. The aft end includes a major axis Mj and a minor axis Mi, and the nacelle is configured such the minor axis Mi is closer to vertical V than the major axis Mj when the nacelle is coupled to the wing and the aircraft is stationary on the ground. An aircraft system and an aircraft are disclosed each including the aircraft engine nacelle.

The disclosure is towards an inlet cowl for a turbine engine including a surface defining an inlet with a flow path and a method towards controlling the airflow in the flow path. The inlet cowl further includes an inlet lip and inner and outer barrels. The inlet lip confronts the inner barrel at a junction defining a gap.

A propulsion system for an aircraft includes an electric propulsion engine configured to be mounted to the aircraft at an aft end of the aircraft. The electric propulsion engine includes a power gearbox mechanically coupled to an electric motor. The electric propulsion engine further includes a fan rotatable about a central axis of the electric propulsion engine by the electric motor through the power gearbox. Moreover, the electric propulsion engine includes an attachment assembly for mounting at least one of the electric motor or the power gearbox. The attachment assembly includes a torsional damper for accommodating a torsional vibration of the electric motor or the power gearbox.

An aircraft incorporating a cabin air recovery system in which the aircraft comprises a pressurizable cabin, main turbofan engines, each turbofan engine having fan blades, a gas turbine coupled with the fan blades and a by-pass duct bypassing the gas turbine. The cabin fluidly communicates with the by-pass duct downstream of the fan blades so that, during operation, cabin outflow air is discharged into the by-pass duct downstream of the fan blades. By re-utilizing excess cabin air, engine thrust and efficiency is improved, and fuel consumption is reduced.

An aircraft is provided and includes fuselage having a nose, a main section aft of the nose and a tail aft of the main section, an engine nacelle partially embedded in the tail and including a boundary layer ingestion (BLI) propulsor with an inlet directly adjacent to the fuselage and a nozzle element disposed upstream from the inlet and configured to accelerate boundary flows flowing toward the interior side of the engine nacelle.

An aircraft structure has a fuselage, a wing and an air inlet for receiving air for an engine. The air inlet contains an elevation which rises from the fuselage and the wing. The elevation is arranged in a transition region between the wing and the fuselage and extends asymmetrically with respect to an angle bisector of an angle between a surface of the wing and the lateral surface of the fuselage. By virtue of this construction, a leading edge of the wing can be arranged further forward than the air inlet, and the air inlet configured according to these principles can positively influence a flow boundary layer on the aircraft structure.