A method for operating a propulsion system of an aircraft includes moving a plurality of forward and aft propulsors to a vertical thrust position. While in the vertical thrust positions, the method also includes providing a first forward to aft ratio of electric power to the plurality of forward and aft propulsors. The method also includes moving the plurality of forward and aft propulsors to a forward thrust position. While in the forward thrust positions, the method also includes providing a second forward to aft ratio of electric power to the plurality of forward and aft propulsors. The first forward to aft ratio of electric power is different than the second forward to aft ratio of electric power to provide certain efficiencies for the aircraft.

A method for operating an electric fan of an aircraft propulsion system includes driving a plurality of fan blades of the electric fan with an electric machine to generate thrust for the aircraft; and driving the electric machine with the plurality of fan blades of the electric fan to generate electrical power subsequent to driving the plurality of fan blades of the electric fan with the electric machine to generate thrust for the aircraft.

An aircraft with an integrated boundary layer ingesting propulsion having a mechanically-distributed propulsion system. The mechanically-distributed propulsion system may include an engine to generate a mechanical drive power, a drive shaft, a direction-reversing transmission, and a propulsor fan. The drive shaft may be operatively coupled to the engine to receive the mechanical drive power. The direction-reversing transmission may have a first rotating shaft and a second rotating shaft, the first rotating shaft operatively coupled to the drive shaft to receive the mechanical drive power, which is configured to redirect the mechanical drive power received at the first rotating shaft from a first direction to face a second direction at the second rotating shaft. The propulsor fan may be coupled to the second rotating shaft to convert the mechanical drive power into thrust.

A propulsion system for an aircraft including at least two main gas turbine engines and a plurality of dedicated boundary layer ingestion fans. The propulsion system is arranged such that a combined thrust produced by the boundary layer ingestion fans is less than 20 percent of a total thrust of the main engines and the boundary layer ingestion fans. The boundary layer ingestion fans are controllable and selectively turned off at lower speeds.

A fan assembly for gas turbine engine according to an exemplary embodiment of this disclosure includes, among other possible things, a plurality of fan blades rotatable about a fan rotation axis, each of the plurality of fan blades movable about an axis transverse to the fan rotation axis, a fan nacelle partially surrounding the plurality of fan blades, and a pitch mechanism coupled to the plurality of blades that changes an angle of pitch for each of the plurality of blades corresponding to a circumferential position of the fan blade about the fan rotation axis.

Systems and methods for integrating Boundary Layer Ingestion (BLI) apparatus into an aircraft (1). The longerons (34) in the aft fuselage (18) may be extended to support an aft propulsor (20). The aft propulsor may be a turbofan or turboelectric propulsion system (46). An upper longeron (34a) may support a tail section (14) of an aircraft. The aft fuselage skin (22) is contoured to permit boundary layer airflow to enter an intake fan (24) of the aft propulsor.

A propulsion system for an aircraft includes an electric power source, an electric propulsor assembly having an electric motor and a propulsor configured to generate thrust for the aircraft, and a power bus electrically connecting the electric power source to the electric propulsor assembly such that the electric power source powers the electric propulsor assembly. The power bus includes an electric line and a fluid cooling system, the fluid cooling system extending along at least a portion of a length of the electric line. The fluid cooling system is in thermal communication with the electric line for cooling the electric line during operation and is further in thermal communication with the electric motor of the electric propulsor assembly for cooling the electric motor of the electric propulsor assembly.

A transverse fan propulsion system includes a first transverse fan configured to rotate in a first direction, and a second transverse fan configured to rotate in a second direction. The second direction is opposite to the first direction. The second transverse fan is located coaxially with and radially inward of the first transverse fan.

An aircraft propulsion unit includes a drive unit with a static part and a rotary part which rotates a fan situated downstream from the drive unit, an assembly of fixed blades situated downstream from the fan, and a nacelle in which the fan and the assembly of fixed blades are accommodated. The propulsion unit also includes an assembly of at least two coaxial shafts, wherein a fan shaft connects the fan to the rotary part, and a stator blading shaft connecting the assembly of fixed blades to the static part extends concentrically, and for at least part of its length in the interior of the fan shaft. This rigid and compact configuration limits the variations of distance between the end of the fan blades and a fan housing situated in the inner duct of the nacelle.

A propulsion system for an aircraft includes at least two gas turbine engines and at least one auxiliary propulsion fan. The at least one auxiliary propulsion fan is configured to selectively receive a motive force from either or both of the at least two gas turbine engines through at least one shaft operatively coupled to the at least one auxiliary propulsion fan.