Abstract: An aircraft extending between a forward end and an aft end is provided. The aircraft includes an auxiliary power unit positioned proximate the aft end of the aircraft, the auxiliary power unit having an auxiliary power unit inlet duct and an auxiliary power unit exhaust duct, and a boundary layer ingestion fan positioned proximate the aft end of the aircraft, the boundary layer ingestion fan having a support shaft, wherein the auxiliary power unit exhaust duct extends through a portion of the support shaft of the boundary layer ingestion fan.

Abstract: The present disclosure is generally related to aircraft having one or more unducted fan propulsors at locations within specific regions relative to an airfoil, such as a wing or horizontal stabilizer. More specifically, the specific regions are located where there is a relatively higher pressure air flow beneath the wings or above a horizontal stabilizer. That higher pressure air flow can be utilized to provide increased thrust from the unducted fan propulsor.

Abstract: The present disclosure is generally related to aircraft having one or more unducted fan propulsors at locations within specific regions relative to an airfoil, such as a wing or horizontal stabilizer. More specifically, the specific regions are located where there is a relatively higher pressure air flow beneath the wings or above a horizontal stabilizer. That higher pressure air flow can be utilized to provide increased thrust from the unducted fan propulsor.

Abstract: A propulsion system is provided, the propulsion system including a rotor assembly configured to rotate relative to the engine centerline axis, and wherein one or more blades of the rotor assembly are configured to rotate along a blade pitch angle axis. A vane assembly is positioned in aerodynamic relationship with the rotor assembly. The vane assembly includes one or more vanes, wherein each vane includes a vane pitch angle. A controller is configured to execute operations, the operations including moving each blade to a reverse thrust position about its respective blade pitch axis, and adjusting each vane about its respective vane pitch axis when the plurality of blades is in the reverse thrust position to modify an amount of reverse thrust generated by the propulsion system.

Abstract: A rotor blade comprises an elongated body that has a pressure side and a suction side. The pressure side and suction side intersect at a leading edge and a trailing edge. The elongated body extends outward from a rotor hub. A span is described by a first straight line distance extending outward from the rotor hub along the elongated body. A chord of the elongated body is defined by a second straight-line distance extending between the leading edge and the trailing edge. At least one passageway extends through the elongated body between the pressure side and the suction side allowing a corrective flow of air to move from the pressure side to the suction side. The corrective flow of air interacts with and energizes low momentum airflow occurring along the suction side.

Abstract: The present disclosure is generally related to aircraft having one or more unducted fan propulsors at locations within specific regions relative to an airfoil, such as a wing or horizontal stabilizer. More specifically, the specific regions are located where there is a relatively higher pressure air flow beneath the wings or above a horizontal stabilizer. That higher pressure air flow can be utilized to provide increased thrust from the unducted fan propulsor.

Abstract: The present disclosure is generally related to aircraft having one or more unducted fan propulsors at locations within specific regions relative to an airfoil, such as a wing or horizontal stabilizer. More specifically, the specific regions are located where there is a relatively higher pressure air flow beneath the wings or above a horizontal stabilizer. That higher pressure air flow can be utilized to provide increased thrust from the unducted fan propulsor.

Abstract: The present disclosure is generally related to aircraft having one or more unducted fan propulsors at locations within specific regions relative to an airfoil, such as a wing or horizontal stabilizer. More specifically, the specific regions are located where there is a relatively higher pressure air flow beneath the wings or above a horizontal stabilizer. That higher pressure air flow can be utilized to provide increased thrust from the unducted fan propulsor.

Abstract: A shroud assembly for a turbine engine having a centerline axis. The shroud assembly having a shroud hanger, at least one shroud segment, and at least one biasing element extending between the two. The biasing element configured to radially bias the at least one shroud segment between an outboard position and an inboard position radially outward from the outboard position with respect to the centerline axis.

Abstract: An unducted thrust producing system, includes a rotating element, a stationary element. An inlet may be located forward or aft of the rotating element and the stationary element. An exhaust may be located forward, aft, or between the rotating element and the stationary element.

Abstract: An aircraft defines a vertical direction and includes a fuselage and a propulsion system comprising a power source and a plurality of vertical thrust electric fans driven by the power source. A wing extends from the fuselage. The plurality of vertical thrust electric fans are arranged along a length of the wing along a lengthwise direction of the wing. The wing comprises a diffusion assembly along the lengthwise direction of the wing and includes a first diffusion member positioned downstream of at least one of the plurality of vertical thrust electric fans. The first diffusion member defines a curved shape relative to a longitudinal direction of the aircraft. The longitudinal direction is generally perpendicular to the lengthwise direction of the wing.

Abstract: An aircraft defines a vertical direction and includes a fuselage and a propulsion system comprising a power source and a plurality of vertical thrust electric fans driven by the power source. A wing extends from the fuselage. The plurality of vertical thrust electric fans are arranged along a length of the wing along a lengthwise direction of the wing. The wing comprises a diffusion assembly along the lengthwise direction of the wing and includes a first diffusion member positioned downstream of at least one of the plurality of vertical thrust electric fans. The first diffusion member defines a curved shape relative to a longitudinal direction of the aircraft. The longitudinal direction is generally perpendicular to the lengthwise direction of the wing.

Abstract: An unducted thrust producing system, includes a rotating element, a stationary element. An inlet may be located forward or aft of the rotating element and the stationary element. An exhaust may be located forward, aft, or between the rotating element and the stationary element.

Abstract: An aircraft equipped with a distributed fan propulsion system and methods of operating such aircraft are provided. In one aspect, an aircraft includes a wing having a top surface and a bottom surface. The aircraft also has a distributed propulsion system that includes a suction fan array having one or more fans mounted to the wing and a pressure fan array having one or more fans mounted to the wing. The fans of the suction fan array are each positioned primarily above the top surface of the wing and the fans of the pressure fan array are each positioned primarily below the bottom surface of the wing. The fans of the suction fan array are controllable independent of the fans of the pressure fan array so that the air pressure above and/or below the wing can be locally controlled, allowing for adjustment of lift on the wing.

Abstract: There is provided apparatuses and methods for a gas turbine engine. The embodiments include a core section with a flow path. The flow path includes a stator vane array having outlet vanes. Each outlet vane has a trailing edge. A strut has a leading edge that is upstream of the trailing edges. Alternatively, the flow path includes a stator vane array having inlet vanes. Each inlet vane has a leading edge. The strut has a trailing edge that is downstream of the leading edges. There also is increased spacing between adjacent vanes and rotor blades.

Abstract: A method is provided of operating a single unducted rotor engine, the single unducted rotor engine comprising a single stage of unducted rotor blades. The method includes operating the single unducted rotor engine to define a flight speed, V0, in a length unit per second and an angular speed, n, in revolutions per second, the single stage of unducted rotor blades defining a diameter, D, in the length unit; wherein operating the single unducted rotor engine comprises operating the single unducted rotor engine to define an advance ratio greater than 3.8 while operating the single unducted rotor engine at a net efficiency of at least 0.8, the advance ratio defined by the equation V0/(n×D).

Abstract: An aircraft equipped with a distributed fan propulsion system and methods of operating such aircraft are provided. In one aspect, an aircraft includes a wing having a top surface and a bottom surface. The aircraft also has a distributed propulsion system that includes a suction fan array having one or more fans mounted to the wing and a pressure fan array having one or more fans mounted to the wing. The fans of the suction fan array are each positioned primarily above the top surface of the wing and the fans of the pressure fan array are each positioned primarily below the bottom surface of the wing. The fans of the suction fan array are controllable independent of the fans of the pressure fan array so that the air pressure above and/or below the wing can be locally controlled, allowing for adjustment of lift on the wing.

Abstract: A flow conditioning structure is disposed about a central axis of an unducted thrust producing apparatus. The unducted thrust producing apparatus has a propeller that generates thrust in a working fluid by rotating about the central axis. The propeller is comprised of blades each with a free end. Each blade also has a leading edge where the working fluid enters during forward thrust operation. The flow conditioning structure comprises a structure forming a passage and the structure forming the passage controls a speed and a direction of the working fluid drawn into the unducted thrust producing apparatus so as to approximate operational speeds and operational directions of the working fluid entering the unducted thrust producing apparatus during operations of a vehicle.

Abstract: A gas turbine engine is provided including a turbine section including a turbine having a plurality of first speed turbine rotor blades; a compressor section including a compressor having a plurality of first speed compressor rotor blades and a plurality of second speed compressor rotor blades; a gearbox; and a first spool rotatable by the plurality of first speed turbine rotor blades, the first spool coupled to the plurality of first speed compressor rotor blades for driving the plurality of first speed compressor rotor blades in a first direction and to the plurality of second speed compressor rotor blades across the gearbox for driving the plurality of second speed compressor rotor blades in a second direction, opposite the first direction.

Abstract: There is provided apparatuses and methods for a gas turbine engine. The embodiments include a core section with a flow path. The flow path includes a stator vane array having outlet vanes. Each outlet vane has a trailing edge. A strut has a leading edge that is upstream of the trailing edges. Alternatively, the flow path includes a stator vane array having inlet vanes. Each inlet vane has a leading edge. The strut has a trailing edge that is downstream of the leading edges. There also is increased spacing between adjacent vanes and rotor blades.