An exemplary aircraft includes a turbine engine having a gas generator spool and a power spool, the power spool operational to drive a rotor, a first generator coupled to the gas generator spool, and a controller operable to increase a load on the gas generator spool when the gas generator spool is on a speed limit thereby increasing a speed limit margin in order to increase power available from the turbine engine.

An exemplary aircraft includes a turbine engine having a gas generator spool and a power spool, the power spool operational to drive a rotor, a first generator coupled to the gas generator spool, and a controller operable to increase a load on the gas generator spool when the gas generator spool is on a speed limit thereby increasing a speed limit margin in order to increase power available from the turbine engine.

An aircraft power plant comprising novel air management features for high-power fuel cell applications, the features combine supercharging and turbocharging elements with air and hydrogen gas pathways, utilize novel airflow concepts and provide for much stronger integration of various fuel cell drive components.

Apparatuses and systems are provided herein for unducted propulsion systems. The system includes an aft housing for low drag for high subsonic sustained flight. A plurality of blades are affixed to the aft housing, wherein the housing defines a flowpath curve extending from the axial extent of the aft blade root to the aft end of the aft housing. The flowpath curve is described by an axial direction parallel to an axis of rotation and a radius from the axis of rotation. The flowpath curve includes first point having a first radius where the radius reaches a maximum aft of the aft blade root and a second point forward of the first point having a second radius where the radius stops decreasing. The ratio of the first radius to the second radius is greater than or equal to 1.081.

A method of operating a multi-engine system of an aircraft having first and second engines includes accumulating compressed air in a pressure vessel external to the engines, and operating the first and second engines asymmetrically, by controlling the first engine to operate in an active operating condition providing sufficient power and/or rotor speed for demands of the aircraft, and controlling the second engine to operate in a standby operating condition wherein the second engine produces less power output than the first engine. In response to a power demand request, the second engine is accelerated out of the standby operating condition by introducing therein compressed air from the pressure vessel at a location upstream of a combustor of the second engine.

A method of operating a multi-engine system of an aircraft having first and second engines includes accumulating compressed air in a pressure vessel external to the engines, and operating the first and second engines asymmetrically, by controlling the first engine to operate in an active operating condition providing sufficient power and/or rotor speed for demands of the aircraft, and controlling the second engine to operate in a standby operating condition wherein the second engine produces less power output than the first engine. In response to a power demand request, the second engine is accelerated out of the standby operating condition by introducing therein compressed air from the pressure vessel at a location upstream of a combustor of the second engine.

An acoustic panel system is provided that includes a perforated first skin, a second skin and a core. The core is connected to the perforated first skin and the second skin. The core includes a plurality of chambers and a first constriction. Each of the chambers extends vertically through the core between the perforated first skin and the second skin. The chambers include a first chamber. The first constriction is configured to divide the first chamber into a plurality of fluidly coupled sub-chambers. The first constriction is configured from or otherwise includes a shape memory material.

There is disclosed an aircraft engine assembly including an engine having an engine shaft; an output shaft; a clutch in driving engagement between the engine shaft and the output shaft. The clutch has a first component in driving engagement with the engine shaft and a second component. The clutch is operable between first and second configurations. In the first configuration, the first component is rotatable relative to the second component and the engine shaft is rotatable relative to the output shaft. In the second configuration, the first and second components are engaged with one another and the engine shaft rotates with the output shaft. A mechanical lock is operable between first and second positions. In the first position, the mechanical lock is disengaged from the first component. In the second position, the first and second components are secured for joint rotation one relative to the other.

A gas turbine engine designed to take-off and land as a conventional turbofan engine at subsonic speeds and accelerate to supersonic speeds during flight by converting into a hybrid turbojet and ramjet engine. This is achieved by introducing an afterburner in the bypass duct of the engine and by retracting the bypass fan backward into a cylinder. This operation is carried out before the aircraft enters the transonic regime, at any stage below Mach 1. At supersonic speed, the shock wave is deflected through a needle cone that is projected out of the nose of the engine in order to prevent the intake air from being choked.

A gas turbine engine designed to take-off and land as a conventional turbofan engine at subsonic speeds and accelerate to supersonic speeds during flight by converting into a hybrid turbojet and ramjet engine. This is achieved by introducing an afterburner in the bypass duct of the engine and by retracting the bypass fan backward into a cylinder. This operation is carried out before the aircraft enters the transonic regime, at any stage below Mach 1. At supersonic speed, the shock wave is deflected through a needle cone that is projected out of the nose of the engine in order to prevent the intake air from being choked.