Abstract: Methods and systems for operating an aircraft having two or more engines are described. The method comprises operating the two or more engines of the aircraft in an asymmetric operating regime, wherein a first of the engines is in an active mode to provide motive power to the aircraft and a second of the engines is in a standby mode to provide substantially no motive power to the aircraft, receiving a request to exit the asymmetric operating regime, the request having at least one parameter associated therewith, selecting one of a plurality of available exit protocols as a function of the at least one parameter, and applying the exit protocol by commanding the engines accordingly.

Abstract: A heat engine comprising a compressor providing a flow of compressed air from a core flowpath of the heat engine; a cooled cooling air (CCA) heat exchanger system to which the flow of compressed air is provided from the compressor; a coolant supply system providing a flow of coolant to the CCA heat exchanger in thermal communication with the flow of compressed air at the CCA heat exchanger, in which the coolant supply system and CCA heat exchanger together define a CCA circuit through which the compressed air flows in thermal communication with the coolant; and a hot section disposed downstream of the compressor section along the core flowpath through which combustion gases flow, in which the hot section defines a secondary flowpath through which the flow of compressed air from the CCA heat exchanger is provided.

Abstract: A hybrid metal composite (HMC) structure comprises a first tier comprising a first fiber composite material structure, a second tier longitudinally adjacent the first tier and comprising a first metallic structure and a second fiber composite material structure laterally adjacent the first metallic structure, a third tier longitudinally adjacent the second tier and comprising a third fiber composite material structure, and a fourth tier longitudinally adjacent the third tier and comprising a second metallic structure and a fourth fiber composite material structure laterally adjacent the second metallic structure. At least one lateral end of the second metallic structure is laterally offset from at least one lateral end of the first metallic structure most proximate thereto. Methods of forming an HMC structure, and related rocket motors and multi-stage rocket motor assemblies are also disclosed.

Abstract: An example compressor bleed slot apparatus includes an annular compressor casing, a blade row mounted for rotation about a centerline axis inside the compressor casing, a bleed slot passing through the forward section of the compressor casing, wherein the bleed slot is bounded by inboard and outboard walls defined within the compressor casing, the bleed slot extending along a slot axis, at least a portion of the bleed slot lying within an axial extent of the blade row, an array of struts interconnecting the inboard and outboard walls, and an annular supplemental flange extending radially outward from the forward section of the compressor casing, wherein at least a portion of the supplemental flange is axially positioned within an axial extent of the bleed slot, wherein the supplemental flange includes a necked-down portion adjacent the forward section of the compressor casing, the necked-down portion positioned axially between an inlet of the bleed slot and an outlet of the bleed slot.

Abstract: Systems and methods including a reformer stack extended around a combustion chamber. The reformer stack is configured to provide output products to the combustion chamber.

Abstract: There are described methods and systems for operating an aircraft turboprop engine. The method comprises controlling a propeller of the turboprop engine based on a selected one of a reference propeller rotational speed and a minimum propeller blade angle while the turboprop engine is running; detecting an inflight restart of the turboprop engine; and controlling the propeller during the inflight restart in accordance with at least one of a modified reference propeller rotational speed and a modified minimum propeller blade angle to maintain an actual propeller blade angle above an aerodynamic disking angle during the inflight restart.

Abstract: A gas turbine engine includes an engine case along an engine axis, a conformal accessory drive gearbox housing mounted to the engine case, and at least one accessory mounted to the conformal housing.

Abstract: An acoustic liner includes a core including a plurality of cells extending between a first side of the core and a second side of the core opposite the first side of the core. The acoustic liner further includes a back skin including a light-reflecting layer. The light-reflecting layer includes a first side attached to the first side of the core. The acoustic liner further includes a face skin. The face skin includes a first side attached to the second side of the core.

Abstract: The present disclosure concerns an acoustic attenuation panel for an aircraft turbojet engine nacelle and a method for manufacturing this panel. The acoustic attenuation panel includes an alveolar central core interposed between an acoustic front skin comprising perforations and a rear skin, the acoustic attenuation panel including a front structure and a rear structure. The front structure includes the acoustic front skin and a first network of alveolar walls, the rear structure including the rear skin and a second network of alveolar walls, the first and second networks of alveolar walls being complementary so as to form, in an assembled position, the alveolar central core, the front structure and the rear structure being positioned opposite to each other and so that the network of alveolar walls of a structure is spaced from the skin of the other structure facing it by a clearance d.

Abstract: In general, techniques are described by which to provide a turbine engine compressor particulate offtake. A gas turbine engine comprising a compressor may perform the techniques. The compressor may comprise a plurality of compressor stages, where each compressor stage comprises a circumferential row of stator vanes and a rotor. The compressor may also include an outer circumferential casing that defines a fluidic opening within or between adjacent compressor stages. The fluidic opening may be configured to receive particulate flowing and air through the compressor and output the particulate and air outside of the gas turbine engine. The gas turbine engine also includes a combustor in series flow downstream of the compressor, and a turbine in series flow downstream of the combustor.

Abstract: In a convergent-divergent flap pair for a turbojet engine nozzle of the variable-geometry convergent-divergent type, the convergent flap and the divergent flap include respective cooling-air ducts connected to one another through air passage openings formed in respective contact surfaces of the convergent flap and of the divergent flap arranged facing one another.

Abstract: Devices and methods of rocket propulsion are disclosed. In one aspect, a staged combustion liquid rocket engine with preburner and turbopump unit (TPU) integrated into the structure of the combustion chamber is described. An initial propellant mixture is combusted in a preburner combustion chamber formed as an annulus around a main combustion chamber, the combustion products from the preburner driving the turbine of the TPU and subsequently injected into the main combustion chamber for secondary combustion along with additional propellants, generating thrust through a supersonic nozzle. The preburner inner cylindrical wall is shared with the outer cylindrical wall of the engine's main combustion chamber and the turbine is axially aligned with the main combustion chamber.

Abstract: A twin-engine system includes a gas turbine engine comprising a core and a first output shaft drivable by the core. An electric engine has an electric motor configured to drive a second output shaft. A reduction gear box (RGB) has an RGB input drivingly engaged to both the first output shaft and the second output shaft. The RGB has an RGB output to provide rotational output to a rotatable load.

Abstract: A thermal management system is provided for incorporation into a gas turbine engine, wherein the gas turbine engine, the aircraft, or both define a vertical direction. The thermal management system including: a thermal transport bus having a thermal fluid flowing therethrough; a plurality of heat source exchangers in thermal communication with the thermal fluid in the thermal transport bus; and a pump assembly in flow communication with the thermal transport bus, the pump assembly including: a pump; and a pump protection device positioned below the pump along the vertical direction.

Abstract: A pressure relief latch includes a housing configured to be mounted to a pressure relief door. A bolt is coupled to the housing about a first axis and is rotatable about the first axis between a first bolt position and a second bolt position. The bolt includes a bearing centered about a second axis. The bearing is configured to rotate about the second axis. A spring assembly includes a first assembly end mounted to the bearing and a second assembly end in rotational communication with the housing about a third axis. The spring assembly is rotatable about the second and third axes and further includes a spring extending between the first and second assembly ends. The bolt is configured to permit movement of the pressure relief door from the closed position to the open position as the bolt rotates from the first bolt position to the second bolt position.

Abstract: An aircraft propulsion assembly includes a turbine engine surrounded by a nacelle with an annular air-intake lip extending around the turbine engine by two annular walls, inner and outer, respectively, intended for being swept across by air flows at least when the aircraft is in flight. The inner and outer walls each includes or supports at least one network of pipes forming heat exchangers. The inner wall pipe network having liquid outlet connected with a liquid intake of the outer wall pipe network. The propulsion assembly further includes means for circulating the liquid, connected to at least one liquid intake of the network of pipes of the inner wall.

Abstract: A method of monitoring a sealing component of a gas turbine engine, comprising: collecting oil leaked from the component; detecting a volume of the collected oil upstream of an oil return path of the gas turbine engine; and signalling for inspection of the component when the volume of the collected oil exceeds a threshold volume. Also disclosed is an oil leakage monitoring system for a gas turbine engine, comprising: one or more sealing components to be lubricated by oil; a valve downstream of the one or more components and fluidly connected to an oil system; a reservoir downstream of the one or more components to collect oil, the reservoir upstream of the valve; and a volume measurement device configured to detect the oil collected in the reservoir, and to signal for inspection of the one or more components when the oil collected in the reservoir exceeds a threshold volume.

Abstract: A system (1) for vibration management comprises a stator (24, 45); a rotor (26) being mounted rotatably with respect to the stator (24, 45) about a rotational axis (9); one or more active devices (41A-41C) adapted to apply forces and/or moments on the rotor (26) and/or on the stator (24, 45); at least two sensors (42) for measuring vibrational parameter values with respect to two or more different positions, particularly along the rotational axis (9); and a controller (44) adapted to provide control signals to the one or more active devices (41A-41C) based on the vibrational parameter values of the at least two sensors (42) and on the respective position.

Abstract: An air intake scoop intended to be fastened on a panel of an aircraft includes an air inlet mouth having a wall, a peripheral collar intended to be fastened to the panel, and a bearing element intended to support the air circulation duct. The air inlet mouth is made of a thermoplastic material and the bearing element is fastened on the peripheral collar so as to achieve a pressure barrier in case of breakage of the wall of the air inlet mouth.

Abstract: A fuel injector system includes an outer support and an inner support, with a feed arm extending radially between the inner support and the outer support. A plurality of outlet openings extend in an axial direction from the feed arm for feeding respective injection nozzles. The outer support and feed arm define a plurality of fuel passages therethrough to convey fluid from an external source through the outer support and feed arm to the outlet openings. A heat shield extends around the feed arm from the outer support to the inner support. The heat shield is spaced apart from the feed arm with an insulative gap therebetween.