Abstract: A method for monitoring an aircraft thrust reverser having stowable doors, the thrust reverser being a reverser having hydraulic actuators equipped with switches arranged to each return a data item on the position of the doors, the engine including a computer configured to make measurements of a representative parameter of the position of the switches based on the data returned by the switches, includes computation of one or a plurality of statistical indicators of the parameter measured and an analysis of the temporal progression of the statistical indicator(s) computed. The invention also applies to a computer program for the implementation of this method.

Abstract: Techniques for using an unmanned aerial vehicle (UAV) to deliver a payload while generating an expected sound by the UAV during delivery may be provided. For example, during delivery or while in flight, propellers of different sizes that are associated with the UAV may be instructed to modulate at different rotational speeds to thereby generate an expected sound.

Abstract: An actuation arrangement for effecting actuation of pivotable vane, for example, variable inlet guide vane in gas turbine engine. The actuation arrangement includes an actuator having a support plate and pivotable plate. The pivotable plate is fixedly connected to pivotable vane and pivotable plate and pivotable vane are pivotable about a pivot axis. The actuator further includes at least one actuation element having a length extending from support plate to proximal a transverse edge portion of pivotable plate substantially perpendicular to pivot axis. The or each actuation element is fixedly connected to each of the support and pivotable plates and formed of a material that changes dimension upon application of external energy. Thus, upon application of external energy, for example, heat, a change in length of the or each actuation element occurs such that change in length effects pivoting of pivotable plate and pivotable vane about the pivot axis.

Abstract: An airflow control system for a combined cycle turbomachine system in accordance with an embodiment includes: an airflow generation system for attachment to a rotatable shaft of a gas turbine system, the airflow generation system drawing in an excess flow of air through an air intake section; a mixing area for receiving an exhaust gas stream produced by the gas turbine system; an air extraction system for extracting a first portion of the excess flow of air to provide bypass air, and for diverting the bypass air into the mixing area to reduce a temperature of the exhaust gas stream; and an airflow regulation system for diverting a second portion of the excess flow of air into the compressor component and, in response to an under-frequency grid event, for increasing the second portion of the excess flow of air diverted into the compressor component.

Abstract: One example of a gas turbine engine can include a first compressor and a first turbine connected to the first compressor by a first shaft. The engine can include a reheat combustor, which is disposed downstream of the first turbine, and a second turbine, which is disposed downstream of the reheat combustor. The engine can further include a second compressor, which is connected to the second turbine by a second shaft and is disposed upstream of the first compressor. The first and second turbines can be disconnected from one another, and the first and second compressors can be disconnected from one another. The second compressor may have an outlet including a flow to the first compressor, such that the first and second turbines provide a shaft worksplit. The reheat combustor can be configured to receive fuel and generate a reheat exit temperature, so as to control an apparent capacity of the second turbine based on a plurality of parameters of the second compressor.

Abstract: A bleed valve for a gas turbine engine, the bleed valve comprising: an inlet coupled to an air source; and an outlet coupled to an air sink. The bleed valve also comprises a first stage of flow area modulation between the inlet and the outlet. Also a second stage of flow area modulation between the first stage and the outlet. The pressure can be equalized between the first and second stages. There is also an arrangement comprising a plurality of bleed valves and a controller to control the flow areas of at least one of the first and second stages of each bleed valve.

Abstract: A fiber connector, comprising a housing having a chamber extending in a lengthwise direction from a first end configured to receive a fiber to a second end configured to connect the fiber to a laser processing head and a channel disposed on an exterior surface of the chamber, the channel comprising a double helical structure.

Abstract: A hybrid electric propulsion system includes a turbomachine, an electric machine coupled to the turbomachine, and a propulsor coupled to the turbomachine. A method for operating the hybrid electric propulsion system includes operating the turbomachine to drive the propulsor; receiving data indicative of a failure condition of the hybrid electric propulsion system; reducing a fuel flow to a combustion section of the turbomachine in response to receiving the data indicative of the failure condition; and extracting power from the turbomachine using the electric machine to slow down one or more rotating components of the turbomachine in response to receiving the data indicative of the failure condition.

Abstract: A gas turbine engine is provided, comprising a tail cone and a low-pressure spool outside the tail cone. An input shaft may be coupled to the low-pressure spool and inside the tail cone. A differential may be coupled to the input shaft and inside the tail cone. A generator may be coupled to the differential and also disposed inside the tail cone. An oil pump may be configured to pump oil through the generator to the differential. A generator assembly is also provided. The generator assembly may comprise an input shaft, a differential coupled to the input shaft, a rotating transfer tube coupled to the differential, a generator coupled to rotating transfer tube, and an oil pump configured to pump oil from the generator, through the rotating transfer tube, and into the differential.

Abstract: An example gas turbine engine with multiple flow paths includes, among other things, a core flow path extending from a compressor section to an exhaust section, a bypass duct providing a bypass flow path radially outside the core flow path, and a flow injection device to selectively communicate a first amount of flow or a second amount of flow from the bypass flow path to the exhaust section, the first amount of flow different than the second amount of flow.

Abstract: A baffle within a gas turbine engine includes a cylindrical flange with a multiple of holes at least partially therearound.

Abstract: A gas turbine engine according to an example of the present disclosure includes, among other things, a fan, a compressor section, and a turbine section including a fan drive turbine and a second turbine. The fan drive turbine has a first exit area at a first exit point and is rotatable at a first speed. A mid-turbine frame is positioned intermediate the fan drive turbine and the second turbine, and can include a bearing support. The second turbine has a second exit area at a second exit point and is rotatable at a second speed. A first performance quantity is defined as the product of the first speed squared and the first area. A second performance quantity is defined as the product of the second speed squared and the second area.

Abstract: An exemplary method for the operation of a CCPP with flue gas recirculation to reduce NOx emissions and/or to increase the CO2 concentration in the flue gases to facilitate CO2 capture from the flue gases as well as a plant designed to operate is disclosed. To allow a high flue gas recirculation ration (rFRG) an imposed combustion inhomogeneity ratio (ri) is used for flame stabilization. The imposed combustion inhomogeneity ratio (ri) is controlled as function of the flue gas recirculation rate (rFRG) and/or combustion pressure. Oxygen or oxygen enriched air to the gas turbine inlet gases or to the combustor is admixed to enhance operatability.

Abstract: A gas turbine includes an exhaust cylinder comprising an inner circumferential slot, a diffuser shell disposed at least substantially concentrically within the exhaust cylinder and one or more baffle plates extending between the exhaust cylinder and the diffuser shell, a proximal end of each of the one or more baffle plates being fixed to the diffuser shell by one or more holding rings and a distal end of each of the one or more baffle plates being slidingly received within the inner circumferential slot of the exhaust cylinder. The one or more holding rings are secured to the diffuser shell, at one or more holding segments disposed along an inner diameter of the diffuser shell, via a plurality of radially inserted fastening members.

Abstract: A heat exchanger assembly for a gas turbine engine including a frame, including a non-planar outer wall, a non-planar inner wall spaced radially inward from the non-planar outer wall to form a frame cavity therebetween, an inlet side extending between the non-planar outer wall and the non-planar inner wall, an inlet passage extending through the inlet side, an outlet side extending between the non-planar outer wall and the non-planar inner wall opposite the inlet side; an outlet passage extending through the outlet side, and a continuous non-planar core disposed within the frame cavity and in flow communication with the inlet passage and the outlet passage.

Abstract: A 2-shaft gas turbine can suppress an increase in NOx emission from a combustor even when degradation of compressor efficiency occurs due to a decrease in performance with long-term use. The 2-shaft gas turbine has a gas generator and a power turbine, and includes a controller configured to set, in accordance with a degree of degradation of compressor efficiency computed from measured control parameters, a target speed of the gas generator at a level lower than a target speed in a state where degradation of the compressor efficiency has not occurred. The controller is configured to control the rotating speed of the gas generator on the basis of a difference between the target speed thus set and an actual rotating speed.

Abstract: The invention relates to a primary cowl for a turbofan comprising a primary body generating a primary stream to be ejected through a primary nozzle, and a secondary body generating a secondary stream to be ejected through a secondary nozzle, the primary cowl being shaped so as to be positioned downstream from the primary body and to define, on the inside of the turbofan, the path followed by the primary stream downstream from the primary nozzle and, on the outside, the path followed by the secondary stream downstream from the secondary nozzle. The primary cowl comprises a coupling to a system for supplying a pressurized gas and at least one perforation for injecting the pressurized gas, through the perforation, into the secondary stream. The primary cowl preferably comprises a ring which has perforations and which is rotated about the axis of rotation of the turbofan.

Abstract: A method for determining a buffer effect of an activated carbon filter for a tank venting system of a fuel container for hydrocarbon-containing fuels involves feeding a defined quantity of hydrocarbon molecules to the activated carbon filter (320) via a tank connection (320_1) of the activated carbon filter (320) by a hydrocarbon feed system (310). A carrier gas flow is introduced into the activated carbon filter (320) via an air connection (320_2) of the activated carbon filter (320), and a defined volumetric flow is sucked out of the activated carbon filter (320) via an engine connection (320_3) of the activated carbon filter (320) by a hydrocarbon measuring device (340), and its content of hydrocarbon molecules is measured. The defined quantity of hydrocarbon molecules is made available by the hydrocarbon feed system (310) in the form of a thermodynamically isolated gas quantity.

Abstract: A method for determining a suction mass flow of a gas turbine is provided. A turbine inlet pressure, a combustion chamber pressure loss and a pressure loss between an environment and a compressor inlet are determined as input parameters. For each input parameter a provisional value for the suction mass flow is ascertained and for each provisional value a validated value by cross-balancing with the other provisional values is ascertained. A characteristic quantity of the suction mass flow of the gas turbine is generated as an average value from the validated values. The suction mass flow is determined without solving energy balances, without information relating to a fuel calorific value, and without information relating to a fuel mass flow.

Abstract: A cryogenic thruster assembly including: a reignitable main thruster; a first cryogenic tank connected to the main thruster to feed the main thruster with a first propellant; a first gas tank; at least one settling thruster; and a first feed circuit for feeding the first gas tank. The feed circuit of the first gas tank is connected to the first cryogenic tank and includes a heat exchanger for using heat given off by the at least one settling thruster to vaporize a liquid flow of the first propellant as extracted from the first cryogenic tank to feed the first gas tank with the first propellant in the gaseous state. A method feeds the first gas tank with the first propellant in the gaseous state.

Abstract: A turbine engine exhaust nozzle includes a core gas duct, a nozzle duct, and a thrust vectoring duct system having a duct valve, a first vectoring duct and a second vectoring duct. The nozzle duct directs a first portion of core gas from the core gas duct through a nozzle duct outlet along a centerline. The duct valve connects the core gas duct to the first vectoring duct during a first mode of operation, and connects the core gas duct to the second vectoring duct during a second mode of operation. The first vectoring duct directs a second portion of core gas from the core gas duct through a first vectoring duct outlet along a first trajectory. The second vectoring duct directs a third portion of core gas from the core gas duct through a second vectoring duct outlet along a second trajectory that is angularly offset to the first trajectory.

Abstract: A gas exhaust nozzle for aircraft propulsion includes at least a downstream part with a trailing edge of chevron type formed of chevrons distributed along the periphery of the nozzle. Each chevron extends downstream between an upstream transverse plane and a downstream transverse plane with free edges oriented in two converging downstream directions and defining the trailing edge. The chevrons generate vortices at the boundary of the jet emitted by the nozzle. The gas exhaust nozzle includes a device to inject auxiliary gas jets upstream of the free edges of the chevrons in the main jet through orifices placed upstream of the upstream plane in such a way as to discharge upstream of the upstream plane of the chevrons to generate the vortices upstream of the free edges of the chevrons.

Abstract: An exhaust diffuser arrangement for a turbine system includes an inlet for receiving a flow proximate a last stage bucket of the turbine system, the flow flowing in a first flow direction. Also included is a flow redirecting component. The flow redirecting component includes a first wall having a first side of a concave surface geometry for redirecting the flow and a second side of a convex surface geometry. The flow redirecting component also includes a second wall spaced downstream of the first wall and having at least one flow exit for reducing a boundary layer along the second side of the first wall.

Abstract: A gas turbine engine has a fan, a compressor section, a combustor, and a turbine section. The fan delivers a portion of air into the compressor, and into a duct, as bypass air. A bleed air system bleeds a quantity of air from the compressor into a chamber at least at low power conditions of the engine. The bleed air system has an opening which may be selectively closed to block bleed air, or opened to allow bleed flow from the compressor into the chamber. A heat exchanger is positioned such that a first surface of the heat exchanger is contacted by bypass air in the duct, and a second surface of the heat exchanger is contacted by bleed air when the bleed air system directs air from the compressor into the chamber.

Abstract: Active clearance control ejector systems and methods are disclosed. An example system may include an air ejector; an entrance pipe arranged to supply compressor bleed air to the air ejector; an inlet duct arranged to supply fan bypass air to the air ejector; and a supply pipe arranged to receive ejector outlet air from the air ejector and supply the ejector outlet air to an active clearance control system. The ejector outlet air may include a mixture of the compressor bleed air and the fan bypass air. The air ejector may include a venturi arranged to conduct the compressor bleed air therethrough, thereby drawing the fan bypass air into the air ejector.

Abstract: A computer-implemented method for in-flight assessment of freedom from flutter of an airplane, involving analyzing the airplane structure vibrations based on signals indicated by sensors located on the airplane structure. The computations are performed in real-time based on current measurement data collected from the sensors. For measurement data from individual sensors there are determined mode shapes of vibrations. The relevancy of modes of vibrations is determined by subtracting from the vibrations signal the particular mode of vibrations and calculating the value of decrease in the rest sum of squares.

Abstract: The disclosure is directed to a system and method of fueling and mitigating debris for an illumination source. An illumination system may include a plasma-based illumination source. The illumination system may provide illumination along an illumination path emanating from an illumination origin of the illumination source. A gas jet nozzle may be disposed at a selected distance from the illumination origin or proximate to the illumination origin. The gas jet nozzle may be configured to provide fuel gas to fuel the plasma-based illumination source. The gas jet nozzle may be further configured to provide fuel gas in a selected direction substantially opposite to a direction of illumination emanating from the illumination origin to remove at least a portion of debris from the illumination path.

Abstract: Systems and methods for acoustic feedback or resonance mitigation are provided. The systems and methods include an exhaust acoustic noise reduction apparatus having an exhaust port comprising an exhaust aperture, a first vane extending at least partially across the exhaust aperture, and a second vane extending at least partially across the exhaust aperture and intersecting the first vane, such that the first and second vanes are oriented to interfere with formation of an acoustic feedback loop and reduce an acoustic noise signature of the exhaust port.

Abstract: A gas turbine engine includes a controller that controls a fan blade flutter characteristic through control of a variable area fan nozzle.

Abstract: A control system comprises a TRAS actuator 14, a VAFN actuator 40, and a control arrangement 52 operable to control the operation of the TRAS actuator 14 and the VAFN actuator 40, wherein at least one control circuit 54 of the control arrangement 52 is a common control circuit, common to the operation of both the TRAS actuator 14 and the VAFN actuator 40.

Abstract: One embodiment of the present invention is a unique gas turbine engine. Another embodiment is a unique aircraft. Other embodiments include apparatuses, systems, devices, hardware, methods, and combinations for gas turbine engines and gas turbine engine powered aircraft. Further embodiments, forms, features, aspects, benefits, and advantages of the present application will become apparent from the description and figures provided herewith.

Abstract: A method, system and apparatus for generating thrust. The method, system and apparatus can include a fuel that may be accelerated into one or more openings on a rotating wheel. The rotating wheel, which may be balanced, may then have a temporary increase in mass in one location on the wheel. Additionally, the fuel that is accelerated into one or more openings in the wheel may be decelerated and may exert an outward force on the wheel. This generation of force can be repeated and increased to provide thrust.

Abstract: A nacelle assembly for a high-bypass gas turbine engine includes a core nacelle defined about an engine centerline axis. A fan nacelle is mounted at least partially around the core nacelle to define a fan bypass flow path. A variable area fan nozzle is in communication with the fan bypass flow path. The variable area fan nozzle has a first fan nacelle section and a second fan nacelle section. The second fan nacelle section is axially movable relative to the first fan nacelle section to define an auxiliary port at a non-closed position to vary a fan nozzle exit area and adjust fan bypass airflow. The second fan nacelle section includes an acoustic system that has an acoustic impedance located on a radially outer surface.

Abstract: An exoatmospheric vehicle uses a control system that includes a thrust system to provide thrust to control flight of the vehicle. A regenerative heat system is used to preheat portions of the thrust system, prior to their use in control of the vehicle. The heat for preheating may be generated by consumption of a fuel of the vehicle, such as a monopropellant fuel. The fuel may be used to power a pump (among other possibilities), to pressurize the fuel for use by thrusters of the thrust system. The preheated portions of the thrust system may include one or more catalytic beds of the thrust system, which may be preheated using exhaust gasses from the pump. The preheating may reduce the response time of the thrusters that have their catalytic beds preheated. Other thrusters of the thrust system may not be preheated at all before operation.

Abstract: An exhaust nozzle for a gas turbine engine may include a plurality of flap trains in the exhaust stream of the gas turbine engine. The flap trains are operable to selectively control three separate flow paths of gas that traverse the engine. A first stream of is the core airflow. The second stream of air is peeled off of the first stream to form a low pressure fan bypass air stream. The third stream of air traverses along the engine casing and is passed over a flap assembly to aid in cooling. The flaps are operable converge/diverge to control the multiple streams of air.

Abstract: A pneumatic system 131 for use with gas turbine engines 10 and aircraft 100. The pneumatic system 131 comprises a first engine core compressor bleed offtake in the form of an engine handling bleed offtake 140, and a second engine core compressor bleed offtake in the form of first and second cabin bleed offtake 132, 134, the handling bleed being configured to supply higher pressure air than the cabin offtakes 132, 134. The system 131 comprises a turbocompressor 144 comprising an air compressor 148 driven by a turbine 146. The handling bleed offtake 140 is in fluid communication with the turbocompressor air turbine 146 to thereby drive the air turbine 146, and the cabin bleed offtakes 132, 134 are in fluid communication with the turbocompressor air compressor 148 such that air from the offtakes 132, 134 is compressed by the turbocompressor air compressor 148.

Abstract: One embodiment includes a pivot thrust reverser. The pivot thrust reverser includes a first tandem pivot door subassembly comprising an inner panel and an outer panel. The inner panel and the outer panel are connected so as to rotate simultaneously about respective pivot axises that are each positionally fixed axises relative to the gas turbine engine assembly. A second tandem pivot door subassembly is included, spaced from the first tandem pivot door subassembly and comprising an inner panel and an outer panel. The inner panel and the outer panel are connected so as to rotate simultaneously about respective pivot axises that are each positionally fixed axises relative to the gas turbine engine assembly.

Abstract: A gas turbine engine includes a core engine, a first bypass passage disposed about the core engine and a second bypass passage disposed about the first bypass passage. A flow control is disposed within the second bypass for controlling bypass airflow through the second bypass. The flow control translates axially between an open position and a closed position to vary and control airflow through the second bypass passage.

Abstract: A nozzle is provided that is capable providing flowpaths for a combined cycle aircraft propulsion system that in one form includes a gas turbine engine and a ramjet. The gas turbine engine produces an exhaust flow that is offset from an exhaust flow from the ramjet. The two streams can be flowed independent of each other or together depending on the application and relevant portion of a flight envelope. The nozzle includes a movable portion that can selectively open and close an exhaust flowpath for the gas turbine engine. The nozzle includes a surface that provides expansion for both low speed (gas turbine engine) flow and high speed (ramjet) flow.

Abstract: A flow control device includes a first axially extending flow control surface, a second axially extending flow control surface radially offset from the first surface to define a gas flow path therebetween, the gas flow path having a downstream flow path exit, and a third axially extending flow control surface radially offset from the first surface and capable of axially translating with respect to the first and second surfaces for modifying the gas flow path and selectively closing the flow path exit. A turbofan engine includes a core flow passage, a fan bypass passage located radially outward from the core flow passage, a third stream bypass passage located radially outward from the fan bypass passage, and a flow control device that dynamically regulates the third stream bypass passage, allowing fluid flowing through the third stream bypass passage to provide thrust to the turbofan engine and reduce afterbody drag.

Abstract: A thrust reverser system and operation suitable for high-bypass turbofan engines. The thrust reverser system includes a cascade system adapted to be translated with a translating cowl in an aft direction of an engine to expose a circumferential opening. The cascade system is deployed from a stowed position as the translating cowl and the cascade system are translated in the aft direction. During deployment of the cascade system, a fore end thereof translates in the aft direction and an aft end thereof initially translates in the aft direction and then subsequently rotates about the fore end so that further translation of the cascade segment in the aft direction causes the cascade segment to move to a deployed position and divert bypass air within a bypass duct of the engine through the circumferential opening.

Abstract: The present disclosure relates to an engine having two modes of operation—air breathing and rocket—that may be used in aerospace applications such as in an aircraft, flying machine, or aerospace vehicle. The engine's efficiency can be maximized by using a precooler arrangement to cool intake air in air breathing mode using cold fuel used for the rocket mode. By introducing the precooler and certain other engine cycle components, and arranging and operating them as described, problems such as those associated with higher fuel and weight requirements and frost formation can be alleviated.

Abstract: An electric thruster includes at least one electric engine, a feed system for the engine including a high-pressure tank of ionizable gas, a low-pressure buffer tank connected to the high-pressure tank by a valve, and a system of pipes for conveying the gas from the low-pressure buffer tank to an anode and to a cathode of the engine. The low-pressure buffer tank is in open connection with the engine. The thruster detects that a magnitude of the discharge current between the anode and the cathode is less than a threshold value and switches off the discharge voltage as a result of the detection. The thruster can be for use in a satellite.

Abstract: A system for enhancing movement of a multi-engine flight vehicle about either of pitch or yaw axes. The engines are oriented relative the centerline of the flight vehicle and a portion of the engines have a positive tangential cant and the remaining engines have a negative tangential cant. The attitude of the flight vehicle about the pitch, yaw and roll axes is controlled by differentially throttling the multi-engine flight vehicle.

Abstract: A propulsion device including a chamber that stores a superfluid, a substrate coupled to a portion of the chamber, a plurality of orifices extending through the substrate, each of the plurality of orifices having a first end and a second end opposite the first end, the first end disposed in an interior of the chamber and the second end disposed outside the chamber; and a pressure source that generates a pressure differential between the first end of each of the plurality of orifices and the second end of each of the plurality of orifices.

Abstract: Systems and methods for rejecting waste heat generated by one or more operating systems installed on an aircraft employ an endothermic fuel that can participate in endothermic catalytic cracking at temperatures below about 80° C. when exposed to a cracking catalyst that contains a superacid operative to induce low-temperature catalytic cracking of the branched alkanes. The endothermic fuel contains an effective amount of the branched alkanes so that a net endothermic effect is realized when the fuel is exposed to the cracking catalyst. The low-temperature, heat-consuming cracking of the branched alkanes increases the heat sink capacity of the endothermic fuel.

Abstract: A system and methods are provided for combining systems of an upper stage space launch vehicle for enhancing the operation of the space vehicle. Hydrogen and oxygen already on board as propellant for the upper stage rockets is also used for other upper stage functions to include propellant tank pressurization, attitude control, vehicle settling, and electrical requirements. Specifically, gases from the propellant tanks, instead of being dumped overboard, are used as fuel and oxidizer to power an internal combustion engine that produces mechanical power for driving other elements including a starter/generator for generation of electrical current, mechanical power for fluid pumps, and other uses. The exhaust gas from the internal combustion engine is also used directly in one or more vehicle settling thrusters. Accumulators which store the waste ullage gases are pressurized and provide pressurization control for the propellant tanks.

Abstract: An acoustic resonance igniter uses gas expanding through a nozzle to form a sonic, or under-expanded supersonic, jet directed against the opening of a blind resonance cavity in a central body, setting up a high-frequency sonic resonance which heats the gas within the cavity. A pintle extends coaxially with the nozzle and injects liquid propellant into the jet. The liquid propellant ignites with the heated gas within the resonance cavity forming combustion gases. The combustion gases flow through openings in a flange which supports the resonance cavity into a combustion chamber in the same direction as the gas jet flows. The liquid propellant is injected from within the support flange in the direction of combustion gas flow to film cool the combustion chamber wall and the flange and the central body supported by the flange. The acoustic resonance igniter may form a rocket engine ignition torch or a RCS thruster.

Abstract: A magnetically enhanced micro-cathode thruster assembly provides long-lasting thrust. The micro-cathode thruster assembly includes a tubular housing, a tubular cathode, an insulator, an anode and a magnetic field. The tubular housing includes an open distal end. The tubular cathode is housed within the housing and includes a distal end positioned proximate the open distal end of the housing. The insulator is in contact with the cathode forming an external cathode-insulator interface. The anode is housed within the housing, proximate the open distal end of the housing. The magnetic field is positioned at or about the external cathode-insulator interface and has magnetic field lines with an incidence angle of about 20 to about 30 degrees and preferably about 30 degrees relative to the external cathode-insulator interface.

Abstract: A method of varying a fan duct nozzle throat area of a gas turbine engine includes pivoting a fan nozzle outwardly relative to a longitudinal axis of the gas turbine engine. The fan nozzle is configured to move axially non-contemporaneously with the pivoting of the fan nozzle.