Abstract: An electronic control system (35) for a turbopropeller (2) having a gas turbine engine (20) and a propeller assembly (3) coupled to the gas turbine engine (20), the control system (35) having: a propeller control stage (35a), implementing a closed loop control for controlling operation of the propeller assembly (3) based on a scheduled propeller speed reference (Nrref) and a propeller speed measure (Nr); a gas turbine control stage (35b), implementing a closed loop control for controlling operation of the gas turbine engine (20) based on a scheduled reference (Ngdotref) and at least a feedback quantity. The control system (35) further envisages an auxiliary control stage (35c), coupling the propeller control stage (35a) and the gas turbine control stage (35b) and determining a limitation of the operation of the gas turbine engine (20), if a propeller speed overshoot is detected, with respect to the propeller speed reference (Nrref).

Abstract: A fuel metering system for a combustion section of a turbo machine is provided. The turbo machine includes a main fuel line configured to provide a flow of fuel and a zone fuel line split from the main fuel line through which at least a portion of the flow of fuel is provided. A fuel valve is disposed at the zone fuel line and is configured to obtain and receive a present fuel valve area value and a present valve position value. A first pressure sensor is disposed upstream of the fuel valve, in which the first pressure sensor is configured to obtain a first pressure value. A second pressure sensor is disposed downstream of the fuel valve, in which the second pressure sensor is configured to obtain a second pressure value. A flow meter is disposed downstream of the fuel valve.

Abstract: Herein provided are methods and systems for setting a fuel flow schedule for starting a gas turbine engine of an aircraft. Aircraft speed and engine rotational speed are obtained. A compressor inlet recovered pressure is estimated by combining a first component influenced by the aircraft speed and a second component influenced by the engine rotational speed, and a fuel flow schedule is selected for engine start in accordance with the estimated compressor inlet recovered pressure.

Abstract: A debris monitoring system has a first sensor configured to generate a first signal indicating a presence of a metallic particle in a lubrication system. A second sensor is configured to generate a second signal indicating the presence of a metallic particle in the lubrication system. A signal processor is configured to determine a presence of a metallic particle in a fluid passage based on a comparison of at least the first signal and the second signal; the second signal being used to verify accuracy of the first signal. A gas turbine engine and a method for monitoring a fluid passage for debris are also disclosed.

Abstract: A pump assembly includes a pump unit having a centrifugal pump and a variable pump supplying pressurized flow. A fuel control assembly receives flow from the pump unit and includes at least one metering valve and at least one throttling valve. A control for the variable pump receives first and second pressure signals indicative of a pressure differential across the throttling valve, or across the metering valve/throttling valve combination, for altering operation of the variable pump in response to the pressure differential.

Abstract: A water-propelled or water-powered unmanned aerial vehicle including a base configured to carry a payload, and at least one nozzle attached thereto. The at least one nozzle is configured to selectively receive pressurized fluid from a source located remotely from the vehicle. The vehicle includes a control system configured to alter or otherwise selectively dictate the flow of fluid through the at least one nozzle and/or the orientation of the at least one nozzle with respect to the base in response to a received control signal for providing controlled unmanned vehicle flight.

Abstract: A fuel system includes a centrifugal pump which pressurizes and delivers fuel that is supplied to an aircraft engine, and a transmission which connects the engine and the centrifugal pump to each other, is able to regulate a gear ratio and which modifies and transmits a rotational speed of rotational power that is output from the engine to the centrifugal pump.

Abstract: The invention concerns an aircraft propulsion control system in which multiple gas turbine engines (10) are under the control of a controller (30). One or more sensor is arranged to sense a condition indicative of vapor trail formation by an exhaust flow from one or more of the engines. The controller (30) is arranged to be responsive to a thrust demand (51) for the aircraft and to control the thrust produced by each of the engines (10) concurrently so as to alter the efficiency of the engines upon sensing of the vapor trail formation condition, while satisfying the aircraft thrust demand. The controller (30) may output a separate throttle control signal (35) to each engine (10).

Abstract: A water-propelled or water-powered unmanned aerial vehicle including a base configured to carry a payload, and at least one nozzle attached thereto. The at least one nozzle is configured to selectively receive pressurized fluid from a source located remotely from the vehicle. The vehicle includes a control system configured to alter or otherwise selectively dictate the flow of fluid through the at least one nozzle and/or the orientation of the at least one nozzle with respect to the base in response to a received control signal for providing controlled unmanned vehicle flight.

Abstract: A valve control device is provided in a gas turbine having a combustor for generating combustion gas, a turbine driven by the combustion gas generated by the combustor, a flow rate regulating valve for regulating the flow rate of the fuel to be supplied to the combustor, and a pressure regulating valve disposed upstream of the flow rate regulating valve, for regulating the fuel pressure. The valve control device controls the opening degree of the valve. The valve control device includes a load decrease detection part which detects a load decrease of the gas turbine, and a pressure control part which controls the opening degree of the valve in accordance with the output of the gas turbine. The valve control device suppresses instability of the gas turbine output even when the load rapidly decreases.

Abstract: A system for fluid temperature control and actuation control for an aircraft engine fueled by dual fuels. The system includes a first fuel system having a first fuel tank fluidly coupled to the engine, a second fuel system having a second fuel tank fluidly coupled to the engine, with the second fuel being different from the first fuel and having a different temperature than the first fuel, a fuel distribution unit (FDU) fluidly coupled to the first fuel tank of the first fuel system, and a fuel-to-fuel cooler (FFC) configured to transfer heat between the first fuel in the first fuel system and the second fuel in the second fuel system.

Abstract: A split control unit in a distributed flow unit includes a flow inlet configured to receive a fuel flow, a first manifold having flow lines to supply fuel to one or more primary nozzles, and a second manifold having flow lines to supply fuel to one or more secondary nozzles. In an embodiment, the second manifold is in fluid communication with the flow inlet. A metering valve has a first port in fluid communication with the flow inlet and with the second manifold. The metering valve is configured to supply a metered fuel flow to the first manifold. A flow passage is in fluid communication with, and runs between, a flow line of the first manifold and a flow line of the second manifold to allow for a continuous cooling flow in the second manifold when all of the one or more secondary nozzles are closed.

Abstract: In a method for switching over a gas turbine plant from gaseous fuel (16, 20) to liquid fuel (18, 22) and vice-versa, in which the gas turbine plant includes a first combustor and a second combustor fed with the flue gases of the first combustor, the first and second combustors are sequentially switched over while the other combustor maintains its operating conditions.

Abstract: A method and device producing a setpoint signal representing a flow rate of fuel that a metering unit having a slide valve is to supply to a fuel injection system of a combustion chamber in a turbine engine, the position of the valve depending on the setpoint signal. The method: obtains a first signal representing a measurement as delivered by a flow meter of a flow rate of fuel injected into the chamber; evaluates a second signal representing the flow rate of fuel injected into the chamber based on a measurement of the position of the valve; estimates a third signal representative of the measurement delivered by the flow meter by applying a digital model of the flow meter to the second signal; and produces the setpoint signal by adding a compensation signal to the first signal, the compensation signal obtained by subtracting the third signal from the second signal.

Abstract: An integral combined cycle electric power generation system capable of generating electricity in any environment in which a fluid, such as air, moves relative to the system. Preferably this system is integrated with a hybrid airplane, though it is applicable in a number of other scenarios including, but not limited to, integration with: locomotives, ships, automobiles, trucks, and wind turbines. An exterior surface of the machine in which the system is thermally integrated is a condenser in a closed loop Rankine or Brayton cycle.

Abstract: A gas turbine engine comprises a fan configured to produce propulsive thrust from a fan discharge air stream. A bypass duct is located between a cowl and an engine core, the bypass duct is fluidly coupled to the fan. An impeller pump has an intake manifold fluidly coupled to the bypass duct. The impeller pump has an outlet coupled to an outlet duct fluidly coupled to an environmental control system, wherein the impeller pump is configured to raise pressure of the fan discharge air stream and pump the fan discharge air into the environmental control system for cooling. An integrated drive pump is connected to the impeller pump for driving the impeller pump at a constant speed. The integrated drive pump is positioned on the engine core.

Abstract: An aircraft fuel system is provided and includes a metering valve having inlet and outlet sides to monitor fuel flow from the inlet to the outlet side, a check valve that, when opened, allows fuel to flow toward the inlet side during start and climb conditions and, when closed, prevents such fuel flow and an ejector pump, which is operably disposed between the check valve and the metering valve, and which, with the check valve closed, pumps fuel toward the inlet side during idle conditions.

Abstract: An example fuel system includes a fuel sensor configured to sense at least one characteristic of a fuel provided to an engine. The fuel is selected from a plurality of different fuel types. The fuel system also includes a controller that is configured to meter the fuel in response to the at least one characteristic of the fuel.

Abstract: An accessory flow recovery system includes an inlet that receives a first fluid flow, and a pump with a pump inlet and outlet. The pump inlet receives the first fluid flow from the inlet and discharges a second fluid flow from the outlet. The accessory flow recovery system has an actuation unit for supplying a third fluid flow to accessory components, a metering system to regulate the flow rate of the second fluid flow based on a flow demand, and an inlet pressurizing valve coupled between the outlet and the metering system. The inlet pressurizing valve regulates the second fluid flow between the pump and the metering unit. The accessory flow recovery system further includes a return switch valve to direct the third fluid flow to the metering system when the recovery system is operating in one mode, and to the inlet when the system is operating in another mode.

Abstract: High thrust at sea level and high Isp at high altitudes with low ambient pressure are obtained in a vehicle with an engine of fixed geometry including an exit of non-changing cross section, by incorporating a series of propellant injectors in a divergent section of the engine, spaced apart along the engine axis at points of different engine cross section. At takeoff, the injectors at sites with a large cross section are used, and as the vehicle climbs, these injectors are successively closed leaving injectors activated at sites of successively smaller cross sections. The injectors establish thermal choke points, and the area ratio of the cross section at the exit to the cross section at the thermal choke point thus increases as the vehicle climbs from low to high altitudes.

Abstract: A rocket engine feed system, includes a feed circuit including a device for varying a gas volume in the feed circuit to suppress the POGO effect. A method of suppressing the POGO effect varies at least one hydraulic resonant frequency by varying a rate at which gas is injected into the feed circuit.

Abstract: A hybrid combustor combines two distinct fuel injection sources to spray fuel in the combustor. The combustor combines a rotary fuel slinger for spraying fuel in a first combustion zone during high power level and cruise conditions and a set of fuel nozzles for spraying fuel in a second combustion zone during lower power level and starting conditions.

Abstract: The device for injecting a liquid mono-propellant with a large amount of modulation of its flow rate and disposed at an upstream end of the wall of a combustion chamber of a rocket engine has a feed channel for feeding a mono-propellant from a tank. The device includes a single annular speed-up channel connected to the feed channel and having its outlet opening out via an annular injection section, the speed-up channel and the annular injection section being defined firstly by a first wall forming a stationary surface of revolution situated level with said upstream end, and secondly by a second wall forming a surface of revolution that is on a part that is movable in translation relative to the first wall forming a stationary surface of revolution.

Abstract: A controller receives a power-level command representative of a level of power to be transmitted by a single-spool turboshaft engine to a controllable load. A torque command determined responsive to a measure of inlet pressure, from a control schedule responsive to the power-level command, is representative of a level of torque to be transmitted by an element to drive the controllable load. Under some operating conditions, a rotational speed command provides for at least nearly minimizing a measure of associated fuel consumption when the transmitted torque is regulated to the level corresponding to the torque command by controlling one of the controllable load and a fuel flow to the engine, and the other of the controllable load and the fuel flow to the engine is controlled so as to regulate an associated rotational speed to a level corresponding to the rotational speed command.

Abstract: A hybrid combustor combines two distinct fuel injection sources to spray fuel in the combustor. The combustor combines a rotary fuel slinger for spraying fuel in a first combustion zone during high power level and cruise conditions and a set of fuel nozzles for spraying fuel in a second combustion zone during lower power level and starting conditions.

Abstract: One subject of the present invention is a propulsion method comprising: the injection, into at least one combustion chamber (1), of at least one liquid oxidizer (OX) and of hydrogen (H2); the combustion of said at least one liquid oxidizer (OX) and hydrogen (H2), in said at least one combustion chamber (1), for the generation of combustion gases; and expulsion of said combustion gases. Said process comprises, upstream of said injection: the generation of at least one portion of said hydrogen (H2), advantageously of all said hydrogen (H2), from at least one solid compound (5?); said generation from said at least one solid compound (5?) comprising a combustion reaction between said at least one solid compound (5?) chosen from alkali metal borohydrides, alkaline-earth metal borohydrides, borazane, polyaminoboranes and mixtures thereof and an oxidizing charge (5?). Another subject of the present invention is a propulsion device suitable for the implementation of said method.

Abstract: A fuel delivery and control system is provided including a dual pump fluid circuit configuration comprising a fixed positive displacement pump sized to supply the main engine burn flow ranging from above windmill through cruise, a positive displacement actuation pump including a variable pressure regulator, wherein the actuation pump is sized to supply fluid to engine actuators, valves and other hydraulically operated engine components and a pump flow sharing system interconnecting the two pumps. The combined flow from the two pumps is sufficient to meet the engine flow demand for windmill relight and maximum flow conditions. During cruise or normal operating conditions, the pumps operate in completely isolated flow circuits, minimizing recirculation and therefore heat input into the fuel supply system.

Abstract: A method and apparatus for improving fuel efficiency in an aircraft having a digital avionics system and at least first and second engines. The avionics system includes first and second full-authority digital engine control (FADEC) systems and corresponding first and second engines. At least one processor is provided that is programmed with a differential specific fuel consumption (DSFC) algorithm and first and second engine optimization algorithms. The DSFC algorithm adjusts the throttle of the first and second engines to substantially equalize the differential specific fuel consumption of the engines and thereby improve the fuel efficiency of the aircraft. The first and second engine optimization algorithms adjust at least one operating parameter of the first and second engines respectively to improve the fuel efficiency of the first and second engines.

Abstract: Compensation is provided for a fuel demand signal of a gas turbine controller during transition between operating modes. The compensation adjusts fuel demand to account for combustion efficiency differences between the starting and ending operating mode that otherwise can lead to severe swings in combustion reference temperature and lean blowout.

Abstract: Methods and apparatus are provided for detecting an anomaly in fuel demand data and fuel supply data generated by a fuel metering system for an engine, The method comprises collecting the fuel demand data and the fuel supply data during operation of the fuel metering system, generating expected fuel supply data based on the collected fuel demand data and a nominal response model describing the expected behavior of the fuel metering system, and detecting the anomaly if a difference between the expected fuel supply data and the collected fuel supply data exceeds a predetermined threshold.

Abstract: A fuel delivery and control system is provided including a dual pump fluid circuit configuration comprising a fixed positive displacement pump sized to supply the main engine burn flow ranging from above windmill through cruise and a variable displacement pump sized to supply fluid to engine actuators, valves and other hydraulically operated engine components with a pump flow sharing system interconnecting the two pumps. The combined flow from the two pumps is sufficient to meet the engine flow demand for windmill relight and maximum flow conditions. During cruise or normal operating conditions, the pumps operate in completely isolated flow circuits, minimizing recirculation and therefore heat input into the fuel supply system.

Abstract: A gas delivery system includes a gas booster module for delivering natural gas from a utility gas service to power generation equipment installed in or around a building in a manner that meets the minimum volume and pressure requirements of the power generation equipment. The gas delivery system advantageously uses pipe of a relatively small size for delivering gas to the power generation equipment, thereby substantially reducing installation costs and eliminating the need for a welded gas line. The gas delivery system also provides a control system that facilitates close control over the gas flow and ensures compliance with local building codes and safety regulations and requirements.

Abstract: Monopropellant and pre-mixed bipropellant storage and supply systems for rocket engines and other work producing systems are subject to damage when detonation progresses upstream from a combustion chamber to and through supply lines. Interposing one or more micro porous or micro fluidic elements into the supply conduit can limit the flame front that accompanies such unintended detonation, but inevitably restrict the flow of the propellant to the combustion chamber. A tiered micro fluidic element where a bulk of the element has relatively large pores but forms a structurally robust supports a second, relatively thin region having appropriately small mean pore diameter provides an effective flashback barrier that can resist catastrophic failure during such detonations. Such elements can be used in isolation, or they can be incorporated into detonation wave arrestors or pressure wave-triggered cut-off valves or the like to decrease the incidence of unintended detonations.

Abstract: There is provided a mixture ratio stabilizer for a liquid propellant rocket engine which comprises: a body internally having a chamber and a fuel supply hole communicating with an end of the chamber to receive fuel from a fuel supply pump, an oxidizer inlet, and a fuel outlet; a spool guide in the chamber and including a plurality of first orifices for the fuel outlet and the fuel supply hole to communicate with each other; a bellows in the chamber and having one end adjacent to the spool guide and the other end positioned adjacent to the oxidizer inlet, to expand and contract in accordance with the pressure of an oxidizer which flows into the oxidizer inlet; and a spool having a part placed in the spool guide.

Abstract: High thrust at sea level and high Isp at high altitudes with low ambient pressure are obtained in a vehicle with an engine of fixed geometry including an exit of non-changing cross section, by incorporating a series of propellant injectors in a divergent section of the engine, spaced apart along the engine axis at points of different engine cross section. At takeoff, the injectors at sites with a large cross section are used, and as the vehicle climbs, these injectors are successively closed leaving injectors activated at sites of successively smaller cross sections. The injectors establish thermal choke points, and the area ratio of the cross section at the exit to the cross section at the thermal choke point thus increases as the vehicle climbs from low to high altitudes.

Abstract: A flashback-arresting shut-off valve is disclosed herein. Propellant is moved from a propellant reservoir, through the shut-off valve in an open configuration to a point of combustion in a normal propellant flow direction. During a flashback, the propellant is ignited within the propellant line and substantial physical/thermal energy caused by the flashback travels in the direction opposite to the normal propellant flow direction back to the shut-off valve. A burst member within the shut-off valve fails because of the flashback. Failure of the burst member causes compression on a spring-loaded portion of the shut-off valve to be released, thereby closing the shut-off valve and sealing the propellant reservoir from the flashback. Failure of the burst member also causes one or more pressure relief outlets to open that direct the physical/thermal energy and/or un-combusted/combusted propellant out and away from the shut-off valve.

Abstract: A protocol for assembling a fuel shut off pin valve assembly for a turbo fan engine. The protocol outlines a specific sequence of events in order to ensure failsafe incorporation of a fuel shut off valve assembly within the low pressure turbine area and specifically within the engine casing of the turbo fan.

Abstract: A fuel-flow-rate control device, a power generation system, and a fuel-flow-rate control method which can prevent overshooting of a gas turbine output (gas turbine inlet temperature) and which can improve power generation efficiency are provided. The fuel-flow-rate control device includes a computing portion for obtaining a state quantity relating to operating conditions and temperature conditions of a gas turbine as an input signal and computing a fuel-flow-rate command for controlling a fuel flow rate supplied to a combustor based on the above input signal, and a second selection circuit for setting the above fuel-flow-rate command to be not more than a fuel-flow-rate upper limit. The fuel-flow-rate upper limit is a fuel flow rate at which the gas turbine inlet temperature is set to be not more than a predetermined upper temperature limit.

Abstract: A fuel system for a gas turbine engine having at least one augmentor zone which fuel system includes a fuel pump (12) drawing fuel from a fuel tank (10) and pumping the fuel in a downstream direction, at least one fuel line (14) connecting the fuel pump (12) to the at least one augmentor zone, at least one augmentor metering valve (20) in the at least one augmentor fuel line (14) for metering fuel to the at least one augmentor zone, and a fuel return path (32) returning fuel from a point in the fuel line (14) downstream of the fuel pump (12) to the fuel tank (10), wherein the point is downstream of the at least one augmentor metering valve (20). A selector valve (30) is provided to allow thermal recirculation of fuel using an augmentor metering valve. Also a method of controlling fuel recirculation in a gas turbine engine.

Abstract: A control apparatus 50 for a gas turbine engine for an aircraft includes engine control means 52 forming part of an outer fuel control loop and fuel control means/overthrust protector 76 forming part of an inner fuel control loop. Overthrust protection is provided within each of the engine control means 52 and the fuel control means/overthrust protector 76, which are powered and housed separately. Thus, a failure within one of these systems could not result in overthrust and demonstrably reliable overthrust protection is provided within a single channel.

Abstract: A fuel control system for reheat burners of a gas turbine engine has a plurality of metering valves for respective burners, and throttle valves in series with the respective metering valves. A pressure regulating valve is provided for introducing pressurized fuel into fuel manifolds downstream of the respective throttle valves when the metering and throttle valves are shut. The pressure regulating valve also acts to relieve pressure in low pressure parts of the system when the latter is closed down and to prevent excessive temperature rise at the inlet of a fuel supply pump. The metering valves include pressure return ports which communicate with the metering valve outlets when those valves are shut.

Abstract: An apparatus comprising: an aerodynamic surface adapted for producing an adverse pressure gradient in a fluid flow; and a first pulse detonation actuator disposed adjacent the aerodynamic surface and adapted for impulsively detonating a fuel/air mixture to produce a pressure rise and velocity increase of combustion products therein, the aerodynamic surface having a plurality of separation control holes adapted for communicating combustion product flows from the first pulse detonation actuator to the aerodynamic surface for modulating separation of the fluid flow from the aerodynamic surface.

Abstract: An apparatus for providing a backup fuel metering system for the gas generator section (24) of a gas turbine engine (10) is disclosed that includes a gas generator (24) and an augmentor (40). The apparatus includes a gas generator fuel metering system (52) providing fuel to the gas generator nozzles (32) and an augmentor fuel metering system (54) providing fuel to an augmentor (40). The augmentor fuel system (54) includes a diverter valve (88) which selectably directs fuel to the augmentor (40) during augmentation operation or to the gas generator nozzles (32) during a gas generator metering system failure or critical engine operation. The system allows the gas generator nozzles (32) to be supplied with fuel flow from the gas generator metering system (52), the augmentor metering (54) system or both. When the gas generator nozzles (32) are being supplied with flow from both metering systems the system is capable of improved fault accommodation.

Abstract: The invention concerns a throttle control device for an aircraft turbine engine. It comprises a control assembly acting on the native command of the turbine engine (MT1–MT3) as a function of a manual input defined by a pilot control element (1). The pilot control element gives a lever angular position signal (CL, 10JS). The control assembly comprises: an automatic device (4) for converting the lever angular position signal into a transformed angular position signal following a selected command law, and an interface (70) for converting the transformed angular position signal into two sinusoidal signals of the resolver type, thus allowing control by the same device of different turbine machines such as turbine machines which have native command by sinusoidal type signals.

Abstract: A fuel control system for a staged combustion engine comprising, a fuel metering unit including a fuel metering valve having a fuel metering orifice the opening of which is varied to meter the flow of fuel through the metering valve in use, a fuel staging unit receiving fuel from the metering valve of the fuel metering unit and incorporating a staging valve for dividing the flow of fuel from the fuel metering unit to pilot burner and main burner output lines, a connection between a fuel pressure region of said fuel metering unit and a port of said staging valve, and, overthrust detection means causing said staging valve, in response to overthrust detection, to connect said port of said staging valve to low pressure, whereby to drain fuel under pressure from said pressure zone of said fuel metering unit to low pressure to limit or reduce the fuel supplied from the fuel metering unit to the fuel staging unit and thus to the engine in use.

Abstract: According to the invention, during level automatic flight of the aircraft (A) at steady altitude, the preset value EPRt, common to all the turbojets (M1 to M4) and corresponding to a particular value of the ratio EPR of the gas pressures at the outlet and at the inlet of the turbojets, is converted into a preset value N1t related to the speed of rotation N1 of the fan of said turbojets and the fuel supply to all said turbojets is slaved to said preset value N1t.

Abstract: A fuel control system as claimed in claim 1 wherein, the pressure raising valve includes: a pressure raising valve member exposed to fuel pressure within a reference chamber, an inlet to which fuel at supply pressure is supplied, wherein the pressure raising valve member is movable against a force due to pressure within the reference chamber by means of fuel at supply pressure, an outlet through which fuel at delivery pressure is supplied to the engine, and feedback means for permitting fuel at delivery pressure to flow to the reference chamber. There is also disclosed a pressure raising valve for use in such a system.

Abstract: A control system for a gas turbine, wherein a number of regulators generate respective control signals selectable to regulate fuel supply to a combustion chamber of the gas turbine. The regulators include at least one speed/load regulator, wherein a first and a second regulating block, separate from each other, generate respective control signals which are selectable to perform speed control of the turbine and load control of the turbine.

Abstract: A method for selecting a setpoint for a turbofan engine having a fan speed and a core idle speed scheduling includes determining a weighting factor based upon a throttle lever position, the weighting factor being zero in an idle region and ranging from zero to one in a dead band region and applying the weighting factor to an output of a fan speed governor and to an output of a core speed governor to select the setpoint.

Abstract: In accordance with one aspect of the present invention, in a control system for controlling a gas turbine engine, there is provided a system and a method for determining an optimized output shaft speed for a required thrust and setting an appropriate engine power. The method comprises the steps of: providing a required thrust value at a particular flight condition; determining input values for each of a power, output shaft speed, airspeed, and altitude; determining whether the required thrust is a low power condition; if the required thrust is a low power condition, determining a reduced propeller speed value from the input values and the required thrust value; at least one of increasing and decreasing the optimized output shaft speed using the reduced propeller speed value.