Abstract: An accessory drive for an engine includes a power takeoff (PTO) configured to couple power from a rotating shaft of the engine and to convey the power through an opening in a housing of the engine. A gearbox is coupled to and configured to be driven by the PTO. The gearbox is disposed external to the housing and includes a planetary gear train. At least one engine accessory is coupled to and configured to be driven by the planetary gear train.

Abstract: There is provided in an embodiment a hydraulic fluid heat dissipation control assembly for an aircraft hydraulic system. The hydraulic fluid heat dissipation control assembly has one or more heat exchangers. The hydraulic fluid heat dissipation control assembly further has at least one flow control element coupled to the one or more heat exchangers to control flow and heat dissipation of a hydraulic fluid. There is also provided a method of controlling heat dissipation of a hydraulic fluid in an aircraft hydraulic system using the hydraulic fluid heat dissipation control assembly disclosed herein.

Abstract: A technique for identifying, projecting, displaying, and enhancing the thermal capacity for an aircraft is disclosed wherein the thermal capacity is defined as the amount of time or range the aircraft can continue until a thermal limit is exceeded.

Abstract: A system includes a controller configured to control a semi-closed power cycle system. The controller is configured to receive at least one of a first signal indicative of an oxygen concentration within a first gas flow through a primary compressor, a second signal indicative of power output by the semi-closed power cycle system, a third signal indicative of a temperature of a second gas flow through a turbine, and a fourth signal indicative of a mass flow balance within the semi-closed power cycle system. The controller is also configured to adjust at least one of the first gas flow through the primary compressor, a fuel flow into a combustor, a fraction of the first gas flow extracted from the primary compressor, and an air flow through a feed compressor based on the at least one of the first signal, the second signal, the third signal, and the fourth signal.

Abstract: A method and systems for controlling a thrust output of a gas turbine engine are provided. The system includes a first sensor for measuring a first engine operating parameter, a second sensor for measuring a first engine condition parameter, and a processor programmed to determine an expected value of the first engine condition parameter and determine a first variance value using a difference between the expected value of the first engine condition parameter and the measured first engine condition parameter. The processor is further programmed to determine a trim value using the first variance value and a first engine operating parameter demand and to determine a modified operating parameter demand based on the nominal operating parameter demand and the determined trim value. The system also includes a controller coupled to the processor for controlling engine thrust based on the modified demand of the first engine operating parameter.

Abstract: Apparatus for controlling the power output efficiency of a power generation system based on an operator input. A processor is coupled to the input means and (i) receives the generated operator command, (ii) receives a plurality of detected ambient air conditions, (iii) receives a plurality of detected engine performance parameters, (iv) determines first and second engine control commands based on the received pilot thrust command, the detected ambient environmental conditions, and the engine performance parameters, and (v) outputs control commands to optimize the efficiency of the power generation system.

Abstract: A computer-implemented model of fan section of a gas turbine engine accounts for the turbulence in the gas flow emanating from the rotor assembly and impinging upon an inlet to the stator vane cascade. The model allows for user-input variations in the sweep and/or lean angles for the stator vanes. The model determines the resulting acoustic response of the fan section as a function of the turbulence and the lean and/or sweep angles of the vanes. The model may be embodied in software that is rapidly executed in a computer. This way, an optimum arrangement in terms of fan noise reduction is quickly determined for the stator vane lean and sweep physical positioning in the fan section of a gas turbine engine.

Abstract: In a control system for a gas turbine aero engine, the control system (ECU) is configured as a dual control system comprising two channels, Ch-A and Ch-B. Ch-A has two CPUs which conduct calculations separately based on the sensor outputs and one of the CPUs compares the results and if they coincide, the CPU sends the result of the other CPU to the FCU. If not, one of the CPUs determines that an abnormality arises in Ch-A and sends a result to Ch-B. Ch-B is constituted as a standby channel having only one CPU whose operation is monitored by a simple watchdog timer circuit. This enhances CPU failure detection with a relatively simple configuration, and eliminates the need for provision of an overspeed protector.

Abstract: In an aircraft gas turbine engine having a variable area exhaust, gas turbine compressor operating conditions are sensed to determine a sub-idle condition or a rotating stall. The exhaust area is increased to a maximum when a sub-idle condition is present. If a condition associated with a rotation stall is sensed, fuel flow is decremented but not below a minimum flow. When the rotating stall ends, fuel flow is restored to the normal level and then the engine reaches stabilized operating conditions, the nozzle area is restored at a scheduled rate.

Abstract: A control system for a gas turbine engine receives a signal representative of a first target engine operating condition and also receives a signal representative of an actual engine condition. The system produces an error signal representative of the difference between the target signal and the actual engine condition signal. A gain means adjusts the gain of the error signal to be equal to the desired change in the controlled engine parameter. The output of the gain means is then coupled to an activator of the engine which controls the parameter.

Abstract: This control serves to optimize thrust during steady state and transient operation modes of a turbofan engine of the mixed flow type by adjusting or trimming the exhaust nozzle area as a function of fan pressure ratio and fan rotor speed and by adjusting or trimming the core engine fuel flow as a function of fan rotor speed and/or turbine inlet temperature. The control serves to enhance stability by assuring airflow in the engine and its inlet is within a given value avoiding inlet buzz and high distortion to the engine and avoiding even transient operation in conditions that might cause compressor flow instability or stall. Fuel flow is adjusted or trimmed as a function of fan rotor speed or turbine inlet temperature limits depending on which is calling for the least amount of fuel.

Abstract: A method and apparatus for optimally controlling a gas turbine engine utilizes feedback signals each of which is a function of a plurality of output variables. Control signals are generated and transmitted to actuators which vary engine control variables to provide a desired level of engine performance. Signals representative of rated values of a plurality of engine output variables for the selected level of engine performance are generated and are compared with signals representative of actual values of the corresponding output variables to produce difference signals. One or more of the difference signals may also be integrated. The difference signals may also be weighted relative to each other as a function of ambient conditions and/or the selected level of engine performance. A plurality of the difference signals are then utilized to generate an individual feedback signal for each of the control variables. The feedback signals are tailored to modify the corresponding control variables.

Abstract: An integrated control system for a gas turbine engine of the turbofan type receives signals from a plurality of engine sensors and from the engine operator and generates control signals therefrom. A first control signal regulates the fan exhaust nozzle area in order to control inlet throat Mach number to maintain a low level of engine noise. Additional control signals regulate fuel flow to control engine thrust and fan pitch to control fan speed. A plurality of schedules are utilized to maintain a predetermined relationship between the controlled parameters and a number of fixed and calculated limits can override the control signals to prevent unsatisfactory engine performance.

Abstract: Increased thrust during the transonic flight mode of an aircraft powered by a gas turbine engine is realized by a closed loop control that closes the loop on the pressure ratio across the fan by adjusting fuel flow and/or exhaust nozzle area in a turbofan, variable exhaust nozzle installation. Fan pressure ratio is scheduled as a function of corrected fan speed and actual pressure ratio provides an error signal to readjust engine operation to null out this error signal. A turbine inlet temperature limit signal is generated to prevent inadvertent overheating and it or this pressure ratio error signal is selected for providing the lower fuel flow value.

Abstract: A rocket motor that has a main exhaust nozzle area and a secondary exhaust ozzle area with the secondary exhaust nozzle area being closed by burst discs that rupture and open secondary nozzle areas when predetermined temperatures and pressures are reached when propellant is burned inside the rocket motor.