Abstract: A control circuit adapted to receive at least first, second and third input signals. The first input signal is a signal representative of the fuel pressure at the output of a pump. The second signal is a signal representative of the fuel pressure in the manifold of fuel disbursement means which is supplied through a controllable valve, by the fuel pump. The third signal is a signal representative of the pressure at the inlet to the pump. The control circuit further includes a feedback path for continuously circulating fuel from the manifold to the pump inlet. In one arrangement of the fuel supply system, there is an aperture in parallel with the controllable valve and an aperture in the feedback path.

Abstract: A fan blade and/or propeller blade such as found in a gas turbine engine having a dovetail former having sections of composite unidirectional wrap material wrapped about the dovetail former from the concave to the convex side of the airfoil and filling cutout spaces between dovetail sections. Layers of non-wrapped composite material are cut and tapered and attached to the front and back sides of the dovetail sections.

Abstract: A butterfly valve comprises a butterfly vane including a radial notch. A seal groove is situated in the vane and a seal including tabs is disposed within the seal groove wherein the tabs are adapted to fit within the notch. The tabs are designed to bear against the sides of the notch. The notch is located on the high pressure side of the butterfly vane and in a position such that the butterfly housing limits the radial motion of the tabs when the valve is in the open position.

Abstract: A switched reluctance machine comprising a housing, a stator attached to the housing and a rotor mounted within the housing. The stator including teeth wound with electrical coils which are connected to form phase windings. The rotor comprising a series of laminates including teeth pressed onto a shaft. According to the present invention, at least one set of opposing phase wound stator teeth comprise permanent magnets.

Abstract: The discharge flow from a rotary vane pump is metered by directing a portion of the pump discharge back into the pump inlet area. A servo controlled actuator apportions the relative amounts of inlet fluid and returns fluid which enters the vane cavities. This arrangement allows for the use of a fixed cam which provides improved pump performance as compared to comparable movable cam pump designs.

Abstract: Control of a gas turbine engine, suitable for powering an aircraft, is accomplished by varying outlet nozzle cross section and/or a mixing of bypass air with exhaust gas at an inlet to the nozzle. The engine includes a core engine having a combustion chamber and high and low pressure turbines followed by an exhaust plenum. High and low pressure compressors driven by the turbine assembly direct air into the combustion chamber and into a bypass duct. The bypass duct extends from an outlet of the low pressure compressor. Pressure of fluid (air or exhaust) is measured at an inlet to the high pressure compressor, in the bypass duct, and in the exhaust plenum. Ratios of the pressure of the duct pressure or of the pressure at the inlet of the high-pressure compressor, to the plenum pressure are employed in a feedback loop for control of nozzle size, and also of mixing valve position in an alternate embodiment of the invention.

Abstract: An electronic fuel control for a gas turbine engine monitors the mass density of the fuel. As the mass density of the fuel varies when the fuel temperature changes or when the fuel type changes, the electronic fuel control adjusts an initial mass density to a corrected value based on the most recent measurement of mass fuel flow that was taken when the mass fuel flow measurement was known to be accurate. Accurately controlling mass fuel flow permits gas turbine engine designers to reduce tolerances in moving parts which improves the efficiency of the gas turbine engine.

Abstract: In the present invention, the DEC output voltage is limited by comparing the DEC output and the Collective input to a predetermined maximum acceleration and generating an error signal when the maximum acceleration is exceeded. The error signal is fed back to the DEC and acts to limit its input. More particularly, the present invention is directed to a method of limiting the output of a DEC by generating a first signal representative of the acceleration demanded by the DEC, generating a second signal representative of the acceleration demanded by the collective, adding the first and second signals to form a third signal representative of the total demanded acceleration, generating a fourth signal representative of the maximum allowable demanded acceleration, subtracting the third signal from the fourth signal to obtain an error signal, and limiting the DEC output signal according to the error signal.

Abstract: In a gas turbine engine, combustor flame temperature is maintained within predetermined limits by increasing the combustor airflow during periods of increasing fuel flow and by increasing the burner area when the airflow has reached an upper limit. Increases in burner area are countered by decreasing airflow until the airflow reaches a lower limit, at which time the procedure repeats itself. When the fuel flow is decreased, the airflow is reduced until it reaches its lower limit, at which time the burner area is decreased, allowing the airflow to rise to its upper limit, at which time, the procedure repeats itself.

Abstract: In a gas turbine engine, fuel is supplied to a fuel metering valve which is connected to a shutoff valve. The shutoff valve supplies fuel to a manifold. Fuel flow between the manifold and main fuel nozzles is controlled by fuel staging valves while the pilot nozzle is connected directly to the manifold by a fuel line which may include an orifice. The orifice is designed to match the flow in the pilot nozzle with the flow in main nozzles when the fuel staging valve is on.

Abstract: Inserting a woven composite layer between laminates of composite material layers where the insert layer comprises composite, carbon fibers woven in a three dimensional weave. The woven insert is injected with a resin material and partially cured prior to deposition of the composite layers. The complete blade is then molded and cured as a unit.

Abstract: A control system and method provide thrust droop compensation in a gas turbine engine. A droop compensation signal is generated for increasing turbine exit temperature T.sub.5 based on a predetermined model, and is selectively reduced for limiting the increase in temperature T.sub.5 when the temperature T.sub.5 is above a predetermined threshold temperature for a predetermined time. The reduced droop signal is added as a bias signal into an error signal which effects thrust droop concentration in a variable area exhaust nozzle of the engine.

Abstract: A pneumatic multiplexer including a stator portion adapted to receive multiple inputs. The stator including a plurality of channels therethrough adapted to channel compressible fluid from the inputs to a stator face. The stator portion including arc grooves therein at each of the stator output holes and pressure relief grooves between the arc grooves.

Abstract: A method and system are provided to bias a control subsystem of a gas turbine engine having a fan and compressor. The method includes the steps of measuring an operating parameter of the engine and differentiating this parameter over time to obtain a derivative thereof. A bias signal is generated in a predetermined bias schedule in response to the parameter derivative, and provided to the control subsystem for biasing the subsystem. The bias signal has a zero value for values of the parameter derivative from zero to a first value thereof at a first time. The bias signal has a maximum value for values of the parameter derivative between second and third values thereof corresponding with second and third times. And, the bias signal returns to a value of zero after a fourth time greater than the third time.

Abstract: An electronic fuel control for a gas turbine engine monitors the mass density of the fuel. As the mass density of the fuel varies when the fuel temperature changes or when the fuel type changes, the electronic fuel control adjusts an initial mass density to a corrected value based on the most recent measurement of mass fuel flow that was taken when the mass fuel flow measurement was known to be accurate. Accurately controlling mass fuel flow permits gas turbine engine designers to reduce tolerances in moving parts which improves the efficiency of the gas turbine engine.

Abstract: A hollow core airfoil including a root adapted to attach the airfoil to a disk. An airfoil portion including a leading edge, a trailing edge, and a tip portion. The hollow core airfoil includes radial ribs extending from the root to the tip. Chord-wise stringers run from the leading edge to the trailing edge providing support along the chord-wise direction.

Abstract: An arrangement for a main fuel pump, a backup fuel pump, a main hydraulic pump, and a backup hydraulic pump, typically for a as turbine engine in an aircraft, includes an isolated fuel and hydraulic fluid system and a backup pumping arrangement employing two mechanically-coupled gear-type reversible pump-motors and appropriate control valves.

Abstract: A rate controlled noise filter according to the present invention comprises a transient detector adapted to receive an input signal and detect the rate at which the input signal is changing. The transient detector may be, for example, a filter having a second order filtered rate. The output of the transient detector is input to a function generator which outputs a signal indicative of the rate of change of the input signal. A noise filter, including a controllable time constant, also filters the input signal. The output of the function generator controls the time constant of the noise filter.

Abstract: The invention comprises a motor including a stator having stator teeth. The motor further includes a rotor having rotor teeth wherein the rotor is mounted on a shaft which is supported by a bearing. According to the present invention, the rotor is conically shaped such that the gap between the rotor and stator increases in proportion to the distance from the bearing.

Abstract: A gas turbine engine control system which receives an engine condition and generates a parameter signal representative of the condition. The control system also receives a temperature signal representative of the engine temperature downstream of the engine combustor. A comparator is used to compare the parameter signal with the temperature signal and a nonrecoverable stall output signal is produced when the temperature signal indicates the temperature is greater than a scheduled value for the given parameter signal. The invention also includes a method for monitoring a gas turbine engine comprising the steps of receiving an engine condition and for generating a parameter signal representative of the condition.