Abstract: A pressure relief valve is provided that includes a valve housing, a poppet valve and a damper. The valve housing includes a valve seat and a bore. The poppet valve includes a head and a stem. The head is configured to engage the valve seat when the poppet valve is in a closed position. The head is configured to disengage the valve seat when the poppet valve is in an open position. The stem projects axially out from the head and through the bore. The damper includes a damper chamber axially between the valve housing and the head.

Abstract: A system is provided for alternating starter use during multi-engine motoring in an aircraft. The system includes a first engine starting system of a first engine. A first controller is in communication with a second controller that controls a second engine starting system of a second engine, the first controller being configured to intermittently direct power to the first engine starting system to alternately accelerate and decelerate the first engine during motoring with respect to the second engine.

Abstract: A gas turbine engine includes a compressor section, a combustor, and a turbine section. A bleed tap taps air from the compressor section through a bleed valve. The bleed valve is selectively opened by a control to dump air from the compressor section to a dump outlet. A heat exchanger duct includes a duct air inlet to cool a fluid in a heat exchanger and a duct air outlet. The dump outlet is within the heat exchanger duct.

Abstract: A gas turbine engine includes a compressor section, a combustor, and a turbine section. A bleed tap taps air from the compressor section through a bleed valve. The bleed valve is selectively opened by a control to dump air from the compressor section to a dump outlet. A heat exchanger duct includes a duct air inlet to cool a fluid in a heat exchanger and a duct air outlet. The dump outlet is within the heat exchanger duct.

Abstract: A gas turbine engine includes a compressor section, a combustor, and a turbine section. A bleed tap taps air from the compressor section through a bleed valve. The bleed valve is selectively opened by a control to dump air from the compressor section to a dump outlet. A heat exchanger duct includes a duct air inlet to cool a fluid in a heat exchanger and a duct air outlet. The dump outlet is within the heat exchanger duct.

Abstract: An aspect includes a globe butterfly valve that includes a valve inlet, a valve outlet, a globe housing with a spherical body between the valve inlet and the valve outlet, and a globe butterfly valve disc operably disposed within the globe housing. The globe housing has a larger interior diameter than an inlet diameter of the valve inlet and an outlet diameter of the valve outlet. The globe butterfly valve disc is configured to block a flow path between the valve inlet and the valve outlet responsive to an outer edge of the globe butterfly valve disc being positioned proximate to an interior surface of the globe housing between the valve inlet and the valve outlet.

Abstract: A bowed rotor prevention system for a gas turbine engine includes a bowed rotor prevention motor. A motor shaft of the bowed rotor prevention motor is operable to drive rotation of the gas turbine engine through an engine accessory gearbox. The motor shaft interfaces with an air turbine operable to rotate an output shaft mechanically linked to the engine accessory gearbox. The bowed rotor prevention system also includes a controller operable to engage the bowed rotor prevention motor and drive rotation of the gas turbine engine below an engine starting speed until a bowed rotor prevention threshold condition is met.

Abstract: A system for gas turbine engine motoring includes an air turbine starter coupled to a gearbox of a gas turbine engine and a starter air valve in fluid communication with the air turbine starter to drive motoring of the gas turbine engine responsive to a regulated pressure from a compressed air source. A manual override of the starter air valve is adjustable to one or more predefined intermediate positions that partially open the starter air valve to limit a motoring speed of the gas turbine engine below a resonance speed of a starting spool of the gas turbine engine responsive to the regulated pressure.

Abstract: A bowed rotor prevention system for a gas turbine engine includes a core turning motor operable to drive rotation of an engine core of the gas turbine engine. The bowed rotor prevention system also includes a full authority digital engine control (FADEC) that controls operation of the gas turbine engine in a full-power mode and controls operation of the core turning motor to drive rotation of the engine core using a reduced power draw when the FADEC is partially depowered in a low-power bowed rotor prevention mode.

Abstract: A gas turbine engine includes a compressor section, a combustor, and a turbine section. A bleed tap taps air from the compressor section through a bleed valve. The bleed valve is selectively opened by a control to dump air from the compressor section to a dump outlet. A heat exchanger duct includes a duct air inlet to cool a fluid in a heat exchanger and a duct air outlet. The dump outlet is within the heat exchanger duct.

Abstract: A system is provided for alternating starter use during multi-engine motoring in an aircraft. The system includes a first engine starting system of a first engine. A first controller is in communication with a second controller that controls a second engine starting system of a second engine, the first controller being configured to intermittently direct power to the first engine starting system to alternately accelerate and decelerate the first engine during motoring with respect to the second engine.

Abstract: A system is provided comprising: a starter air valve in fluid communication with an air turbine starter to drive motoring of a gas turbine engine responsive to a compressed air flow from a compressed air source; a manual override operably connected to the starter air valve, the manual override is operable to open the starter air valve a select percentage by moving the manual override to a detent engaged position, wherein the select percentage is operable to allow enough airflow to achieve the maximum allowed motoring speed of the gas turbine engine; and a pressure regulating bleed valve in fluid communication with the starter air valve, the pressure regulating bleed valve operable to bleed a portion of the compressed air flow to regulate a motoring speed of the gas turbine engine in response to detection of the manual override in a detent engaged position.

Abstract: An aspect includes a dual valve system that includes a first valve body and a first valve disc operably disposed within the first valve body, where the first valve disc has a first disc geometry. The dual valve system also includes a second valve body and a second valve disc operably disposed within the second valve body, where the second valve disc has a second disc geometry. The dual valve system further includes a mechanical linkage operably coupled to the first valve disc and the second valve disc, where the second disc geometry differs from the first disc geometry such that opening of a first flow area between the first valve body and the first valve disc occurs prior to opening of a second flow area between the second valve body and the second valve disc responsive to movement of the mechanical linkage.

Abstract: According to an aspect, a system includes a starter air valve in fluid communication with an air turbine starter to drive motoring of a gas turbine engine responsive to a compressed air flow from a compressed air source. The system also includes a variable-position electromechanical device operable to adjust positioning of the starter air valve and a discrete-position electromechanical device operable to adjust positioning of the starter air valve and limit a motoring speed of the gas turbine engine below a resonance speed of the gas turbine engine responsive to a pulse width modulation control based on a failure of the variable-position electromechanical device.

Abstract: A system is provided for alternating starter use during multi-engine motoring in an aircraft. The system includes a first engine starting system of a first engine and a controller. The controller is operable to coordinate control of the first engine starting system to alternate use of power from a power source relative to use of the power by one or more other engine starting systems of the aircraft while maintaining a starting spool speed of the first engine below a resonance speed of the starting spool during motoring of the first engine.

Abstract: A bowed rotor prevention system for a gas turbine engine includes a core turning motor operable to drive rotation of an engine core of the gas turbine engine. The bowed rotor prevention system also includes an auxiliary electric motor control operable to control the core turning motor to drive rotation of the engine core using electric power while a full authority digital engine control that controls operation of the gas turbine engine is either depowered or in a power state that is less than a power level used by the full authority digital engine control in flight operation.

Abstract: An aspect includes an offset parallel valve system that includes a first valve body and a first valve disc operably disposed within the first valve body. The offset parallel valve system also includes a second valve body in parallel with the first valve body and a second valve disc operably disposed within the second valve body, where the second valve disc is laterally offset from the first valve disc. A linkage system is operably coupled to the first valve disc and the second valve disc. The linkage system includes an armature coupled to a grooved linkage member having a first groove and a second groove. The first groove delays movement of the second valve disc as the first valve disc rotates, and the second groove controls a rotation angle of the second valve disc.

Abstract: An aspect includes a globe butterfly valve that includes a valve inlet, a valve outlet, a globe housing with a spherical body between the valve inlet and the valve outlet, and a globe butterfly valve disc operably disposed within the globe housing. The globe housing has a larger interior diameter than an inlet diameter of the valve inlet and an outlet diameter of the valve outlet. The globe butterfly valve disc is configured to block a flow path between the valve inlet and the valve outlet responsive to an outer edge of the globe butterfly valve disc being positioned proximate to an interior surface of the globe housing between the valve inlet and the valve outlet.

Abstract: An aspect includes an offset parallel valve system that includes a first valve body and a first valve disc operably disposed within the first valve body. The offset parallel valve system also includes a second valve body in parallel with the first valve body and a second valve disc operably disposed within the second valve body, where the second valve disc is laterally offset from the first valve disc. A linkage system is operably coupled to the first valve disc and the second valve disc. The linkage system includes an armature coupled to a grooved linkage member having a first groove and a second groove. The first groove delays movement of the second valve disc as the first valve disc rotates, and the second groove controls a rotation angle of the second valve disc.

Abstract: An aspect includes a dual valve system that includes a first valve body and a first valve disc operably disposed within the first valve body, where the first valve disc has a first disc geometry. The dual valve system also includes a second valve body and a second valve disc operably disposed within the second valve body, where the second valve disc has a second disc geometry. The dual valve system further includes a mechanical linkage operably coupled to the first valve disc and the second valve disc, where the second disc geometry differs from the first disc geometry such that opening of a first flow area between the first valve body and the first valve disc occurs prior to opening of a second flow area between the second valve body and the second valve disc responsive to movement of the mechanical linkage.