A bleed valve includes a housing with an inlet coupled to an outlet by a duct, a guide tube with an orifice fixed in the housing between the inlet and the outlet, a piston, and baffle. The piston is slideably supported on the guide tube and is movable between an open and a closed position, the duct fluidly coupling the inlet and outlet in the open position, the duct fluidly separating the inlet and outlet in the closed position. The orifice fluidly couples the inlet and outlet in the open and closed positions to move piston between the open and closed positions according to differential pressure between the bleed valve inlet and outlet. The baffle is slideably supported by the guide tube to set the differential pressure at which the piston moves between the open and closed positions. Gas turbines and differential pressure adjustment methods are also described.

A bleed valve includes a housing with an inlet coupled to an outlet by a duct. A guide tube is fixed within the housing between the inlet and the outlet. A piston with a piston orifice is slideably supported on the guide tube and movable between an open position and a closed position. The duct fluidly couples the inlet to the outlet in the open position, the duct fluidly separates the inlet from the outlet in the closed position, and the piston orifice fluidly couples the inlet with the outlet in the open position and the closed position to move piston between the open position and the closed position according to differential in pressure between the inlet and the outlet of the bleed valve. Compressors, gas turbine engines, and methods of controlling fluid flow are also described.

An anti-ice arrangement for a gas turbine engine may comprise an engine static structure, a fan blade housed for rotation within the engine static structure, and a magnetic field source mounted in close proximity to the fan blade and configured for inducing eddy currents in the fan blade to increase a surface temperature of the fan blade.

A system for controlling blade tip clearances in a gas turbine engine may comprise an active clearance control system and a controller in operable communication with the active clearance control system. The controller may be configured to identify a cruise condition, reduce a thrust limit of the gas turbine engine to a de-rated maximum climb thrust, determine a first target tip clearance based on the de-rated maximum climb thrust, and send a command signal correlating to the first target tip clearance to the active clearance control system.

An oil thermal management system for a gas turbine engine includes a control system operable to selectively heat oil in the oil system with the heater system greater than a predetermined temperature prior to engine start. A method of starting a gas turbine engine includes sensing an oil temperature with respect to a predetermined oil temperature for engine start; and heating the oil to the predetermined oil temperature for engine start in response to the oil temperature being less than the predetermined oil temperature.

A gas turbine engine includes, among other things, a propulsor section including a rotor and blades, a gear train, a compressor section and a turbine section. A static structure includes a first case and a second case. The first case includes a first engine mount location. The second case includes a second engine mount location. The first engine mount location is axially near the gear train.

A system includes an injector including a scheduling valve assembly and a nozzle in fluid communication with the valve assembly. The scheduling valve assembly is configured for regulation of flow from an inlet of the injector to the nozzle. The injector includes one fluid circuit between the inlet of the injector and a respective outlet of the nozzle. A solenoid valve is connected in fluid communication with the scheduling valve assembly. The solenoid valve is configured to adjust position of a hydromechanical valve spool of the valve assembly.

A system includes an injector having a scheduling valve assembly and a nozzle in fluid communication with the valve assembly. The scheduling valve assembly is configured for regulation of flow from an inlet of the injector to the nozzle. The injector includes two fluid circuits between the inlet of the injector and two respective outlets of the nozzle for staged flow output from the nozzle. A first one of the two fluid circuits is a primary circuit, and a second one of the two fluid circuits is a secondary circuit. A solenoid valve is connected in fluid communication with the scheduling valve assembly, wherein the solenoid valve is configured to adjust position of a hydromechanical valve spool of the valve assembly.

Dampers for bearing assemblies of gas turbine engines are provided. For example, a damper comprises a damper housing, a lubricant passage defined in the damper housing, and a valve positioned within the lubricant passage. The lubricant passage includes an inlet and an outlet. In one embodiment, the valve is configured to restrict a flow of lubricant from the inlet into the damper when a reference temperature is below a threshold temperature. In another embodiment, the valve is configured to increase leakage of a lubricant through the outlet when a reference temperature is below a threshold temperature. In other embodiments, the valve is passively actuated and is configured to move within the lubricant passage to control a flow of lubricant from the inlet to the outlet based on a reference temperature.

A gas turbine engine includes, among other things, a fan section including a fan rotor, a gear train defined about an engine axis of rotation, a first nacelle which at least partially surrounds a second nacelle and the fan rotor, the fan section configured to communicate airflow into the first nacelle and the second nacelle, a first turbine, and a second turbine followed by the first turbine. The first turbine is configured to drive the fan rotor through the gear train. A static structure includes a first engine mount location and a second engine mount location.