Methods and systems for operating an engine, the engine having an engine core, an exhaust nozzle, and variable geometry mechanisms, are provided. A request for an increase in thrust generated by the engine is received. In response to receipt of the request, it is determined that at least one operating condition for engine degradation thrust is met. In response to this determination, the variable geometry mechanisms are modulated to degrade an efficiency of the engine, thereby increasing a temperature of core air flowing through the engine core. The increase in thrust is generated from the increased temperature of the core air flowing through the engine core and into the exhaust nozzle.

A rotor blade system includes a rotor, a casing radially spaced apart from the rotor, and a plurality of blades coupled to the rotor and positioned between the rotor and the casing. The one or more of the plurality of blades have a radial length different from a remaining one or more of the plurality of blades so as to vary a tip gap between a tip of the one or more of the plurality of blades and the casing to break up a frequency content of a leakage vortex at the tip to modify natural frequencies of the plurality of blades and mode shapes to reduce or substantially eliminate flutter.

A rotor blade system includes a rotor, a casing radially spaced apart from the rotor, and a plurality of blades coupled to the rotor and positioned between the rotor and the casing. The one or more of the plurality of blades have a radial length different from a remaining one or more of the plurality of blades so as to vary a tip gap between a tip of the one or more of the plurality of blades and the casing to break up a frequency content of a leakage vortex at the tip to modify natural frequencies of the plurality of blades and mode shapes to reduce or substantially eliminate flutter.

There is provided a system and a method for controlling a tip clearance between a turbine casing and turbine blade tips of an aircraft engine. At least one operational parameter of the aircraft engine is obtained. Based on the at least one operational parameter, a current value of the tip clearance and a target value of the tip clearance are determined. A limiting factor to be applied to the target value of the tip clearance is computed. The limiting factor is applied to the target value of the tip clearance to obtain a tip clearance demand for the aircraft engine. A tip clearance control apparatus of the aircraft engine is controlled based on a difference between the current value of the tip clearance and the tip clearance demand.

A system of a machine includes a waveguide system and a radio frequency transceiver/detector coupled to the waveguide system and configured to emit a calibration signal in the waveguide system to establish a reference baseline between the radio frequency transceiver/detector and a calibration plane associated with an aperture of the waveguide system, emit a measurement signal in the waveguide system to transmit a radio frequency signal from the radio frequency transceiver/detector out of the aperture of the waveguide system, and detect a reflection of the measurement signal at the radio frequency transceiver/detector based on an interaction between the measurement signal and a component of the machine. A measurement result of the reflection of the measurement signal can be adjusted with respect to a reflection of the calibration signal.

According to an aspect, a gas turbine engine includes a turbine section with a turbine case and a plurality of turbine blades within the turbine case. The gas turbine engine also includes an active clearance control system with an active clearance control cooling air supply, a valve pneumatically coupled to the active clearance control cooling air supply, and a controller. The controller is configured to determine an active cooling control schedule adjustment based on a condition of the gas turbine engine, operate the active clearance control system according to an active cooling control schedule as modified by the active cooling control schedule adjustment, apply a decay function to the active cooling control schedule adjustment to reduce an effect on the active cooling control schedule adjustment, and resume operating the active clearance control system according to the active cooling control schedule based on an active cooling control condition being met.

According to an aspect, a gas turbine engine includes a turbine section with a turbine case and a plurality of turbine blades within the turbine case. The gas turbine engine also includes an active clearance control system with an active clearance control cooling air supply, a valve pneumatically coupled to the active clearance control cooling air supply, and a controller. The controller is configured to determine an active cooling control schedule adjustment based on a condition of the gas turbine engine, operate the active clearance control system according to an active cooling control schedule as modified by the active cooling control schedule adjustment, apply a decay function to the active cooling control schedule adjustment to reduce an effect on the active cooling control schedule adjustment, and resume operating the active clearance control system according to the active cooling control schedule based on an active cooling control condition being met.

An assembly for a gas turbine engine includes, among other things, an end wall including a main body extending between a first end portion and a second end portion to establish a seal face. The end wall includes a first attachment portion dimensioned to fixedly attach the main body to a static structure at a first attachment point. An airfoil extends radially inwardly from the end wall relative to an assembly axis. The airfoil includes an inner cavity extending between a first end portion and a second end portion, the first end portion adjacent the end wall of the airfoil. A spar member includes a spar body extending between a first end portion and a second end portion. The spar body extends at least partially through the inner cavity. The first end portion of the end wall is cantilevered from the first attachment point.

A multi-mode microwave waveguide blade sensing system includes a transceiver, a waveguide, and a probe sensor. The transceiver generates a microwave energy signal having a first waveguide mode and a different second waveguide mode. The waveguide includes a first end that receives the microwave energy signal. The probe sensor includes a proximate end that receives the microwave energy signal from the transceiver and a distal end including an aperture that outputs the microwave energy signal. The probe sensor directs the microwave energy signal at a first direction based on the first waveguide mode and a different second direction different based on the second waveguide mode. The probe sensor receives different levels of reflected microwave energy based at least in part on a location at which the at least one microwave energy signal is reflected from the machine.

A turbine containment system is provided. The turbine containment system includes a first containment member surrounding a portion of a turbine including a plurality of rotor disks and rotor blades; and a second containment member in communication with the first containment member, wherein the first containment member and the second containment member together contain each of the rotor disks and the rotor blades therein.