Abstract: A method of controlling an aeronautical gas turbine engine may be performed with an electronic controller. The method may include determining an airfoil pitch control command for at least one of a plurality of airfoils of the aeronautical gas turbine engine based at least in part on an excitation load acting upon the aeronautical gas turbine engine, and outputting the airfoil pitch control command to one or more actuators actuatable to change a pitch angle of the at least one of the plurality of airfoils. The airfoil pitch control command may be configured to augment and/or compensate for the excitation load acting upon the aeronautical gas turbine engine. The method may be embodied by a non-transitory computer-readable medium that includes computer-executable instructions, which when executed by a processor associated with the electronic controller, cause the electronic controller to perform the method.

Abstract: An open rotor engine includes a core engine, a plurality of guide vanes positioned within or extending from the core engine; and a pitch change assembly operably coupled to the plurality of guide vanes. The pitch change assembly includes one or more actuators configured to change a pitch angle of respective ones of the plurality of guide vanes, and a plurality of linkage arms that are respectively movable by actuation of at least one of the one or more actuators. The plurality of linkage arms are directly or indirectly coupled to a corresponding one of the plurality of guide vanes. The plurality of linkage arms may have a length that differs from one another, and such length may orient a displacement or a range of motion of the respective linkage arm to an envelope of rotation about a guide vane axis that differs as between the plurality of guide vanes.

Abstract: An open rotor aeronautical engine may include a core engine, a plurality of unducted airfoils, and a pitch change assembly. The pitch change assembly may include an ensemble actuator assembly and a unitary actuator assembly. The ensemble actuator assembly may have one or more ensemble actuators and a unison ring that is movable by actuation of the one or more ensemble actuators to collectively change a pitch angle of the plurality of unducted airfoils. The unitary actuator assembly comprising a plurality of unitary actuators respectively coupled to a corresponding one of the plurality of unducted airfoils, the plurality of unitary actuators respectively movable to change the pitch angle of the corresponding one of the plurality of unducted airfoils.

Abstract: Composite airfoils and methods for forming composite airfoils are provided. For example, a composite airfoil of a gas turbine engine comprises opposite pressure and suction sides extending radially along a span from a root to a tip, which define opposite radial extremities of the airfoil. The composite airfoil further comprises a body section and a tip section, which includes the tip, that each extend radially along the span. The composite airfoil is formed from a composite material comprising fibers disposed in a matrix material. The tip section has a tip fiber volume, and the body section has a body fiber volume that is greater than the tip fiber volume. Another composite airfoil comprises a tip cap applied over the tip that tapers from a first end to a second end such that each of the pressure and suction side walls of the tip cap narrows from a first thickness to a second thickness.

Abstract: An airfoil defining a span extending between a root and a tip. The airfoil includes a frangible airfoil portion extending between a leading edge and a trailing edge and extending between the tip and a fusion line along the span. The frangible airfoil portion includes a first material defining a first modulus of elasticity and further defines an internal cavity. The airfoil includes a residual airfoil portion coupled to the frangible airfoil portion extending from the fusion line to the root along the span and including a second material defining a second modulus of elasticity greater than the first modulus of elasticity. The residual airfoil portion meets the frangible airfoil portion at the fusion line.

Abstract: A method for operating a gas turbine engine includes receiving data indicative of an operational vibration within a section of the gas turbine engine; and providing electrical power to a shaker mechanically coupled to one or more components of the section of the gas turbine engine to generate a canceling vibration to reduce or minimize the operational vibration within the section of the gas turbine engine.

Abstract: An airfoil defining a span extending between a root and a tip and a chord at each point along the span extending between a leading edge and a trailing edge. The airfoil includes a frangible airfoil portion at the tip extending between the leading edge and the trailing edge and extending between the tip and a frangible line along the span. The frangible airfoil portion includes an exterior surface. The exterior surface at least partially defines at least one fusion cavity at least partially defining the frangible line. The airfoil further includes a residual airfoil portion extending from the frangible line to the root along the span. The residual airfoil portion meets the frangible airfoil portion at the frangible line. As such, the frangible airfoil portion deforms or partially or fully detaches relative to the residual airfoil portion at the frangible line following an event creating imbalance.

Abstract: A blade for a propulsion apparatus. The blade includes a body having opposed pressure and suction sides. The blade extends in span between a root and a tip and the blade extends in chord between a leading edge and a trailing edge. The blade includes a fracture structure that is defined within the body and positioned such that it is spaced-away from the tip. The fracture structure includes at least one chamber. A first fracture wall is disposed between the at least one chamber and the pressure side, and a second fracture wall is disposed between the at least one chamber and the suction side. The fracture structure is configured to fail when a predetermined force is applied to the tip such that the tip separates from the remainder of the body.

Abstract: An airfoil defining a span extending between a root and a tip. The airfoil includes a frangible airfoil portion extending between a leading edge and a trailing edge and extending between the tip and a fusion line along the span. The frangible airfoil portion includes a first material defining a first modulus of elasticity and further defines an internal cavity. The airfoil includes a residual airfoil portion coupled to the frangible airfoil portion extending from the fusion line to the root along the span and including a second material defining a second modulus of elasticity greater than the first modulus of elasticity. The residual airfoil portion meets the frangible airfoil portion at the fusion line.

Abstract: An airfoil defining a span extending between a root and a tip and a chord at each point along the span extending between a leading edge and a trailing edge. The airfoil includes a frangible airfoil portion at the tip extending between the leading edge and the trailing edge and extending between the tip and a frangible line along the span. The frangible airfoil portion includes an exterior surface. The exterior surface at least partially defines at least one fusion cavity at least partially defining the frangible line. The airfoil further includes a residual airfoil portion extending from the frangible line to the root along the span. The residual airfoil portion meets the frangible airfoil portion at the frangible line. As such, the frangible airfoil portion deforms or partially or fully detaches relative to the residual airfoil portion at the frangible line following an event creating imbalance.

Abstract: A containment structure comprising an annular structure configured to provide close tolerance to a rotation structure. The containment structure includes a first abradable structure, a second abradable structure, and a shroud that is defined in part by the first abradable structure and in part by the second abradable structure. An annular surface of the shroud is defined by the first abradable structure and by the second abradable structure. The first abradable structure is harder than the second abradable structure.

Abstract: A method for operating a gas turbine engine includes receiving data indicative of an operational vibration within a section of the gas turbine engine; and providing electrical power to a shaker mechanically coupled to one or more components of the section of the gas turbine engine to generate a canceling vibration to reduce or minimize the operational vibration within the section of the gas turbine engine.

Abstract: A containment structure comprising an annular structure configured to provide close tolerance to a rotation structure. The containment structure includes a first abradable structure, a second abradable structure, and a shroud that is defined in part by the first abradable structure and in part by the second abradable structure. An annular surface of the shroud is defined by the first abradable structure and by the second abradable structure. The first abradable structure is harder than the second abradable structure.

Abstract: A gas turbine engine airfoil includes leading and trailing edges, pressure and suction sides extending from airfoil base to airfoil tip, trailing edge cladding made of cladding material bonded to composite core made of composite material, cladding material less brittle than composite material, composite core including central core portion extending downstream from leading edge portion to trailing edge portion of composite core, and trailing edge cladding including wavy wall and trailing edge. Pressure and suction side flanks of trailing edge cladding may be bonded to pressure and suction side surfaces of trailing edge portion. Waves of wavy wall may extend normal to and away from the pressure and suction side surfaces. Trailing edge cladding may include wavy pressure and suction side trailing edge guards including waves of wavy wall. Airfoil may extend outwardly from platform of a blade. Root may include integral dovetail.

Abstract: A gas turbine engine airfoil includes leading and trailing edges, pressure and suction sides extending from airfoil base to airfoil tip, trailing edge cladding made of cladding material bonded to composite core made of composite material, cladding material less brittle than composite material, composite core including central core portion extending downstream from leading edge portion to trailing edge portion of composite core, and trailing edge cladding including wavy wall and trailing edge. Pressure and suction side flanks of trailing edge cladding may be bonded to pressure and suction side surfaces of trailing edge portion. Waves of wavy wall may extend normal to and away from the pressure and suction side surfaces. Trailing edge cladding may include wavy pressure and suction side trailing edge guards including waves of wavy wall. Airfoil may extend outwardly from platform of a blade. Root may include integral dovetail.

Abstract: Vibration is monitored in a dual rotor engine. A first total vibration of the engine is measured during operation. Relative phase of the two rotors is then clocked, and a second total vibration of the engine is then measured during operation. First and second total unbalances are then resolved at a common response frequency from the measured total vibrations. First and second rotor unbalances are then resolved for the corresponding rotors from the first and second total unbalances. In a further method, corresponding corrective balance weights may be determined for offsetting the resolved rotor unbalances.

Abstract: A processor-implemented method of assembling a rotatable machine is provided. The machine includes a plurality of blades that extend radially outwardly from a rotor. The method includes determining a geometric parameter for each blade in a row of blades that is relative to a ratio, R of an inlet area and an outlet area of a predetermined volume defined between each pair of blades, determining an initial sequence map for the row of blades that facilitates minimizing a difference of R between circumferentially adjacent pairs of blades, and iteratively remapping the sequence of the blades to facilitate reducing a moment weight vector sum of the rotor to a value that is less than a predetermined value.

Abstract: A method for fabricating a fan assembly is provided, wherein the method includes providing a rotor having a plurality of rotor blades. At least one rotor blade is fabricated from a frangible material. The method also includes coupling a casing substantially circumferentially about the rotor, and positioning the casing a distance from the plurality of rotor blades. The distance is selected to facilitate increasing an amount of initial resistance created between the casing and the plurality of rotor blades after a bladeout.

Abstract: Embodiments described herein generally relate to a method of measuring the vibration of an aircraft engine. One embodiment herein provides an engine monitoring system either connected to and/or positioned in close proximity to an aircraft engine. Also provided is a clearance measuring device within the engine monitoring system. The clearanceometer collects clearance data that is later converted into vibration data.

Abstract: A method of assembling a gas turbine engine includes providing at least one blade assembly. The method also includes forming at least one blade tip fuse within at least a portion of the at least one blade assembly. The method further includes coupling the at least one blade assembly into the gas turbine engine. The blade assembly includes an airfoil and a metal leading edge (MLE) coupled to at least a portion of the airfoil. The MLE includes the at least one blade tip fuse.