Abstract: A method of monitoring the health of an aircraft propeller whilst the propeller is in operation, the propeller having a plurality of blades extending radially outwardly from hub arms of a propeller hub, which in turn extend radially outwardly from a central axis extending through the propeller and a propeller drive shaft, is provided. The method comprises obtaining measurements representative of the strain in each of at least some of the hub arms using strain sensors, each of the strain sensors being provided on a respective hub arm. A corresponding propeller health monitoring system, an aircraft propeller comprising the system and an aircraft comprising the propeller are also provided.

Abstract: A system for monitoring propeller health includes a processing unit having a processor which is programmed to apply a plurality of algorithms to inputted aircraft parameter data. The system also includes a plurality of data inputs for inputting aircraft parameter data into the algorithms, wherein the processor is configured to apply the physics based algorithms to the aircraft parameter data to determine at least the fatigue life consumption of one or more critical components of a propeller. In addition, the system includes an output device which is able to output an indication of the determined fatigue life consumption to an observer.

Abstract: A system for monitoring propeller health includes a processing unit having a processor which is programmed to apply a plurality of algorithms to inputted aircraft parameter data. The system also includes a plurality of data inputs for inputting aircraft parameter data into the algorithms, wherein the processor is configured to apply the physics based algorithms to the aircraft parameter data to determine at least the fatigue life consumption of one or more critical components of a propeller. In addition, the system includes an output device which is able to output an indication of the determined fatigue life consumption to an observer.

Abstract: A method of monitoring the health of an aircraft propeller whilst the propeller is in operation, the propeller having a plurality of blades extending radially outwardly from a central axis extending through the propeller and a propeller drive shaft, is provided. The method includes obtaining measurements representative of strain in the propeller drive shaft using multiple primary strain sensors, each primary strain sensor providing respective measurements representative of strain. The primary strain sensors are located around a circumference of the drive shaft of the propeller, and each strain sensor is located such that it crosses a plane defined by the radial direction of a blade and the central axis, the plane being bounded by the central axis. A corresponding propeller health monitoring system, an aircraft propeller comprising the system and an aircraft comprising the propeller are also provided.

Abstract: A method of monitoring the health of an aircraft propeller whilst the propeller is in operation, the propeller having a plurality of blades extending radially outwardly from a central axis extending through the propeller and a propeller drive shaft, is provided. The method comprises: obtaining measurements representative of strain in the propeller drive shaft using multiple primary strain sensors, each primary strain sensor providing respective measurements representative of strain; wherein the primary strain sensors are located around a circumference of the drive shaft of the propeller; and wherein each strain sensor is located such that it crosses a plane defined by the radial direction of a blade and the central axis, the plane being bounded by the central axis. A corresponding propeller health monitoring system, an aircraft propeller comprising the system and an aircraft comprising the propeller are also provided.

Abstract: A method of monitoring the health of an aircraft propeller whilst the propeller is in operation, the propeller having a plurality of blades extending radially outwardly from hub arms of a propeller hub, which in turn extend radially outwardly from a central axis extending through the propeller and a propeller drive shaft, is provided. The method comprises obtaining measurements representative of the strain in each of at least some of the hub arms using strain sensors, each of the strain sensors being provided on a respective hub arm. A corresponding propeller health monitoring system, an aircraft propeller comprising the system and an aircraft comprising the propeller are also provided.

Abstract: A gas turbine engine fan section is disclosed that includes a hub. Circumferentially spaced fan blades are supported on the hub. A spacer is arranged between adjacent fan blades and is operatively supported by the hub. The spacer is configured to be collapsible in response to a fan blade load exerted on the spacer in excess of a threshold load. The spacer is generally rigid at fan blade loads below the threshold load.

Abstract: An airfoil assembly includes an airfoil body extending between a leading edge, a trailing edge, a suction side, and a pressure side. A first sheath having an outer side and an inner side forms a cavity for receiving at least a portion of the airfoil body and is bonded on the inner side to the leading edge of the airfoil body. The first sheath is formed of a titanium-based metallic material. A second sheath is bonded to the outer side of the first sheath.

Abstract: A composite fan blade having an airfoil with a leading edge and a trailing edge and a dovetail root includes a first pressure face and second pressure face, a lower horizontal face connecting the pressure faces at the bottom of the dovetail and a first and a second dovetail runout fillet connecting the pressure faces to the airfoil. The pressure faces are each angled outward at about 65 degrees to about 75 degrees from horizontal.

Abstract: The disclosed composite airfoil includes a three-dimensional composite core extending longitudinally and having a chord-wise direction. The core has a core in-plane thickness extending between opposing sides in a through-plane direction generally perpendicular to the chord-wise and longitudinal directions. A composite skin covers the opposing sides and has an exterior surface providing an airfoil contour. The skin includes a total skin in-plane thickness corresponding to a sum of thicknesses through the skin in the through-plane direction from each of the opposing sides to their adjoining exterior surface. A sum of the core in-plane and total skin in-plane thicknesses at a central portion of the composite airfoil is a total in-plane thickness. The total skin in-plane thickness at the central portion is less than 50% of the total in-plane thickness.

Abstract: A composite fan blade having an airfoil with a leading edge and a trailing edge and a dovetail root includes a first pressure face and second pressure face, a lower horizontal face connecting the pressure faces at the bottom of the dovetail and a first and a second dovetail runout fillet connecting the pressure faces to the airfoil. The pressure faces are each angled outward at about 65 degrees to about 75 degrees from horizontal.

Abstract: A method of forming a composite blade having a sheath on a portion of the blade by placing the dry composite blade and sheath in a mold, adding a resin, and curing the resin to integrally bond the blade to the metal sheath. The portion of the blade having the sheath bonded thereto may be at least one of the leading edge, the tip and the trailing edge of the blade.

Abstract: A method of forming a composite airfoil having a suction side and pressure side includes the steps of designing a mold, designing a woven core, designing a plurality of plies and assembling the designed mold, core and plies to create the composite airfoil. The hollow mold has an inner surface which defines the surface profile of the composite airfoil. The plurality of plies is designed to fit between the inner surface of the mold and an outer surface of the woven core. The plurality of plies is designed after the step of designing the woven core.

Abstract: An example airfoil assembly includes an airfoil body extending between a leading edge, a trailing edge, a suction side, and a pressure side. The assembly further includes a first protective sheath, an indicator sheath, and a second protective sheath. The first protective sheath has an outer side and an inner side that forms a cavity for receiving at least a portion of the airfoil body. The inner side being bonded to the leading edge of the airfoil body. A portion of the indicator sheath is positioned forward the first sheath relative to the leading edge of the airfoil. A portion of the second protective sheath is positioned forward the indicator sheath relative to the leading edge of the airfoil.

Abstract: The disclosed composite airfoil includes a three-dimensional composite core extending longitudinally and having a chord-wise direction. The core has a core in-plane thickness extending between opposing sides in a through-plane direction generally perpendicular to the chord-wise and longitudinal directions. A composite skin covers the opposing sides and has an exterior surface providing an airfoil contour. The skin includes a total skin in-plane thickness corresponding to a sum of thicknesses through the skin in the through-plane direction from each of the opposing sides to their adjoining exterior surface. A sum of the core in-plane and total skin in-plane thicknesses at a central portion of the composite airfoil is a total in-plane thickness. The total skin in-plane thickness at the central portion is less than 50% of the total in-plane thickness.

Abstract: A gas turbine engine fan section is disclosed that includes a hub. Circumferentially spaced fan blades are supported on the hub. A spacer is arranged between adjacent fan blades and is operatively supported by the hub. The spacer is configured to be collapsible in response to a fan blade load exerted on the spacer in excess of a threshold load. The spacer is generally rigid at fan blade loads below the threshold load.

Abstract: An airfoil assembly includes an airfoil body extending between a leading edge, a trailing edge, a suction side, and a pressure side. A first sheath having an outer side and an inner side forms a cavity for receiving at least a portion of the airfoil body and is bonded on the inner side to the leading edge of the airfoil body. The first sheath is formed of a titanium-based metallic material. A second sheath is bonded to the outer side of the first sheath.

Abstract: An annular turbine blade tip shroud is provided having a construction for minimizing leakage of the cooling fluid and preventing ingestion of hot gases into said cooling flow. A tip shroud support ring is located on the inner surface of said casing with tip shroud members affixed thereto and encasing the blade tips. An annular metal can is located over the forward ends of said tip shroud members and has a sealing engagement with the tip shroud support ring. This annular metal can also seals with feather seals located between adjacent ends of cooperating tip shroud members. A positive metal bellows seal is also provided between downstream vanes and the outer casing. A sheet metal seal is located between each tip shroud member and tip shroud support ring to aid in maintaining proper cooling flow through the shroud.