Abstract: A gas turbine engine includes rotor having a hub, and a plurality of blades extending generally radially from the hub. Each of the blades has an airfoil portion. The airfoil portion has a leading edge and a trailing edge defining a chordwise direction, and a root and a tip defining a spanwise direction. Only a sub-set of the blades has a cutback at at least one of the trailing edge and the leading edge. A method of designing and a method of assembling a rotor having noise reduction properties in a gas turbine engine is also presented.

Abstract: The gas turbine compressor for an aircraft gas turbine engine includes a compressor rotor having a plurality of compressor blades circumferentially distributed around a hub. Each of the compressor blades has an airfoil extending radially outward from the hub to a blade tip. A circumferential row of the compressor blades includes two or more different blade types, at least one modified blade of the two or more different blade types having means for generating different shock patterns between adjacent ones of the two or more different blade types when the gas turbine compressor operates in supersonic flow regimes. The means for generating different shock patterns on the modified blade aerodynamically mistune the two or more different blade types.

Abstract: A method of manufacturing a compressor stator having: a first stator blade with a first leading edge and a first trailing edge; a second stator blade disposed a circumferential distance from the first stator blade, the second stator blade having a second leading edge disposed an axial distance from the first leading edge and a second trailing edge disposed an axial distance from the first trailing edge; the method comprising: using additive manufacturing to deposit and fuse together progressive layers of metal material commencing at a substrate to form the first stator blade, the second stator blade, at least one intermediate support structure disposed between the first stator blade and the second stator blade, and at least one primary support structure disposed between the substrate and at least one of: the first stator blade; and the second stator blade; and removing the primary support structure and the intermediate support structure.

Abstract: Am aircraft engine including an axially extending inlet wall surrounding an inlet flow path. A radial distance between the inlet wall and the inner wall adjacent the fan defines a downstream height of the inlet flow path. A plurality of vanes are circumferentially spaced around the inlet, each of the vanes extending radially inwardly from the inlet wall, a maximum radial distance between a tip of each of the vanes and the inlet wall defining a maximum height of the vane. The maximum height of the vane is at most 50% of the downstream height of the flow path. In another embodiment, the maximum height of the vane is at most 50% of the maximum fan blade span. A method of reducing a relative Mach number at fan blade tips is also discussed.

Abstract: A compressor diffuser for a gas turbine engine is described which includes diffuser pipes having a tubular body defining a pipe center axis extending therethrough. The tubular body includes a first portion extending in a generally radial direction, a second portion extending in a generally axial direction and terminating at a pipe outlet, and a bend portion fluidly linking the first portion and the second portion. A first curved side wall of the tubular body along the second portion is shorter than a second curved side wall of the tubular body along the second portion. The second portion of the tubular body has a cross-sectional profile defined in a plane normal to the pipe center axis. The first curved side wall of the cross-sectional profile has a smaller radius than a radius of the second curved side wall of the cross-sectional profile.

Abstract: A gas turbine engine includes rotor having a hub, and a plurality of blades extending generally radially from the hub. Each of the blades has an airfoil portion. The airfoil portion has a leading edge and a trailing edge defining a chordwise direction, and a root and a tip defining a spanwise direction. Only a sub-set of the blades has a cutback at at least one of the trailing edge and the leading edge. A method of designing and a method of assembling a rotor having noise reduction properties in a gas turbine engine is also presented.

Abstract: A turbofan engine including an axially extending inlet wall surrounding an inlet flow path. A radial distance between the inlet wall and the inner wall adjacent the fan defines a downstream height of the inlet flow path. A plurality of vanes are circumferentially spaced around the inlet, each of the vanes extending radially inwardly from the inlet wall, a maximum radial distance between a tip of each of the vanes and the inlet wall defining a maximum height of the vane. The maximum height of the vane is at most 50% of the downstream height of the flow path. In another embodiment, the maximum height of the vane is at most 50% of the maximum fan blade span. A method of reducing a relative Mach number at fan blade tips is also discussed.

Abstract: A method of manufacturing a compressor stator having: a first stator blade with a first leading edge and a first trailing edge; a second stator blade disposed a circumferential distance from the first stator blade, the second stator blade having a second leading edge disposed an axial distance from the first leading edge and a second trailing edge disposed an axial distance from the first trailing edge; the method comprising: using additive manufacturing to deposit and fuse together progressive layers of metal material commencing at a substrate to form the first stator blade, the second stator blade, at least one intermediate support structure disposed between the first stator blade and the second stator blade, and at least one primary support structure disposed between the substrate and at least one of: the first stator blade; and the second stator blade; and removing the primary support structure and the intermediate support structure.

Abstract: A gas turbine engine includes rotor having a hub, and a plurality of blades extending generally radially from the hub. Each of the blades has an airfoil portion. The airfoil portion has a leading edge and a trailing edge defining a chordwise direction, and a root and a tip defining a spanwise direction. Only a sub-set of the blades has a cutback at at least one of the trailing edge and the leading edge. A method of designing and a method of assembling a rotor having noise reduction properties in a gas turbine engine is also presented.

Abstract: A method of manufacturing a compressor stator having: a first stator blade with a first leading edge and a first trailing edge; a second stator blade disposed a circumferential distance from the first stator blade, the second stator blade having a second leading edge disposed an axial distance from the first leading edge and a second trailing edge disposed an axial distance from the first trailing edge; the method comprising: using additive manufacturing to deposit and fuse together progressive layers of metal material commencing at a substrate to form the first stator blade, the second stator blade, at least one intermediate support structure disposed between the first stator blade and the second stator blade, and at least one primary support structure disposed between the substrate and at least one of: the first stator blade; and the second stator blade; and removing the primary support structure and the intermediate support structure.

Abstract: The gas turbine compressor for an aircraft gas turbine engine includes a compressor rotor having a plurality of compressor blades circumferentially distributed around a hub. Each of the compressor blades has an airfoil extending radially outward from the hub to a blade tip. A circumferential row of the compressor blades includes two or more different blade types, at least one modified blade of the two or more different blade types having means for generating different shock patterns between adjacent ones of the two or more different blade types when the gas turbine compressor operates in supersonic flow regimes. The means for generating different shock patterns on the modified blade aerodynamically mistune the two or more different blade types.

Abstract: A rotor for a gas turbine engine. The rotor includes blades circumferentially distributed around a hub. The blades have airfoils with a span defined between a root and tip, a chord defined between a leading edge and a trailing edge, and a thickness defined between a pressure side surface and suction side surface. The blades include first blades and second blades. The airfoil of the first blades has a first thickness distribution defining a first natural vibration frequency of the airfoils of the first blades. The airfoil of the second blades has a second thickness distribution defining a second natural vibration frequency different than the first natural vibration frequency. The first thickness distribution is different than the second thickness distribution along a radially-inner half of the span, and the first thickness distribution matches the second thickness distribution along a radially-outer half of the span.

Abstract: A compressor rotor for a gas turbine engine is described which includes sets of blades having different airfoil thickness distributions, each including a frequency modifier forming a thickness differential relative to a baseline blade thickness. The frequency modifiers provide different natural vibration frequencies for each of the blades, and facilitate modifying natural vibration frequency separation between adjacent blades of the compressor rotor.

Abstract: An inlet for a turbofan engine, including an inlet wall surrounding an inlet flow path. The inlet wall extends axially from an upstream end to a downstream end adjacent the fan. The inlet wall has a shape defining a plurality of teeth circumferentially spaced around the inlet. The teeth extend axially and project radially inwardly toward the central longitudinal axis. A central portion of the inlet flow path has a cross-sectional dimension measured diametrically between opposed teeth, the cross-sectional dimension varying along the axial direction. The central portion defines a geometric throat at a minimum value of the cross-sectional dimension. The inlet wall is shaped so that the geometric throat is axially spaced from the upstream end and the downstream end. A gas turbine engine and a method of shielding tips of fan blades from impact by an object having a predetermined minimum dimension are also discussed.

Abstract: A fan for a gas turbine engine comprises blades distributed around a hub. The blades include first and second blades, having geometric parameters and/or material properties that differ from each other to frequency mistune the fan. The blades are distributed about the hub with at least one second blade between adjacent first blades. The leading edge of the airfoil of the second blades is disposed axially aft of the corresponding leading edge of the first blades in at least a portion of the blade span.

Abstract: A compressor diffuser for a gas turbine engine is described which includes diffuser pipes having a tubular body defining a pipe center axis extending therethrough. The tubular body includes a first portion extending in a generally radial direction, a second portion extending in a generally axial direction and terminating at a pipe outlet, and a bend portion fluidly linking the first portion and the second portion. A first curved side wall of the tubular body along the second portion is shorter than a second curved side wall of the tubular body along the second portion. The second portion of the tubular body has a cross-sectional profile defined in a plane normal to the pipe center axis. The first curved side wall of the cross-sectional profile has a smaller radius than a radius of the second curved side wall of the cross-sectional profile.

Abstract: An inter-compressor case for a gas turbine engine is disclosed. The inter-compressor case comprises: an outer casing and an inner casing radially spaced apart relative to a longitudinal axis; a gas path extending from a plurality of radial inlets arranged in a circumferentially spaced apart array around the outer casing to an annular outlet defined by an axially extending downstream portion of the outer casing and an axially extending downstream portion of the inner casing; a plurality of struts having a gas path surface extending across the gas path between the outer casing and the inner casing; and a plurality of flow separators extending from the adjacent radial inlets. The flow separators have trailing edges disposed upstream of the annular outlet and include a plurality of full length flow separators and a plurality of truncated flow separators.

Abstract: A turbofan engine is disclosed having a bypass duct with an asymmetry in aerodynamic profile caused by a local obstruction in the bypass duct. The engine comprises stator vanes circumferentially spaced-apart around a circumference of the bypass duct. A first group of adjacent stator vanes includes a majority of the plurality of stator vanes and are arranged in a first circumferential sector of the bypass duct and have equal stagger angles. A second group of adjacent stator vanes includes a minority of the plurality of stator vanes and are arranged in a second circumferential sector circumferentially positioned relative to the local obstruction. The stator vanes of the second group have stagger angles different from the stagger angles of the stator vanes of the first group.

Abstract: An airfoil for a gas turbine engine including a tip extension disposed at the tip of the airfoil body. The tip extension extends from the suction side surface and/or the pressure side surface and defines a tip thickness that is larger than a true thickness of the airfoil body. The true thickness is defined within a plane perpendicular to a root axis and extending transversely to the airfoil chord around a midpoint thereof. The tip extension includes a side transitional surface forming a curve extending tangentially from the side surface and/or the pressure side surface. The tip thickness increases over a radial dimension in the plane that is at least 2 times the true thickness.

Abstract: A turbofan engine is disclosed which includes a nacelle assembly, having an interior surface for directing airflow, and a flow disruptor positioned on the interior surface upstream of the fan, the flow disruptor extending towards the axis a height greater than the anticipated boundary layer height of the airflow. A turbofan engine which includes an array of circumferentially disposed flow disruptors extending from a fan case inner surface is also disclosed. A method of mitigating fan flutter in a gas turbine engine by generating a circumferential asymmetrically in the airflow, upstream of the fan, is also described.