Abstract: A turbofan engine includes a fan section that drives air along a bypass flow path in a bypass duct. An epicyclic gear system in driving engagement with the fan shaft and has a gear mesh lateral stiffness and a gear mesh transverse stiffness. A gear system input to the gear system defines a gear system input lateral stiffness and a gear system input transverse stiffness. The gear system input lateral stiffness is less than 5% of the gear mesh lateral stiffness. A first performance quantity is defined as the product of a first speed squared and a first area and a second performance quantity is defined as the product of a second speed squared and a second area. A performance quantity ratio of a first performance quantity to a second performance quantity is between 0.5 and 1.5.

Abstract: A vibration mitigation coating for an integrally bladed rotor including a disk including an interior radius proximate an axis and an exterior radius distal from the axis, the disk including a substrate with an external surface, said external surface extends from the interior radius to the exterior radius; and a damping material disposed directly onto the external surface of the substrate.

Abstract: An acoustic attenuation structure for a gas turbine engine includes a periodic structure having a first unit cell, the first unit cell having a first central body and a first axial tube disposed on the first central body and a second axial tube disposed on the first central body, opposite the first axial tube, each of the first axial tube and the second axial tube being in fluid communication with one another through the first central body.

Abstract: A gas turbine engine includes, among other things, a fan, a fan drive gear system that is coupled with the fan and a fan drive input shaft, a compressor section that includes a first compressor and a second compressor, and a turbine section. The turbine section includes a first turbine coupled with a first shaft and a second turbine coupled through a second shaft to the second compressor. A bearing supports the fan drive input shaft. The bearing is located proximal to, and radially spaced from, a forward end of the first shaft. The bearing includes a speed sensor target that is rotatable with the forward end and that defines a rotation path. A speed sensor probe is situated proximal to the rotation path and is operable to read the speed sensor target.

Abstract: Airfoil for gas turbine engines are described. The airfoils have internal walls and internal cavities. A leading edge cavity is defined within the airfoil body along a leading edge and a leading edge feed cavity is arranged aft of the leading edge cavity. A bent leading edge rib is arranged between the leading edge cavity and the leading edge feed cavity. A main body cavity is arranged aft of the leading edge feed cavity and defined at least in part by two interior ribs that define a part of the leading edge feed cavity. The main body cavity is fluidly connected to the leading edge feed cavity by an interior fluid connection through the intersection of the two interior ribs. A shield cavity is arranged to thermally shield the leading edge feed cavity from heat pickup along the suction side of the airfoil body.

Abstract: A disclosed drive assembly for an auxiliary power unit includes a first drive shaft driven by an auxiliary power unit, a second drive shaft driven by a first electric motor, a differential gear system including a ring gear driven by the second drive shaft, a and planet gears supported within a carrier attached to the ring gear. The first drive shaft and an output shaft are coupled to the planet gears and a generator is driven by the output shaft. The electric motor and the auxiliary power unit combine to drive the output shaft.

Abstract: A turbo-expanding cracking assembly includes a plurality of stages each including a rotating blade coupled to an output shaft and a fixed stator, at least one heat exchanger configured to transfer heat to an ammonia containing fuel flow, and a catalyst that is configured to decompose an ammonia containing fuel flow into a flow containing hydrogen (H2).

Abstract: A hydrostatic seal assembly includes a primary seal assembly configured to maintain a selected gap between the primary seal and a rotating component, and a seal carrier. The seal carrier includes a radial outer wall, an axial wall extending from the radial outer wall at a first axial end of the radial outer wall, and a carrier arm extending from the radial outer wall at a second axial end of the radial outer wall opposite the first axial end. The carrier arm is secured to a static structure for sealing between the rotating component and the static structure.

Abstract: Waste heat management systems are described. The waste heat management systems include a turbine engine having a compressor section, a combustor section, a turbine section, and a nozzle. The compressor section, the combustor section, the turbine section, and the nozzle define a core flow path that expels through the nozzle. The waste heat management systems also include an auxiliary power unit (APU) system and a waste heat recovery system operably connected to the APU system. The APU system is integrated into a working fluid flow path of the waste heat recovery system.

Abstract: A tandem rotor disk apparatus may include a rotor disk body concentric about an axis. The tandem rotor disk apparatus may also include a first blade extending radially outward of the rotor disk body and a second blade extending radially outward of the rotor disk body. The first blade may be offset from the second blade in a direction parallel to the axis. The tandem rotor disk apparatus may be implemented in a gas turbine engine with no intervening stator vane stages disposed between the first blade and the second blade.

Abstract: A seal assembly for a gas turbine engine according to an example of the present disclosure includes, among other things, a first side plate and a backing plate that extend circumferentially about an assembly axis. The backing plate includes a main body and a first set of abutments that extend outwardly from the main body to abut the first side plate. A first set of pockets are established between adjacent abutments of the first set of abutments. A first brush seal is between the first side plate and the backing plate. Sections of the first brush seal received in respective pockets of the first set of pockets are dimensioned to join together to establish a first sealing relationship with a first gas turbine engine component. A method of assembly is also disclosed.

Abstract: A blade outer air seal assembly includes a support structure and a blade outer air seal having a plurality of segments extending circumferentially about an axis and mounted to the support structure. At least two segments have a base portion extending from a first circumferential side to a second circumferential side, a first protrusion extending from the first circumferential side and having a first slot, and a second protrusion extending from the second circumferential side and having a second slot. A feather seal is arranged in the first slot and the second slot between the at least two segments such that the feather seal is pivotable between first and second positions in response to relative movement between the first and second protrusions.

Abstract: A core structure for a providing a cooling passage in a gas turbine engine includes a core body that has a first passage core. The first passage core has a first width in a chord-wise direction near a first wall. A second width in the chord-wise direction near a second wall. A third width in the chord-wise direction between the first and second walls. The third width being smaller than the first and second widths to form an hourglass shape.

Abstract: Supercritical fluid systems and aircraft power systems are described. The systems include a compressor, a turbine, and a generator. A primary working fluid flow path has a primary working fluid that passes through the compressor, a separator, the turbine, and back to the compressor. A secondary working fluid flow path having a secondary working fluid that passes through the generator, the compressor, the separator, and back to the generator. The primary working fluid and the secondary working fluid are compressed and mixed within the compressor to form a mixture of the two fluids and the separator separates the mixture of the two fluids to direct the primary working fluid back to the turbine and the secondary working fluid to the generator.

Abstract: A seal assembly for a gas turbine engine according to an example of the present disclosure includes, among other things, a seal arc segment including a sealing portion, and a first rail and a second rail opposed to the first rail. The sealing portion extends in a circumferential direction between opposed mate faces and extends in an axial direction between a leading edge and a trailing edge. Each of the first and second rails extend outwardly in a radial direction from the sealing portion to respective first and second edge faces, and the sealing portion has a sealing face dimensioned to bound a gas path and includes a backside face opposed to the sealing face. The first and second rails include respective first and seconds pairs of hooks dimensioned to mount the seal arc segment to an engine static structure in an installed position. The seal arc segment is radially opposed to the sealing face between the first and second edge faces establishing a first region.

Abstract: A method of forming a gas turbine engine component including an airfoil and at least one shroud includes the steps of (1) machining a gas path surface of the at least one shroud utilizing a non-electrochemical machining (ECM) process, and (2) then utilizing ECM on at least the airfoil.

Abstract: Disclosed is a ceramic matrix component having a fibrous core and a ceramic matrix composite shell surrounding at least a portion of the fibrous core. The ceramic matrix composite shell comprises a fibrous preform. The fibrous core has a greater porosity than the fibrous preform. A method of making the ceramic matrix component is also disclosed.

Abstract: An assembly is provided for rotational equipment. This assembly includes a seal carrier, a seal element and a retainer. The seal carrier is configured with a receptacle. The seal element is seated in the receptacle. The retainer is configured to secure the seal element to the seal carrier. The seal element is arranged radially between the seal carrier and the retainer.

Abstract: A bearing is mounted to a static structure outwardly of the shaft, and supporting the shaft. A bearing compartment is defined by face seal arrangements on each of two axial sides of a bearing. Each face seal arrangement includes a seal seat rotating with the shaft and a non-rotating sealing ring. The seal housing is exposed to high pressure air outward of the bearing compartment. A coil spring biases the seal housing towards the seal seat, such that the sealing face is biased into contact with the seal seat by a bias force including a net fluid force acting on the seal housing and the coil spring. The sealing face is defined by a contact portion contacting the seal seat and a feed portion recessed from the seal seat. The feed portion includes a plurality of circumferentially spaced feed slots fluidly connected to at least one annular groove.

Abstract: An embedded processing system includes processing circuitry configured to execute a plurality of computer executable instructions. The embedded processing system also includes a memory system configured to store a plurality of configuration items, where at least one of the configuration items includes a sequence of the computer executable instructions. The embedded processing system also includes an authentication control configured to authenticate an immutable anchor associated with the embedded processing system, authenticate integrity of a reconfigurable entity map associated with the memory system, authenticate the configuration items based on the reconfigurable entity map, and perform an accommodation measure based on an authentication failure of at least one of the configuration items.