Abstract: A vibration damper is disposed between each adjacent pair of turbine buckets of a gas turbine engine to act in a V-shaped groove defined by bevelled platform surfaces of the adjacent buckets. The damper is wedge-shaped in cross section and is provided with a pad on one side and two pads on another side. When the damper is propelled into the groove by centrifugal force, it assumes a consistent equilibrium position with the raised surface of the one pad slidingly engaging one of the platform bevelled surfaces and the raised surfaces of the other two pads slidingly engaging the other bevelled platform surface to dissipate vibrational energy in the buckets.

Abstract: Larger cutting tools which have inherently greater strength can be used to form mounting grooves for side-entry rotor blades when the bottom-most neck of the groove is increased in width in the machining process. The larger width leaves a gap on both sides of the bottom-most neck of the root at a location away from load bearing surfaces.

Abstract: To eliminate stress peaking at the bearing surface interface of the blade and disk slot dovetails in a gas turbine engine, the slot dovetail in undercut to remove disk material from contact with the blade dovetail radially inner edges where surface stress peaking would otherwise occur. The undercut contour radially inward of the blade dovetail is determined by analysis based on each engine design such as to achieve a substantially uniform distribution of surfaces stress along the dovetail slot fillet radius.

Abstract: A laminated airfoil for use in a high bypass engine. The airfoil preferably has a large tip chord and is comprised of alternating layers of thin metallic foil and elastomeric layers. The exterior surfaces of the airfoil are comprised of a thin, metallic foil. The airfoil also has a metal sheath secured to the leading edge. High strength metal members extend through the dovetail root sections.

Abstract: A seal is provided for preventing passage of working medium gases between the roots of the rotor blades of a gas turbine engine and the rotor thereof. The seal comprises a compressed laminar exfoliated graphite piece placed in the cavity between the root of the rotor blade and the receiving slot in the rotor disk, which piece expands upon heating to seal said cavity.

Abstract: A seal is provided for preventing passage of working medium gases between the roots of the rotor blades of a gas turbine engine and the rotor thereof. The seal comprises a laminar exfoliated graphite piece placed in the cavity between the root of the rotor blade and the receiving slot in the rotor disk.

Abstract: Each of a pair of axially spaced turbine disks (12,14) has a plurality of blade retention fingers (20) at the periphery. Each blade has a pair of chevrons (64,66), one engaging a contiguous chevron (70) on a corresponding disk finger. The interacting chevron surfaces are located on the center plane (74) of a corresponding disk. Each finger is shaped to have a linear locus (75) of neutral axis (77) from the body of the disk to the chevron location. Each blade has a hollow platform structure (24), structural members (86,88,92,94) associated with a chevron (70), an airfoil extension (63) extending through the platform (28). High temperature cooling air (34) is directed into the blades (32,26,22) while being baffled away (42) from the turbine disks (12,14). Low temperature cooling air (48) bathes the live disks.

Abstract: A single crystal turbine blade has a portion of its attachment section reinforced by a core containing a fine grained, polycrystalline alloy. The blade is prepared by casting a single crystal body with a cavity within the attachment section, and then filling the attachment section with the polycrystalline superalloy to form a composite structure. Filling is preferably accomplished by plasma spraying the cavity with the superalloy, and hot isostatically compacting the sprayed superalloy to minimize porosity. The composite structure is then heat treated to develop an optimized microstructure in the dual alloy attachment section. The resulting turbine blade has improved low cycle fatigue life of the composite attachment section.

Abstract: A gas turbine engine blade is disclosed which includes a dovetail having retention lobes and fillets. Compression loads are provided in the dovetail for introducing compressive prestresses at the fillets for reducing tensile stresses at the fillets due to loads in the blade such as centrifugal tension loads. In an exemplary embodiment, the compression means comprises a cavity in the dovetail and an insert disposed therein in an interference fit for generating compressive stresses at the cavity and at the fillets.

Abstract: Crack formation in the root portion of a turbine blade is prevented by locating the trailing edge of the air foil portion at the base section thereof in close vertical proximity to the uppermost root neck, thus minimizing trailing edge overhang which has been determined to be the cause of root tracking.

Abstract: A retention system for a rotor blade (10) utilizes the combinatioin of a fixed retention flange (13) and a removable retention plate (16) with a closed-sided retention member (12). This system enables the rapid replacement or removal of the rotor blade (10) for inspection, maintenance, or replacement purposes without requiring removal of surrounding major engine components or structural members. The rotor blade (10) is installed in a retention member (12) contained in a rotatable hub (not shown) by inserting an outwardly extending portion (20) of a shaped blade root (22) of the rotor blade (10) below a radially-inwardly projecting shaped flange (13) peripherally disposed within the interior of the retention member's structure. A removable shaped retention plate (16), which is releasably secured to, and adapted to mate with, the retention member (12), then captures and secures another outwardly extending portion (21) of the shaped root of the rotor blade (10) with a releasable fastener (18).

Abstract: A new and improved rotor blade and bladed disk assembly are disclosed. In the preferred embodiment, the blade includes a curved and twisted dovetail disposed generally parallel to a sloping outer perimeter of a rotor disk which allows the dovetail to accommodate centrifugal loading of the blade through complementary dovetail slots for obtaining improved low cycle fatigue and high cycle fatique life limits and a relatively stiff blade for maintaining 2/REV margin. In an exemplary embodiment, the dovetail comprises a section of a helix and the dovetail is self retaining in the dovetail slot against axial components of centrifugal loading.

Abstract: Rotor blades having roots of the hammer-head type which are received in a circumferential groove in the rim of a rotor disc to secure the blades on the disc are provided with a raised portion on the underside of the blade platform which extends over the entire circumferential length of the platform and has a width equal to that of the mouth of the groove in the rim of the disc. The root of each blade is mounted on this raised portion, and when the root is received in the groove of the disc the raised portion is received closely in the mouth of the groove to ensure the correct alignment of the blade.

Abstract: A pitch retention member rotatably mounts a propeller or fan hereto radially outwardly from a spinner or a hub. The member attaches to the blade of a pair of tenons, each tenon having a hole passing therethrough for receiving a pin about which the blade may rotate. The pitch retention member cooperates with a motion limiter provided at the base of the blade to: damp rotational movement of the blade about the pin to minimize blade angular excursions when centrifugal loads are low; improve high speed blade stability; moderate blade vibratory motion and tune out undesirable blade resonant frequencies; and, absorb force created by impact with foreign objects. Such impact is adsorbed at a desired threshold level of bending load of a crushable material disposed within the blade retention pitch member.

Abstract: An essentially composite propeller or fan blade is provided which is rotatably mounted to a blade retention pitch member by a pin radially outside of a propeller spinner or hub. The blade has a plurality of composite layers wrapped directly around a root fairing which engages the pin. The propeller blade has a motion limiter provided at the base thereof which cooperates with the blade retention pitch member to damp rotational movement of the blade about the pin to minimize blade angular excursions when centrifugal loads are low, to moderate blade vibratory motion, to help tune out undesirable blade resonant frequencies and to transmit force created by impact with foreign objects to the pitch member. By cooperating with the pitch retention member, the root of the blade may be more aerodynamically shaped than other composite blades which must absorb the force of impact in their root portions.

Abstract: Compressor disk (10) has a plurality of rim portions (16, 20, 24) of increasing diameter. Parallel blade retention grooves (30, 32, 34) at locations commensurate with their respective rim portion diameters receive blade tongues (46, 48, 50). Dead load is decreased resulting in a smaller, lighter weight compressor.

Abstract: A composite gas turbine engine blade is made by braiding a plurality of fibers to form a preform having an airfoil precursor portion and an integral root precursor portion. A plurality of fiber shaping inserts are positioned in the root precursor portion, either by braiding the root precursor portion around the inserts or inserting the fiber shaping inserts into the root precursor portion after braiding, to impart an enlarged, divergent shape (e.g., dovetail precursor shape) to the braided root precursor portion. The braided preform with the enlarged, shaped root precursor portion is infiltrated with matrix material and shaped to near net shape to provide the composite blade with a dovetail shaped root.

Abstract: A composite rotor blade (2) with airfoil surfaces (4) used in rotary machines and a method for making the rotor blade (2) are disclosed. The rotor blade (2) includes a spar (8) with a root (12) which incorporates chordwise distributed recesses (13) which capture the composite laminate (16) which forms external airfoil surfaces (4). The root recesses (13) are sized so as to capture the volumetric bulk of the composite laminate (16) below the loadbearing surfaces (21) of the root (12) which fits into a complementary shaped recess (7) located within the rotatable hub (14). The method includes the steps of forming a composite rotor blade (2).

Abstract: A fiber-structured [guide] rotor blade is connected to a metallic rotor in that a supporting core, around which fiber layers are wound, and which extends over the whole blade width, has radial webs in its central section. This results in a form-locking fastening which utilizes the characteristics of the fiber materials.

Abstract: A propeller for a prop-jet engine having a propellor blade formed as a hollow shell member whose outer surface has an aerodynamic blade profile, the propellor blade being secured to a rotor via an adjustment pin. The hollow shell member is internally braced partly along its radial length by a flexible spar secured to the pin and made of thermoplastic material. The flexible spar is hollow and receives a metal spar hich is fixed to the pin and is given flexibility in bending by the provision of a slot therein.

Abstract: A fiber reinforced thermoplastic propeller is attached to a metallic rotor by an integral shank at the base of the propeller. By virtue of the manufacture of the shank and the propeller as an integral construction, improved transmission of centrifugal forces especially where the propeller and hub have greatly different cross-sections can be effected while simultaneously reducing weight. Attachment of the shank to the hub is made through a connection by which pre-stress can be applied to the propeller to assist in resistance of lateral impact force.

Abstract: A self-locking retention system is provided for a composite rotor blade supported on a rotor hub. A radially extending, stud-like retention member is provided on the rotor hub. A composite thickness projects radially inwardly from the rotor blade and substantially surrounds the retention member. The composite thickness is woven in a pattern which grips the retention member in response to outward forces applied to the rotor blade and the woven composite thickness.

Abstract: A structure for the root portion of a turbine blade and for the attachment grooves on a turbine rotor in conjunction with blades having integral shrouds and platforms as well as blades which are not attached to one another, blades which are joined by nonintegral shrouds and blades which do not include platforms. The invention is applicable to straight side entry blade roots and rotor grooves as well as curved side entry blades and curved rotor grooves. The invention results in reduced stress levels in the blade attachment structure by decreasing the land widths and increasing the fillet radii of curvature associated with each tang on a turbine blade root. In addition, the fillet radii of curvature are individually dimensioned to more uniformly distribute stress levels among blade root tangs. The reduction in land widths is accomplished by increasing land contact stresses for a given blade design.

Abstract: The invention pertains to a fan blade and a method for making a fan blade wherein the stresses within the blade material are substantially constant throughout the length of the blade and the unique construction of the blade reduces the concentration of loading on the blade material. Preferably, the blade is molded of a synthetic plastic material and includes a ribbed structure locating material offset from the concave convex configuration of the blade air flow portion such that the section modulus of blade sections from the air flow portion toward the root portion increases by increasing the distance of the blade material from the neutral bending axis in such a manner that no abrupt changes occur and the stresses imposed upon the blade material throughout its length are substantially constant.

Abstract: The present invention discloses a turbomachinery blading configuration. The configuration includes a circumferential recess in a blade support structure and a plurality of blades. Each blade has a platform for mounting the blade within the recess. Each platform includes oppositely directed, generally circumferentially facing edges, each edge having a first and second axial surfaces separated by a recess. The surfaces contact matching surfaces on adjacent blades thereby determining predictable load paths for tangential and twisting moment reaction forces acting on the blades.

Abstract: A rotor blade 14 having a spar 138 and shell 134 is disclosed. Various construction details are developed for efficiently transferring rotational loads on the rotor blade to the root section 28 of the spar. The spar has a projection 139 over which extends a portion 100 of the shell and a platform 36 of the rotor blade.

Abstract: An adjustable-pitch axial fan wheel. A hub has an outer surface forming a portion of a sphere. A plurality of blades are attached to the hub, each blade having a substantial flange at the base portion, the inner surface of the flange being spherical to match the surface of the hub. A central strengthening bolt extends through the blade and projects into the hub to form a pivot axis for the blade. Arcuate holes are formed in the flange, the arcuate holes being alignable with bolt holes in the hub to bolt the flange to the hub while permitting blade pitch adjustment within about 28.degree. of rotation of each blade with respect to the hub.

Abstract: A propeller includes a rotatable hub with a plurality of sockets, blades with roots that fit in the sockets and a plurality of pitch blocks which fit between the blade root and the socket walls. Hubs with two, three, and four sockets are shown. The blades have no twist and are formed of molded, glass reinforced nylon. The pitch blocks are also nylon and different pairs of pitch blocks may be used to hold the blades at different angles. All nylon components are designed to minimize stress concentrations. The hubs although also of nylon have steel reinforcing plates within them which take the centripetal forces. These forces are transmitted through bolts to passage walls in the pitch blocks, and from the pitch blocks through interengaging teeth to the blade roots. A snap on, snap off aerodynamic spinner is also provided.

Abstract: Disclosed is a bladed disk assembly having a new and improved rotor blade. The blade includes a shank and dovetail extending from an airfoil portion thereof. The shank includes a pocket extending therein from an end surface thereof. The shank pocket allows for reduced weight of the blade while maintaining acceptable bending stiffness thereof. In an exemplary embodiment of the invention, the bladed disk assembly is effective for being interchangeable with a blisk assembly having an inlet hub radius ratio of about less than about 0.5 and a root solidity of greater than about 2.2.

Abstract: A rotor assembly 10 having a coolable rotor blade 14 for a gas turbine engine is disclosed. Various construction details are discussed which enable the rotor blade to satisfy the aerodynamic requirements of the engine and the requirements of fatigue life for the rotor assembly. The rotor blade includes a spar 38 and a shell 34 which extends chordwisely beyond the root 42 of the spar. In one embodiment, an axis of symmetry A.sub.r of the root of the spar is parallel to the axis of rotation A of the rotor assembly.

Abstract: The disclosure relates to a turbine rotor and method of manufacture thereof. A plurality of blades having dovetails at the radially inner ends thereof are arranged in a circumferentially spaced circular array. A metallic hub is cast about the dovetails of said blades which are metallurgically bonded by the operation. Alternatively, the blades may be joined to the hub thereafter by an electron beam weld that extends axially to the rotor.

Abstract: A blade assembly for use in an axial flow compressor or turbine. The blade assembly includes a disc provided with a circumferential blade root retaining channel in its periphery and an annular array of aerofoil blades having roots located in the channel so that gaps are defined between adjacent roots. Each root is provided with two circumferentially extending sealing skirts which are arranged so that they cooperate with the blade roots to define an annular sealing surface which is in operation in sealing engagement with an annular portion of the internal surface of the root retaining channel.

Abstract: A hollow rotor shaft 34 having a bore 36 sealed by an end cap 40 is disclosed. The end cap abuttingly engages a first side 42 and second side 44 on the shaft which extend radially inwardly into the bore of the shaft. The sides face in opposite directions and are oriented in a generally axial direction. The end cap includes at least one dog 48, a cover 46 pressed tightly against the first side by the rotatable dog and a lock means such as the bolt 50. The dogs are rotatable to a first position during insertion and rotatable to a second position during assembly by the lock means which extends through the cover to permit assembly and disassembly of the end cap from the exterior of the rotor shaft. In one embodiment a gasket 72 is trapped between the side of the shaft and the cover by the side of the shaft and the cover.

Abstract: The present rotor blade is constructed as a so-called monocoque or shell type blade for use in large fans and windmill rotors. For this purpose the blade is made of fiber reinforced synthetic material with a differnt orientation of the fibers in different sections of the blade. The transition between the blade proper and the connecting end of the blade is formed by a blade root section which has a connecting end of circular or elliptical cross-section and a wing facing end corresponding in cross-section to the blade cross-section. The blade root section has three zones. In the main leading edge zone including the leading edge and adjacent sides of the blade root section the reinforcing fibers extend in parallel to one another. The fibers also extend unidirectionally in a rear zone forming the trailing edge of the blade root section and in this trailing edge zone the fibers also extend in parallel to one another but at an angle relative to the fibers in the leading edge zone.

Abstract: An adjustable pitch aircraft propeller has peripherally spaced composite blades each including an elongated core of expanded rigid foam material extending from a metal base member having a reduced neck portion and an outwardly projecting flange portion. A casing or skin of plastic resin impregnated fabric material surrounds the core of each blade and extends inwardly along the neck portion and also has a flange portion overlying the flange portion of the base member. The skin material overlying the neck portion of the base member is retained by a filament winding impregnated with plastic resin, and the blade is coupled to the propeller hub by an annular lip portion which projects inwardly and overlies the flange portion of the skin material. The foam core of each propeller blade has longitudinally extending slots, and strips of resin impregnated fabric material extend through the slots to form corresponding webs which connect the skin material forming opposite side of the propeller blade.

Abstract: An adjustable pitch aircraft propeller has peripherally spaced composite blades each including an elongated core of expanded rigid foam material extending from a metal base member having a reduced neck portion and an outwardly projecting flange portion. A casing or skin of plastic resin impregnated fabric material surrounds the core of each blade and extends inwardly along the neck portion and also has a flange portion overlying the flange portion of the base member. The skin material overlying the neck portion of the base member is retained by a filament winding impregnated with plastic resin, and the blade is coupled to the propeller hub by an annular lip portion which projects inwardly and overlies the flange portion of the skin material. The foam core of each propeller blade has longitudinally extending slots, and strips of resin impregnated fabric material extend through the slots to form corresponding webs which connect the skin material forming opposite side of the propeller blade.

Abstract: A wind motor blade of composite construction has a blade shell of plastics material reinforced internally by transverse ribs and intersecting longitudinal struts in which metal fork arms are embedded, the fork arms being connected to a metal root attachment spigot through a metal cross-piece encapsulated in the plastics material.

Abstract: A large wind turbine rotor blade having a filament wound composite spar securely mounted to a support structure in a manner by which blade loads are transmitted via redundant load paths. Concentric inner and outer metallic adapter sleeves are bonded to the inboard end of the blade spar, and the adapter sleeves and blade spar are joined by a first series of shear bolts and nuts which pass radially through the spar. A second series of radially extending bolts and nuts join the inner and outer sleeves slightly inboard of the end of the spar. The end of the spar is of slightly reduced diameter forming a conical surface which interacts with the inner and outer sleeves to produce a positive lock when the blade is subject to centrifugal loads. The outer sleeve is adapted to be connected to the support structure by conventional techniques such as by a plurality of bolts which extend axially into the butt end of the outer sleeve.

Abstract: A two-bladed propeller fan for wind machines, having a teetering hub for mounting in spaced relationship on a driving shaft, a pair of tangs 180.degree.

Abstract: A turbine blade comprised of at least a pair of abutting blade parts with each part having a root coupled to an attachment piece, the latter adapted to be coupled to a turbine rotor. The blade parts can be curved and each blade part may have a hollow space in the region where it abuts the other blade part to reduce the weight of the blade. The blade parts may be spigoted or mated with tongue and groove structure to reduce fluid leakage through the junction between the blade parts.

Abstract: A flow directing apparatus for use in an axial flow turbomachine is disclosed. Techniques for reducing aerodynamic drag along the walls of the flow directing apparatus are developed. In one embodiment, rotor blades have multiplanar platform surfaces which reduce aerodynamic drag pressure losses at the interface between each blade platform and the adjacent structure.

Abstract: A rotor blade for a gas turbine engine comprises an aerofoil, an inner platform and a root portion. In order to restrain the movement of the blade should it become detached from its rotor, the platform has an indentation in that edge adjacent the convex flank. If the blade detaches, this indentation engages with the leading edge of the next adjacent blade in the row, tending to restrict motion of the detached blade to the radial plane.

Abstract: The present invention provides an assembly for mounting a row of ceramic rotor blades in the metal rotor disc of a gas turbine engine. The major components of the assembly comprise a well known ferritic metal rotor disc in which is mounted, in a conventional fir-tree root configuration, a plurality of high temperature metal alloy or super alloy intermediate members forming an annular array thereof and defining "dog-bone" shaped axial grooves in the annular face for receipt of a complementary "dog-bone" or single serration root of a ceramic blade for mounting an annular array of ceramic blades. The root shank portion and the air foil portion of the blade are separated by a platform and centrifugal-force pins are inserted between adjacent platforms to fix the blade against low frequency vibration and to seal the gap therebetween against leakage of the motive fluid into the root area.

Abstract: This invention concerns fibre reinforced plastics structures, and is particularly concerned with the attachment of such structures, for example, a helicopter rotor blade, to a supporting metal member by bolting through holes provided in the structure. Accordingly the invention teaches an arrangement in which the or each attachment hole is defined by at least two metal bushes secured in the structure with the outer ends of the outermost bushes flush with the surfaces of the structure and so that the bushes are spaced-apart axially within the structure.In a preferred embodiment, a resilient washer is located in the spacing between ends of adjacent bushes and in contact therewith.

Abstract: A rotor blade system which is adaptd for long term reliable operation in a gas turbine engine is disclosed. Techniques incorporating composite materials into the rotor system are developed. One rotor structure shown utilizes a paired blade assembly having a core of continuous fibers running from the tip of one blade to the tip of the adjacent blade. Each of said paired blade assemblies is mchanically detachable from the engine rotor.

Abstract: Improved attachment structure for connecting ceramic blades to the rotor disk of a gas turbine rotor. The structure includes a plurality of metallic attachment pieces having roots inserted into respective grooves in the outer periphery of the rotor disk. Each attachment piece has an outer peripheral groove for receiving the root of a corresponding turbine blade formed of ceramic material. Specific embodiments of an attachment piece and a blade are disclosed, the blade having a base which engages the outer peripheral face of the corresponding attachment piece. The blade base and the corresponding attachment piece have aligned, spaced grooves at the opposed ends thereof for receiving ceramic plates which cover the adjacent parts of the attachment piece. Certain ends of the ceramic plates define recesses for receiving metallic plates which extend radially of the rotor disk and transmit torque from the blade to the attachment piece and thereby to the rotor disk.

Abstract: A turbine rotor having a number of metallic attachment pieces for coupling a plurality of ceramic blades to a metallic rotor disk. The blades have roots which are received within grooves formed in the attachment pieces. Each attachment piece has passage means therethrough cooperating with passages in the rotor disk for receiving a coolant for cooling the attachment pieces without causing the coolant to contact the ceramic blades. The attachment pieces keep the rotor disk isolated from the hot gases which contact the ceramic blades.

Abstract: An improved rotor for a gas turbine engine wherein the rotor has a plurality of ceramic turbine blades coupled by attachment pieces of high-temperature metal to a rotor disk. Each attachment piece has a root received in a corresponding groove in the outer periphery of the rotor disk. Also, each attachment piece is made to couple a pair of turbine blades to the rotor disk, the attachment piece having a pair of axially spaced, radially extending walls, each wall having a hole therethrough and the holes of the walls being aligned with each other. The roots of the two blades for each attachment piece are positioned between its spaced wall and the roots have cooperating projecting parts which engage each other and form a recess through which a pin extends when the ends of the pin are in the holes of the end walls. The roots of the blades of adjacent attachment pieces abut each other to keep the blades from moving laterally relative to respective attachment pieces.

Abstract: A variable pitch blade and blade mount which is suitable for propellers, fans and the like and which has improved impact resistance. The invention is particularly directed to composite fan blades and blade mounting arrangements wherein the blades are permitted to pivot relative to a turbine hub about an axis generally parallel to the centerline of the engine upon impact of a large foreign object, such as a bird. By thus providing for the pivoting of the blades upon impact, centrifugal force recovery becomes the principal energy absorbing mechanism and a blade having improved impact strength is obtained.

Abstract: A turbomachinery blade platform comprising a pair of complementary platform halves, each having an outer flow path defining shroud adapted to extend generally laterally of the blade. An inner flange on each platform half, also extending generally laterally of the blade, is retained in a cooperating slot formed within the support structure retaining the blade. A structural member extending between the shroud and the flange is contoured to conform to an overlapping wedging surface disposed about the blade airfoil surface. The platform is thus provided with redundant retention by both the blade and by the blade support structure.