Abstract: The present invention provides a gas turbine engine blade having a dovetail, a shank extending radially outward from the dovetail, and a platform joined to the shank. An inner surface of the platform faces radially inwardly and an opposite outer surface of the platform faces radially outwardly. An airfoil extends radially outwardly from the platform and has pressure and suction airfoil sides that define pressure and suction blade sides of the blade. The platform extends axially between leading and trailing platform edges and transversely between pressure and suction side platform edges of the platform. At least one transversely extending bracing rib is in a corner of the shank and the platform between one of the blade sides and the inner surface of the platform. The preferred embodiment further includes the bracing rib, the shank, and the platform being integrally cast. The bracing rib is preferably wider along the platform and the shank than at a distal edge of the rib.

Abstract: A gas turbine blade includes an airfoil, platform, and dovetail. The blade is cast with a chamfer along one edge of the platform thereof. The platform edge is then machined to truncate the chamfer in a simple and precise method.

Abstract: A fan rotor assembly (30) for a gas turbine engine (10) comprises a fan rotor (32) and a plurality of radially extending fan blades (34). Each fan blade (34) has a root (64) which is retained in a corresponding groove (54) in the periphery of the hub (54) of the fan rotor (32). Each fan blade root (64) comprises four axially spaced root portions (66, 68, 70 and 72) which locate in a corresponding number of axially spaced groove portions (56, 58, 60 and 62). The flanks (94, 98) of two of the root portions (66, 70) are arranged at an angle to the axis of the fan rotor (32) and the flanks (96, 100) of the other two root portions (68, 72) are arranged at an angle in the opposite sense. The flanks (74, 76, 78 and 80) of the groove portions (56, 58, 60 and 62) are arranged at the same angle as the flanks (94, 96, 98 and 100) of the corresponding root portions (66, 68, 70 and 72). The arrangement provides improved retention of the fan blades (34) and reduces the weight of the fan blades (34) and fan rotor (32).

Abstract: A final kit of a selected plurality of first and second groups of articles, for example turbine engine blading members, for subsequent assembly within a tolerance range along a distance in an article holder, is provided prior to assembly in the holder. This is accomplished by measuring dimensions of the first and second groups, and adjusting, if necessary, the numbers of articles in each group while maintaining the total number in the plurality.

Abstract: A fan in an axial flow gas turbine engine includes a plurality of fan blades. Each fan blade includes an airfoil portion and a root portion with a platform disposed radially therebetween. The platform of each blade extends circumferentially from the blade and is dimensioned to define, with an adjacent platform, an enlarged gap to insure that contact between adjacent platforms is avoided when a blade is released during a blade loss condition. A seal is provided to seal the enlarged gap between adjacent platforms during normal operation of the gas turbine engine.

Abstract: A turbine blade with a cooling air flow path specifically directed toward cooling the platform portion of the blade root. Cooling air passages are formed in the blade root platform just below its radially outward facing surface on an overhanging portion of the platform opposite the convex surface of the blade airfoil. Each of these passage extends radially outward from an inlet that receives a flow of cooling air, and then extends through the platform. Cavities are formed in a radially inward facing surface of an over hanging portion of the platform opposite the concave surface of the blade airfoil. An impingement plate directs cooling air as jets into these cavities. A passage is connected to the cavities and directs this cooling air through the overhanging portion of the platform opposite the concave surface.

Abstract: An arrangement for attenuating vibrations of blades attached to a peripheral surface of a rotor of an axial turbine. A through hole is formed in each rotor blade in a generally thickness direction of the blade so that the through holes in combination define a single annular passage near a rotor surface when all of the rotor blades are attached to the rotor. A wire is provided to extend through the aligned through holes. Thus, the wire frictionally contacts the through holes when the blades are caused to vibrate due to a gas pressure and a centrifugal force generated upon operation of the axial turbine. Friction contact between the wire and the through holes attenuates vibrations of the blades.

Abstract: Platform cooling having a guide-blade platform (30; 60) which is subjected to a hot-gas stream (20) and is separated by a gap (36; 66) from a combustion-chamber segment (40; 70) arranged upstream, one or more segment cooling bores (42; 72) being made in the combustion-chamber segment (40; 70), which segment cooling bores (42; 72) connect a cooling-air chamber (44; 74) to the gap (36; 66). The guide-blade platform (30; 60) has a surface (34; 64) on the downstream side in the region of the gap (36; 66), the axes of the one or more segment cooling bores (42; 72) running roughly tangentially to said surface (34; 64).

Abstract: A deflector for redirecting cooling air leakage to improve the efficiency of a gas turbine engine rotors. Adjacent rotor blades have a radially extending gap between each adjacent rotor blade and cooling air leaks into the gaps resulting in engine inefficiency. A deflector, disposed circumferentially on a forward face of the coverplate, deflects cooling air leakage, flowing from the running seal through the cooling air leakage path, away from the gaps between the blades, onto the outward surface of the blade platform, and into the gaspath at an acute angle relative to rearwardly axial flow. A forwardly extending flange deflects cooling air leakage forwardly around the blade platform lip.

Abstract: A damper for the blades of a turbine rotor for attenuating the vibrations excited in a radial direction by configuring the damper to have at least two legs bearing against the blade and the disc supporting the blade for grounding the radial vibrations transmitted radially through the damper and offsetting the center of gravity of the damper from the point of contact with the blade.

Abstract: A rotor blade includes an airfoil, an integral platform, and a dovetail integrally joined to the platform. The dovetail includes a neck extending between a pair of dovetail lobes configured to engage a complementary slot in a rotor disk. The dovetail includes an undercut extending between an outer face of the dovetail lobes and the neck for introducing a stress concentration thereat. The stress concentration relieves stress at the outer face at the expense of the neck for increasing the high cycle fatigue life of the blade.

Abstract: In a turbine having a rotor wheel with axially extending female dovetails spaced circumferentially one from the other about the circumference of the wheel, buckets having male dovetails at their radially inner ends are axially inserted relative to the rotor wheel to secure the buckets to the wheel. Where the buckets have shrouds at their radial outer ends prohibiting axial entry and assembly of the final or closure bucket onto the wheel, an axial entry dovetail segment having radially opposite male dovetails is employed to secure the final or closure bucket to the wheel. The final bucket includes a female dovetail at its radial inner end while the axial entry dovetail segment has radial inner and outer male dovetails.

Abstract: A turbine or compressor disk assembly comprises a plurality of blades attached to a central hub by means of the blade root of each blade engaging a corresponding slot in the hub. According to the principles of the present invention, a turbine or compressor disk assembly includes one or more locally bulging regions extending axially away from the surface of the disk in the vicinity of the bottom contact plane of the disk attachment firtree. The locally bulging regions reduce the peak Macke stress in the disk bottom fillet and blade attachment root. In an illustrative embodiment, two locally bulging regions are incorporated into the disk and the corresponding blades, one of which extends forward from the leading edge of the disk and the other of which extends rearward from the trailing edge of the disk. The rearward locally bulging region has an exaggerated extension which allows the stress reduction ring to form an aft flow discourager as well as functioning to reduce peak stress.

Abstract: A cooling system is disclosed for cooling the platforms of turbine blades fixed to the periphery of a turbine rotor, each turbine blade having an airfoil portion, a platform with opposite longitudinal edges, a root portion affixed to the turbine rotor, and a shank portion connecting the root portion to the platform. Adjacent turbine blades are located such that a longitudinal edge of one platform is adjacent to a longitudinal edge of an adjacent platform. A cavity is formed bounded by a portion of the periphery of the turbine rotor, the shank portions of the adjacent turbine blades, and the platforms of the adjacent turbine blades. A cooling air passage supplies cooling air to the cavity. One or more cooling channels are formed in a side of the platform facing the turbine rotor, each cooling channel having a cooling air collector at an end located adjacent to the air supply passage and communicating with the cavity.

Abstract: A rotary turbomachine, and particularly a turbojet engine, has a compressor stage that is especially adapted for operation in the transonic region. The compressor stage includes a rotor (1) having a hub (2) and a plurality of compressor blades (3) extending radially therefrom, and a stator having a plurality of compressor blades extending radially between a stator hub and a housing. The hub (2) of the rotor (1), and/or the hub of the stator, and/or the housing of the stator, have a circumferential surface contour that is not continuously rotationally symmetrical. Namely, a concave contour (K) is provided in the circumferential surface of the hub near the base of each blade (3) on the pressure side (PS) thereof, while the circumferential surface on the suction side (SS) of the base of each blade has a contour that is linear, slightly convex, convex/concave, or slightly concave to a lesser degree than the concave contour (K) on the pressure side of each blade.

Abstract: A cover plate for a bladed rotor in a turbine section of a gas turbine engine which comprises an annular plate segment comprising a plurality of spaced-apart seats with each seat coincident with a rivet. The rivets are the rivets used for anchoring the root of the blade in the disc, and the seats and the covers have frusto-conical surfaces having an axis which is the axis of the rivet.

Abstract: A first-stage turbine blade includes an airfoil having a profile according to Table I. The airfoil has a plurality of cooling air passages extending linearly from the root portion to the tip portion of the airfoil. The blade includes a shank having a pair of cavities in communication through the blade dovetail with a plenum in the wheel space for supplying cooling air to the passages in the airfoil. The cooling passages in the airfoil terminate in a recess at the tip portion which has an opening adjacent the trailing edge of the airfoil and along the suction side to enable egress of cooling air into the hot gas stream on the low pressure side of the airfoil. The majority of the cooling passages are turbulated. Certain of those passages are arranged in rows lying adjacent to the pressure and suction sides of the airfoil.

Abstract: In connection with a turbine rotating disk with disk grooves, constituted by disk fingers, for receiving turbine blades, as well as with measures for guiding a cooling air flow from a chamber located in front of the disk to one behind the disk, a cooling air transfer channel is provided in at least some of the disk fingers, which respectively starts at the front disk face, and makes a transition into a cooling air exhaust channel, also essentially extending in the radial direction in the disk finger, whose outlet opening on the rear disk face side lies closer to the disk axis than the disk ring section, which has the disk grooves and is widened in the disk axial directions. By means of this it is possible to convey a larger cooling air flow which, in an advantageous manner, indirectly aids the cooling of the disk in the area of the disk grooves.

Abstract: An annular seal plate for an interstage air riding seal arrangement for the internal cooling system of a gas turbine engine is mounted on a rotatable disc by means of an annular mortise and tenon mounting. The contact faces of the mortise and tenon are angled relative to a radial plane of the disc so that centrifugally generated forces are reacted by the faces in a sense to counter axial tilt so that a seal face of the plate lies exactly in a radial plane, at a design rotational speed, thereby to eliminate convergence or divergence between the seal faces of the air riding seal.

Abstract: A movable gas turbine blade includes a platform (10) which is provided with a groove (15). The groove is located on a blade trailing side of the platform. Also, the groove is rounded and has a depth which does not enter a stress line of the platform caused by a load on the blade. The groove functions to suppress a high thermal stress arising at a connection portion of a blade trailing edge and the platform of the gas turbine air cooled moving blade during unsteady (start and stop) operation of the turbine.

Abstract: A seal for a turbine blade in a gas turbine engine has a sealing portion with two subportions, where the subportions are longitudinally offset from one another, so that the seal may provide sealing for adjacent turbine blades having longitudinally offset inner platform surfaces. The offset between the sealing subportions should correspond generally to the offset between the platform surfaces.

Abstract: A rotor for a ducted fan gas turbine engine includes a rotor disc on which a number of circumferentially spaced apart blades are mounted. Wall members are positioned to bridge the space between adjacent blades. The wall members correspond in profile with the blades adjacent thereto. A seal is mounted on a side face of each wall member and is bonded to a flexible mounting which is bonded itself to the wall member. The flexible mounting has elastic properties so as to allow the seal to deflect relative to the wall member under centrifugal loading during operation.

Abstract: A vane for a fan including a platform, a root and a blade. The platform has opposite outer and inner surfaces, and opposite upper and lower surfaces. The upper surface has a camber shape, and the lower surface has a concave shape corresponding to the camber shape of the upper surface. The root is fixed to the inner surface of the platform and adapted to be fixed to a hub of the fan. The blade is fixed to the outer surface of the platform at a position shifted toward the lower surface from a center line between the upper and lower surfaces.

Abstract: The present invention relates to a fan blade in an axial gas turbine engine. The blade platform is constructed to fracture adjacent the airfoil portion of the blade so as to locate the fractured edge of the platform in the root portion. As a result of this benign platform, damage to successive fan blades during a blade loss condition is reduced. In addition, various construction details are developed in the airfoil and root portion of the fan blade to reduce damage to fan blades during impact with adjacent blades.

Abstract: A damper for a turbine blade in a gas turbine engine includes a main body and may include at least one extended end which is adapted to clear radially inner surfaces of two adjacent blade platforms, to enhance the damping profile of the damper and radial support for a seal. An associated seal for the turbine blade includes supported and sealing portions and may further include a locator that interfaces with a catch structure on the blade to maintain the seal in the proper axial position with respect to the radially inner surfaces of the adjacent platforms. The seal may further include a projection adapted to provide interference with the blade in the event that the damper and seal are installed improperly with respect to each other to prevent such improper assembly.

Abstract: A turbomachine is provided with a rotor assembly. A seal member 18 is mounted between a blade 12 and a rotor disc 11 of the rotor assembly, the seal member 18 rocking under centrifugal force about an axis 24 to give substantially straight line sealing contact 26, 27 therealong, e.g. with the blade 12.

Abstract: A damper which provides both blade to blade and blade to ground damping is described. In one embodiment, the damper includes a retainer and a chicklet. The retainer is secured to a rotor disk by a bolt which extends through an opening in the disk and an opening in the retainer. The retainer includes support flanges which facilitate positioning retainer relative to the disk, and sidewalls (or guides) for limiting movement of the chicklet. The chicklet is movably positioned within the retainer, and movement of the chicklet is limited by sidewalls and a cross wall member of the retainer. The retainer positions the chicklet so that in operation, a contact surface of chicklet makes blade to blade contact with adjacent blades. In operation, centrifugal forces drive the chicklet into contact with the blade platforms. Since the chicklet is in contact with adjacent blades, blade to blade damping is provided.

Abstract: A rotor blade for a rotor of a gas turbine engine having an axis of rotation including a root portion, a platform portion connected to the root portion and having a damper pocket formed therein, an airfoil portion connected to the platform portion, a generally bar-shaped damping member loosely arranged in the damper pocket having at least one scrubbing surface, and at least one retainer pin for retaining the bar-shaped damping member in the damper pocket. The bar-shaped damping member is slidably displaceable and rotatable within the damper pocket during rotation of the rotor. The damper pocket in the platform portion has a rear surface with an upper portion and a lower portion at an angle to the upper portion, a pair of spaced side surfaces, and a pair of spaced lower surfaces extending from the rear surface lower portion which are substantially coplanar.

Abstract: A rotor blade for a rotor of a gas turbine engine having an axis of rotation including a root portion, a platform portion connected to the root portion and having a damper pocket formed therein, an airfoil portion connected to the platform portion, a generally bar-shaped damping member loosely arranged in the damper pocket having at least one scrubbing surface, and at least one leg extending from the bar-shaped damping member for retaining the bar-shaped damping member in the damper pocket. The bar-shaped damping member is slidably displaceable and rotatable within the damper pocket during rotation of the rotor. The damper pocket in the platform portion has a rear surface with an upper portion and a lower portion at an angle to the upper portion, a pair of spaced side surfaces, and a pair of spaced lower surfaces extending from the rear surface lower portion which are substantially coplanar.

Abstract: A bladed rotor for the high pressure compressor of a gas turbine engine comprises a disc carrying an annular array of aerofoil blades in axially extending fir tree root slots. Retention plates carried in radially inner and outer slots prevent axial movement of the blade roots in their slots. A locking member is interposed between an adjacent pair of retention plates to prevent their circumferential movement relative to the disc. The locking member in turn interacts with the disc to anchor itself to the disc.

Abstract: Turbines having rotor blades (3, 5) fixed in dovetail grooves (14) in the rotor periphery have bridge pieces (17) which provide in effect a false floor to the inter-stage recess (8, 11) to close off the machining recess from the fluid path. This invention provides a method of fixing this bridge piece which is simple, positive and avoids loading the rotor disc rims with additional centrifugal force. The dovetail groove (14) for the blade root is continued into a raised portion or the rotor recess periphery. This raised portion is grooved circumferentially (21) and the stem (19) of the `T` section bridge piece fits snugly in the groove. A dovetail section key (23) is inserted through the blade root dovetail groove (14) and into the raised portion of the rotor, passing through a hole in the stem (19) of the bridge piece. The latter is thus positively located and locked in position.

Abstract: A seal for sealing the gaps between adjacent turbine blade structures is disclosed in which the seal is disposed in a compartment formed between adjacent turbine blade structures having first and second sealing surfaces adjacent to a generally axially extending gap and a generally radially extending gap, respectively. The seal also has a thrust surface extending obliquely to a radius from the axis of rotation of the rotor disk to which the turbine blade structures are attached which is engaged with a reaction surface formed on a reaction member located in the compartment. During rotation of the rotor disk, centrifugal force acting in a radially outward direction is transmitted both radially and axially to a seal by contact between the reaction surface and the oblique thrust surface to cause the first sealing surface to seal the generally axially extending gap and the second sealing surface to seal the generally radially extending gap.

Abstract: A stage of fan blades in a ducted fan gas turbine engine have the spaces between them filled by a rotary annulus wall filler which has a leading portion made from metal and a trailing portion made from a composite material. The metal portion resists the impact damage from the ingress of foreign bodies and the trailing portion provides a lighter structure.

Abstract: An apparatus is provided that includes a bladed device having a hub which is rotatable about an axis and one or more blades attached to the hub by self-energizing, self-locking, insertion and retention features which are formed integrally with the blade and hub. The insertion and retention features include a locking tang formed integrally with the root of the blade, and detent features which are part of the locking tang and hub. As the blade is inserted axially into the hub, the locking tang deflects radially inward and then snaps radially outward by spring action of the tang to engage the detent feature of the hub, and thereby lock the blade against further axially or radially movement with respect to the hub. The locking tang is oriented and configured in such a manner that the locking tang is self-energizing, thereby causing the tang to grip the hub more tightly as rotational speed of the bladed device increases.

Abstract: Assembly for a rotor whose disk alternately bears vanes (1) and platforms (2). The plays (i.e. clearances) (7) are filled up with linings (15) composed of a mainly flexible casing (16) occupied by a small rod (20) which moves outwardly under the action of the centrifugal forces for filling up the play (7).

Abstract: Gas turbine blades 14 are slid axially into disc 12 with a retention tang 22 on each abutting the disc. An axially extending space 28 between blade platforms 26 and the disc receives elongated strip 30. With prebent end 34 resiliently held against the disc the opposite end 36 is bent radially outward against the roots of adjacent blades. A bow 38 biases the blades outwardly, deterring vibration.

Abstract: An apparatus for sealing a gap between adjacent blades in a rotor assembly for a gas turbine engine is provided. The rotor assembly includes a plurality of blades circumferentially disposed around a disc. Each of the blades includes an airfoil, a root, and a platform extending outward in a lateral direction in a transition area between the root and the airfoil. The disc includes a plurality of complementary recesses circumferentially distributed around the disc for receiving the blade roots. The gaps are formed between edges of adjacent platforms. The platforms collectively form a flow path for primary fluid flow passing by the airfoil side of the platforms and secondary fluid flow passing by the root side of the platforms. The apparatus comprises a thin plate body and apparatus for conducting secondary flow between the thin plate body and root side surfaces of adjacent blade platforms, and thereafter into the gap.

Abstract: Fan blades of a rotor stage do not have platforms and separate wall members are provided to bridge the space between adjacent blades with the wall members defining an inner wall of a flow annulus through the rotor; each wall member has a plurality of hooks which extend radially inwardly to engage correspondingly shaped hooks provided on the radially outer face of the disc and further hooks engage rings mounted on the rotor adjacent to the disc to lock the wall member in position and insure that the hooks on the wall member engage the hooks on the radially outer face of the disc.

Abstract: A fan rotor has separate wall members bridging the space between adjacent blades of the rotor to define an inner wall of a flow annulus through the rotor; each wall member is attached to the radially outer face of a disk and opposing side faces to which resilient seal strips are bonded; the seal strips have flange portions which are inclined radially inwardly along a curved edge to produce undulations to enhance the flexibility of the flange portion so that, in operation, as the fan rotor rotates about a central axis of the engine, the flange portions are deflected radially outwardly by centrifugal forces into sealing contact with the adjacent fan blade to seal the inner wall of the flow annulus.

Abstract: In a turbofan engine a fan designed for reduced damage during a blade-out condition wherein the fan blade airfoil is disposed asymmetrically on the platform and includes a forwardly displaced leading edge. The platform is configured to make early contact with a following airfoil upon blade-out.

Abstract: A separate inter-blade platform for a turbomachine rotor comprises a structural rectilinear longitudinal member formed by a foam core, plies of a carbon/epoxy type material in bidirectional layers of crossed fibres oriented at 45.degree. laid around the core and around an insert at each end of the longitudinal member, each insert being made of juxtaposed radial plies of a carbon/epoxy type material in bidirectional layers of fibres crossed at .+-.45 degrees, and further plies of a carbon/epoxy type material in unidirectional layers oriented in the direction of the major axis of the longitudinal member covering the upper and lower faces of the member, the platform further comprising lateral packing cores made of a foam material, plies of a glass/epoxy type material covering the lateral faces of the longitudinal member and connecting it to the lateral foam cores, and peripheral plies of a glass/epoxy type material covering the assembly formed by the longitudinal member and the lateral cores connected thereto.

Abstract: A rotor assembly 10 having a rotor disk 12 and a plurality of outwardly extending rotor blades 16 is disclosed. Various construction details are developed to provide effective cooling to the platform sections 20 of such rotor blades. In one particular embodiment, a damper 58 engages the underside of the rotor blades 16 and a seal member 42 inwardly of the damper engages the damper to provide damping of vibrations in the rotor blades. Both the damper and the seal member are provided with cooling air holes 42, 74 to positively distribute cooling air collected inwardly of the damper and seal member and to direct the cooling air preferentially between the adjacent platform sections 20 of the rotor blades to effectively cool the rotor blades.

Abstract: A flow directing assembly 24, 24a for a rotary machine 10 is disclosed. Various construction details are developed to decrease aerodynamic losses and promote the ease of design. In one particular embodiment, a concave region 58 of an end wall is employed to create convex wall regions 54, 56 upstream and downstream of the concave region.

Abstract: A generally wedge-shaped vibration damper for rotor blades of a gas turbine engine has a pair of scrubbing surfaces and is loosely retained in a pocket incorporated in the rotor blade platform. The pocket is partly defined by a plurality of surfaces which orient the damper so that it is slidably displaceable and rotatable only in a predetermined plane. During rotation of the rotor disk, the damper of one rotor blade is displaced in a plane transverse to the rotor axis of rotation by centrifugal forces to a position at which one scrubbing surface of the damper abuts a side surface of the platform of the adjacent rotor blade and the other scrubbing surface abuts an inner surface of the platform of the rotor blade in which the damper is inserted. The scrubbing action of the damper serves to damp vibratory motion in the platforms of both blades.

Abstract: A turbine vane for a gas turbine engine core adaptable to be operated in a variety of thrust regimes is disclosed. Various construction details are developed which provide cooling to an inner platform of the turbine vane. In one particular embodiment, a turbine vane includes a hollow core permitting cooling fluid to pass through the vane and an inner platform having a pocket disposed therein, the pocket being in fluid communication with the core. Heat is exchanged between the platform and the cooling fluid within the pocket. Cooling holes extend between the pocket and a flow surface of a platform to provide cooling of the flow surface.

Abstract: An integrated damper and windage cover 52 has a windage cover portion 56 cantilevered at the upstream end, free of contact with the blade platform 24, 32. The contact portion 54 is rigid and bears against the underside of the blade platform 24, spanning blade platform clearance 50.

Abstract: A generally wedge-shaped vibration damper for rotor blades of a gas turbine engine has a pair of scrubbing surfaces and is loosely retained in a pocket incorporated in the rotor blade platform. The pocket is partly defined by a plurality of surfaces which orient the damper so that it is slidably displaceable and rotatable only in a predetermined plane. During rotation of the rotor disk, the damper of one rotor blade is displaced in a plane transverse to the rotor axis of rotation by centrifugal forces to a position at which one scrubbing surface of the damper abuts a side surface of the platform of the adjacent rotor blade and the other scrubbing surface abuts an inner surface of the platform of the rotor blade in which the damper is inserted. The scrubbing action of the damper serves to damp vibratory motion in the platforms of both blades.

Abstract: A last-stage steam turbine bucket having a profile according to Charts I-XXXXI of Table I.The bucket is divided into a number of profile sections each of which is a predetermined radial distance from the root section. Each point on a profile section at the predetermined radial distance from the root is defined by an X-Y coordinate and a radius R along the arc of a circle connecting adjacent points.

Abstract: Freestanding rotor blades are mixed tuned by varying the dimensions of the blades at two locations. First, a profiled tip includes a machined-out strip, having a height which can be varied to achieve the desired tuning effect. The longer or deeper the profile, the higher the frequency will become. This tuning technique is used in conjunction with a broadened base section. Blades having a shorter profile tip are machined beginning at the base section, so as to remove enough mass from between the base section and a next upper section to provide the desired tuning effect. The lower frequency blade has a thinner base section and a shorter profile tip.

Abstract: A fan assembly includes a plurality of discrete platforms disposed between adjacent rotor blades extending radially outwardly from a rotor disk. Each platform includes forward and aft axially spaced apart ends, and radially upper and lower spaced apart surfaces extending between the ends. Forward and aft retainer rings capture the platform to the disk with a predetermined clearance therebetween for allowing the platform to move radially upwardly under centrifugal force for retention by the retainer rings, while also allowing the platform to move radially inwardly under a radially inwardly directed impact load on the platform, which impact load is channeled through the platform lower surface at both the forward and aft ends into the rotor disk.