Abstract: A cast turbine airfoil to which a squealer tip is added. The turbine airfoil is cast slightly undersize. The squealer tip is comprised of an alloy that is different from the cast alloy of the airfoil, the oxidation resistance and strength of the squealer tip alloy being greater than the strength of the turbine airfoil alloy. The cast turbine alloy having the added squealer tip can utilize a material in the squealer tip that is more difficult to cast than the cast alloy material, yet is more suited for severe environmental conditions and temperature extremes.

Abstract: A thin film that forms an interface between metal surfaces and polymeric inserts of aircraft engine fan blades. The thin film is formed from a chemical comprised of carbon black, at least one evaporable solvent, a combination of phenolic-like resins dissolved in the solvent and the balance filler and inert ingredients. The thin film, upon drying of the evaporable solvent, forms a phenolic that bonds with the metallic portion of the fan blade. After the polymeric material is applied to recesses in the fan blade and cured, a chemical bond is formed between the thin film and the elastomeric inserts. The bonded structure has improved FWT peak stresses and improved fracture toughness.

Abstract: An erosion resistant ceramic component is synthesized from a silicon oxynitride precursor powder with a sintering aide. The sintering aide, preferably aluminum oxide and/or lutetium oxide are added to the silicon oxynitride precursor powder and ball milled. The composition is then decanted, dried and granulated. The composition is then formed into the shape of the desired component by hot pressing in a graphite die. A heat treatment process may also be applied after hot pressing to further improve erosion resistance by crystallizing amorphous grain boundary phases to provide a ceramic component having sand erosion characteristics superior to electro-formed nickel. The component provides a dielectric constant which is much lower than the dielectric constant of an electro-formed nickel component.

Abstract: A rotor blade for a gas turbine engine including a tip region that facilitates reducing operating temperatures of the rotor blade is described. The tip region includes a first tip wall and a second tip wall extending radially outward from a tip plate of an airfoil. The tip walls extend from adjacent a leading edge of the airfoil to connect at a trailing edge of the airfoil. A notch is defined between the first and second tip walls at the airfoil leading edge. At least a portion of the second tip wall is recessed to define a tip shelf.

Abstract: A rotor blade for a gas turbine engine including a tip region that facilitates reducing operating temperatures of the rotor blade is described. The tip region includes a first tip wall and a second tip wall extending radially outward from a tip plate of an airfoil. The tip walls extend from adjacent a leading edge of the airfoil to connect at a trailing edge of the airfoil. A notch is defined between the first and second tip walls at the airfoil leading edge. At least a portion of the second tip wall is recessed to define a tip shelf.

Abstract: A gas turbine engine fan blade (26) comprises a root portion (40) and an aerofoil portion (42). The aerofoil portion (42) has a leading edge (44), a trailing edge (46), a concave metal wall portion (50) extending from the leading edge (44) to the trailing edge (46) and a convex metal wall portion (52) extending from the leading edge (44) to the trailing edge (46). The aerofoil portion (42) has a hollow interior (54) and the interior (54) of the aerofoil portion (42) is at least partially filled with a vibration damping material (56). The vibration damping material (56) comprises a material having viscoelasticity for example one formed by mixing an amine terminated polymer and bisphenol a-epichlorohydrin epoxy resin.

Abstract: An edge member for use on a composite flexure having an exposed edge surface. The edge member includes an innermost composite ply attached to the edge surface, an outermost composite ply attached to the innermost composite ply, and at least one interior composite ply disposed between the innermost composite ply and the outermost composite ply.

Abstract: A fan blade includes a metal airfoil having a pocket disposed in a first side thereof, with the pocket including a filler bonded thereto. The pocket includes a plurality of cells separated by corresponding ribs which are submerged in the filler.

Abstract: Increased impact resistance capability is achieved in a cost and weight efficient manner by providing a spinner made of a 3-D orthogonal woven composite material. The spinner defines a generally conical shell having a plurality of axial rib stiffeners and at least one circumferential rib stiffener integrally formed thereon. The combination of the integral rib stiffeners with the 3-D orthogonal woven composite material results in a substantially greater torsional stiffness. The use of the 3-D orthogonal woven composite material also eliminates delamination found in laminated composite spinners.

Abstract: A gas turbine engine fan blade (26) comprises a root portion (36) and an aerofoil portion (32). The aerofoil portion (32) has a convex surface (44), a concave surface (42), a leading edge (38) and a trailing edge (40). The leading edge (38) of the aerofoil portion (32) is formed from a harder material than the regions of the concave surface (42) and convex surface (44) immediately adjacent the leading edge (38) such that the leading edge (38) of the aerofoil portion (32) remains pointed. This improves the efficiency of the fan blade (26) and hence the gas turbine engine (10) and reduces flutter of the fan blade (10).

Abstract: The present invention is a nanocomposite layer applied to the leading edge of an airfoil. The nanocomposite is an elastomeric matrix reinforced with nanosized reinforcing particles ranging in size from about 0.5 to 1000 nanometers and preferably ranging in size from about 5 to 100 nanometers. These nanosized reinforcing particles improve the mechanical properties of a pure elastomer. Improving such properties assists the nanocomposite layer in absorbing and dissipating the impact energy caused by the repeated impact of particulate matter, such as sand and rain. Adding the nanosized reinforcing particles to an elastomer allows the nanocomposite to absorb the impact energy over a larger volume in comparison to a pure elastomeric material. The nanocomposite layer is, therefore, capable of withstanding the repeated impact caused by the particulate matter for a greater length of time compared to a pure elastomer.

Abstract: The devices according to the invention serve to direct a cooling fluid 230 in a cooled blade 210 of a turbomachine, in particular a gas turbine. In this case, the blade 210 has at least one cooling channel 213 running in the blade. According to the invention, at least one drawer 220 is arranged in at least one slot 221 of the blade 210. In a preferred embodiment of the invention, the drawer 220 arranged in the slot 221 is directly adjacent to the cover wall 212 and/or at least one side wall 211 of the blade. Furthermore, arranged in the drawer is at least one flow channel 222, which is preferably formed from a groove arranged in the drawer 220 and from the directly adjacent cover wall 212 and/or side wall 211. The flow channel 222 is connected to the cooling channel 213 by means of at least one opening 223. In addition, the cooling fluid 230 fed to the flow channel 222 flows off through a passage opening 224 in the cover wall 212 and/or the side wall 211 into the main flow flowing around the blade.

Abstract: A high temperature repairable airfoil having a plurality of flow path cover tiles coupled to a single crystal spar member. In one embodiment, the plurality of flow path cover tiles include an attachment portion that is received within a groove formed in the outer surface of the spar. The attachment portion slides into a retaining feature within the groove so as to limit movement of the plurality of flow path cover tiles. Upon rotation of the airfoil, the plurality of flow path cover tiles become centrifugally loaded with a portion of the spar member. In one embodiment, the plurality of flow path cover tiles are formed of a material selected from the group consisting of ceramics, intermetallic, and thermal barrier coated single crystal alloy material.

Abstract: A method and shield assembly 12 for use in processing a flow directing assembly 10, such as a stator vane or rotor blade, is disclosed. Various details are developed for the construction of the shield assembly and for the method of masking the flow directing assembly. The shield assembly has a shield having two sides 52, 56 and at least one tab 56 which extends from one of the sides and through the other side and is pressed against the other side. In one embodiment, the method includes exerting a force against the shield to block movement of the shield from the installed position. The shield assembly might include a locking member for this purpose which has a projection 106a which is attached to the shield or a locking member 42 which is not attached to the shield and which has a tab 114 which engages the shield and a projection 112 which engages the airfoil. Alternatively, the shield assembly might include a clamp 92 which presses the shield against the airfoil.

Abstract: A mechanical vapor recompression fan comprises a blade wheel and an electric motor to operate the blade wheel. The blade wheel at least mainly consists of carbon-fibre-based composite material and is mounted directly on the shaft of the blade wheel, and the tips of the blades of the blade wheel are provided with an erosion shield.

Abstract: A locking member for engaging a shield 40 which is disposed during processing about an airfoil 24 of a flow directing assembly 10, such as a stator vane or rotor blade, is disclosed. Various details are developed for the construction of the locking member. In one embodiment, the locking member is separate from the shield and has projections 112, 116 that each engage an opening 36a, 36b in the airfoil and tabs 114, 118 which engage an opening 78, 84 in the shield. In another embodiment, the shield has a projection 106a which is attached to the shield.

Abstract: A composite thermal barrier coating system includes a honeycomb metallic structure filled with high thermal expansion ceramic hollow spheres in a phosphate bonded matrix. The composite thermal barrier coating system may be manufactured to thicknesses in excess of current thermal barrier coating systems, thereby imparting greater thermal protection. Superior erosion resistance and abrasion properties are also achieved. The composite thermal barrier coating is useful on combustion turbine components such as ring seal segments, vane segment shrouds, transitions and combustors.

Abstract: A high temperature repairable airfoil having a plurality of flow path cover tiles coupled to a single crystal spar member. In one embodiment, the plurality of flow path cover tiles include an attachment portion that is received within a groove formed in the outer surface of the spar. The attachment portion slides into a retaining feature within the groove so as to limit movement of the plurality of flow path cover tiles. Upon rotation of the airfoil, the plurality of flow path cover tiles become centrifugally loaded with a portion of the spar member. In one embodiment, the plurality of flow path cover tiles are formed of a material selected from the group consisting of ceramics, intermetallic, and thermal barrier coated single crystal alloy material.

Abstract: A turbine blade squealer tip includes an airfoil shaped tip cap having a squealer tip wall extending radially outwardly from and around the perimeter of the airfoil shaped tip cap to define a radially outwardly open tip cavity. The tip wall has an inboard side facing the interior of the cavity and an outboard side facing away from the cavity and the tip cap has an outer tip side on a bottom of the cavity. Thermal barrier coatings are disposed on the inboard and outboard sides of the squealer tip wall and on the outer tip side of the tip cap. One embodiment provides the tip cap with cooling holes disposed therethrough to flow cooling air into the cavity.

Abstract: A compressor blade that has a blade root, an airfoil having a first end, and a second end opposite the first end, the second end having at least one edge, and the airfoil is made of a first material having a first modulus of elasticity. A blade platform connects the blade root to the first end of the airfoil, and a flexible seal is connected to the airfoil adjacent the second end, and the seal is made of a second material having a modulus of elasticity that is substantially less than the first modulus of elasticity.

Abstract: A wear and/or abrasive resistant tile e.g. for use on a scroll of a classifier, comprises a front, working face and a rear, mounting face defined by an upper face portion and a lower face portion spaced rearwardly from the upper face portion, the upper and lower face portions being in parallel planes; an upwardly projecting, upper lip formation defining an upper edge of the lower face portion; a downwardly projecting lower lip formation defining a lower edge of both the lower face portion and the tile, the lower lip defined by a chamfered face extending towards the lower face portion, with a lower surface of lower lip formation being non-pointed, and stepped upwardly from a geometrically projected apex, and at least one groove provided in the rear mounting face of the tile. A carrier is also included, and the carrier has a transverse slot. Also included are a tile and carrier combination, and a scroll provided with tile and carrier combinations.

Abstract: An assembly and method for welding an article, such as an air-cooled superalloy airfoil of a gas turbine engine nozzle. The method entails inserting a fixture into a cooling passage of the airfoil. The fixture is configured to close a first opening to the passage through which the fixture is inserted into the passage. The fixture is also configured to introduce a gas into the passage through a longitudinal row of ports. A through-wall crack in the airfoil is weld repaired while the gas flow is maintained to the cavity at a rate that sufficiently pressurizes the passage to prevent the molten filler material from entering the passage through the crack, while allowing the filler material to fill the crack.

Abstract: A heat dissipating fan for an induction motor comprises a motor shaft with a circular groove and an end part. A fan has blades and a hollow central shaft with a hole, and tennons are provided on an inner wall of the hole for fitting with the circular groove. A protection cover has an opening being passed through by the motor shaft. Furthermore, heat releasing fins are provided on the protection cover and space apart with each other surrounding the opening. The fan is characterized by that the blades is attached to the fan and is fixed to an annular base plate. The base plate has a slanted curvy surface structure. When said fan is rotating synchronously with said motor shaft, the air current can be directed smoothly and backwards into the motor.

Abstract: A high-strength hybrid component including a relatively soft first part made of a composite material including an organic matrix reinforced with fibers, a relatively hard second part made of metal, metal alloy, or ceramic, and a transition layer made of a composite material including a matrix of a material that is weldable to the hard part and fibers that are extensions of the fibers of the soft part. The transition layer matrix and the hard part may be formed by deposition of molten material on to the fiber preform of the soft part using flame, electric arc, or plasma. The resin matrix of the soft part is impregnated into the preform and polymerized afterwards. Alternatively, the hard part may be machined to shape and welded to the transition layer before completing the soft part.

Abstract: A shield 40 for use in processing a flow directing assembly 10, such as a stator vane or rotor blade, is disclosed. Various construction details are developed for the shield. The shield has two sides 52, 56 and at least two tabs 56, 58 which each extend from one of the sides and through the other side.

Abstract: The shielding of the blade against lightning comprises a conducting component forming a leading edge glove and a cover for protecting the blade tip across its entire chord. Mechanical means, such as screws and rivets, with protruding shapes, fix the cover on the composite structure of the blade, in addition to some gluing, possibly conductive gluing, and are earthed by the cover, forming points where the lightning can enter or exit, protecting the surrounding composite structure of the blade against damage. At least the cover may have a suction face arm and a pressure face arm of different dimensions, at least in the direction of the span. When the blade is mounted on a member for linking to the hub, electrical continuity with this member and the hub is provided.

Abstract: The invention provides a vacuum processing system comprising a vacuum processing chamber and a turbo-molecular pump having a rotor and/or stator comprised of metal matrix composites. Another aspect of the invention provides a turbo-molecular pump having a rotor and/or a stator comprised of metal matrix composites. Because metal matrix composites are able to withstand higher operating temperatures than the aluminum alloys currently used in rotors and stators, the rotor vanes and the stator vanes that are made of metal matrix composites can provide a higher exhaust capacity with faster rotor rotations.

Abstract: An airfoil having improved fatigue strength is disclosed. The airfoil comprises a tip, a root section, a platform, and an airfoil section located between the tip and the platform. The airfoil section has a leading edge and a trailing edge. A metallic coating is located along the leading edge and the trailing edge excluding a portion of the leading edge and the trailing edge located near the platform.

Abstract: A method for preparing a Ni base superalloy inner wall surface of a body open end, such as an end of a turbomachinery blade, and an end plate, such as a blade tip cap, for brazing together at a rim of the end plate includes electrochemically removing oxides from the inner wall surface. The end plate is prepared, at least at its rim, by first removing surface and subsurface oxides, for example by mechanical abrading or a combination of such abrading and acid cleaning. Then at least the rim is electroplated with Ni which is heated to diffuse the Ni into the rim substrate. This provides an improved combination of surfaces for brazing, for example with a Ni base brazing alloy. After brazing the rim to the inner wall, there is provided an article with an improved relatively low oxide brazed joint, including less than about 20 volume % oxides, and a plate rim of substantially Ni along with elements diffused from the brazing alloy and the rim.

Abstract: A hollow airfoil (34) for a gas turbine engine having a leading edge (50), a trailing edge (52), a pressure side (54), and a suction side (56) includes a solid region of enhanced chordal thickness (78), and buttresses (82, 84, 86, 88). The present invention airfoil is preferentially strengthened so as to reduce the risk of airfoil fracture due to impact of airfoil with successive airfoils during an airfoil loss condition.

Abstract: A fan blade includes a metal airfoil having first and second opposite sides extending radially between a root and a tip, and axially between a leading edge and a trailing edge. The airfoil further includes a pocket disposed in the first side having an elastomeric filler bonded therein. A panel is bonded to the filler along the pocket for allowing differential movement therebetween for damping vibratory response of the airfoil.

Abstract: A turbine assembly comprises a plurality of rotating blade portions in a spaced relation with a stationery shroud. The rotating blade portions comprise a root section, a tip portion and an airfoil. The tip portion has a pressure side wall and a suction side wall. A number of flow discouragers are disposed on the blade tip portion. In one embodiment, the flow discouragers extend circumferentially from the pressure side wall to the suction side wall so as to be aligned generally parallel to the direction of rotation. In an alternative embodiment, the flow discouragers extend circumferentially from the pressure side wall to the suction side wall so as to be aligned at an angle in the range between about 0.degree. to about 60.degree. with respect to a reference axis aligned generally parallel to the direction of rotation.

Abstract: A guide blade for steam turbines, having in the blade interior a cavity (18) to which a vacuum is applied, is provided with an opening (3) for drawing off fluid in the region of the trailing blade edge (4). This opening is provided with a porous cover (7). The cover is dimensioned in such a way that, during operation, all its capillaries are filled with the fluid to be drawn off. It is anchored in the guide blade by a mechanical fastening element (20).The mechanical fastening element (20) is a spring-loaded quick-acting lock and comprises a bush (21) which fixes the cover in the blade opening (3) and projects with its cylindrical part (24) into the blade cavity (18), and a pin (25) which is axially displaceable in the interior of the bush, is equipped with spring means (26) and is provided at its end with a cap (28), which rests on the inner wall of the blade.

Abstract: A gas turbine engine fan blade includes an airfoil and dovetail having an integral aluminum core and a fatigue resistant reinforcing sheath.

Abstract: A turbine blade which is provided for use in a wet steam region of penultimate and ultimate stages of turbines and is subject to erosive wear caused by impinging water droplets, is treated in a region of leading edges and parts of a blade leaf in such a way as to reduce the erosive wear. In order to reduce the erosive effect of the water droplets, the blade leaf has a surface roughness in the region of its leading edge and its blade back or in at least a partial region thereof. The surface roughness is markedly increased in comparison with the surface roughness of a front side of the blade leaf.

Abstract: A composite article comprising of a non-metallic composite core, a fluoroelastomer adhesive layer which has a curing temperature substantially similar to the composite core, and a metallic structure which overlays the fluoroelastomer adhesive layer, wherein the composite article can be formed by co-curing the core and the fluoroelastomer adhesive layer.

Abstract: A blade for a fluid flow machine such as a jet turbine engine includes a blade body (2) that is to be exposed to the fluid flow and therefore is subject to damage by erosion due to abrasive particle entrained in the fluid flow and due to thermal loading. The blade body (2) is a layered body including base layers (6) of a fiber reinforced synthetic material and a metallic cover layer (7) applied as an erosion protective layer onto at least a portion or the entirety of the surface of the base layers (6). The cover layer (7) includes metallic fibers or threads (9A, 9B) which are bonded with the fiber reinforced synthetic material of the adjacent base layers (6) by the same synthetic resin binder material permeating through and forming a matrix for all the layers (6 and 7). The metallic fibers or threads (9A, 9B) embedded in a synthetic resin matrix are characterized by a high degree of erosion resistance and a good tolerance for defects in the case of local impact or erosion damage.

Abstract: A gas turbine engine rotor blade includes an airfoil having a concave side wall and a convex side wall joined together at leading and trailing edges. Concave and convex tip walls extend from adjacent the leading edge along the respective concave and convex side walls to adjacent the trailing edge and are spaced apart to define a tip cavity therebetween. A hole or channel is disposed in a trailing edge tip region connecting the tip cavity to the trailing edge for channeling cooling fluid through the trailing edge tip region.

Abstract: A fan blade includes a metal airfoil having first and second opposite sides extending longitudinally between a root and a tip, and laterally between a leading edge and a trailing edge. The airfoil further includes a plurality of fine striations spaced laterally apart between the leading and trailing edges in the airfoil first side, and extending longitudinally between the root and the tip. A viscoelastic filler is bonded in the striations for damping torsional vibrations of the airfoil.

Abstract: A method is disclosed for repairing a worn helicopter rotor blade made of composite materials by adhesively securing a supplemental leading edge abrasion wear strip made of nickel to the leading edge of the rotor blade. The periphery of the bonding surface of the leading edge of the rotor blade is masked. The bonding surfaces of the supplemental leading edge strip and the rotor blade are cleaned with a medium-grit scrubbing pad, grit-blasted with aluminum oxide and then rinsed with DI water. A strip of a structural adhesive film is hot bonded to the bonding surface of the supplemental leading edge strip using vacuum and a high temperature oven cure. The side of the structural adhesive film bonding surface which will be secured directly to the rotor blade bonding surface is first abraded and then wiped with a solvent. An epoxy adhesive mix is applied to the bonding surfaces of the rotor blade and the structural adhesive film of the supplemental leading edge strip.

Abstract: An electroformed sheath is disclosed for protecting composite components of a part, such as a fan blade of a modern gas turbine engine. The electroformed sheath includes a sheath body having a leading edge; a pressure side and an opposed suction side of the body that meet at the leading edge and extend away from the leading edge to define a sheath cavity therebetween; a head section of the body between the leading edge and the sheath cavity; and an electrically conductive mandrel insert positioned between the pressure and suction sides of the body. In manufacture of the electroformed sheath, the mandrel insert is secured in an appropriate mandrel having an exterior surface approximating the blade's airfoil configuration. The leading edge, head section and pressure and suction sides are electroplated around the mandrel insert so that the insert remains in the sheath body after removal of the mandrel.

Abstract: A composite tip cap assembly for a helicopter main rotor blade includes a composite main fairing, a unitary composite rib detail internally integrated in combination with the composite main fairing, a composite closure fairing bonded in combination with the composite main fairing, and an abrasion strip bonded in combination with the composite main fairing and the composite closure fairing.

Abstract: A sheath for covering and protecting a component leading edge of an airfoiled component is disclosed. The sheath includes a sheath leading edge, and a first protective side and a second protective side, wherein the first and second protective sides are merged at the sheath leading edge. A cavity is formed between the first and second protective sides, wherein the cavity is adapted to have the airfoiled component positioned therein and engage an inside surface of each of the first and second protective sides. The sheath is formed from a material including cobalt, and preferably a nickel-cobalt composition. Preferred embodiments include cobalt in the nickel-cobalt composition present between 8-32 wt. % and 30-54 wt. %, based on the weight of the sheath. An airfoiled component construction is also disclosed.

Abstract: An apparatus for shielding a blade against lightning includes a conducting component forming a leading edge glove and a conducting cover, for protecting the blade tip across its entire chord. Mechanical devices, such as screws and rivets with protruding shapes, in addition to some gluing, fix the cover on the composite structure of the blade, and are earthed by the cover, forming points where lightening can enter or exit, protecting the surrounding composite structure of the blade against damage. At least the cover may have a suction face arm and a pressure face arm of different dimensions at least in the direction of its span.

Abstract: In a thermally loaded blade for a turbomachine, the front edge of such a blade is made from a ceramic material for providing better protection. The front edge has a shell-shaped form which covers at least one part of the head stage against which flow occurs. The connection between front edge and head stage is produced on the one side by a coupling-forming indentation and on the other side by an elastic element. The elastic element produces a retaining action at the location where it is placed and a frictional connection, having an effect on the indentation, on the other side of the blade. Cooling air bores in the head stage provide for a cooling effect on the ceramic front edge.

Abstract: An apparatus for shielding a blade against lightning includes a conducting leading edge glove and a conducting cap, distinct from the glove, and overlapping the blade tip across its entire chord. At least the cap has a suction face arm and a pressure face arm of different dimensions at least in the direction of its span. Mechanical devices, such as screws and rivets with protruding shapes, in addition to some glueing, fix the cap on the composite structure of the blade, and are earthed by the cap, forming points where lightning can enter or exit, protecting the surrounding composite structure of the blade against damage. When the blade is mounted on a member for linking to the hub, electrical continuity with this member and the hub is provided.

Abstract: A marine propeller including a hub rotatable about a longitudinal axis and having a plurality of blades extending outwardly from the hub. Each of the propeller blades includes a fixed propeller blade stem and a removable cup extension. The cup extension defines the trailing edge of each propeller blade and is removably mounted to the propeller blade stem. The cup extensions can selectively be removed from the blade stems and new cup extensions attached in order to modify the amount of cupping included on the propeller.

Abstract: The present invention provides a composite airfoil, particularly useful as a wide chord fan blade having a high degree of twist in a large high bypass ratio turbofan engine. The composite airfoil of the present invention has a reinforced region of its airfoil that extends a portion of its span from its tip and a portion of its chord from its trailing edge. The region is covered by thin metallic sheathing bonded to trailing edge surfaces of the blade in a manner to reinforce that portion of the composite blade.

Abstract: An apparatus for protecting the leading edge of an aerodynamic blade such as a propeller blade and more particularly to an apparatus for improving the maintainability of the leading edge protective sheath. In the preferred embodiment, a protective sheath made of a ductile material of sufficient hardness material such as titanium, stainless steel, nickel or a nickel alloy is attached to the leading edge of a propeller blade. The protective sheath has an interior surface that complements the leading edge of the underlying propeller blade material, while the exterior surface of the sheath is optimized to achieve an efficient dynamic profile for the propeller blade. The protective sheath is further modified so that a harder material such as ceramic can be secured to the surface of the protective sheath along its leading edge at the tip end of the propeller blade wherein erosion rates are highest.

Abstract: A gas turbine engine fan blade includes a main body having a radially spaced apart root and tip, and axially spaced apart leading and trailing edges. A front shell is fixedly joined to a portion of the body leading edge to collectively define with the body an airfoil having first and second opposite sides extending between the root, tip, shell, and trailing edge for pressurizing air flowing thereover. The shell is hollow to offset toward the trailing edge a collective center of gravity of the airfoil to reduce steady stress at the airfoil leading edge.