Abstract: To provide a light and economical separable blade for a wind turbine that is also equipped with a lightning rod function. A separable blade for a wind turbine wherein the blade as a whole is assembled by connecting two electrically non-conductive part blades 1T and 1R in the lateral direction, comprising metal fasteners 4, 5, 6, and 7 for fastening together the two adjacent part blades, and lightning discharge conductive wires 8 and 9, provided in an inner blade portion. The fastener 4 is exposed on the blade surface of the part blade 1T, and is connected to the lightning discharge conductive wire 9 through the other fasteners 5, 6, and 7, or a lightning discharge conductive wire 8. The lightning discharge conductive wire 9 extends to the blade root.

Abstract: A method for manufacturing a turbine engine component includes forming a component to include a first side and an opposite second side, positioning at least one capillary adjacent to an external surface of at least one of the first and second sides, and securing the at least one capillary to the component with at least one composite layer.

Abstract: To address certain deficiencies of carbon fiber material as a filler in a hybrid blade, a glass composite layer is provided as a barrier layer between a carbon fiber resin filler and the metallic main body of the blade. The glass composite layer also advantageously provides a gradient in thermal expansion between the carbon fiber composite and the body of the blade (steel) to reduce interfacial residual stress.

Abstract: A wind turbine rotor blade includes a pressure side sparcap having a carbon fiber reinforced section extending substantially a full longitudinal length of the pressure side sparcap and a suction side sparcap having a glass fiber reinforced section extending substantially a full longitudinal length of the suction side sparcap.

Abstract: An air cooled airfoil for use in a gas turbine engine includes a base, a porous material on the base, and a thermal barrier coating (TBC) applied to the porous material, with cooling holes in the base and the TBC to allow for cooling air to flow from within the airfoil to the surface of the airfoil, and where the porous material has a higher density near the TBC interface than at the base interface. The higher density at the TBC interface provides for a rigid support structure for the TBC as well as higher heat transfer than would the lower density porous material near the base, the lower density porous material near the base acting to reduce heat transfer to the base and therefore promote heat transfer into the cooling air passing through the porous material and out onto the airfoil surface. An additional embodiment includes an airfoil having a plurality of outward facing cavities, each cavity being filled with a porous material having varying density and covered with a TBC layer.

Abstract: A rotor blade for use in a wind energy system is provided with the rotor blade having a rotor blade body comprising a rotor blade body tip; a rotor blade body cavity; and a lightning protection unit. The lightning protection unit includes a conductive part that is connected to a down conductor and positioned within the rotor blade body cavity close or at the rotor blade body tip, the conductive part having an extension protruding out of the rotor blade body for receiving a receptor. According to another aspect of the invention, a wind energy system is provided with at least one of such a rotor blade.

Abstract: A blade or a vane preferably used in a gas turbine engine, the blade or vane being formed of a metallic core or insert with a ceramic airfoil surface bonded to the metallic insert. The insert includes a series of concave and convex portions arranged along the outer surface, in which a plurality of hoop fibers are secured within a resin matrix to firmly secure the metallic insert to the ceramic airfoil body. Axial loads between the insert and the ceramic body are transferred to the hoop fibers. The hoop fibers are strong enough to resist extending in length that would permit the hoop fibers from sliding over the widest portion of the insert.

Abstract: A fluid turbine, such as a wind or hydro turbine, for generating electrical power, the turbine having a rotor assembly comprising a hub, a rim and a plurality of tensioned cable members joining them together, the cable members being grouped into sets to define a plurality of supports for individual skin members to create a plurality of lightweight blade members.

Abstract: A method for making a blade includes stacking a plurality of modular segments having formed conduits, threading and tensioning cables through the conduits of the stacked segments, and clamping the cables to hold the modular segments together.

Abstract: A wind turbine rotor including a rotor hub (3) and a plurality of blades (4), and where each blade root (16) is connected to said rotor hub through a pitch bearing (5) in such a manner that the pitch angle of the blade is adjustable by a turning of the blade about its longitudinal axis relative to the rotor hub. The blade is provided with at least one electrically conducting lightening down-conductor (6) extending in the longitudinal direction of the blade to the blade root and being electrically isolated from the pitch bearing (5). A spark gap (15) is provided between the lightning down-conductor and the rotor hub, said spark gap (15) being adapted to conduct a lightning current passing through the lightning down-conductor.

Abstract: The invention relates to a lightning arrester system for wind generator blade, which replaces the standard main copper cable and which employs two strips of copper that extend along the entire length of the beam such as to be in direct contact with the carbon fibre. In this way, the carbon fibre laminate and the copper strip are always at the same potential, thereby preventing any possible arc-over between the two elements. The carbon fibre laminate is barely affected by the passage of current owing both to the electrical characteristics of the two components and to the selected configuration which conveys most of the current through the copper strips. In addition, with said novel system it is possible to position intermediate receivers on the actual laminates and in direct contact with the copper strip.

Abstract: A composite blade (26) comprises a root portion (36) and an aerofoil portion (38). The aerofoil portion (38) has a tip (42), a chord (C), a leading edge (44), a trailing edge (46), a suction surface (48) extending from the leading edge (44) to the trailing edge (46) and a pressure surface extending from the leading edge (44) to the trailing edge (46). The composite blade (26) comprises reinforcing fibres (52) in a matrix material (54). The aerofoil portion (38) adjacent the root portion (36) has regions (56, 58) at least at the leading edge (44) and trailing edge (46) comprising an asymmetric lay up of reinforcing fibres (52) and the aerofoil portion (38) adjacent the tip (42) having at least a region (62) at the mid-chord comprising an asymmetric lay up of reinforcing fibres (52).

Abstract: A wind blade spar cap for strengthening a wind blade including an integral, unitary three-dimensional woven material having a first end and a second end, corresponding to a root end of the blade and a tip end of the blade, wherein the material tapers in width from the first to the second end while maintaining a constant thickness and decreasing weight therebetween, the cap being capable of being affixed to the blade for providing increased strength with controlled variation in weight from the root end to the tip end based upon the tapered width of the material thereof. The present inventions also include the method of making the wind blade spar cap and a wind blade including the wind blade spar cap.

Abstract: In a wind turbine (104, 500, 704) having a plurality of blades (132, 404, 516, 744) and a blade rotor hub (120, 712), a lightning protection system (100, 504, 700) for conducting lightning strikes to any one of the blades and the region surrounding the blade hub along a path around the blade hub and critical components of the wind turbine, such as the generator (112, 716), gearbox (708) and main turbine bearings (176, 724).

Abstract: The invention relates to a wind turbine blade and a transitional shell blank for the manufacture of the shell of a wind turbine blade, the blade or the transitional shell blank being made of fibre-reinforced polymer including a first type of fibres (1, 3, 6) of a first stiffness and a first elongation at breakage, and a second type of fibres (2, 5, 7) of a different stiffness and a different elongation at breakage. According to the invention the two types of fibres are distributed in the polymer matrix. When seen in a sectional view perpendicular to longitudinal direction of the blade or the transitional shell blank, the quantitative ratio of the two types of fibres varies continuously in the longitudinal direction of the blade or of the transition shell blank.

Abstract: A method of manufacturing a root portion of a wind turbine blade includes, in an exemplary embodiment, providing an outer layer of reinforcing fibers including at least two woven mats of reinforcing fibers, providing an inner layer of reinforcing fibers including at least two woven mats of reinforcing fibers, and positioning at least two bands of reinforcing fibers between the inner and outer layers, with each band of reinforcing fibers including at least two woven mats of reinforcing fibers. The method further includes positioning a mat of randomly arranged reinforcing fibers between each pair of adjacent bands of reinforcing fibers, introducing a polymeric resin into the root potion of the wind turbine blade, infusing the resin through the outer layer, the inner layer, each band of reinforcing fibers, and each mat of random reinforcing fibers, and curing the resin to form the root portion of the wind turbine blade.

Abstract: An engine cooling fan system including a hub disc about which first and/or second pluralities of elongated fan blades characterized by a first and second respective pitch angles may be fastened. Each respective fan blade further comprises a hub-engaging portion, a twisted transition portion and an air-engaging portion. Each fan blade is formed from a composite material having a thermoset resin matrix phase and an evenly dispersed continuous fiber reinforcement phase.

Abstract: With regard to hollow blades for turbine engines, it will be understood there is a problem with respect to percussive impact resulting in excessive distortion of the blade as well as potential failure as a result of blade tip bulging. By provision of ridges 107, 207, 307 which coincide and engage each other under impact, the extent of impact deformation is limited as well as a result of the narrowing between the ridges, a reduction in the possibility for fragmentary insert movement to bulge the cavity towards the tip 102, 202, 302 of a blade 100, 200, 300.

Abstract: A turbomachine blade comprising a root portion and an aerofoil portion, the aerofoil portion having a leading edge, a trailing edge, a concave metal wall portion extending from the leading edge to the trailing edge and a convex metal wall portion extending from the leading edge to the trailing edge. The concave metal wall portion and the convex metal wall portion form a continuous integral metal wall. The aerofoil portion has a hollow interior defined by at least one internal surface and the hollow interior of the aerofoil portion is at least partially filled with a vibration damping and stiffening system that comprises a vibration damping material. The vibration damping material is bonded to the at least one internal surface and the vibration damping and stiffening system comprises a variation of material properties between the wall portions.

Abstract: There is described a method for casting a component comprising at least partly of fibre-reinforced plastic laminate by which the fibre-reinforcement is arranged in a casting mould, wherein at least one venting duct is placed, wherein said fibre-reinforcement and said venting duct are at least partly wetted by the plastic during the casting process in such a way that venting is achieved through said venting duct, and wherein the surface of the venting duct is at least partially made with a semi-permeable membrane that allows the passage of gases but does not allow or only slowly allows the passage of plastics. Furthermore there is described a component comprising at least partly of fibre-reinforced plastic laminate, wherein the plastic laminate inside comprises of one or more venting ducts, wherein the surface of a venting duct is at least partially made with a semi-permeable membrane that allows the passage of gases but does not allow or only slowly allows the passage of plastics.

Abstract: A damping arrangement for a blade (20) of an axial turbine, in particular a gas turbine, includes a damping element (17) which is arranged in a recess (16) in the blade aerofoil (10) of the blade (20) and frictionally dampens the vibrations of the blade (20). In such a damping arrangement, simplified manufacture and assembly and a reliable and effective function are achieved by the recess being configured as a cavity (16) extending in the radial direction through the inside of the blade aerofoil (10), the damping element (17) being inserted in the radial direction into said cavity (16).

Abstract: A laminate material for damping a vibrational mode of a structure is provided, the laminate material comprising a viscoelastic layer and a stiff constrained layer adhered to the viscoelastic layer, wherein the viscoelastic layer is elastomer based and the constrained layer is made of steel, galvanized steel or aluminum. Furthermore, a damping arrangement for damping at least one vibrational mode of a structure is provided, comprising a laminate material having a soft viscoelastic layer and a stiff constrained layer, wherein the laminate material is provided in the form of at least two longish stripes, the soft viscoelastic layer of the at least two stripes being adhered to a surface of the structure, and the at least two stripes being oriented at an angle of 0° to 180°, preferably 90°, with respect to each other.

Abstract: The present invention relates to an integrally bladed rotor for use in a gas turbine engine. The integrally bladed rotor comprises a plurality of pairs of airfoil blades. Each pair of blades has a spar which extends from a first tip of a first one of the airfoil blades in the pair to a second tip of a second one of the airfoil blades in the pair. The rotor further comprises an outer shroud integrally joined to the first and second tips in each pair of airfoil blades and an inner diameter hub.

Abstract: The invention relates to a wind turbine blade comprising a number of pre-fabricated strips arranged in a sequence along the outer periphery. The strips consist of a fibrous composite material, preferably carbon fibres, and consist of a wooden material, preferably plywood or wooden fibres held in a cured resin. The advantage is that it is possible to manufacture blades for wind turbines which are very stiff and generally have a high strength, but which nevertheless are easy to manufacture and also is much cheaper to manufacture compared to conventional manufacturing techniques. The invention also relates to methods for manufacturing prefabricated strips and for manufacturing wind turbine blades.

Abstract: A separable blade for a wind turbine, the separable blade being divided at a center part thereof in a longitudinal direction into an inner blade portion corresponding to a blade root side and an outer blade portion corresponding to a blade end portion, wherein the separable blade is structured by joining the inner blade portion and the outer blade portion with a joining member made of metal, the separable blade includes: a metal plate placed between the inner blade portion and the outer blade portion and electrically connected to the joining member; and an in-blade electrical conduction wire arranged to extend from the metal plate through a blade root part of the inner blade portion to outside of the blade.

Abstract: A wind turbine has a generator (7) with a connected rotor (3) having a hub (4) and blades (5) rotatably connected to the hub for adjusting the pitch angle. In a method of operating such a wind turbine under climatic conditions, where there is a risk of icing on the blades and no or weak wind, the generator is used as a motor for driving the rotor and the pitch angle of the blades is adjusted to ensure that the resulting wind substantially hits the leading edge of the blades. It is thus ensured that any icing only occurs on the leading edge of the blades. Any ice formed may be removed by means of de-icing in a known manner.

Abstract: The present invention can be generally described as a blade monitoring and wireless communications system. This monitoring and communications system is formed by the integration of commonly available or easily developed hardware and/or software components, which may be controlled by non-proprietary, open architecture software. This allows the present invention to easily incorporate a variety of sensors and/or detectors; thereby, providing the user with the first blade monitoring system capable of providing an improved blade monitoring capability.

Abstract: A braided rotor blade spar includes a tri-axle braid in which braided bias angled fibers are located non-parallel to a longitudinal axis of the spar. Zero degree fibers are located parallel to the axis and are positioned to be on the upper and lower surfaces of the spar. The bias angle fibers are braided around the zero degree fibers. In a method of manufacture of the braided spar, a braided sleeve is formed dry over a mandrel by a multi-axial braiding machine. Once the braided sleeve is formed upon the mandrel, the mandrel is located within a matched metal mold, resin impregnated, and cured. The mandrel is then removed from the finished braided spar.

Abstract: An embedding element (11) for embedment in the root of a wind turbine rotor blade (15) of a fibre composite material, said embedding element being elongated and having a first end portion (1) and a second end portion (2) and provided with fastening means, eg a threaded hole, a threaded rod or the like in its first end portion (1). Between its two end portions (1, 2) the embedding element (11) is provided with a first longitudinal lateral face (14) extending substantially concavely in a cross-sectional view perpendicular to the longitudinal axis of the embedding element, and with a second longitudinal lateral face (16) facing opposite the first lateral face (14) and extending substantially correspondingly convexly in a cross-sectional view perpendicular to the longitudinal axis.

Abstract: A steam turbine blade includes a shank portion and an airfoil portion. The airfoil portion is formed with at least one pocket filled with a polymer filler material chosen as a function of natural frequency impact on the turbine blade or as a function of the damping characteristics of the filler materials. A steam turbine rotor wheel includes a plurality of blades secured about a circumferential periphery of the wheel, each blade having one or more pockets in the airfoil portion, the plurality of blades divided into two groups of blades. The pockets of one group of blades are filled with one or more polymer filler materials, and the pockets of the other group of blades filled with one or more polymer filler materials, wherein the polymer filler materials in the one group of blades creates different natural frequencies or damping characteristics in the blades of the one group than the polymer filler materials in the blades of the other group.

Abstract: A method for controlling a wind turbine having twist bend coupled rotor blades on a rotor mechanically coupled to a generator includes determining a speed of a rotor blade tip of the wind turbine, measuring a current twist distribution and current blade loading, and adjusting a torque of a generator to change the speed of the rotor blade tip to thereby increase an energy capture power coefficient of the wind turbine.

Abstract: The composite turbomachine blade of the present invention comprises a preform made of yarns or fibers woven in three dimensions and a binder maintaining the relative disposition between the yarns of the preform. Said preform is made up of warp yarns and of weft yarns, the direction of the warp yarns forming the longitudinal direction of the preform. In characteristic manner, said preform comprises at least a first portion made using a first weave forming the airfoil of the blade, and a second portion made using a second weave forming the root of the blade, and the first and second portions are united by a transition zone in which the first weave is progressively modified to end up with the second weave, thereby obtaining a reduction at least in the thickness of the blade between the second portion and the first portion. The invention is applicable to making a fan blade for a turbojet.

Abstract: An airfoil (30) having a continuous layer of ceramic matrix composite (CMC) material (34) extending from a suction side (33) to a pressure side (35) around a trailing edge portion (31). The CMC material includes an inner wrap (36) extending around an inner trailing edge portion (38) and an outer wrap (40) extending around an outer trailing edge portion (42). A filler material (44) is disposed between the inner and outer wraps to substantially eliminate voids in the trailing edge portion. The filler material may be pre-processed to an intermediate stage and used as a mandrel for forming the outer trailing edge portion, and then co-processed with the inner and outer wraps to a final form. The filler material may be pre-processed to include a desired mechanical feature such as a cooling passage (22) or a protrusion (48).

Abstract: A lightning protection system for a wind turbine including an internal lightning conducting means, an external lightning conducting means mounted on the surface or in immediate proximity of the surface of the wind turbine, and a connection means for connecting the internal and external lightning conducting means is provided. A method of manufacturing a lightning protection system for a wind turbine is also provided.

Abstract: Rotatable lifting surface devices, such as propellers, impellers, and turbines, and blades for such devices use camber profiles and pitch distributions to obtain performance from flexible devices and blades, made from materials like polymers and polymer-composites and even metals, that is substantially the same as the performance of stiff devices and blades, usually made from materials like steel and aluminum.

Abstract: A rotor for cooling pumps is provided. The rotor is of the type which includes a core to be assembled on a shaft connected with an engine and a body, fitted in the core, provided with a plurality of radial tabs in flexible material. The core and the body with the tabs are both of a material like rubber, but with different hardness. In particular the core is made of a mixture of neoprene, nitrile, PVC and aramidic fiber. The rotor combines the features of lightness and wearproof of the rotors with a nylon core, but it is as strong and resistant as rotors with a metallic core.

Abstract: A rotor for a rotary wing aircraft includes a blade having a leading edge, and a trailing edge. The rotor has a leading edge tip extension at a tip of the blade and a weight within the leading edge tip extension. The rotor also includes a trailing edge tip extension extending from a selected point at an outboard portion of the blade to the tip of the blade, a leading edge of the extension extending rearward from the trailing edge of the blade.

Abstract: A wind turbine rotor blade (10) comprising one or more means (4) secured to the blade (10) for changing the profile thereof depending on the atmospheric temperature. The means comprises at least one laminate having at least two layers of materials with differing thermal expansion coefficients.

Abstract: The invention concerns a wind power installation. Such wind power installations of modern type, for example one of type E-40 or E-66 from Enercon are usually equipped with a lightning protection system which is known for example from DE 44 36 197. The present invention assists to minimise the number of interference with the electronic system by virtue of the flash-over effects at the spark path. A wind power installation comprising an arrangement for continuously discharging electrostatic charging of at least one rotor blade of a wind power installation.

Abstract: In an integrated vane 1 for use in wind or water, main blades 3 arranged around an axial shaft 2 of the vane and support blades 4 for joining the main blades to the axial shaft are integrally formed with light and high strength fiber material such as glass fibers and carbon fibers. The main blade is symmetrical or asymmetrical in its cross sectional view and the support blade is symmetrical in its cross sectional view. The upper support blade may be asymmetrical in its cross sectional view and the lower support blade may have an up-and-down reversed shape of that of the upper support blade. A mountain-shaped portion may be formed at the ends of the main blade for reducing noise. The strength of crossing portions between the main and support blade of the vertical axis vane for use in wind or water is thus improved.

Abstract: A lightweight, composite structural element for turbo engines, includes a thin metallic shell and a metallic core structure, of which a large proportion of the volume is empty space, the shell and the core structure being rigidly connected to each other. The core structure has a spatial, felt-like and/or mesh-like construction and is made of one or more wires, strips, shavings, or comparable elements. The core structure is sintered together, and sintered to the shell.

Abstract: A fan blade has a three dimensional shape that resembles a leaf. The blade is made of balsa or other suitable wood with the grain of the wood running along its length. The obverse surface of the blade is contoured and has a central vein and lateral veins running from the central vein to opposite edges. The reverse side has one or more channels. Braces are set in the channels. The braces are also made of balsa or comparable wood and their grain runs transverse to the direction of the gain of the blade.

Abstract: There is provided a rotor for a turbo/drag vacuum pump, the rotor comprising an upstream rotor segment of the turbine type made of metal or alloy, and a downstream rotor segment of Holweck type made of composite material. The downstream segment of the rotor has a reinforcing structure made of long fibers that are distributed in a manner that varies as a function of the section under consideration: in the annular connection region connected to the upstream segment of the rotor, the fibers are inclined and/or spaced apart in order to conserve sufficient flexibility for the composite material to enable it to deform so as to track deformation of the metal of the upstream rotor segment while it is in operation; in contrast, the fibers are close together and form turns that touch in the downstream region of the skirt, thereby guaranteeing greater stiffness in order to withstand the mechanical stresses that occur during high-speed rotation of the rotor in operation.

Abstract: The present invention relates to an integrally bladed rotor for use in a gas turbine engine. The integrally bladed rotor comprises a plurality of pairs of airfoil blades. Each pair of blades has a spar which extends from a first tip of a first one of the airfoil blades in the pair to a second tip of a second one of the airfoil blades in the pair. The rotor further comprises an outer shroud integrally joined to the first and second tips in each pair of airfoil blades and an inner diameter hub.

Abstract: A turbine engine composite blade attachment mechanism is provided, including a blade having an airfoil section, a neck section, and a root section. The root section includes a continuous loop integral with the blade and branching out from the neck section to completely surround a root insert. The blade includes a plurality of fibers which extend from the airfoil section through the neck and around the core. The root section and neck are enveloped by a jacket having a thickness which increases from the distal side surface of the loop to the neck portion, and has an inner contour substantially aligned with the proximal side surface contour of the loop and the core. The jacket and root are disposed inside a rotary disk cavity such that when tensile loading is applied, the neck width is maintained and compressive transverse loads may be applied to the fibers to prevent lamination thereof.

Abstract: In the embodiments described in the specification, an impeller is manufactured by providing a mold for one angular segment containing one vane of an impeller and corresponding hub and rim portions, injection-molding fiber-reinforced polymer composite resin material into the mold to produce a plurality of substantially identical segments, and assembling the segments into an impeller by bonding corresponding mating end surfaces of the hub and rim portions of the segments. A veil cloth is applied to the outer surface of the rim portion and impregnated with resin material to complete the impeller structure.

Abstract: The present invention provides a process for the lay-up of a composite laminate article, the article produced by this process, and the apparatus used to produce the composite laminate article. The composite laminate article may be, for example, an airfoil, particularly useful as a fan blade in a large high bypass ratio turbofan engine, wherein the blade is generally regarded as large and having a high degree of twist. In a preferred embodiment, the present invention provides a process for laying up a composite laminate article comprising a) reading a data set to enable the projection of an image of a ply section onto a work surface, the image indicating a ply section target point; b) laying up a ply section of composite laminating material within the image, wherein the ply section first contacts the work surface at the target point; and c) repeating steps (a)-(b) until the composite laminate article is complete.

Abstract: A flexbeam (1) having flapping portions (3) and lead-lag and feathering portions (5). Each lead-lag and feathering portion has: a central portion with an elongated and narrow width; middle portions each of which continuously connects to the central portion and branches from both ends of the central portion extending along the longitudinal direction thereof, and extends upward and downward; and edge portions each of which continuously connects to the middle portion and bends from each end of the middle portions and extends almost in parallel with the central portion. At corners formed on branch portions (40, 50) and/or bending portions (60, 70), concaves (41-43, 51-53, 61, 62, 71, 72) each of which has a cross-section of an approximate arc shape and which continuously and smoothly connects to two surfaces forming each of the corners and is formed inside extended planes of the two surfaces.

Abstract: A turbine blade extends along a major axis from a root region via a blade leaf region capable of being acted upon by hot gas to a head region. The turbine blade is formed essentially from carbon-fiber-reinforced carbon, at least the blade leaf region having a blade outer wall with carbon-fiber-reinforced carbon, the blade outer wall being surrounded by a protective layer.

Abstract: An aerodynamic blade 12 and method of manufacture wherein the blade includes a tip 14, a root 16, materials comprising skins 18A, 18B, reinforcement strips 20A, 20B, 20C, 20D, glass sheets 22A, 22B, stiffeners 24A, 24B, and pre-cut sheets 26A, 26B, 26C, 26D layered into each of top and bottom molds 28, 30 using a resin 32 to define a mating perimeter 34 surrounding a depression 36 in said layered materials in each mold 28, 30. The molds 28, 30 are adapted to be mated together to engage the mating perimeters 34, and the depressions 36 define a core cavity 38. The molds 28, 30 are mounted to a mold bracket assembly 41 which enables the molds 28, 30 to be mated together after the blade 12 and materials are prepared. Each blade 12 further includes foam 40 disposed in the depressions 36 for filling the core cavity 38.