Abstract: Provided is a rotor blade configured to be implanted in a disc of a rotating body, the rotor blade including a blade root, wherein in a cross-sectional shape of the blade root, the blade root includes at least one stage of protruding parts protruding toward opposite sides with respect to a direction containing a circumferential component, the protruding parts being configured to lock the blade root to the disc, each of the protruding parts has a contact surface configured to come into contact with the disc and inclined so as to extend toward a center part of the blade root from radially inside to radially outside, and each of the protruding parts has a non-contact surface configured not to come into contact with the disc and inclined so as to extend toward the center part of the blade root from the radially inside to the radially outside.

Abstract: The invention relates to a method for manufacturing a composite platform (30) for a fan of an aircraft turbine engine, wherein said platform comprises an elongate wall (32) and is configured to extend between two fan blades (3), said wall comprising an outer aerodynamic surface (32a) and an inner surface (32b), on which a fastening tab is located (34), said fastening tab being configured to be fixed to a fan disc (2). The invention is characterized in that it comprises the steps of: a) preparing fabrics or sheets which are pre-impregnated with a resin, b) depositing the fabrics or sheets in a mold, c) positioning a metal reinforcement (36) in the mold on the fabrics or sheets, the reinforcement being integrally formed with said fastening tab, d) depositing the fabrics or sheets on a part of the reinforcement, and e) closing and heating the mold for solidification of the assembly formed by the fabrics or sheets and the reinforcement.

Abstract: A rigid thermoplastic polymeric sheet material forming process. The process includes heating, while under a heating vacuum range, a rigid thermoplastic polymeric sheet in a heating zone to a forming temperature to form a heated rigid thermoplastic polymeric sheet material. The process further includes transferring, while under a feeding vacuum range, the heated rigid thermoplastic polymeric sheet material from the heating zone to feed the heated rigid thermoplastic polymeric sheet material into a forming zone under the feeding vacuum range. The process also includes forming, in the forming zone, the heated rigid thermoplastic sheet material into a formed article.

Abstract: A method of bonding a blade cuff to a rotor blade includes installing the blade cuff to a root end of the rotor blade. The method includes mounting the rotor blade within a plurality of supports. The method includes coupling the blade cuff to a first fixture. The method includes installing a second fixture about the blade cuff. The method further includes applying localized and constant heat and pressure to the blade cuff via the second fixture.

Abstract: A ring segment and a turbomachine including the ring segment are provided. The ring segment installed on an inner circumferential surface of a casing and disposed to face an end of a blade existing inside the casing, the ring segment includes a segment body disposed inside the casing in a radial direction of the casing and having a channel through which cooling air flows, and a pair of segment protrusions protruding outward from the segment body, coupled to the inner circumferential surface of the casing, and spaced apart from each other along a flow direction of fluid flowing through the casing to form an RS cavity through which cooling air flows, wherein the segment body includes a cavity for supplying cooling air introduced from the RS cavity to the channel.

Abstract: A composite material blank comprising an elongate blank body extending between a first end face and a second end face; said blank body extending in a longitudinal direction, parallel to a longitudinal axis thereof, and having four peripheral sides; each said first and second end face having edges which define a trapezoid shape; wherein the peripheral sides of said blank body connect the edges of said first end face with the edges of said second end face; and wherein said first trapezoid end face is inverted in relation to said second trapezoid end face. A method of manufacturing a composite blank, and a wind turbine blade root insert which may be formed from a blank.

Abstract: Sacrificial inserts for use in gas turbine engines to reduce friction and wear damage between compressor fan blades and the fan rotors are disclosed. The consumable metallic shims have low friction and reduce fretting and galling on fan blade roots and fan rotor dovetail slots thereby increasing their operating lives, as well as reduce engine noise and improve engine efficiency. The electroformed, compliant, multi-purpose shims may have variable thickness and, when positioned between the blade dovetail root and the rotor disk dovetail slot, prevent movement and slippage between air foil blades and the rotor.

Abstract: Devices, systems, and methods of manufacturing wind turbine root attachment are provided. In various embodiments, an assembly for wind turbine root attachments includes a bushing, a core, and a filler. The bushing includes a body having cutouts extending from the proximal end to the distal end on either side of the bushing and a core cutout at the distal end. The bushing further includes an ear disposed at the proximal end of the bushing and within the first cutout. The core includes two wedges where the thick end of each wedge abut one another. The thin end of the proximal wedge is disposed within the core cutout and the core includes cutouts extending from the proximal end to the distal end on either side of the core. The filler is disposed within the cutout on the side of the assembly having the ear.

Abstract: A ceramic matrix composite gas turbine blade comprising a root portion coupled to a disk, said root portion having a neck; a platform region is disposed along an upper portion of the neck; an airfoil is located opposite the neck relative to the platform and extends outwardly from the platform; and a limiting section fuse formed in the blade proximate the neck.

Abstract: A vibration-damping system for turbomachine blade(s) in a turbomachine is provided. Each turbomachine blade includes a platform having a radially inner surface. The system includes a spacer axially adjacent the platform of at least one turbomachine blade in the turbomachine, e.g., adjacent a turbomachine blade stage. The spacer includes a body. A damping element coupler is on the body of the spacer, and a vibration-damping element is configured to couple to the damping element coupler. The vibration-damping element and the damping element coupler are disposed to cause the vibration-damping element to engage the radially inner surface of the platform of the turbomachine blade(s) to dampen vibration of the turbomachine blade(s), e.g., during operation of the turbomachine.

Abstract: A duct for a gas turbine engine, the duct has a wall defining a flow passage for an airflow, the wall defining a baseline surface, the duct comprising an off-take port for drawing a portion of the airflow out of the duct, the off-take port including a projected portion projecting away from the baseline surface into the flow passage, a conduit opening defined within the projected portion for receiving the portion of the airflow, and an off-take conduit communicating with the conduit opening for directing the portion of the airflow away from the duct, the projected portion having a hump upstream of the conduit opening relative to a direction of the airflow and a scoop downstream of the opening relative to the direction of the airflow.

Abstract: A method using machine learned, scenario based control heuristics including: providing a simulation model for predicting a system state vector of the dynamical system in time based on a current scenario parameter vector and a control vector; using a Model Predictive Control, MPC, algorithm to provide the control vector during a simulation of the dynamical system using the simulation model for different scenario parameter vectors and initial system state vectors; calculating a scenario parameter vector and initial system state vector a resulting optimal control value by the MPC algorithm; generating machine learned control heuristics approximating the relationship between the corresponding scenario parameter vector and the initial system state vector for the resulting optimal control value using a machine learning algorithm; and using the generated machine learned control heuristics to control the complex dynamical system modelled by the simulation model.

Abstract: Platforms for airfoils in gas turbine engines are provided. The platforms include an aero-structure defining a gaspath surface and a non-gaspath surface, a first securing element arranged to receive a locking pin and secure the aero-structure to a rotor disk, and a first securing element structure extending between the non-gaspath surface and the first securing element, wherein the first securing element structure comprises at least two legs defining a hollow space between the two legs and the non-gaspath surface.

Abstract: A gas turbine engine comprises an engine core, a tie bolt, and a fail-safe system. The engine core includes a compressor, a turbine, and a shaft that couples the compressor with the turbine for rotation with the turbine about an axis. The tie bolt locates axially the compressor relative to the turbine. The fail-safe system is configured to transmit torque from the turbine to the compressor through the tie bolt in response to a shaft disconnect event.

Abstract: Hydrostatic pressure turbine runners according to the present disclosure are designed for maximally exploiting the hydrostatic pressure of a flowing fluid, rather than maximizing extraction of kinetic energy from the flow. The design converts less kinetic energy of the flow into hydropower as compared with current run-of-river turbine runner technologies. However, hydrostatic pressure turbine runners according to the present disclosure convert substantially more potential energy into hydropower. As a result, the total amount of energy converted into hydropower is significantly higher than the hydropower available from conventional run-of-river turbine runner designs, and, without promising any particular utility, may be capable of surpassing the upper limit of converted energy as defined by Betz' law. In a run-of-river context, the total amount of converted energy—mainly converted potential energy—may surpass the amount of kinetic energy of the flow engaged by the turbine runner.

Abstract: A shroud assembly for a turbine engine comprising a plurality of circumferentially arranged shroud segments having confronting end faces defining first and second radially spaced surfaces. The shroud assembly includes a forward edge spanning to an aft edge to define an axial direction and a set of confronting seal channels formed in each of the confronting end faces with a spline seal located within the confronting seal channels.

Abstract: An aero gas turbine engine with a last stage turbine disc of a solid bore design. The solid bore turbine disc includes a center tie bolt that attaches to an upstream face of the solid bore disc. The attachment location is under the bore of the upstream stage. The aft side of the solid disc creates a stub shaft upon which a bearing is directly mounted. No fasteners pass through the solid bore disc. Omission of outboard fasteners allow for ease of assembly, reduced cost, reduced weight, and a reduced part count.

Abstract: A damper pin for damping adjacent turbine blades coupled to a rotor disk comprises a first elongated body having a center portion disposed between a first end portion and a second end portion. The first end portion, center portion and second end portion define a generally arcuate top portion of the first elongated body. The first elongated body defines a slot that extends axially therethrough. The damper pin further includes a second elongated body having a generally arcuate top portion. The second elongated body is at least partially disposed within the slot and is slideably engaged in an axial direction with the first elongated body.

Abstract: A hollow CMC article, a mandrel for forming the article and a method for forming the article are disclosed. The article includes a ply-wrap layer defining a cavity. The ply-wrap layer includes a first face, a second face, a root portion bridging the faces, and a plurality of CMC wrap plies. The root portion defines a terminus of the ply-wrap layer including a cross-sectional conformation consisting of a curve having a single turning point. Each of the plurality of CMC wrap plies are disposed along the first face, wrap over the root portion, and extend along the second face. The hollow article further includes a plurality of CMC lateral plies disposed along the faces.

Abstract: A turbine wheel for a turbine engine comprising a disc carrying blades. Each blade comprises an upstream radial wall and a downstream radial wall which extend inwards from the platform of the blade. Inter-blade cavities each accommodate one inter-blade sealing and vibration damping member. According to the invention, each inter-blade sealing and vibration damping member comprises at least a first transverse partition wall axially arranged at a distance from a downstream (or upstream, respectively) portion of the member and axially opposite two upstream (or downstream, respectively) so as to obstruct a flow of incoming air into the cavity between two adjacent upstream radial walls or two adjacent downstream radial walls.

Abstract: A damper seal for a gas turbine engine rotor assembly has an axially elongated body with a leading edge, a trailing edge, a pressure side, and a suction side. The elongated body includes a first enlarged portion formed on the pressure side at the leading edge and a second enlarged portion formed on the suction side adjacent the trailing edge.

Abstract: The present disclosure provides systems for preventing improper installation of a damper seal. In various embodiments, an airfoil assembly may comprise a platform, an airfoil extending from the platform, and a platform tab. The airfoil may comprise a gaspath face and a non-gaspath face. The non-gaspath face may at least partially define a cavity. The airfoil may comprise a pressure side and a suction side. The platform tab may be located adjacent to the suction side of the airfoil. The platform tab may extend from the platform in the opposite direction as the airfoil and may be configured to prevent a damper seal tab from being inserted radially inwards of the platform tab.

Abstract: The invention refers to a blade of a rotary flow machine including an airfoil having a suction surface and a pressure surface joining each other along a trailing and a leading edge. A radially outward directed airfoil tip and a radially inward directed end joining an inner platform connect the airfoil to a shank at a radial end of the airfoil and providing, at least one shank pocket radially encircled by an axially extending portion of the platform. At least one radially extending rim extends from the trailing edge side of the shank and has an essentially radially orientated first slot for receiving a seal. A mount extends radially inwardly from said shank pocket. The first slot has a first aperture on a shank surface orientated in an axial direction.

Abstract: A fan section for a gas turbine engine includes a fan hub having a slot. A platform is supported by the fan hub. A fan blade has a root that is received in the slot. A wear pad is provided between the fan hub and the root and includes a flap integral with the wear pad to provide a seal relative to the platform. A fan blade for a gas turbine engine includes an airfoil extending from a root. A wear pad is secured to the root and has a free end providing a flap canted toward the root.

Abstract: A turbine wheel designed to exploit the head of watercourses that operates partially or totally submerge with means for a wheel mounting enclosure having a cavity equal to 50% of the height of the runner where the runner rest exposing the upper end into the bed of the flowing body of water and said cavity mask the runner from the water incident flow allowing the wheel to perform fully submerged gaining its power and momentum through water current acting upon an array of multifaceted cells attached to spokes radiating from a central circular body member to the outer perimeter of a wheel, distributed wall-to-wall occupying the peripheral annulus of the water stream always presenting a new facet as it rotate around it axis covering 180 degrees of the water incident flow. The outside surface of the runner attaches to a multiplicity of similar runners by means of mechanical devices and to the central circular body member.

Abstract: A system and method for securing a blade within a disk so as to eliminate the need for permanently deforming materials associated with the blade disk is disclosed. A recess is formed generally within each slot used to secure a blade within the disk. A retaining insert is positioned within the recess and a wedge insert is positioned within a slot of the retaining insert, such that a pressure is applied to the retaining insert thereby deflecting the retaining insert into a pre-set radial position to prevent axial movement of the blade within the slot of the disk.

Abstract: A turbine blade of an axial turbine includes internal cooling fluid passages with radially outwardly extending passages connected to holes in the blade root. The holes are generally core printouts providing stability to the core during the casting process, but are not needed and need to be closed to guarantee the functioning of the cooling system. This is achieved by at least one covering plate. The plate is held by at least two slots located at the root of the turbine blade. Thus, the supply holes for cooling fluid located at the root section are closed by a simple mechanical device, e.g., a plate that does not require any subsequent brazing/welding operations. In addition, the plate is removable to facilitate inspection/cleaning, or further processing of the blade at service intervals.

Abstract: A blade of a gas turbine engine is provided having an airfoil, a platform, a shank, a dovetail, and a skirt. The airfoil may extend distally from the platform, and the shank may extend proximally from the platform. The dovetail may also be provided to extend proximally from the shank. The skirt may be disposed on an aft side of the shank and may extend from the shank in a direction at least partially axially aft from the shank.

Abstract: A turbomachinery blade includes: an airfoil; and a shank extending from a root of the airfoil, the shank being constructed from a composite material including reinforcing fibers embedded in a matrix The shank includes a pair of spaced-apart side faces that cooperatively define: a dovetail disposed at a radially inboard end of the shank, comprising spaced-apart, diverging faces; a first neck portion having a concave curvature disposed radially outboard of the dovetail, and defining a primary minimum neck at which a thickness of the shank is at a local minimum; and a second neck portion disposed radially outboard of the first minimum neck, the second neck portion having a concave curvature and defining a secondary minimum neck at which the thickness of the shank is at a local minimum.

Abstract: A blade for a turbomachine impeller including an airfoil and at least one platform at one end of the airfoil, the blade configured to be arranged with a plurality of substantially identical blades so as to form a ring, the platform surface having a suction surface profile and a pressure surface profile respectively along the suction surface and the pressure surface. In the blade, the pressure surface profile including a pressure surface recessed part is located axially in an upstream half of the airfoil. Due to this configuration, efficiency of the blade is improved.

Abstract: A blade arrangement on a wall of a fluid flow path of a turbomachine includes a locating channel disposed in the wall and having undercut flanks. A plurality of blades each having a blade-side root section corresponding to the undercut flanks. A plurality of intermediate filling pieces correspond to the undercut flanks and separate each of the blade-side root sections. The plurality of blade-side root sections and intermediate filling pieces are seated in a form-fitting manner and fixed in a force-locking manner in the locating channel. The plurality of intermediate filling pieces fill out the locating channel so as to form a gas flow-side surface essentially free of a disturbing contour between the blade-side root sections. Each of the plurality of intermediate filling pieces includes a threaded hole disposed essentially perpendicular to a base of the channel. A screw is disposed in the threaded hole.

Abstract: The rotorcraft may include an airframe, at least one engine connected to the airframe, and a rotor connected to the airframe. The rotor may include a hub, a rotor blade, and a feathering spindle connected to the hub. The rotor blade may have a root and a tip and form a conduit extending in the radial 5 direction from the root to the tip. The root may comprise a wall forming a hollow circular cylinder. The hollow circular cylinder may form a portion of the conduit. A plurality of bolts may be distributed circumferential within the wall of the root. The plurality of bolts may extend in the radial direction from the wall of the root to secure the rotor blade to the feathering 10 spindle.

Abstract: A composite blade assembly for mounting on a turbine wheel includes a ceramic airfoil and an airfoil platform. The ceramic airfoil is formed with an airfoil portion, a blade shank portion and a blade dovetail tang. The metal platform includes a platform shank and a radially inner platform dovetail. The ceramic airfoil is captured within the metal platform, such that in use, the ceramic airfoil is held within the turbine wheel independent of the metal platform.

Abstract: A turbine wheel for a turbine engine, comprising a disk carrying blades, each having a platform carrying an airfoil and connected by a tang to a root, and sealing and damping sheets housed in the inter-tang spaces, the platforms including projections on their radially internal faces against which the sheets bear radially in operation, in order to define radial clearance and create at least one space between the sheets and the platforms, and the sheets including holes for feeding air to the or each space.

Abstract: A turbine engine airfoil structure including an airfoil adapted to be supported to extend across a gas passage for a hot working gas in a turbine engine. The airfoil structure further includes a platform structure located at one end of the airfoil and positioned at a location forming a boundary of the gas passage. The platform structure includes a platform member including a gas side surface extending generally perpendicular from the airfoil at a junction with the airfoil, and providing a structural connection to the airfoil. The platform structure further includes a separately formed platform cover attached to the platform member at the gas side surface. The platform cover extends from a location adjacent to one of the sidewalls of the airfoil, and includes an outer surface located for contact with the hot working gas passing through the gas path.

Abstract: A rotor blade assembly for a wind turbine, and a method for installing a rotor blade assembly on a wind turbine, are disclosed. The rotor blade assembly includes a rotor blade having exterior surfaces defining an aerodynamic profile including a pressure side and a suction side extending between a leading edge and a trailing edge. The rotor blade further extends in a generally span-wise direction between a root and a tip. The rotor blade assembly further includes a blade extension extending in the generally span-wise direction from the root towards the tip, and a plurality of connection devices connecting the blade extension to the rotor blade. Each of the plurality of connection devices includes a mechanical fastener extending through the root in the generally span-wise direction for connecting the rotor blade to a hub of the wind turbine.

Abstract: A rotor blade for an axial flow turbomachine, preferably a turbine, and to a mounting for such a rotor blade is provided. In the rotor blade, the two opposing lateral walls of the blade base are continuously curved along their extension between platform and bottom side of the blade base in order to reduce the mechanical load in the blade base and that of the walls supporting the blade base of a rotor.

Abstract: A rotor blade arrangement (20), especially for a gas turbine, which can be fastened on a blade carrier (19) and includes in each case a blade aerofoil element (10) and a platform element (14), wherein the platform elements (14) of a blade row form a continuous inner shroud. With such a blade arrangement, a mechanical decoupling, which extends the service life, is achieved by the blade aerofoil element (10) and the platform element (14) being formed as separate elements and by being able to be fastened in each case separately on the blade carrier (19).

Abstract: By providing a tube of deformable material which can be located within a hollow cavity of a blade it is possible to provide an element which through friction engagement can absorb vibration energy and therefore damp vibration in a hollow blade. The tube incorporates a number of cuts and/or grooves in an appropriate pattern in order to define a deformation profile once the tube is expanded in location. The tube is secured in position internally upon an expandable element which is typically an inflatable device. Once in position the tube is retained in its expanded deformable profile and the engagement between the tube and the hollow cavity wall surface results in energy absorption through vibration episodes. It is possible to provide a tube formed from a shape memory alloy which will expand in location to engage the hollow cavity wall surfaces for energy absorption during vibration episodes.

Abstract: An attenuation bracket is provided and includes an annular body having an annular attenuation arm defining first through-holes and an annular base defining second through-holes. A cross-section of the attenuation arm includes a flange, a connector opposite the flange and a curvilinear section extending between the flange and the connector. A cross-section of the base includes a first side corresponding with the flange and a second side opposite the first side and corresponding with the connector. The second side is connectable with the connector such that each of the first through-holes is defined in positional alignment with a corresponding one of the second through-holes.

Abstract: An axial turbomachine rotor is provided. The turbomachine includes a rotor body designed in a rotation symmetrical manner around the rotor axis, a rotor blade ring including rotor blades that are each fixed to the rotor body by the blade foot thereof and a sealing disc designed in a rotation symmetrical manner around the rotor axis that is arranged having the outer edge thereof radially inside, neighboring an axially extending protrusion of the blade foot, so that a hollow space is formed between the blade foot and the sealing disc, wherein a groove exists on the outer edge leading radially to the outside, wherein a sealing ring is mounted that may slide radially to the outside in the groove during operation of the rotor by centrifugal force until the sealing ring radially contacts the inside of the protrusion and thus seals the hollow space on the blade foot.

Abstract: A wheel dovetail groove with a wheel hook retains blade hooks of mounted blades. Opposed arcuate cut-outs in upper recessed areas of the groove may form an assembly gate. Blade hooks may be inserted into the groove in a first orientation, rotated to a second orientation at the assembly gate, and slid into a predetermined position. Blades may be secured with shims between adjacent bucket dovetails. Blade tip cover blocks may be included to form a cover. All blades may be substantially identical and not need special mounting arrangements at the assembly gate.

Abstract: Systems, methods and devices adapted to ease installation of turbine bucket assemblies about a rotor and to reduce related stress concentrations in the rotor are disclosed. In one embodiment, an insert includes: a base portion adapted to complement an entry slot in a rotor of a turbine; and a neck portion extending radially outboard from the base portion, the neck portion adapted to complement a post of the rotor to form a substantially continuous dovetail about the rotor.

Abstract: Certain embodiments of the invention may include systems methods, and apparatus for sealing a bucket dovetail in a turbine. According to an example embodiment of the invention, a method is provided for sealing a gap between a bucket dovetail and a rotor wheel slot. The method can include providing a bucket tab associated with a bucket dovetail, wherein the bucket tab is configured to accept a seal tab; configuring the bucket tab and the seal tab to engage at least one dimension upon insertion of the seal tab into the bucket tab; and sealing a gap between the bucket dovetail and a rotor wheel slot with the seal tab; wherein at least a portion of the seal tab changes as a function of temperature for further sealing gap between the bucket dovetail and the rotor wheel slot.

Abstract: Rotor blade or rotor blade segment for a wind turbine, having at least one cable for fixing the rotor blade or rotor blade segment to a rotor hub or to a further rotor blade segment, wherein the at least one cable is redirected in a U-shaped manner within the rotor blade or rotor blade segment.

Abstract: One embodiment of the present invention is a unique gas turbine engine blade. Another embodiment is a unique gas turbine engine. Other embodiments include apparatuses, systems, devices, hardware, methods, and combinations for gas turbine engines and blades. Further embodiments, forms, features, aspects, benefits, and advantages of the present application will become apparent from the description and figures provided herewith.

Abstract: A turbomachine is disclosed. The turbomachine includes a rotor, a plurality of blades arranged side by side on the rotor in a circumferential direction, and a plurality of sealing apparatuses each disposed on a respective blade shaft of the plurality of blades. Each of the plurality of sealing apparatuses includes first and second bottom plates protruding in a respective axial direction on the respective blade shaft and first and second bulkheads which extend in a radial direction along the respective blade shaft and form a double-walled seal in the axial direction. A respective rounded or parabolic transitional cross-section from the bottom plates to the bulkheads is provided and at least one of the bulkheads is offset with respect to a blade root edge of the respective blade shaft in a direction toward a radial longitudinal axis of the respective blade shaft.

Abstract: Provided is a blade for a rotor of a wind turbine having a substantially horizontal rotor shaft, said rotor comprising a hub, from which the blade extends substantially radially when mounted, said blade having a chord plane extending between a leading edge and a trailing edge of said blade, a root area closest to the hub, an airfoil area furthest away from the hub, a transition area between the root area and the airfoil area, a first airfoil extending substantially along the entire airfoil area, and a second airfoil separately mounted to the blade, said second airfoil arranged at a mutual distance transverse to the chord plane and extending along the root area of the blades.

Abstract: Spacers interposed between blades attached to the disk of a rotor having slots and bottoms of the slots are disclosed. Each spacer is made of an elastically deformable material and at least one longitudinal segment of the spacer presents a transverse profile of arcuate shape to define two lateral contact zones.

Abstract: A blade for a rotor of a wind turbine having a substantially horizontal rotor shaft, the rotor comprising a hub, from which the blade extends substantially in a radial direction when mounted to the hub. The blade comprises a main blade part having a profiled contour comprising a pressure side and a suction side as well as a leading edge and a trailing edge with a chord extending between the leading edge and the trailing edge. The profiled contour generates a lift when being impacted by an incident airflow. The profiled contour is divided in the radial direction into a root region with a substantially circular or elliptical profile closest to the hub, the substantially circular or elliptical profile having a diameter, an airfoil region with a lift generating profile furthest away from the hub, and a transition region between the root region and the airfoil region.