Abstract: An impeller for wind power generation includes: a plurality of blades; and a hub which is provided with a rotating shaft at a center and around which the plurality of blades are arranged at substantially equal intervals in a circumferential direction. The blade is formed to extend while widening a width toward an outer periphery of the impeller, a line segment connecting a leading edge and a trailing edge of the blade is inclined at an angle of approximately 10 degrees or more and approximately 20 degrees or less with respect to a plane perpendicular to a rotating shaft of the impeller, and in the plurality of blades, a trailing edge of a blade on a front side in a rotation direction of the impeller and a leading edge of a blade on a rear side in the rotation direction partially overlap each other in a front view of the impeller.

Abstract: Provided is a wind turbine blade, with a generally hollow blade body including half shells and webs the webs including flanges connecting the respective web to the respective half shell, and with webs being supported via reinforcement structures relative to the respective half shell, which reinforcement structures are arranged between an outer and an inner layer of each half shell and extend in the lengthwise direction of the blade, whereby the reinforcement structures each include at least one stack composed of several glass fiber layers infused with resin, and that at least one stiffening element extending parallel to the first and second reinforcement structures over at least a part of their length including at least one stack composed of several pultruded composite strips including carbon fibers with the strips being fixed in the resin is arranged between the first and second reinforcement structures.

Abstract: A rotor blade for a wind turbine includes a first blade segment and a second blade segment extending in opposite directions from a chord-wise joint. Each of the first and second blade segments includes at least one shell member defining an airfoil surface and an internal support structure. The first blade segment includes a beam structure extending lengthwise that structurally connects with the second blade segment via a receiving section. The rotor blade also includes at least one chord-wise extending pin positioned through the chord-wise joint so as to secure the first and second blade segments together. Further, the chord-wise extending pin includes a hollow cross-section that extends from a trailing edge end to a leading edge end thereof.

Abstract: An apparatus for securing first and second skins to a core in a composite rotor blade includes an elongated member configured to be installed through a passage in the core of the composite rotor blade. The elongated member has a first end configured to be attached to an outer surface of the first skin and a second end configured to be attached to an outer surface of the second skin. The apparatus also includes a first patch configured to adhere the first end to the outer surface of the first skin, and a second patch configured to adhere the second end to the outer surface of the second skin such the elongated member extends from the outer surfaces of the first and second skins through the passage in the core.

Abstract: An insert (105) for a wind turbine blade root. The insert (105) has a bushing (40) and an outer surface with circumferential annular grooves (68). A transition layer 5 (102) is built up around the bushing (40). The transition layer (102) has fibrous material sheet layers and filamentary material windings (80) in the grooves which alternate with fibrous plies (98) covering the grooves (68). Each fibrous ply (98) is anchored into the grooves (68) by the windings (80). Fibrous battens (148) are fitted around the transition layer (102) to form an insert body (108). Each batten (148) 10 has a deltoid cross-section so that the battens give the insert a quadrilateral or trapezoidal cross-section.

Abstract: The present invention relates to a wind turbine blade (10) comprising a shell body with at least one pressure side shell member (36) and at least one suction side shell member (38), and a plurality of shear webs (70) arranged within the shell body. The plurality of shear webs (70) is successively arranged spanwise within the shell body such that adjacent shear webs overlap along part of their spanwise extent (L), wherein a gap (88) in the chordwise direction is provided between adjacent shear webs (70).

Abstract: The present invention relates to wind turbine blade and a method of manufacturing the wind turbine blade. An aerodynamic shell is provided with a recess (70) at its inner surface, the recess (70) extending with-in the shell along a spanwise direction of the blade. A first region of the recess (70) has a first width and a second region of the recess (70) has a second width exceeding the first width. A transition region is provided between the first region and the second region of the re-cess. A first and a second spar cap (80, 82) are arranged within the shell.

Abstract: A pultruded fibrous composite strip, a spar cap made from such strips, a wind turbine rotor blade having such a spar cap and a method for making a spar cap from such strips is provided. The strip is stacked with similar strips to form the spar cap. The strip has a substantially constant cross-section defined by first and second mutually opposed and longitudinally extending sides, and by first and second longitudinal edges. The first and the second sides include first and second abutment surfaces, respectively. The first and the second abutment surfaces are non-planar. When the strip is stacked with similar strips, and subsequently integrated within shell of the wind turbine blade, the non-planar profile of the strips at least partially obviates formation of resin rich pockets at the interface of the spar cap and the shell and/or stress concentration between the edges of the spar cap and the shell.

Abstract: A method of forming a rotor blade, including forming at least one of a partial upper skin, a partial lower skin, and a partial support network using an additive manufacturing process; and forming a first receptacle in at least a one of the partial upper skin, the partial lower skin, and the partial support network using the additive manufacturing process. The first receptacle is configured to receive of at least one of an electronic component and a mechanical component. In some embodiments, there is a method of manufacturing a rotor blade that includes forming a first locating receptacle in at least one of the upper skin, the lower skin, and the support network using the additive manufacturing process; and positioning at least one of the upper skin, the lower skin, and the support network in a desired position on a fixture based, in part, on the first locating receptacle.

Abstract: A structure for a trailing edge portion of a rotor blade, wherein the rotor blade has a leading edge, a trailing edge, and opposed upper and lower airfoil profiles each beginning at the leading edge and terminating at the trailing edge. The structure includes an inner core having a generally caret-shaped cross-sectional profile and upper and lower skins adhered to the inner core. The upper and lower skins have respective first and second portions adhered to the inner core, and respective third portions which are adhered to each other and which extend aftward to proximate the trailing edge. An upper pocket is defined by the second and third upper skin portions and the upper airfoil profile, and a lower pocket is defined by the second and third lower skin portions and the lower airfoil profile. The upper and lower pockets are filled with a fairing compound and/or an expandable adhesive.

Abstract: A wind turbine blade has a blade body and a leading edge fairing. The blade body has a root, a tip, and a longitudinal direction extending between the root and the tip. The 5 blade body also has a channel extending in the longitudinal direction. The leading edge fairing has a projection extending into the channel and extending in the longitudinal direction so as to be received in the channel. Also, a leading edge fairing for attachment to a blade body of a wind turbine blade; a method of fitting a leading edge fairing to a wind turbine blade; and a kit of parts with a number of the leading edge fairings.

Abstract: An autogyro rotor blade for generating lift by autorotation defines a root-side inner profile region, which has a first profile. The inner profile region has a tip-side main profile region, which has a second profile different from the first profile, and a profile depth curve that decreases monotonically in the longitudinal direction of the autogyro rotor blade from the region of the blade root in the direction of the blade tip. The autogyro rotor blade has a twist having a twist curve that decreases monotonically from the region of the blade root in the direction of the blade tip. The twist curve has a variable slope in the inner profile region and/or main profile region, and therefore the twist curve is concavely curved in this region.

Abstract: The present invention provides a mosquito trapping device, which comprises a carbon dioxide generating module, a temperature control module, a humidity control module, and a mosquito-killing module. The carbon dioxide generating module comprises a container A and a container B, a solution in the container A reacts with a solution in the container B to generate carbon dioxide; the temperature control module controls a temperature of the mosquito trapping device to be between 38° C. and 45° C.; the humidity control module controls humidity of the mosquito trapping device to be between 50% and 80%; the mosquito-killing module generates a guiding wind having a wind speed of 0.7 m/s to 15 m/s. The present invention has a good mosquito-attracting effect and a desirable mosquito-killing ability.

Abstract: An airfoil vane includes an airfoil section including an outer wall that defines an internal cavity; and a baffle situated in the internal cavity, the baffle including a baffle wall that defines a central cavity having a leading end and a trailing end corresponding to a leading end and a trailing end of the airfoil section, and a tail extending from the baffle wall, the tail including at least one feature configured to disturb an airflow surrounding the tail. A baffle for the airfoil vane assembly and a method of assembling a ceramic matrix composite airfoil vane are also disclosed.

Abstract: A pultruded fibrous composite strip for wind turbine spar caps, a spar cap having such a strip, and a wind turbine blade having such spar cap. The strip has longitudinally extending unidirectional fibers and an elongate body having first and second edge regions separated in the longitudinal direction of the strip by an intermediate region. The intermediate region has first and second mutually opposed longitudinally extending and parallelly disposed planar surfaces. The strip's thickness is measurable perpendicular to the planar surfaces and the width is measurable parallel to the planar surfaces and perpendicular to the longitudinal direction of the strip. In the strip, the first and/or the second edge regions, starting from the intermediate region and extending longitudinally, simultaneously tapers along the width and the thickness of the strip.

Abstract: A modular wind turbine blade is described. The modular blade comprises a first blade 5 module having a first spar cap extending longitudinally in a spanwise direction and a second blade module having a second spar cap extending longitudinally in the spanwise direction. The blade modules are configured for connection end-to-end via their respective spar caps. The first spar cap comprises first and second beams arranged side-by-side, each beam having a tapered end defining a scarfed surface. The tapered end of the first 10 beam extends beyond the tapered end of the second beam. The second spar cap comprises first and second beams arranged side-by-side, each beam having a tapered end defining a scarfed surface. The tapered end of the second beam extends beyond the tapered end of the first beam.

Abstract: A winglet is provided for retrofitting to a wind turbine. Aerodynamic and centrifugal forces for winglets having a range of configurations including winglet height, taper ratio, twist, and cant angle are modeled, wherein the winglet height, taper ratio, twist, and cant angle are used to define a grid in a Vector Lattice. An increase in a coefficient of power Cp of each winglet design when applied to a predetermined main blade of the wind turbine can be determined. A winglet configuration can then be selected wherein the coefficient of power Cp of the main blade and winglet is at least 2% greater than the coefficient of power Cp of the main blade alone, and wherein a ratio of normal aerodynamic force generated by the winglet to centrifugal force generated by the winglet during rotation at a nominal rated speed is in a range between 0.75 and 2.

Abstract: An airfoil includes a body that has rib nodes that each define a node cavity therein. A cover panel is carried on the body over the rib nodes. The cover panel includes tabs that project into the node cavities. Plugs are disposed in the node cavities and pinch the tabs against the node cavities to lock the cover panel on the body.

Abstract: An airfoil assembly includes a vane that includes an outer platform, an inner platform, and an airfoil. The outer platform defines an outer boundary of a gas path. The inner platform is spaced apart axially from the outer platform relative to an axis and defines an inner boundary of the gas path. The airfoil extends axially between and interconnects the outer platform and the inner platform.

Abstract: The present disclosure is directed to a method of assembly of a rotor blade for a wind turbine. The method includes placing a first rotor blade section onto a first set location of an assembly fixture, wherein the first rotor blade includes a first locating datum such that the assembly fixture at the first set location constrains movement of the first rotor blade section at the first locating datum along a first direction; placing the first rotor blade section onto a second set location of the assembly fixture, wherein the first rotor blade includes a second locating datum such that the assembly fixture at the second set location constrains movement of the first rotor blade section at the second locating datum along a second direction; and positioning a second rotor blade section onto the first rotor blade section within the assembly fixture.

Abstract: The present invention includes a balancing system that includes a weight box, mounted substantially within the rotor-blade spar, flush with a rotor-blade spar outer surface, operably accessible from a rotor-blade tip, and retained within the rotor-blade spar by a weight-box retention pin, one or more weight-box contact surfaces bonded to a rotor-blade-spar inner surface, or a weight-box lip providing a bearing contact with an edge of a spar rotor-blade spar cutout; and a weight package attached to the weight box, the weight package including a weight-box cover, two or more weight guide-rods attached to the weight-box cover, wherein one of the two or more weight guide-rods is positioned forward of a pitch change axis or center of twist and wherein one of the two weight guide-rods is positioned aft of the pitch change axis or center of twist, and one or more balance weights mounted on the weight guide-rods.

Abstract: A spar cap for a rotor blade of a wind power installation, having a longitudinal extent from a first end to a second end, a transverse extent orthogonal to the longitudinal extent, and a thickness orthogonal to the longitudinal extent and to the transverse extent. A method for producing a spar cap as mentioned at the outset.

Abstract: A composite assembly has an outer spar component having an outer spar component inner profile, an inner spar component having an inner spar component outer profile substantially complementary to the outer spar component inner profile, and an adhesive disposed between the outer spar component and the inner spar component.

Abstract: The present disclosure is directed to a modular rotor blade constructed of thermoset and/or thermoplastic materials for a wind turbine and methods of assembling same. The rotor blade includes a pre-formed main blade structure constructed, at least in part, from a thermoset material. The rotor blade also includes at least one blade segment configured with the main blade structure. The blade segment(s) is constructed, at least in part, of a thermoplastic material reinforced with at least one fiber material.

Abstract: A rotorcraft rotor blade assembly includes a stub spar extending less than a full span of the rotor blade assembly. An upper skin portion extends substantially the full span of the rotor blade assembly. A lower skin portion extends substantially the full span of the rotor blade assembly. The stub spar is positioned between the upper skin portion and the lower skin portion.

Abstract: A jointed wind turbine rotor blade includes a first blade segment and a second blade segment extending in opposite directions from a chord-wise joint line. Each of the blade segments includes a pressure side shell member and a suction side shell member. A sealing tape is applied over the shell members so as to bridge across the chord-wise joint line. The sealing tape includes side edges that are aligned parallel with airflow over the shell members at the chord-wise joint line at a defined load and operational condition on the jointed wind turbine blade.

Abstract: The invention concerns a method for the production of a composite component from at least one hollow profile base element and at least one supporting element positioned in the interior of the at least one hollow profile base element.

Abstract: A jointed rotor blade assembly may include a first blade segment having a first outer shell terminating at a first joint end and a second blade segment coupled to the first blade segment at a blade joint. The second blade segment may include a second outer shell terminating at a second joint end. The outer shells may overlap one another at the blade joint such that an overlapping region is defined between the first and second joint ends. In addition, the first outer shell may be spaced apart from the second outer shell along at least a portion of the overlapping region such that a gap is defined between the outer shells within the overlapping region. Moreover, the rotor blade assembly may include a sealing member positioned between the outer shells within the overlapping region that is configured to allow relative movement between the outer shells at the blade joint.

Abstract: The present disclosure provides a method of manufacturing a composite laminate structure of a wind turbine blade part by means of resin transfer moulding, preferably vacuum-assisted resin transfer moulding. In a resin transfer moulding, fibre-reinforcement material is impregnated with liquid resin in a mould cavity. The mould cavity comprises rigid mould part having a mould surface defining a surface of the wind turbine blade part. The method comprises alternately stacking on the rigid mould part: i. a number of unidirectional fibre-reinforcement layers comprising electrically conductive fibres, such as carbon fibres, and ii.

Abstract: An afterbody for a rotor blade of a rotorcraft is unitarily formed of a single material of construction. The afterbody includes an upper surface disposed from a lower surface, a concave leading edge connected to the upper surface and the lower surface, and a trailing edge formed at an intersection of the upper surface with the lower surface.

Abstract: The present disclosure is directed to a rotor blade that includes a shell defining an interior cavity. The rotor blade also includes exterior surfaces defining a pressure side, a suction side, a leading edge, and a trailing edge. Each of the pressure side, the suction side, the leading edge, and the trailing edge extends between a tip and a root. The shell defines a span and a chord. A shear web is positioned in the interior cavity and coupled to the shell. The shear web includes a lattice structure.

Abstract: The present disclosure is generally directed to a core configured for the manufacturing of a turbine engine blade by lost-wax casting. The core includes a first convex curved outer face and a second concave curved outer face. The first and second faces have a plurality of recesses, each recess including a spherical portion.

Abstract: Wind turbine rotor blade components including pultruded rods and methods of manufacturing the same are disclosed. More specifically, the rotor blade component includes a plurality of pultruded rods housed within an enclosed primary outer casing. The enclosed primary outer casing includes a hollow interior, a root end, and an opposing tip. As such, each of the plurality of pultruded rods is received within the enclosed primary outer casing and secured therein via a first resin material. Further, an arrangement of the plurality of pultruded rods within the primary outer casing and a relationship of a maximum dimension of each of the plurality of pultruded rods and a maximum dimension of the enclosed primary outer casing are configured to maximize flexibility of the rotor blade component.

Abstract: A mould for moulding a wind turbine blade or an elongate structural part thereof, the mould comprising a plurality of longitudinal elongate mould sections adapted to be fitted together in an end-to-end relationship to form a unitary mould, each mould section having a central mould portion between opposite end portions, each mould section being composed of a fibre reinforced resin matrix composite material, at least one end portion of each mould section forming an integral flange oriented substantially orthogonally downwardly with respect to an upper surface of the mould section, and the upper surface including a moulding surface and a recess located between the flange and the moulding surface, the recess extending across a transverse width of the mould section whereby when the flanges of adjacent mould sections are fitted together in an abutting relationship, the adjacent recesses form a combined recess separating the moulding surfaces of the adjacent mould sections.

Abstract: A turbofan engine including a core engine and at least one fan by means of which fluid is guided to a primary flow channel for the core engine as well as to a secondary flow channel of the turbofan engine, wherein the secondary flow channel is provided for an outer fluid flow that is guided past the core engine, and at least one splitter fairing arranged inside the secondary flow channel around which the fluid flow is flowing during operation of the turbofan engine, which cases at least one component of the turbofan engine that is guided radially through the secondary flow channel, and which has an end element with a leading edge section that is facing towards the fluid flow and/or a trailing edge section that is positioned in the flow direction of the fluid flow.

Abstract: The invention relates to a rotor blade of a wind power plant having two rotor blade half-shells (1, 21) with in each case a leading-edge periphery and a trailing-edge periphery (8a, 22a), which rotor blade half-shells are adhesively fastened to each other along the leading-edge and trailing-edge peripheries (8a, 22) and which in case have a trailing-edge girder (3, 25), and each of the trailing-edge girders (3, 25) at least in certain sections is of rectangular design in a cross section along its longitudinal extent.

Abstract: An ceiling fan comprising a motor system. The motor system is mounted around a motor shaft. The motor shaft couples to a downrod for suspending the ceiling fan from a structure. The motor shaft and motor are encased by a motor housing. The motor housing comprises hub arms for mounting a plurality of blade holders. The blade holders coupled to a plurality of blades rotatable about the motor during operation. The downrod comprises a wire disk mounting guy wiring to the downrod. A retention rod is utilized internal of the motor and downrod as a secondary retention method. An electrical connector is internal of the motor shaft and electrically couples to the stator to power the motor.

Abstract: A method of making a wind turbine blade, and the turbine blade resulting form the process, is described in which correct alignment of the shear webs (42a, 42b) upon mould (30) closing is ensured. The method involves providing a first half shell (32a) and a second half shell (32b) to be joined together to form the wind turbine blade. A first edge (46) of a shear web (42) is attached to an inner surface (36a) of the first half shell (32a). A shear web mounting region is defined on an inner surface (36b) of the second half shell (32b). At least one guide block (60a, 60b) is attached to the inner surface (36b) of the second half shell (32b) adjacent to the shear web (42) mounting region. The guide block (60a, 60b) has a guide surface (70) oriented transversely to the inner surface of the second half shell (36b).

Abstract: In a first aspect, there is a method for improving a lift to drag ratio of a rotor blade, including providing a blade member having a leading edge and a trailing edge; providing a leading edge extension member; and coupling the leading edge extension member to a portion of the leading edge of the blade member to form the rotor blade. In a second aspect, there is a rotor blade including a blade member having a leading edge, and a trailing edge; and a leading edge extension member disposed on the leading edge of the blade member, wherein the leading edge extension member is configured to extend the chord length of at least a portion of the rotor blade. In a third aspect, there is a leading edge extension member for a rotor blade including a convex exterior surface configured to extend at least a portion of the chord length of the rotor blade.

Abstract: A joint assembly for a wind turbine rotor blade includes a male structural member extending longitudinally through female structural members configured with a plurality of rotor blade segments. The female structural member includes first bore holes on opposing sides thereof that are aligned in a chord-wise direction. The male structural member includes second bore holes on opposing sides thereof that are aligned with the first bore holes. At least one chord-wise extending gap is defined between an outer side surface of the male structural member and an inner side surface of the female structural member. A chord-wise extending pin extends through the first and second bore holes to join the male and female structural members. At least one flanged bushing is arranged in the first and second bore holes such that a flange of the bushing extends within the chord-wise extending gap.

Abstract: The present disclosure is directed to a method for bonding composite blade components of a rotor blade of a wind turbine. The method includes providing a first blade component being constructed of a first composite material. The method also includes providing a second blade component being constructed of a second composite material. Further, the method includes arranging the first and second blade components together at an interface. Another step includes placing one or more layers of a wetted composite material between the first and second blade components at the interface. The method also includes allowing the one or more layers of the wetted composite material at the interface to cure.

Abstract: A portable radiographic imaging apparatus includes a sensor and a case that houses sensor panel. Radiation detector elements are arrayed two-dimensionally in the sensor panel. The case comprises a corner where two side walls are adjacent. The side walls are made of a continuous fiber reinforced resin that comprises one or more fiber layers oriented in a predetermined direction. The fiber layers are oriented in a direction from one to the other of the adjacent side walls in the corner. A breakpoint where the fiber layers are discontinuous over an entire thickness in a wall thickness direction is not present in an area of at least one of the corners.

Abstract: A rotor blade for a wind turbine includes an upper shell member having a spar cap configured on an internal face thereof, a lower shell member having a spar cap configured on an internal face thereof, and a shear web assembly extending between the spar caps along a longitudinal length of the rotor blade. The shear web assembly includes, at least, a first shear web and a second shear web. The first shear web starts at a blade root of the rotor blade and extends to an intermediate span location. The second shear web overlaps the first shear web at the intermediate span location and extends towards a blade tip of the rotor blade so as to provide increase torsional rigidity to the rotor blade.

Abstract: An airfoil for an aircraft engine is provided. The airfoil may include a plurality of composite plies extending in a chordwise direction from a leading edge to a trailing edge and in a spanwise direction between an airfoil tip and an airfoil base. The airfoil may include at least one discontinuous ply having a first ply segment, a second ply segment, and a butt joint disposed between the first ply segment and the second ply segment. The butt joint may be disposed along a first fragment profile to frangibly attach the first and second ply segments.

Abstract: A fan system includes a motor, a rotatable hub, and a plurality of fan blades. Each of the fan blades includes a substantially rigid spine member, a resilient leading edge member, and a resilient trailing edge member. The leading edge member and trailing edge members are removably coupled with the spine member, such that different leading edge members and different trailing edge members may be chosen to customize the leading and trailing edges of the fan blades. Each fan blade may have more than one type of leading edge member or more than one type of trailing edge member. The leading edge member and trailing edge member may each be coupled with the spine member by urging the leading edge member and trailing edge member in a direction that is substantially perpendicular to the longitudinal axis defined by the spine member.

Abstract: A method of making an elongate wind turbine blade is described. The wind turbine blade extends longitudinally between a root end and a tip end in a spanwise direction, and the method comprises: (a) providing an elongate mould tool (20) extending longitudinally in a spanwise direction; (b) arranging an elongate spar structure (40) in the mould tool, the spar structure (40) N extending longitudinally in the spanwise direction; (c) arranging core material (24) adjacent to the spar structure (40); (d) providing resin-permeable material (114) between the spar structure (40) and the core material (24); and (e) administering resin into the mould during a resin infusion process. The resin-permeable material (114) restricts the flow of resin between the spar structure (40) and the core material (24) in the spanwise direction and thereby substantially prevents lock-offs from forming during the infusion process.

Abstract: The present disclosure is directed to a rotor blade component for a wind turbine. The rotor blade component includes a plurality of pre-cured members arranged in one or more layers. Each of the pre-cured members is constructed of a plurality of fiber materials cured together via a resin material having a first stiffness and at least additional material having a second stiffness. Further, the second stiffness is lower than the first stiffness. As such, the additional low-stiffness material is cured within the resin material so as to increase flexibility of the pre-cured members.

Abstract: Provided is a blade for a wind power generator comprising: a main spar including: an upper main spar flange and a lower main spar flange whose both ends are protruded towards the front and rear side respectively; a front main spar web and a rear main spar web which are connecting the upper main spar flange and the lower main spar flange; a first body, located in the front side of the main spar, including an inverted D-type rib; and a second body, located in the rear side of the main spar, including a curved rib. The inverted D-type rib includes: a vertical frame; and a block frame extendedly formed from the upper side and the lower side of the vertical frame respectively and convexly formed towards the front side.

Abstract: A turbine engine component (100) comprises a fiber structure (125, 126) forming at least a portion of an airfoil (102). A matrix (128) embeds the fiber structure. A carbon nanotube filler (130) is in the matrix.

Abstract: A ceiling fan includes blade (11) that is integrally formed of root (12), vane (13), and step (14) for maintaining vane (13) in a state inclined from horizontal. Blade (11) includes bend (16) on upstream side (11c), first reinforcement (17) on upstream downstream side (11c) (11b), and a plurality of second reinforcements (18) between bend (16) and first reinforcement (17). First reinforcement length (17a) is longer than second reinforcement length (18a). Further, the ceiling fan includes blade drop prevention portion (37) for locking blade (11) to support (10).