DE1629628A1 - Method and apparatus for manufacturing helicopter wings - Google Patents

Description

Method and device for manufacturing helicopter wings. Experience shows the importance of the introduction of new materials, such as plastics and fiber optics, for making helicopter wings.

The known wings generally have the following three components: a) A hollow or solid spar or longitudinal part, which can form the leading edge and can be produced using the following materials, which can be used separately or in combination: Metallg, plastic or with resin enveloped "* STUFFED, and QI, .aßfUqr" nt. b) a part to fill the Frofils foam.

c) A coating of metal or glass fibers that envelops the entire profile, the wing or part of it.

If necessary, such a wing can also be a rear structure have, which by an arrangement of hollow parts made of metal or with glass fabric reinforced plastic is formed, furthermore a protective part on the front edge can be provided.

The glass fiber which is used in the manufacture of the spar or longitudinal part and the cover # s used may be in the form of fabrics or glass threads which are arranged in the depth direction or in the longitudinal direction.

In this training, the spar can be divided into two independent layer halves be made of fiberglass, which are made separately and on the bottom or top of the wing are arranged. It can also be accessed through a jetty Plastic can be formed, with the glass fiber in the form of superimposed Layers of glass threads are used which are arranged in the longitudinal direction and are anchored by threading to stirrups, with a portion thereof embrace.

Finally, it can happen that the glass fabric coating in the part of the leading edge is thickened to form a tail which the Shape of this leading edge.

All of these embodiments require allgemeinenz except the penultimate, zusä.tzliche parts to fix the wing in the fitting. In addition, the production of the final profile of such a wing usually requires machining, which is all the more difficult as the profile of the wing changes in outline or thickness.

In order to remedy these various disadvantages, the object of the B: cfindunr # - is a helicopter wing or a similar aerodynamic surface, which has a longitudinal part forming a spar and / or the leading edge, which is formed by a layered structure a longitudinally union U is formed in the form of, vielches wraps around the Pussbeschlag of Flägels and hnftet this, these various layers of existing under a bias coated with -this thermoplastic resin Glasfiken - are available and anreordnet in the direction of the span, a filling of an has steep and the filling Überdeaktg; lightweight material which is steeply fixedly connected to 12n- and the shape thereof added to the Flägelprofil, and a coating of glass cloth of lower than 45 0 intersecting getrlücten with a thermoplastic resin Faserng which these TjänE..

The above wing is in a manner known per se by one or two Glass fiber tubes completed in the zone of the leading edge of the long part and are partially and locally precipitated with metal masses that are attached to them any known manner are attached to the wing statically and dynamically to balance.

The wing according to the invention can have a rear strip which is formed by a layered U-shaped structure, which the filling is made of a leiclit-en --- Material in a rear zone of the same as well A suitable part of the butt fitting of the wing wraps around, these layers are made with the aid of pre-tensioned glass threads, soft in the direction of the span and coated with a thermoplastic resin are. As a result, the surfaces retain their shape very well.

The invention further relates to a method of manufacturing a helicopter wing of the above type, according to which the glass threads which are subjected to a prestress under a controlled tension in a plane which lies in the direction of the span and perpendicular to the depth of the wing profile around the winding core halves are wound by two CD foot fittings of the wing, the mutual distance between which is greater than the length of the wing to be produced, whereupon the layers of thread obtained after winding are tightened on their arrival at these fittings by brackets, whereupon the structure thus obtained is shaped by means of a mold , then this molded in the form of structures after which the polymerized structure is covered with a glass fabric from below 45 0 crossed resin-impregnated fibers is poly-merized, whereupon the assembly is tightened to the coating with ironing, whereupon this assembly is pressed in the form of and is polymerized9 on what one of the two wrap-around fittings is cut out and an aspiration attachment made from the same thermoplastic resin is molded onto the cut-out section of the coated structure.

In the case of wings with relatively small wingspan, this can be exaggerated and polymerized structures are cut centrally so that two plugs with their Mounting fittings arise at the wing base. If a wing Is to be produced with a very high dimensional stability, takes place after the polymerization of the structure not yet provided with a coating, the winding of the strip.

The invention finally has the manufacturing equipment to practice of the above procedure. This apparatus has a winding frame, in which the two mounting brackets are attached so that they are with their edges adjacent to the trailing edge of the wing to be produced are opposite, These fittings are provided with winding core halves at the end, the axis of which is parallel to the depth of the frame, with the frame also attached to these fittings centered on a four-part mold with the profile of the wing to be produced, of which the rear parts, in which the filling is made of a light material is housed, are attached alone to the frame during the winding, wherein the arrangement formed by the frame, the fittings and the shape around a central, is set in rotation to the axis of the 1, llickelkernh # Twelfth parallel axis, -which this Arrangement of the ITickel cores under tension from an unwinding device picks up incoming glass thread. The unwinding device is expediently through a Formed by a torque limiter braked Glasfaaenspule, whose thread on the desired tension by a stressed dancer between two fixed roles The last fixed roller is brought about its axis parallel to the axis of rotation of the winding frame o carries a device for soaking and draining, which is attached to a slide which is variable in the transverse direction and reversible stroke which is displaceable by the one to be produced -Profile scanning arrangement is controlled, with a fixedly connected to the carriage Guide arm is alternately supported on rollers, which are supported by the rotatable frame to be worn against the fittings attached to this.

The arrangement scanning the profile to be produced contains a printed one This profile reproducing circuit, the surface of which is horizontally displaced by an axially Switch is coated which is attached with friction to a on the carriage Holder is pivotable, this winding by layers parallel to the winding axis this is achieved »that the slide step by step by a diameter that soaked thread advances corresponding step, this advance by a Kontlakt is controlled, which is controlled by a button with each passing of the wing is closed.

The invention is described below with reference to the drawing explained by way of example.

Fig. 1 is a cross section of a helicopter flU # 7 according to the invention, els with a longitudinal part forming the front edge, a strip and two parts for static and dynamic balancing.

Fig. 2 is a perspective view of one of the types shown in Figs. 1 illustrated manner trained helicopter wing with breaking away of parts.

Fig. 3 is a perspective view of the apparatus for winding with a pre-stressed soaked glass thread used for the manufacture of a helicopter wing according to the invention. 4 is a schematic section of the vessel for impregnating the glass thread with a therinoplastic H ar pi! - '. 5 shows, in a larger nap stick, a partial view of the winding frame, seen from the side, in the zone in which it is provided with a fitting part, the felling part and the two rear sections of the mold.

F: Ltrz-. 6 is a fic. Top view corresponding to Fig. 5 , with the rear upper part of the mold removed.

Fig. 7 is a perspective view of the device for controlling the displacements of the slide carrying the glass thread wedding vessel.

Figure 8 is a perspective view of a portion of the carriage showing the printed circuit board representing the profile to be formed and enabling the direction of movement of the carriage to be reversed.

9 is a plan view of a fitting part with a winding core of the longitudinal part forming the front edge and a winding core of the strip.

Figs. 10 to 13 are sections of the rii, -. 9 along lines XX or XI-XI or XII-XII or XIII-XIII after the winding of the longitudinal part forming the front edge.

The helicopter surface shown in FIGS. 1 and 2, which has a relatively high dimensional stability, has a steep length which forms the front edge and the spar. This C - + 'UrEiige part is formed by a U-shaped layered structure 2, which includes the fitting 3 of the wing root and is made with the help of pre-tensioned glass threads, which are arranged in the direction of the span perpendicular to the depth of the profile are. This Li; ngsteil is at the vvrderbn portion 4 of a filling 5 of a light material angebrachtg for example, a plastic foam such as polyurethane foam known under the name "l # loltoprentl type, the shape of the d is component 1 added and the profile of the wing defined At the rear section of the casing 5 there is a bar 6 , which is arranged in the same way as the dimension as steeply for the front edge 1 , ie with the help of pre-tensioned glass threads which run in the direction of the span are arranged U-shaped one is not visible in these figures winding core overlap, which fixedly connected to the bracket 3 of the blade root ist.-the arrangement is -berzogen with a glass fabric-7 having less than 45 0 crossed parsers are u, which with the are soaked in the same thermo-plastic resin.

If the wing only needs to have a relatively low dimensional stability, the strip 6 is omitted, so that the wing then only has the parts 5 and the cover 7 .

In the section of the longitudinal part adjacent to the leading edge, a tube 8 made of glass fibers is arranged in which metal masses are accommodated for the static and dynamic balancing of the wing.

The surface produced in this way uses an essential property of the glass fibers, which when subjected to a regulated pre-tensioning form a material which has a considerably more advantageous relationship between stress / specific mass than aluminum alloys and steel. This wing has the following advantages: -a) the longitudinal part is layered in the direction of the forces; , b) the overloads on the glass fibers on the fastening on the fitting 3 are avoided whereby the .I w fastening of the fibers to the fitting in a perfect manner by wrapping the fitting with the fibers and the approaching of the two layer halves with stirrups, which also allowed gradually the forces to be introduced without requiring further additional parts for fastening in the fitting; c) The longitudinal part of the front edge can be produced with a profile that changes in plan or thickness without requiring processing, as explained below, whereby an abrasion-resistant front edge is created at the same time; , d) the adaptability of the manufacturing process allowed the wing to give a relatively very high or low dimensional stability.

To produce a wing of the type described with reference to FIGS. 1 and 2, with or without a bar, a winding apparatus is used, which is shown in FIGS. 3 to 8 for producing a wing without a bar. This apparatus contains a rotatable which is sufficiently stiff to withstand the pretensioning forces exerted on the glass thread e.g. 2 tolerable which / between 10 and 30 kg / mm. The frame is set in rotation about an axis 10 perpendicular to it by means of a motor 11 (FIG. 3).

Two fastening fittings 3a and 3b are attached to this frame in a plane passing through the axis of the shaft 10. Each fitting is attached to the frame 9 by an axle 12 (pig. 5 and 6) which passes through the leg 13 of the fitting which is on the side of the rear edge of the sash to be produced. Adjustable screws support themselves on these fittings and allow their alignment to be adjusted when they are attached to the frame 9 by rotating the fittings about their fastening axes 12. Each fitting runs into one 15 out which is glued to it, and on which the glass thread is wound. - The rotating frame 9 carries a cross member 16t to which the rear portions 17 and 18 of a shape vierteili.cen are attached, the front parts are not used 19 and 20 during the winding. These YormtaLle form a cavity in which the filling 21, which consists of moltoprene, for example, is arranged. The PÜllung is attached to the rotatable frame before the winding is carried out and is held in its position # - e by the rear mold parts 17 and 18. The rotatable frame 9 also carries axles 22 opposite the fittings 3a and 3b on the side facing away from these, which are perpendicular to the frame and carry a guide roller 23 arranged at the end (FIG. 3).

The unwinding apparatus attached to a frame 24 is arranged opposite the rotating frame (FIG. 3). This apparatus has a scales 25 carrying a glass thread spool 26 , and a regulator 28 for the tension of the padding is also provided. The glass thread 27 unwound from the bobbin runs between rollers 28a which are held by paddles 28b , which are carried by a lever 29 which is provided with a counterweight 30 and is pivotable on arms 31 about an axis parallel to the axis 10, uni to put the thread under tension.

Behind the rollers 28 the thread runs successively over a first fixed roller 32, over a roller 33 of a dancer 34 loaded with weights 35 , via a second fixed roller 36, over the second roller 37 of the loaded dancer and finally via a third fixed Roller 38. This fixed roller 38 is firmly connected to a shaft 39 which is parallel to the shaft 10 and on which a holder 40 is pivotable. The holder 40 carries two guide rods 41 for a slide 429 which is displaceable in the transverse direction by means of a screw spindle 43 driven by a geared motor 44 (FIGS. 7 and 8).

A soaking vessel 45 is attached to the slide, into which the glass thread, after passing the roller 38, enters through a nozzle 46 which has an opening that is widened to the outside (FIG. 4). The thread emerges from the vessel through a nozzle 47 which has the shape of a Ventur tube in cross section and causes the thread soaked with the liquid thermoplastic resin 48 contained in the vessel to drip off. After exiting the vessel, the thread 27 is wound onto the fitting parts 3a and 3b attached to the rotatable frame 9 . The pivoting motion 40 of the des.Halters-Schl-Ittens 42 and the vessel 45 um'die shaft 3-0 is passed through a 49 Am, which is fixed to this holder and with its Bnde'nacheinander at both on the rotatable Frame-mounted rollers 23 supported (Fig. 3). A recovery vessel 50 is arranged under the vessel Iss 45.

The lateral displacement of the thermoplastic resin-impregnated glass thread 27 for winding the winding core tubes 15 attached to the fitting parts 3a and 3b takes place by translational movement of the vessel 45 carried by the carriage 42. The thread 27 is wound up The fitting parts 3a and 3b occur in layers parallel to the axis of the winding core halves 15 and are achieved by a stepwise advance of the carriage 42 a step corresponding to the thread diameter knife. This advance is controlled by a contact 51 which, when the The wing is closed during the winding by a button 52 , which can be pivoted about an axis 53 parallel to the axis 10, which is attached to a holder 54 fixedly connected to the carriage 42 (FIGS. 7- and 8) is firmly connected to an axially displaceable switch 55 , which is displaceable with friction in a fixed holder 56 and horizontally Surface which is delimited by a printed circuit 57 is wiped, which is carried by a part 58 fastened to the holder 40. This printed circuit 57 reproduces the profile of the winding to be produced, taking into account the relationship between the lever arms of the button 52 and the axially displaceable switch 55 and has a horizontal extension which corresponds to the total translational movement of the slide 42 . Whenever the axially displaceable switch hits a leg of the printed circuit 57 , it reverses the supply current of the geared motor 44 and thus reverses the movement of the slide 42.

The manufacture of a wing using the apparatus of FIGS. 3 to 8 proceeds as follows. The previously processed filling 5 of "Iloltoprene" is attached to the rotatable frame 9 , on which it is held by the rear parts 1-7 and 18 of the mold. The fitting parts 3a and 3b are attached to the rotatable frame at "" e-, '! - - - -r-. - -A M brings. Then the glass thread 27, which was soaked in thermoplastic resin during its passage through the vessel 45 and dripped off when it emerged from the vessel, is wound onto the winding core halves 15 of these fitting parts by rotating the frame 9 by means of the geared motor 11 takes place by weighing the coil 26 by means of the balance 25. The control of the distribution lqn "s of the chord of the profile takes place under the combined action of the button 53, the axially movable switch 55 and the printed circuit 57. If a, If compression occurs in the already wound section, the thread is wound several times over the particular point, and the contact 51-52 is only re-established when the wound thread has again reached the point of the adjacent thread.

The layer halves made of resin-soaked glass thread, which are arranged after the winding between the two fitting parts 3a and 3b , are pressed and pressed by attaching the front parts 19 and 20 of the mold and with the help of brackets 59 (Fi, -. 2 and 5) on section 4 of the filling 5 brought to their shape. The longitudinal joints of the mold are arranged in such a way that they serve as guides, and appropriate outlet holes are provided for the removal of the excess resin. The arrangement formed by the frame, the shape and the contents of the same are then polymerized in the oven.

After polymerization, the mold is disassembled and the coating is prepared by DAAs i icrden-wound onto the polymerized part after the removal of several layers of Bägel 59 Qlasfasergewebe 7 with less than 45 0 crossed, resin-impregnated fibers. The covering with the fabric takes place at the trailing edge of the profile in such a way that each time it is wound, it is shifted by a small distance along the tendon. The clamps 5-01 are then tightened onto the cover and the assembly is pressed into the mold and placed in the oven. CD After the polymerization, the part obtained is deburred and sanded down with water using emery paper.

The part produced in this way can be used in two different ways, depending on the desired type of wing. If it is a wing larger than 1, the part near one of the fittings 3a or 3b is cut off CD C) whereby the fitting firmly connected to the wing can be used directly as the pus fitting of the wing. If, on the other hand, a C # wing is to be produced for a relatively shorter length of time, the part can be cut in its middle1, so that two wings of shorter length with their foot fittings are created. In both cases, a trim made of the same thermoplastic resin is combined with the cut portion of the wing by molding.

If a wing with a relatively large as a result of the presence of a ledge in the rear section of the profile, a fitting can be made as described in Ficc). 9 to 13 shown type can be used. This fitting 3c differs from the fitting 3 of FIGS. 5 and 6 in that it has an extension 60 in the direction of the rear edge of the wing to be produced. owns. A winding core 15p for winding the longitudinal part of the front edge and a winding core half 61 for winding the strip are then attached to this fitting. These winding core halves, alternately overlapping the web 62 of the fitting 3v and the extension 60 of the same. To balance the shape changes to produce a stable base for each winding, intermediate pieces 63 made of reinforced synthetic resin are glued to the fitting. Such intermediate pieces can be loaded with the fitting. be used.

To prepare a PlÜgels with strip by use of two Beschlaken of the fitting 11 of Fig. 9 corresponding species is filleted, the resultant structure after winding of the spar and polymerization before the Inbringung of the coating and then reversed to the rotating frame 9, wherein said fittings means of the fastening axles 64 arranged at both sides of the anterior cheek. The strip is then wound onto the winding core halves 61 and the other manufacturing steps remain unchanged.

The shape formed by the parts 17 to 20 can be worked out inside according to the final shape of the profile and lined with metal sheets for the work prior to the application of the coating, the thickness of which is the same as the coating. Two pores can also be produced inside - Weldin, -whose inside shapes correspond to the profile without coating or the Trofile with coating.

For the static and dynamic balancing of the wing , a tube made of a layered material, see the tube 8 of FIG. 6, which is firmly connected to the wing fitting by a V-shaped socket at the tip 66 of the bracing of the winding of the wings This fitting is glued on: If the distribution and the values of the balancing masses have been determined beforehand, the tube can be filled with metal, but it can also be used empty and, after cutting up the arrangement produced, filled with a rod, the weight of which is reduced as required is used to produce the static expansion in depth and in the direction of the wingspan of the wing. The tube can be inserted between the fittings either before the wrapping or after the wrapping, but then before the first insertion into the mold. In this latter case, the profile of the printed circuit 57 is changed in such a way that the wound thread can be pushed back when the tube is being attached in accordance with the outer profile of the plow.

If the wing profile changes in plan or thickness according to # 2 it is produced by the shaping process after the production of the coating, what-it is used a reproducing Porm.

The invention can of course be modified. So can in particular the invention, emasse ** process and .the invention-e-rä ** t, asse apparatus for hel-position one of a helicopter wing-different aerodynamic Area to be used. They can also be used to make a closed spar of any kind can be used instead of the 0-shaped spar described above. In this case, the front section of this closed spar can be in the above specified way, while the rear one forms the web of the spar Section is produced by a second operation.

Claims (1)

Patent claims 1.) Helicopter wing, -, el or similar aerodynamic Placheg characterized by a 1, # n-steep (1) forming a spar and / or the leading edge, which is formed by a layered structure (2) in the form of an elongated U which wraps around the foot fitting (3) of the wing. and adheres to it, these various shells consisting of biased glass filaments wrapped in a thermoplastic resin and arranged in the spanwise direction. a filling made of a lightweight material, which is firmly connected to this lUn- # steep (1) and complements the shape of the same to the F1U.! yel profile, and a (7) made of glass fabric made of 450 intersecting a thermoplastic resin soaked Paserng which covers the longitudinal part (1) and the PÜllung (5) . 2.) Wing according to Ans-, Druch 1, marked. by a winding core half (15) at the end with a closed Which Axis parallel to the bowstring of the PlÜgels / on the butt fitting of the wing is attached and the U-shaped layered structure (2) receives. 3.) Flights-1 according to claim-1, characterized by a rear bar (6), which by a layered U-fört.qi.! - it structure is formed, which the Püllung- (5) made of a light material in a rear zone of the same as well as a suitable part (62) of the butt fitting (3c, Fig. 9) of the cube, which are made with the help of pre-tensioned glass threads, which in the direction of the span # -tn (- " eor-dnet and -with a thernioplasti ---- - - - - -. - - A 91 see resin are encased. 4.) wing according to claim 3, characterized in that a winding core half (61) with a to the tendon of the plane's parallel axis is attached to the foot fitting C.50 of the wing at its section facing the rear edge of the wing, in order to receive the U-shaped layered structure of the strip Z: .i C> . 5.) wing according to Ans-oruch 1 to 47, characterized in that it has a tube (8) in the zone of the front edge of the longitudinal part forming a spar (1) , which is partially and locally known to it at any point fortified metal masses is filled. - 6.) wing according to AnsDruch 1 to 5, characterized in that the läncs'Ueil (1) of the front edge has a C-shaped cross-section (Fig. 1) and a front JA-Ibschnitt (4) of the filling (5) a lightweight material 'surrounds. Method for manufacturing a helicopter wing-according to claims 1 to 6.- d, -:, dtirch characterized in that glass sf, # den, which are under a pretension and a regulated tension in a direction of the span and perpendicular to the depth of the Wing profile lying plane-are exposed to winding core halves (15) of two foot fittings (3a, 3b) of the wing are wound, the mutual distance -rgsser than the length # - e of the wing to be produced, whatau.IL 'after the The layers of thread obtained in the winding are tightened at the point where they arrive at these fittings (3.g, -b) by means of stirrups (59) , whereupon the structure thus obtained is shaped by means of a mold, whereupon this structure formed in the mold polymerizes becomes, 'worau.-L "the polymerized structure with a blown fabric (7) crossed below 45o. coated with resin-soaked fibers, i-zird, whereupon the arrangement including the cover (7) is again tightened with stirrups, whereupon the beginning, 2nd order is pressed in a mold and again polymerisiert.wirde whereupon one of the two Wickelbeschl is cut # igE (3at 3b), to which structure is molded one made of the same thermaplastischen resin final approach to the cut-off portion of the coated, 8.) the method of claim 7 for preparing a Plugels-high Dimensional stability, characterized in that after the polarization of the uncoated structure, the strip (6) is wound. Q.) The method according to claim 71, characterized9 that in the production of a closed spar, the front and the rear section of the spar (1) are produced by two successive wraps with a pre-parinized glass thread. 10.) The method according to claim 7 to 9 for the production of flaps relatively less than 8 mm, P characterized in that the coated and polymerized structure is cut in the middle, so that two wings with their fastening or foot fittings Cav 3b. ) develop. 11.) Apparatus for practicing the method according to claim 7 to 10, characterized by-a winding frame (9) 9 on-which opposite one another with their rear edge of the wing to be produced neighboring cattle with their two running at the end 'Vlickelkernh' * lift a (15) provided attachment fittings 0a, 3b) are attached, the frame (9) also centered on these fittings carries a four-part shape (1-7, 18, 19, 20) with the profile of the wing to be produced, of which the rear parts (17, 18) 9 in which the filling (5) housed in a light material ISTG alone to the frame while the winding are mounted, by the frame (9) 9, the fittings' (3a, 3b) and the mold ( 179 18) is set in rotation about a central axis (10 ) parallel to the axis of the winding core halves (15) , this arrangement on the winding core halves (15) being exposed to the tempered glass coming from an unwinding device the thread (27) . 12.) Apparatus according to claim 11, characterized in that the unwinding device is formed by a bobbin (26) from a Glabfaden (27) which is braked by a regulator (28) to regulate the tension of the thread, the thread (27) to the desired voltage by a loaded dancer (34, 35) between fixed rollers (32, 369 38) is placed, wherein the to the axis of rotation (10) of the winding frame (9) parallel to the axis (3c) of the last fixed roller (38 ). is surrounded by a watering, 7s- and dripping device (45) which is attached to a slide (42), which is swiftly rushed to a variable, reversible stroke in the transverse direction by an arrangement that scans the profile to be produced . 13.) Apparatus according to claim 11 and 12, characterized in that one on the holder (40) of the carriage (42) fastened # -ter FÜhruncsarm (49) is supported alternately on rollers (23) which are supported by the rotatable frame (9) opposite the fittings (3a, 3b) attached to the frame (0) . 14.) Apparatus according to claim 11 to 132, characterized in that the d as to be produced profile scanning arrangement has a printed circuit (57) which this and its Fikhe horizontally by an axially displaceable switch (55) stroked welcIler (56) on a The holder (54) attached to the carriage (42) is pivotable, the winding with layers parallel to the winding axis being carried out in that the carriage (42) advances step by step by a step corresponding to the diameter of the soaked thread (27), whereby this advance is controlled by a contact (51) which is closed by a button (52) with each passage of the wing. 15.) Apparatus according to Ans-oruch 11 to 14) characterized by the fact that, if the wing is to have a strip (6) after winding shape and polymerisation of the longitudinal carrier (1), the two pus solesP *. * Ge (30 des Plägels and the frame (9) are provided with devices which g # - instead of turning them around after detaching the fittings from the rotatable frame (9) and attaching them again to the frame (9) with their edge adjacent to the der.Vorderkante of the wing to be produced , in order to enable the strip to be wound, 16.) Apparatus according to Ans'Druch ltbis 15, characterized in that the tube (8) for receiving the balance, smassen through a V-shaped fit on the tip (66) of the strut for wrapping the threads on the fitting (3) of the wing is glued, either before wrapping or after wrapping, but before the first molding process. 17-.) Apparatus according to claim 16, characterized in that when the tube (8) is attached after the wrapping, the profile of the printed circuit (57) is changed so that the wound pad layers are pushed back in accordance with the outer profile of the wing during this attachment 18.) Apparatus according to claim 11 to 171, characterized in that either a single mold is used for molding, which is combined with lining sheets whose thickness is the same as that of the coating, or two molds which have the profile without coating or with coating correspond, this latter Tiösung is preferably used for the production of a in the base ring or the thickness according to variable profile.