WO2011157849A2

WO2011157849A2 - Rotor blade for a wind turbine

Info

Publication number: WO2011157849A2
Application number: PCT/EP2011/060242
Authority: WO
Inventors: Erik Billeskov Sloth; Thomas Steiniche Bjertrup Nielsen; Esther Peterslund; Lennart Kuhlmeier; Rasmus Jensen
Original assignee: Suzlon Blade Technology B.V.
Priority date: 2010-06-18
Filing date: 2011-06-20
Publication date: 2011-12-22
Also published as: WO2011157849A3

Abstract

The invention concerns a rotor blade for a wind turbine comprising a leading edge and a trailing edge. At least a part of the trailing edge – in the lengthwise direction of the rotor blade – comprises at least one pre manufactured trailing edge part, where said pre manufactured trailing edge part is arranged to cover at least one lengthwise joint of at least one airfoil surface to one other structural part on the rotor blade, where the pre manufactured trailing edge part has a width of 0 to a certain percentage according to a specific rotor radius of the length of the chord of the rotor blade. The pre manufactured trailing edge is preferably made of a fibre composite material or from another suitable material in parts with a length suitable for handling and installing along a rotor blade. The above mentioned structural part can for instance be a full length or part length web, providing stiffness to the construction at the outer area near the trailing edge, by connecting two aerodynamic shell parts. The pre manufactured trailing edge part can then be fixed to a blunt and somewhat roughly shaped rear edge, and thereby act as a cover as well as a well-defined edge of the rotor blade and that the rotor blade has a thickness at the rear edge of said body of 0 to 10 %, preferably of 0 to 5 %, and even more preferred has a thickness of 3 % of the height of the body, where said rear edge has a thickness of at least 2 millimetres, said height is also known as the height of the specific airfoil profile.

Description

ROTOR BLADE FOR A WIND TURBINE Field of the Invention

The present invention relates to a rotor blade for a wind turbine, where the wind turbine comprises at least a tower, a nacelle on top of said tower and a rotor, said rotor having a diameter of 50 metres or more, and comprising one or more of said rotor blades, preferably three rotor blades, where one or more rotor blades are connected to a hub, said hub is further connected to a substantially horizontal main shaft, said main shaft being rotatably mounted in said nacelle, said wind turbine being of the type where the rotor is facing upwind, said one or more rotor blades having an elongated shape with a root end being connectable to said hub and with a tip end, where said rotor blade has a body with an airfoil shape with a suction side and a pressure side constituted at least partly by airfoil surfaces, said rotor blade also comprising a leading edge and a trailing edge.

Background of the Invention

Rotor blades for wind turbines are of cause well-known in the industry and as the wind turbines and also the rotor blades over time have become very large structures with e.g. rotor diameters of 80 metres and for the very largest even up to approximately 125 metres, a number of engineering challenges have occurred. In the future we will see even larger wind turbines and one of the important challenges is to manufacture a wind turbine where the emitted noise is at an acceptable level and where the efficiency of the wind turbine is maintained. The main two reasons are that noise actually is lost energy and another very important reason is the overall impact on the environment such as the nature and the people living in areas with one or more wind turbines.

It is detected that one source of noise from a wind turbine relates from the wind acting on the rotor blades - aerodynamic noise and another source of noise relates from the mechanic constructions in the wind turbine - mechanical noise. Several solutions have been tried to address and to reduce the aerodynamic noise and in WO 95/19500 Al one way of reducing noise emitted from the trailing edge of the rotor blade is shown. It is well known in the business that when the air from the suction side and air from the pressure side of a rotor blade meets at the trailing edge, a vortex and noise can be generated when air with different speeds collides. To address this problem it has become a rule to manufacture rotor blades with as thin a trailing edge as possible, which will overcome or at least minimize this source of noise. This is however quite a challenge as rotor blades for wind turbines, most often is manufactured as two shell parts being glued together at least along the leading edge and along the trailing edge. As two shell parts with a certain thickness are glued together, and the layer of glue also has a certain thickness, it is very difficult to have a trailing edge with a thickness of only a few millimetres, such as e.g. 2 to 4 millimetres in the areas where such a thickness is preferred.

It is well known and accepted in the business that a thin trailing edge is necessary to secure that only a minimum of noise is emitted when rotating the rotor blade. To obtain a rotor blade with a very thin trailing edge when the rotor blade is made in the traditional manner, the most common way is to manually grind the trailing edge into the desired shape and thickness after the two shell parts are glued together. This process is however very time consuming and also has a certain impact on the structure in the construction as material is removed by grinding.

Object of the Invention

It is the object of the invention to provide a rotor blade for a wind turbine, where the above mentioned drawbacks with the trailing edge on said rotor blade is eliminated and where the trailing edge is manufactured as an individual part and with a well-defined shape and edge.

Description of the Invention

As mentioned above this invention concerns a rotor blade for a wind turbine, where said rotor blade has a body with an airfoil shape with a suction side and a pressure side constituted at least partly by airfoil surfaces, said rotor blade also comprising a leading edge and a trailing edge. On a rotor blade according to the invention at least a part of said trailing edge - in the lengthwise direction of the rotor blade - comprises at least one pre manufactured trailing edge part, where said pre manufactured trailing edge part is arranged along a rear edge of said body of the rotor blade, where the pre manufactured trailing edge part at a rotor radius of 0 to 50 % has a width of 0 to 10 % of the length of the chord of the rotor blade, at a rotor radius of 50 to 70 % has a width of 0 to 25 % of the length of the chord of the rotor blade, and at a rotor radius above 70 % has a width of 0 to 45 % of the length of the chord of the rotor blade. In a preferred embodiment said pre manufactured trailing edge part does in other words constitute between 0 to 10 %, 0 to 25 % or 0 to 45 % of the chord of a rotor blade at a specific rotor radius. The pre manufactured trailing edge is preferably made of a fibre composite material or from another suitable material in parts with a length suitable for handling and installing along a rotor blade. The rotor blade has a thickness at the rear edge of said body of 0 to 10 %, preferably of 0 to 5 %, and even more preferred it can have a thickness of 3 % of the height of the body, where said rear edge has a thickness of at least 2 millimetres, said height is also known as the height of the specific airfoil profile. Said rear edge thickness of at least 2 millimetres can be used to fixate the pre manufac- tured trailing edge part to by e.g. adhesive or other kinds of fastener.

In preferred embodiment the trailing edge part at a rotor radius of 0 to 50 % can have a width of 0 to 10 % preferably 1 to 9 % more preferably 3 to 5 % of the length of the chord of the rotor blade, at a rotor radius of 50 to 70 % has a width of 0 to 25 % pref- erably 1 to 20 % more preferably 5 to 15 % of the length of the chord of the rotor blade, and at a rotor radius above 70 % has a width of 0 to 45 % preferably 1 to 45 % more preferably 26 to 45 % of the length of the chord of the rotor blade.

In a preferred embodiment the trailing edge part at a rotor radius of 0 to 50 % has a width of 0 % of the length of the chord of the rotor blade, at a rotor radius of 50 to 70 % has a width of 0 % of the length of the chord of the rotor blade, and at a rotor radius above 70 % has a width of 26 to 45 % of the length of the chord of the rotor blade. The tip section, which is located at a rotor radius above 70 %, is subject to bending loads of a smaller magnitude than further inboards of the blade. The trailing edge part may be a self-supporting non-load carrying structure manufactured to high accuracy and low tolerances. The characteristics of the bending loads at the tip section make it possible to increase the ratio of the width of the trailing edge part to the length of the chord of the blade. As the manufacturing of the trailing edge part may be better con- trolled than the body of the rotor blade it is an advantage to increase the above- mentioned ratio. The trailing edge part may be more cost effective to manufacture and provides for higher accuracy and small tolerances on its shape. Therefore it is especially beneficial to make it as wide as possible.

Furthermore the stiffness of the blade body and the trailing edge part may be close to equal as the width of the trailing edge approaches the higher values of the range of the ratio width to the length of the chord of the rotor blade. Therefore the deflection of the blade body and the trailing edge may be designed to have similar characteristics in a simple manner. Thus reducing the stresses in the joint between the blade body and the trailing edge part.

Manufacturing techniques especially suited for manufacturing of the trailing edge part may be extrusion or pultrusion processes. However the trailing edge part may be manufactured by other techniques.

In a preferred embodiment the rotor blade has a thickness at the rear edge of said body of less than 10 %. The transition between the outer surfaces of said body and the rear edge part is smooth. Therefore the thickness of the rear edge part at the joint between said body and rear edge part is the same as the thickness of the rear edge of said body.

The invention provides a trailing edge part of reduced thickness. Such a trailing edge part is especially suited for use in a slender blade, where the thickness of the blade is small.

The reduced height and/or width of the trailing edge part provide a further advantage in that the stiffness may be smaller compared to a trailing edge part for blade bodies with a thickness at the rear edge outside the range described above. The reduced stiffness at the joint between the body of the blade and the trailing edge part may increase the life of the trailing edge part because said trailing edge part being less stiff than the body will bend more easily, when the blade is subject to cyclic loads and other loads influencing the fatigue life of the joint. The joint will be subject to smaller loads as the blade is bending in response to the load spectrum applied to the blade during operation of the wind turbine.

In a preferred embodiment a rotor blade for a wind turbine according to the invention can have a pre manufactured trailing edge part arranged to cover at least one lengthwise joint of at least one airfoil surface to one other structural part at or near the rear edge on said body of said rotor blade.

The pre manufactured trailing edge part can as mentioned above cover a lengthwise joint of e.g. two shell parts or e.g. joints between one shell part, a structural part and another shell part. Said structural part can for instance be a full length or part length web, providing stiffness to the construction at the outer area near the trailing edge, by connecting the aerodynamic shell parts. The pre manufactured trailing edge part can then be fixed to a blunt and somewhat roughly shaped edge, and thereby act as a cover as well as a well-defined edge on the rotor blade.

The pre manufactured trailing edge can be manufactured in a V-shape where the lower tip of the V is the outer trailing edge and where the flanges of the V are brought into contact with and fixed to the shell parts of the rotor blade. This joining can be done with the flanges fitted into corresponding cut-outs along the edge of the shell parts. The trailing edge part with a V-shape can be made with a uniform cross sectional design and fitted to the rotor blade by elastic deformation of the part, either by "closing" or "opening" the flanges of the V. Thus a precise and easy way of fitment is obtained. Such pre manufactured trailing edge parts can be made in pieces of e.g. 6 metres or less or more, depending on the facilities and the handling of the parts. By producing the trailing edge parts as an individual part, it can be manufactured according to small tolerances with reference to the outer trailing edge, but also with reference to the rest of the part, allowing for an easier installation along a rotor blade.

A pre manufactured trailing edge part can as mentioned be fitted on a blunt trailing edge but can also be fitted on a sharp trailing edge. In the same manner it can be manufactured to be fixed on two or only on one side of the aerodynamic surface of a rotor blade as well as against a blunt edge of the profile. A preferred embodiment of a rotor blade for a wind turbine according to the invention has a trailing edge part made as an add-on part comprising means for connecting to corresponding means on the body of said rotor blade. These connection means can e.g. be cut-outs as mentioned above, where the pre manufactured trailing edge part and the rotor blade both are arranged to fit each other.

A rotor blade for a wind turbine according to the invention is in a preferred embodiment constructed in such a manner that the rotor blade without the pre manufactured trailing edge, is a self carrying structure and where said trailing edge part is a non-load carrying part of said rotor blade, and merely constitutes a aerodynamic part with a well-defined outer trailing edge. Thus the rotor blade is designed to carry the specified loads without the trailing edge part as this part only has an aerodynamic purpose. Having a pre manufactured trailing edge part according to the invention also allows for retro fitment of trailing edge part on existing rotor blades as well as fitment to a rotor blade on site. Thus trouble arising from handling the rotor blade with a some-what fragile trailing edge becomes easier, as this part only will be fitted e.g. just before hoisting the rotor blade into position on a wind turbine. As mentioned above a rotor blade for a wind turbine according to the invention can have a trailing edge part comprising an extension of the pressure side and/or an extension of the suction side of said airfoil shaped body of said rotor blade.

Such a pre manufactured trailing edge part can comprise aerodynamic means compris- ing openings into the inside of said trailing edge part or passages penetrating thru the trailing edge from the pressure side towards the suction side or vice versa, preferably in a direction mainly perpendicular to the surface. These openings or passages can be circular holes, but the geometric appearance can also be slots or with another shape. Thru such openings or passages the difference in pressure between the suction side and the pressure side of the rotor blade can level out before meeting at the trailing edge, and thus lower the emitted noise. When the openings are leading into a cavity inside the trailing edge an even better reduction of the emitted noise can be obtained as the pressures levels out and turbulences in the air flow are minimized by entering the cavity. Said cavity can be filled with a porous material that will help absorbing the noise. Such openings can have a size of a few square millimetres such as e.g. 15 square millimetres to several hundred or even thousands of square millimetres. In another preferred embodiment according to the invention said trailing edge part has aerodynamic means comprising channels or recesses extending along the surface of the trailing edge on at least the pressure side and/or on the suction side, said channels primarily extending in the chord direction. Said channels can be open channels or partly closed channels. Such channels will tend to lead the flow of air in a laminate manner and thus minimize the turbulent airflow at the outer trailing edge part. Such channels can be made straight, curved, with a zigzag shape or with another suitable geometry. The size of such channels can be with a depth of O to e.g. 10 millimetres and ending at the outer trailing edge by completely penetrating the trailing edge leaving it with a slashed appearance. Such channels can be situated on both sides of a rotor blade and can e.g. be with an offset or aligned in such a manner that channels on one side are aligned with channels on the other side of a trailing edge part. The channels can be with a width of a few millimetres to several hundreds millimetres, and can be in various sizes along the trailing edge part. Yet a preferred embodiment of the invention concerns a trailing edge part having aerodynamic means comprising a spoiler, said spoiler being arranged at the outer trailing edge on the pressure side or on the suction side of said spoiler. Such a spoiler can be used to define the outer most trailing edge in a manner to minimize emitted noise, but can also be used to optimize the specific aerodynamic profile to gain more power from the wind e.g. as a Gurney flap.

In another embodiment of the invention the trailing edge part has aerodynamic means comprising a spoiler, preferably arranged at the outer trailing edge, said spoiler having openings or passages penetrating thru the spoiler and virtually extending the airfoil shape of the pressure side and/or the suction side by these openings or passages. The outer trailing edge thus appears with a significant thickness as the aerodynamic shape of the pressure side and the suction side at the trailing edge has a thickness higher than in the area in front of the outer trailing edge. Said passages thru this spoiler will guide the air flow to a virtual trailing edge and the airflow from both sides of the aerodynamic profile will meet at this virtual trailing edge at adapted speeds and thus emit only a minimum of noise. Also these channels can be situated on both sides of a rotor blade and can e.g. be with an offset or aligned in such a manner that channels on one side are aligned with channels on the other side of a trailing edge part. The channels can be with a width of a few millimetres to several hundreds millimetres, and can be in various sizes along the trailing edge part. Such channels can have a size of a few square millimetres such as e.g. 15 square millimetres to several hundred or even thousands of square millimetres.

In yet another embodiment of the invention said trailing edge part has a modulus of elasticity allowing the outer part of the trailing edge to adapt its position on behalf of the specific pressure on the pressure side and on the suction side of the blade at the trailing edge. This will lead to the trailing edge adapting itself in such a manner that pressure difference is relieved automatically and thus the emitted noise will be lower.

The trailing edge part thereby employs passive means to change its shape or incidence. This is more reliable than an active means, for example a flap for changing incidence of the trailing edge part or internal inflatable pockets that changes the camber of the trail- ing edge part,

A rotor blade for a wind turbine according to this invention can be made with a trailing edge part, where this part is connected to the body of said rotor blade as a glue-on part, as a bolted or riveted-on part, as a click-on part or with another suitable way of connection. Further the pre manufactured trailing edge part can be made with a coverage of a part or with a complete coverage by micro vortex generators and/or a so called "shark skin surface". Such features can be made during production as an in- mould process or as an ad-on fixed to the surface of the trailing edge by tape or another adhesive.

Even further the outer parts of the trailing edge can be made with a wave shaped edge or double wave shaped edge, as well as with a serrated zigzag edge or double zigzag edge. Such shapes and contours can be made directly in the material of the pre manu- factured trailing edge part or in the outer most edge of this part as e.g. in a flexible strip or in brushes or in another porous material forming the outer most edge.

Another possible feature that can be arranged on a pre manufactured trailing edge part according to the invention is stall barriers arranged in the chord wise direction of the trailing edge. Such stall barriers will be protruding from the surface or surfaces of the trailing edge and can have a suitable height, width, distance and length according to the specific needs.

In the above description the invention is described in relation to a wind turbine of the type with a horizontal or substantially horizontal main shaft. This type of wind turbine is very well known all over the world. The invention can however also be of interest on rotors for wind turbine constructions with a substantially vertical main shaft. The rotors of such wind turbines are e.g. known as: Savonius-, Darrierus- and H-rotors.

Description of the Drawing

In the following the invention will be described with reference to the drawing, where

Fig. 1 shows the top of a wind turbine

Fig. 2 shows a cross section of a rotor blade profile.

Fig. 3 also shows a cross section of a rotor blade profile.

Fig. 4 shows a rotor blade profile with three different features on the trailing edge part.

Detailed Description of the Invention

In fig. 1 a wind turbine 1 is seen comprising a tower 2, with a nacelle 3 on top. At the nacelle 3 a rotor 4 comprising a hub 5 and three rotor blades 6 are mounted. The rotor blades each have a leading edge 7 and a trailing edge 8.

In fig. 2 a part of a rotor blade 6 is seen as a profile 9, with a blunt rear edge 10 with a lengthwise joint 11 between the parts creating the profile 9. At the blunt rear edge 10 a pre manufactured trailing edge part 12 is fixed in such a manner that the lengthwise joint 11 is covered. Further the chord 13 of the profile 9, extending from the leading edge 7 to the outer most trailing edge 8, at the pre manufactured trailing edge part 12 is seen. In this figure the outer most edge 8 on the pre manufactured trailing edge part 12 is seen as a sharp and straight trailing edge 8.

In fig. 3 the same profile 9 as in fig. 2 is displayed but at the blunt rear edge 10 the de- sign is different. At the blunt rear edge 10 and between the surfaces 14 of the profile 9, there is a web comprising a body 15 and two flanges 16. The two flanges 16 are fixed to the inside of the surfaces 14 and thus the web acts as a structural and load carrying part of the rotor blade 6. Along the length of the body 15 and the flanges 16 there are two adhesive joints 11 , which are covered by the pre manufactured trailing edge part 12. The pre manufactured trailing edge part 12 is V-shaped and with flanges 17 that can be adjusted to fit a blunt rear edge 10 even over a considerable span in thickness. In the shown embodiment the pre manufactured trailing edge 12 is fixed to the surfaces 14 of the profile 9 in cut-outs 18 along the blunt rear edge 10 by adhesive, but other means of fixation could of cause have been used.

Further the pre manufactured trailing edge part 12 has a serrated outer most edge 8, with two different depths in the serrations 19 and 20. This outer most trailing edge 8 can also be made with other shapes such as in a wave or sinus shape. Fig 4 is illustrating four different features on the pre manufactured trailing edge part 12 on a small part of a rotor blade 6. In fig. 4a the trailing edge part 12 has thru going passages 21 arranged in a pattern at the flanges 17. Said passages 21 could also be indentations and can have any suitable cross sectional geometry. In fig. 4b the pre manufactured trailing edge part 12 has a number of channels or recesses 22 starting with a depth of zero and ending with a depth of a few millimetres near the outer most trailing edge 8 and merging with a corresponding channel or recess

22 on the other side of the rotor blade 6, whereby the outer most trailing edge is divided into smaller sections.

In fig. 4c a pre manufactured trailing edge part 12 with a spoiler 23 is seen. The spoiler

23 is present on both surfaces 14 and has thru going passages 24 and 25 that will lead some of the flow to a virtual trailing edge 26, as the spoiler 23 will deflect some of the flow and capture the rest via the thru going passages 24, 25. In this figure the passages 24, 25 are extending from the surface of the pre manufactured trailing edge part 12 and to the virtual trailing edge 26 in such a way that the passages 24 from one side of the rotor blade 6 are ending above the line indicating the virtual trailing edge 26 and the passages 25 from the other side of the rotor blade 6 are ending under the line indicating the virtual trailing edge 26. In another embodiment the passages 24, 25 could cross each other or end besides each other on a single line.

Finally in fig. 4d a pre manufactured trailing edge part 12 is seen having a spoiler 23 on only lower surface 14 of the profile. The spoiler 23 is an integrated part of the pre manufactured trailing edge part 12 and the shown embodiment has the function of a Gurney flap.

Regarding the different features seen in fig. 4 it is obvious to the person skilled in the art that the passages, channels, recesses and openings can have different cross sectional geometry and can be arranged in different patterns and as such appear in a different manner and still be within the scope of the invention as described in the following claims. Further it shall be stated that the shape of the pre manufactured trailing edge part 12 can be different than shown above, as it e.g. can be with only one flange 17 and thus fixed at e.g. a blunt rear edge 10 and in one cut-out 18 along the blunt rear edge 10, but also other designs will be possible.

Claims

1. Rotor blade for a wind turbine, where the wind turbine comprises at least a tower, a nacelle on top of said tower and a rotor, said rotor having a rotor radius of 25 metres or more, and comprising one or more of said rotor blades, preferably three rotor blades, where one or more rotor blades are connected to a hub, said hub is further connected to a substantially horizontal main shaft, said main shaft being rotatably mounted in said nacelle, said wind turbine being of the type where the rotor is facing upwind, said one or more rotor blades having an elongated shape with a root end being con- nectable to said hub and with a tip end, where said rotor blade has a body with an airfoil shape with a suction side and a pressure side constituted at least partly by airfoil surfaces, said rotor blade also comprising a leading edge and a trailing edge characterised in that at least a part of said trailing edge - in the lengthwise direction of the rotor blade - comprises at least one pre manufactured trailing edge part, where said pre manufactured trailing edge part is arranged along a rear edge of said body of the rotor blade, where the pre manufactured trailing edge part at a rotor radius of 0 to 50 % has a width of 0 to 10 % of the length of the chord of the rotor blade, at a rotor radius of 50 to 70 % has a width of 0 to 25 % of the length of the chord of the rotor blade, and at a rotor radius above 70 % has a width of 0 to 45 % of the length of the chord of the rotor blade and that the rotor blade has a thickness at the rear edge of said body of 0 to 10 %, preferably of 0 to 5 %, and even more preferred has a thickness of 3 % of the height of the body, where said rear edge has a thickness of at least 2 millimetres, said height is also known as the height of the specific airfoil profile.

2. Rotor blade for a wind turbine according to claim 1 characterised in that said pre manufactured trailing edge part is arranged to cover at least one lengthwise joint of at least one airfoil surface to one other structural part at or near the rear edge on said body of said rotor blade.

3. Rotor blade for a wind turbine according to any of the claims 1 to 2 characterised in that the trailing edge part is an add-on part comprising means for connecting to corresponding means on the body of said rotor blade.

4. Rotor blade for a wind turbine according to any of the claims 1 to 3 characterised in that the rotor blade without the pre manufactured trailing edge, is a self carrying structure and where said trailing edge part is a nonload carrying part of said rotor blade, and merely constitutes a aerodynamic part with a well-defined outer trailing edge.

5. Rotor blade for a wind turbine according to claim 4 characterised in that said well defined trailing edge has a serrated and/or wave shape.

6. Rotor blade for a wind turbine according to any of the claims 1 to 5 charac- terised in that said trailing edge part comprises an extension of the pressure side and/or an extension of the suction side of said airfoil shaped body of said rotor blade.

7. Rotor blade for a wind turbine according to any of the claims 1 to 6 characterised in that said trailing edge part has aerodynamic means comprising openings into the inside of said trailing edge part or passages penetrating thru the trailing edge part from the pressure side towards the suction side or vice versa, preferably in a direction mainly perpendicular to the surface.

8. Rotor blade for a wind turbine according to any of the claims 1 to 6 charac- terised in that said trailing edge part has aerodynamic means comprising channels extending along the surface of the trailing edge on at least the pressure side and/or on the suction side, said channels primarily extending in the chord direction.

9. Rotor blade for a wind turbine according to any of the claims 1 to 6 charac- terised in that said trailing edge part has aerodynamic means comprising a spoiler, said spoiler being arranged at the outer trailing edge on the pressure side or on the suction side of said spoiler.

10. Rotor blade for a wind turbine according to any of the claims 1 to 6 characterised in that said trailing edge part has aerodynamic means comprising a spoiler, preferably arranged at the outer trailing edge, said spoiler having openings or passages penetrating thru the spoiler and virtually extending the airfoil shape of the pressure side and/or the suction side by these openings or passages.

11. Rotor blade for a wind turbine according to any of the preceding claims characterised in that said trailing edge part has a modulus of elasticity allowing the outer part of the trailing edge to adapt its position on behalf of the specific pressure on the pressure side and on the suction side of the blade at the trailing edge.

12. Rotor blade for a wind turbine according to any of the preceding claims characterised in that the trailing edge part is connected to the body of said rotor blade as a glue-on part, as a bolted or riveted-on part, or as a click-on part.