JP2004299420A - Rudder with fin and vessel - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a rudder with a fin which facilitates attachment of the fin and never reduces the propulsion efficiency, additionally, to obtain the low-cost rudder with the fin by reducing the torque moment applied to a rudder mounting part or a rudder main body. <P>SOLUTION: The rudder 9 is mounted behind a propeller 3 mounted on a stern part of a hull 1 through a rudder shaft 11. The propeller 3 is mounted to be rotated and driven around a rotary shaft center line C. A propeller cap 7 is attached at the end of a propeller boss 5 (on a side facing the rudder 9) constituting a rotation center part of the propeller 3. A valve 12 is mounted in a position facing the propeller cap 7 in the rudder 9. The fin 15a collecting a rotating flow of the propeller 3 is mounted only on the starboard side on which a rapid flow is generated near a rudder side surface, and a fin is not mounted on the port side on which a random, late flow is generated near a rudder side surface. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a rudder provided with fins for generating a force in a propulsion direction by using a wake of a propeller in a marine vessel, and a marine vessel provided with the finned rudder.
[0002]
[Prior art]
On a rudder provided behind a propeller in a ship, fins are sometimes provided to improve propulsion efficiency. The fins generate a lift and a drag in response to the wake (rotational flow) of the propeller, and the propulsion component of the resultant force of the lift and the drag improves the propulsion efficiency of the ship. The fins are formed in the shape of an airfoil in order to improve the energy recovery efficiency of the propeller rotating flow, and various modifications are made to the shape and the mounting position of the airfoil. Reference 1).
[0003]
[Patent Document 1]
Japanese Utility Model Publication No. 6-35918
[Problems to be solved by the invention]
As described above, the fin generates the force of the propulsion direction component by the combined force of the lift and the drag as described above, but on the other hand, the increase in the drag becomes conspicuous, and the fin may not contribute to the improvement of the propulsion efficiency. Therefore, in mounting the fins, it is necessary to precisely adjust the mounting conditions such as the mounting angle and the mounting position according to the state of the wake behind the propeller in each hull during navigation. Otherwise, the propulsion efficiency is rather reduced by the attachment of the fins as described above.
[0005]
However, the fin attachment conditions are actually extremely narrow in the permissible range, and it is extremely difficult to find the most appropriate condition. In particular, when the propeller rotates clockwise, on the port side of the rudder, a vortex (bilge vortex) generated from the hull during navigation is added to the rotating flow of the propeller, and as a result, a random slow flow field is formed near the rudder side. In the vicinity of the outer circumference of the rotating surface, a steep upward flow field is generated. Therefore, in order to obtain a sufficient lift on the port side, it is necessary to extend the fins sufficiently to the outer peripheral portion of the propeller rotating surface, but near the rudder side, the random slow flow field is sufficient as described above. In some cases, lift cannot be obtained, and the effect of drag becomes dominant, resulting in a reduction in propulsion efficiency as a whole.
[0006]
In addition, a method of twisting the fin to change the angle of attack of the wing according to the span can be considered. However, in this case, the workability of the fin is extremely poor, and this leads to a significant increase in cost. In addition, it is more difficult to find the above-mentioned optimum conditions for mounting such fins.
[0007]
In addition, the fin imparts a rotational moment to the rudder mounting part (rudder shaft) or the rudder main body by generating lift, so that it is necessary to ensure the strength of the rudder mounting part or the rudder main body, and the degree of freedom in design is increased. In some cases, the strength is increased and the cost is increased due to the strength improvement.
[0008]
Therefore, the present invention has been made in view of such a situation, and an object of the present invention is to obtain a finned rudder that can easily perform fin mounting work and does not reduce the propulsion efficiency. An object of the present invention is to obtain a finned rudder having a high degree of design freedom and a low cost by reducing a rotational moment applied to a mounting portion or a rudder main body.
[0009]
[Means for Solving the Problems]
In order to solve the above-described problems, a first aspect of the present invention is a rudder provided with fins that generate a force in a propulsion direction by using a wake of a propeller in a marine vessel. A vortex that is generated, and on the rotation surface of the propeller, on the left and right sides of the rotation axis of the propeller, goes upward at the outer peripheral portion of the rotation surface and flows downward toward the rotation axis of the propeller; The fin is provided only on the one side surface when a rapid flow occurs near the one side surface of the rudder due to a synergistic effect of the rotational flow of the propeller.
[0010]
The wake of the propeller is formed by the vortex generated from the hull joining the rotating flow generated only by the propeller. Here, for example, when the propeller is clockwise, on the starboard side of the rudder, a downward steep flow field (rapid flow) is formed near the rudder side due to a synergistic effect of the vortex generated from the hull and the propeller rotating flow. On the other hand, on the port side of the rudder, a random slow flow field (slow flow) is formed near the rudder side due to the canceling effect of the vortex generated from the hull and the propeller rotating flow, and the outer periphery of the propeller rotating surface is Due to the synergistic effect of the generated vortex and the propeller rotating flow, a steep upward flow field is formed.
[0011]
Here, in a random slow flow field generated near the rudder port side surface described above, sufficient lift cannot be obtained, and the drag becomes dominant, which tends to be a factor that lowers propulsion efficiency. Therefore, in the first aspect, the rapid flow is generated near the rudder side surface without using the side surface where the random slow flow field is formed near the rudder side surface (port side in the example of the propeller clockwise). By providing fins only on the side surface (the starboard side in the example of clockwise rotation of the propeller), it is possible to reliably avoid the random slow flow field, thereby reliably preventing a reduction in propulsion efficiency. Can be. In addition, if there is a random slow flow field near the rudder side, it is extremely difficult to adjust the mounting conditions such as the fin mounting angle and mounting position, but use the random slow flow field as described above. By not doing so, the work of attaching the fins can be made extremely easy. Further, since it is not necessary to change the angle of attack of the fin for each span position of the fin, machining of the fin becomes easy and cost reduction can be achieved.
[0012]
In addition, when fins are attached to both sides of the rudder, a rotational moment (a moment force having a rotational axis parallel to the ship's propulsion direction) is applied to the rudder attachment portion or the rudder main body due to the lift generated by the fins. Therefore, it is necessary to secure the strength of the rudder mounting portion or the rudder main body. However, since the fins are provided only on one side of the rudder, the rotational moment can be significantly reduced, so that the degree of freedom of design can be improved and the cost can be reduced.
[0013]
A second aspect of the present invention is a rudder provided with fins for generating a force in a propulsion direction by using a wake of a propeller in a marine vessel, the vortex generated from a hull by propulsion of the marine vessel, In the rotation surface, the vortex flowing upward and downward toward the rotation axis of the propeller on the left and right sides of the rotation axis of the propeller at the outer peripheral portion of the rotation surface, and the rotation flow of the propeller, The fins are provided only on the side surface opposite to the one side surface when the slow flow occurs near the one side surface of the rudder due to the offset effect.
[0014]
According to the second aspect, similar to the first aspect, the one side where the random slow flow field (slow flow) is formed near the rudder side is used without using the one side. By providing fins only on the side of the rudder opposite to the side where the rapid flow occurs near the rudder, the above-mentioned random slow flow field can be reliably avoided, and thus the propulsion efficiency Can be prevented from decreasing. Further, the work of attaching the fins can be made extremely easy, and there is no need to change the angle of attack of the fins for each span position, so that the fins can be easily worked and the cost can be reduced. In addition, the rotational moment applied to the rudder mounting portion or the rudder main body can be significantly reduced, so that the degree of freedom in design can be improved and the cost can be reduced.
[0015]
A third aspect of the present invention is a rudder provided with fins for generating a force in a propulsion direction by using a wake of a propeller in a ship, wherein the propeller rotates rightward as viewed from the stern side to the bow side. The fin is provided only on the starboard side on the starboard side.
[0016]
According to the third aspect, the propeller rotates clockwise, and does not use the port side where the random slow flow field occurs near the rudder side, but only on the starboard side where the rapid flow occurs near the rudder side. By providing the fins, it is possible to reliably avoid the random slow flow field, and it is possible to reliably prevent the propulsion efficiency from lowering. In addition, the work of mounting the fins can be made extremely easy, and there is no need to use deformed wings in which the angle of attack of the airfoil is changed for each span position. Can be achieved. In addition, the rotational moment applied to the rudder mounting portion or the rudder main body can be reduced, the degree of freedom in design can be improved, and the cost can be reduced.
[0017]
According to a fourth aspect of the present invention, in any one of the first to third aspects, the span of the fin is formed to be 20% to 45% of the propeller diameter.
According to the fourth aspect, since the span of the fin is formed so as to be 20% to 45% of the propeller diameter, the fin is provided in the range where the propeller rotational flow exists, thereby improving the efficiency. It is possible to collect the propeller rotating flow.
[0018]
According to a fifth aspect of the present invention, in any one of the first to fourth aspects, the fin is formed by a wing cross-sectional shape having a camber line projecting downward or upward. The thickness is 5% to 25% of the chord length, and the position of the maximum thickness is anywhere from 45% to 50% of the chord length from the leading edge of the wing, and on the side opposite to the convex side, A straight line is formed between the trailing edge and any position between 45% and 55% of the chord length from the trailing edge of the wing, and from the end position of the straight line to the leading edge of the wing, a line extending from the straight line extends. And the maximum distance between the curve and an extension of the straight line is less than 5% of the chord length.
[0019]
According to the fifth aspect, since the maximum thickness of the fin in the cross-sectional shape of the fin is 5% to 25% of the wing length, the increase in drag is kept constant while obtaining a constant camber so as to reliably obtain lift. Can be suppressed. Further, since the position of the maximum thickness is at an arbitrary position of 45% to 50% of the chord length from the leading edge of the blade, the distribution of the blade thickness becomes uniform before and after, and a reduction in blade strength can be prevented. Further, on the side opposite to the convex side, a straight line is formed between the trailing edge of the wing and an arbitrary position within 45% to 55% of the chord length from the trailing edge of the wing. Cost can be reduced. In addition, a curve extending from the terminal position of the straight line to the blade leading edge is located on the blade thickness increasing direction side with respect to the extended line of the straight line, and furthermore, a maximum between the curved line and the extended line of the straight line. Since the distance is less than 5% of the chord length, a sufficient camber can be obtained in the first half of the wing where the wing effect is effectively obtained.
[0020]
A sixth aspect of the present invention is a vessel including the finned rudder according to any one of the first to fifth aspects, according to the sixth aspect. The same operation and effect as those in any of the first to fifth aspects described above can be obtained.
[0021]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to FIGS. Here, FIG. 1 is a stern side view of the ship according to the present invention, FIG. 2 is a flow velocity distribution diagram on a plane perpendicular to the propeller shaft center around the rudder when the propeller is operated (clockwise), FIG. B) is a perspective view of the rudder, FIG. 4 is a view showing respective self-propelled elements when fins are provided only on the port side, only on the starboard side, and both on the port and starboard sides. FIG. FIG. 6 is a front view of the stern portion, and FIG. 7 is a diagram showing a cross-sectional shape (airfoil) of the fin.
[0022]
In FIG. 1, a rudder 9 is provided via a rudder shaft 11 behind a propeller 3 provided at a stern portion of a hull 1. The propeller 3 is provided so as to be driven to rotate around a rotation axis C. A propeller cap 7 is attached to a tip (a side facing the rudder 9) of a propeller boss 5 constituting a rotation center of the propeller 3. ing. A valve 12 is provided at the rudder 9 at a position facing the propeller 3 and intersecting with the rotation axis C of the propeller 3. The valve 12 forms a flow area having a large wake coefficient in the rotation plane of the propeller 3 by blocking the wake flowing into the propeller, so to speak, to improve the wake gain in the propeller 3. Note that a line indicated by a reference sign AP indicates a rotation axis of the rudder 9.
[0023]
The propeller cap 7 is formed in a shape (in this embodiment, a conical shape) having a diameter gradually increasing toward the valve 12, and is configured to improve propulsion efficiency. That is, when the hull 1 sails behind the propeller boss 5, a so-called hub vortex is generated and disturbs the flow. However, by forming the propeller cap 7 into a conical shape as described above, the propeller boss 5 is rearward. The vortex diffuses the hub vortex to the outside of the valve 12, thereby making it possible to rectify the flow turbulence caused by the hub vortex.
[0024]
The fin 15a is attached to the rudder 9. By attaching the fins 15a to the rudder 9, lift and drag by the fins 15a are generated by the wake of the propeller, and the propulsion direction component of the resultant force of the lift and drag is used to collect the rotational flow of the propeller 3 and propulsion efficiency (hereinafter referred to as the symbol). η _P ) can be improved. Hereinafter, a specific embodiment of the fin 15a will be described.
[0025]
First, FIG. 2 is a vector diagram showing the flow direction of the wake of the propeller in the cross section of the rudder 9 (a diagram viewed from the rear of the hull to the front). Since the propeller 3 rotates clockwise as viewed from the rear of the hull, the wake generated only by the propeller 3 becomes an upward flow on the port side of the rudder 9 and a downward flow on the starboard side. However, the propeller 3 is a vortex in the clockwise direction in FIG. 2 on the port side of the rudder 9 from the hull 1 and in the counterclockwise direction on the starboard side, that is, a vortex generated from the hull 1 by the propulsion of the hull 1. In the propeller rotating surface PD of No. 3, a vortex (a so-called bilge vortex) which flows upward at the outer peripheral portion of the propeller rotating surface PD on the left and right sides of the rotating shaft of the propeller 3 and flows downward toward the rotating shaft of the propeller; Comes in. Therefore, due to the canceling effect and the synergistic effect of the bilge vortex and the rotating flow of the propeller 3, a slow random flow field (slow flow) is generated near the rudder side on the port side as shown in FIG. At the outer peripheral portion of the surface PD, a steep upward flow field is generated. On the starboard side, a steep downward flow field (rapid flow) is generated near the rudder side.
[0026]
As described above, when fins are mounted on the rudder 9, the fins mounted on the port side need to be sufficiently extended to the outer peripheral portion of the propeller rotating surface PD so as to reach the above-mentioned steep upward flow field. However, in this case, the fins need to pass through a slow random flow field near the left side of the rudder 9.
[0027]
Here, in a slow random flow field in the vicinity of the left side surface of the rudder 9, the fins cannot exert a sufficient lift, and the drag becomes dominant, which rather tends to be a factor for lowering the propulsion efficiency η _P. In addition, the allowable range of the fin mounting conditions such as the fin mounting position or the mounting angle at which the propulsion efficiency η _P can be improved is extremely narrow, and the adjustment work is likely to be extremely difficult. In most cases, optimum fin mounting conditions cannot be obtained as a result in all navigation conditions of the ship, and the installation of the fins, on the contrary, lowers the propulsion efficiency η _P.
[0028]
Therefore, in order to reliably avoid the slow random flow field generated near the port side surface of the rudder 9 described above, the fins are provided only on the starboard side of the rudder 9 to reliably eliminate the cause of the reduction in the propulsion efficiency η _P. Thus, the propulsion efficiency η _P can be efficiently improved.
[0029]
FIG. 4 is a diagram comparing self-propulsion elements when fins are provided only on the port side, only on the starboard side, and on both the port side and the starboard side (the fin span is 35% of the propeller diameter Dp on both the starboard side and the port side). In FIG. 4, η _R is the propeller efficiency ratio, 1-t is 1-t based on the propulsion reduction coefficient t, and 1-w _S is the wake coefficient w of the actual ship estimated based on the wake coefficient of the model ship. 1−w _S , Ｓη based on _S is the propulsion efficiency η _P (= ((1−w _S ) / (1-t)) × η _R × η _O : η _O is based on the absence of the fin: η _O is the propeller It shows the rate of improvement of individual efficiency).
[0030]
As shown in the figure, it can be seen that the propulsion efficiency η _P when the fins are provided only on the starboard side is improved as compared with the propulsion efficiency η _P when the fins are provided on both sides (particularly, 1-t Noticeably improved). In other words, it can be seen that the port fin is a factor that lowers the propulsion efficiency η _P.
[0031]
Next, FIG. 5 shows the change of the self-propelled element when the span of the starboard fin (the ratio to the propeller diameter Dp) is changed from 0% (no fin) to 20%, 28%, and 35%. As shown in the drawing, it can be seen that as the fin span is increased, the propulsion efficiency η _P increases in proportion to the fin span at least up to 35% (particularly, 1-t significantly increases).
[0032]
On the other hand, when the fins protrude outward from the propeller rotation surface, the fins exist to the extent that the propeller rotation flow does not exist, and the drag becomes dominant and the propulsion efficiency η _P is considered to decrease, The wake of the propeller is contracted because it is accelerated by the propeller, and the range in which the propeller rotating flow exists is actually narrower than the propeller rotating surface.
[0033]
As described above, by setting the span of the starboard fin to be about 20% to 45% with respect to the propeller diameter, the function of the starboard fin can be effectively utilized by utilizing only the downward steep flow field generated on the starboard side. It is possible to demonstrate.
[0034]
Next, FIG. 3 shows an embodiment of the starboard fin. In any of the rudder 9 shown in FIGS. 3A and 3B, no fin is provided on the port side, and the starboard fin is not provided. Fins 15a are provided only on side surface 9a. FIG. 3A shows an embodiment in which the fin 15a is directly attached to the side surface 9a, and FIG. 3B shows an embodiment in which the fin 15a is attached to the valve 12. By attaching the fin 15a to the valve 12, the propulsion efficiency η _P can be further improved. However, even when the valve 12 is not provided, the above-described operation and effect of the fin 15a only on the starboard side can be obtained.
[0035]
In addition, the following effects can be obtained. FIG. 6A is a schematic diagram showing a state in which fins are mounted on both sides of the rudder 9 (reference numeral 15b is a port side fin), and FIG. 6B shows a state in which fins 15a are mounted only on the starboard side. It is a schematic diagram. When fins are attached to both the left and right ports, a lift is generated in each fin in the direction indicated by the arrow in the figure. Here, each lift gives a clockwise rotation moment to the rudder shaft 11 of the rudder 9 or the rudder 9 main body in the figure, and it is necessary to consider this in the strength design of the rudder shaft 11 or the rudder 9. . However, by mounting the fins 15a only on the starboard side, the rotational moment can be remarkably reduced, whereby the strength considered in the design of the rudder shaft 11 or the rudder 9 can be set low, and the design can be reduced. The degree of freedom is improved, and the cost of the rudder shaft 11 or the rudder 9 can be reduced by simplifying the structure.
[0036]
Next, the airfoil of the fin 15a in the present embodiment will be described in detail. As shown in FIG. 1, the fins 15a can be formed in the shape of an airfoil. In this case, the fins 15a on the starboard side are provided so that the camber line is convex downward. FIG. 7 is a diagram showing the wings of the fins 15a so that the camber line is convex upward for convenience of description, and reference numeral CB indicates the camber line. In FIG. 7, in this embodiment, the maximum thickness d in the blade cross-sectional shape is set to be 5% to 25% of the blade length a + b. Accordingly, it is possible to suppress the increase in the drag force while obtaining a constant camber so as to surely obtain the lift force. The position Q of the maximum thickness d is set at an arbitrary position (distance indicated by reference symbol e) of 45% to 50% of the chord length from the blade leading edge. Therefore, the distribution of the blade thickness becomes uniform before and after, and a decrease in blade strength can be prevented.
[0037]
Further, on the side opposite to the convex side (wing bottom surface), a straight line is formed between the trailing edge of the blade and an arbitrary position P at 45% to 55% of the chord length from the trailing edge (a section indicated by the symbol b). (Straight surface) (straight line G). Therefore, the workability of the fin is excellent, and the cost of the fin can be reduced. In addition, from the end position of the straight line to the leading edge of the blade (section indicated by a), a curve (curve F) located on the blade thickness increasing direction side with respect to the extension of the straight line is further provided. , Is formed so that the maximum distance (distance indicated by reference symbol c) between the straight line and the extended line is less than 5% of the chord length a + b. Therefore, a sufficient camber can be obtained in the first half of the wing where the wing effect is effectively obtained.
[0038]
In addition, such a shape of the airfoil is not limited to the embodiment of the present invention in which fins are provided only on the starboard side of the rudder 9, and the above-described effects can be obtained in the conventional embodiment in which fins are provided on both sides of the rudder 9. It goes without saying that you can get it.
[0039]
【The invention's effect】
As described above, according to the present invention, the rapid flow is generated near the rudder side surface without using the side surface on which the random slow flow field is formed near the rudder side surface (port side in the example of the propeller clockwise). By providing fins only on one side surface (the starboard side in the example of clockwise rotation of the propeller), the random slow flow field can be avoided reliably, and the reduction in propulsion efficiency is ensured. Can be prevented. In addition, if there is a random slow flow field near the rudder side, it is extremely difficult to adjust the mounting conditions such as the fin mounting angle and mounting position, but use the random slow flow field as described above. By not doing so, the work of attaching the fins can be made extremely easy. Further, since it is not necessary to change the angle of attack of the fin for each span position of the fin, machining of the fin becomes easy and cost reduction can be achieved. In addition, when fins are attached to both sides of the rudder, a rotational moment (a moment force having a rotational axis parallel to the ship's propulsion direction) is applied to the rudder mounting portion or the rudder main body due to the lift generated by the fins. Thus, it is necessary to ensure the strength of the rudder mounting portion or the rudder main body. However, since the fins are provided only on one side of the rudder, the above-mentioned rotational moment can be remarkably reduced, so that the degree of freedom of design can be improved and the cost can be reduced.
[Brief description of the drawings]
FIG. 1 is a stern side view of a ship according to the present invention.
FIG. 2 is a flow velocity distribution diagram on a plane perpendicular to a propeller axis around a rudder when a propeller is operated (clockwise).
FIG. 3A is an external perspective view of a rudder, and FIG. 3B is an external perspective view of a rudder according to another embodiment.
FIG. 4 is a diagram showing respective self-propelled elements when fins are provided only on the port side, only on the starboard side, and on both sides.
FIG. 5 is a diagram showing a relationship between a span of a starboard fin and a self-propelled element.
FIG. 6 is a front view of a stern.
FIG. 7 is a diagram showing a cross-sectional shape (wing cross section) of a fin.
[Explanation of symbols]
Reference Signs List 1 Hull 3 Propeller 5 Propeller boss 7 Propeller 7a Propeller cap 9 Rudder 11 Rudder shaft 15a Fin (starboard side)

Claims (6)

A rudder provided with fins for generating a force in a propulsion direction by using a wake of a propeller in a ship,
A vortex generated from the hull by the propulsion of the ship, and on the rotation surface of the propeller, on the left and right sides of the rotation axis of the propeller, goes upward at the outer peripheral portion of the rotation surface and toward the rotation axis of the propeller. A vortex flowing down,
Rotating flow by the propeller,
When a rapid flow occurs near one side surface of the rudder due to a synergistic effect, the fins are provided only on the one side surface,
A finned rudder characterized by the following. A rudder provided with fins for generating a force in a propulsion direction by using a wake of a propeller in a ship,
A vortex generated from the hull by the propulsion of the ship, and on the rotation surface of the propeller, on the left and right sides of the rotation axis of the propeller, goes upward at the outer peripheral portion of the rotation surface and toward the rotation axis of the propeller. A vortex flowing down,
Rotating flow by the propeller,
In the case where a gentle flow occurs near the one side surface of the rudder due to the offset effect of the rudder, the fin is provided only on the side surface opposite to the one side surface,
A finned rudder characterized by the following. A rudder provided with fins for generating a force in a propulsion direction by using a wake of a propeller in a ship,
The propeller is clockwise when viewed from the stern side to the bow side,
The fin is provided only on the rudder side on the starboard side,
A finned rudder characterized by the following. 4. The fin according to claim 1, wherein a span of the fin is formed to be 20% to 45% of a propeller diameter. 5.
A finned rudder characterized by the following. The fin according to any one of claims 1 to 4, wherein the fin is formed by a wing cross-sectional shape having a camber line that is convex downward or upward,
In the wing cross-sectional shape, the maximum thickness is 5% to 25% of the chord length,
The maximum thickness position is anywhere from 45% to 50% of the chord length from the wing leading edge;
On the side opposite to the convex side, a straight line is formed between the trailing edge of the wing and any position between 45% and 55% of the chord length from the trailing edge, and extends from the end position of the straight line to the leading edge of the wing. Is a curve located on the blade thickness increasing direction side with respect to the extension of the straight line, and further, the maximum distance between the curve and the extension of the straight line is less than 5% of the chord length.
A finned rudder characterized by the following. A marine vessel comprising the finned rudder according to any one of claims 1 to 5.

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