WO2003022672A1

WO2003022672A1 - Sailing mast

Info

Publication number: WO2003022672A1
Application number: PCT/EP2002/009568
Authority: WO
Inventors: Josef Stempfle
Original assignee: Josef Stempfle
Priority date: 2001-09-08
Filing date: 2002-08-28
Publication date: 2003-03-20
Also published as: EP1427630A1; DE10144113B4; DE10144113A1

Abstract

The invention relates to a sailing mast (1) comprising a hollow profile (2) and means for influencing the aerodynamic form of the sailing mast (1). One such sailing mast enables the obtainable propulsive force or buoyancy force of the sail to be optimised, in that the aerodynamic form of the sailing mast is embodied in such a way that the prevailing flow ratios are as favourable as possible. In order to achieve this, the hollow profile (2) is rigid and the means for influencing the aerodynamic form is formed by a deformable outer skin (3) surrounding the hollow profile (2).

Description

Segelmast

The invention relates to a sail mast according to the preamble of claim 1.

Sail masts with a round profile or with rounded corner profiles which are permanently mounted on a sailing vehicle are known from the prior art. German utility model G 90 14 942, for example, describes a sail mast with an essentially polygonal, preferably triangular, cross section. Such sail masts have a symmetrical cross section with respect to their longitudinal center plane. Furthermore, sail masts with a symmetrical profile are known from the prior art, which are rotatably mounted on the sailing vehicle. Fixed sail masts have the disadvantage that they cause turbulence at their leading edge, especially in half wind and upwind courses, which adversely affect the propulsive force of the sail. The effective sail area is greatly reduced with fixed masts, since the desired bulbous profile only arises after about a third of the sail area. These disadvantages can be avoided by rotating sail masts, since they can be rotated in the direction of the upstream wind.

In order to improve the aerodynamic properties and in particular to increase the effective sail area, sail masts with an asymmetrical cross section have been proposed. Rigid, asymmetrical masts, however, have the disadvantage that the sailing vehicle can only be sailed on one bow.

An aerodynamic element for sailing vehicles, which has means for influencing its aerodynamic shape, is known from the European patent EP 0 511 050. The aerodynamic element comprises a rectangular mast and a sail, which determines the aerodynamic shape of the element. The aerodynamic shape of the sail, in particular its curvature and concavity, can be influenced by two flexible design slats to which the sail is attached. By creating the design slats, the curvature or concavity of the sail can be changed so that the aerodynamic element can be brought into an aerodynamically preferred shape. The disadvantage of this known element is its elaborate design. The known element is therefore very expensive and prone to errors. The complex mechanical construction also contributes to a high weight of the north direction.

The object of the invention is to provide a sail mast which offers the most favorable inflow conditions to the sail arranged thereon and thus optimizes the achievable propulsive or buoyant force of the sail.

This object is achieved with a sail mast with the characterizing features of claim 1. Advantageous configurations of this sail mast can be found in the subclaims.

The invention is described below using exemplary embodiments with reference to the accompanying drawings. The drawings show:

Figure 1: Side view of a sailing vehicle with a mast according to the invention;

Figure 2: Cross section of the sail mast according to the invention;

Figure 3: View of the sailing vehicle of Figure 1 from above in the respective

Rotational positions of the sail mast adapted to the wind and driving direction;

Figure 4a: rear view of the sailing vehicle of Figure 1;

Figure 4b: detailed view of Figure 4a in the area of the upper spreaders of the sail mast;

Figure 4c: cross section through the detailed view of Figure 4b along the line I-I.

FIG. 1 shows a sailing vehicle 14 which is equipped with a sailing mast 1. In the exemplary embodiment shown in FIG. 1, the sailing vehicle 14 is a sailing boat. However, the mast 1 according to the invention is also intended for other sailing vehicles which can be set in motion in the air, on the water or on the ground by the action of wind, such as e.g. Surf boats, surf boards, hang gliders, sailing sledges, kites and the like.

The sail mast 1 is rotatably fastened on the sail vehicle 14 in a known manner by the mast foot 20 being inserted into a conventional sail mast pocket. A main sail 16 is attached to the mast 1 and stretched over a tree 21. Tree 21 is preferred rotatably articulated on the mast 1 via a swivel 30 and in different

Rotational positions with respect to the mast 1 can be locked.

In addition, the sailing vehicle 14 is equipped in a known manner with a headsail 17.

The sail mast 1 is rotatably mounted about a vertical axis 13 running through the mast base 20.

In Figure 2, the sail mast 1 is shown in cross section. The sail mast 1 comprises a rigid hollow profile 2, which has an outer wall 10. The hollow profile is preferably designed as an extruded aluminum profile. However, it can also be made from other materials such as e.g. Titanium, plastic, carbon or glass fiber can be produced using known processes.

The hollow profile 2 is divided into a front area with the outer walls 10a and 10b and a rear area with an outer wall 10c. The leading edge 23 is located at the end of the front region of the hollow profile 2. At the end of the rear region of the hollow profile 2, a mast groove 18 is formed in the outer wall 10c, into which a luff 19 with the main sail 16 attached is formed is introduced. In the front area of the hollow profile 2, the outer walls 10a and 10b enclose a cavity 22. Inside this cavity 22, the outer walls 10a and 10b are connected to one another by cross struts 24, 25. The outer walls 10a and 10b merge on the one hand at the leading edge 23 and on the other hand at the transition to the rear part of the hollow profile 2, at reference number 26. In the rear part of the hollow profile 2, the outer walls 10a and 10b merge into one another to form a profile wall 10c. Overall, the hollow profile 2 has a cross section which is symmetrical with respect to the longitudinal center plane 15, at least the front region of the hollow profile having a substantially drop-shaped cross section. The tip of the drop shape of the front part of the hollow profile 2 merges at reference number 26 into the rear part of the hollow profile with the profile wall 10c

The cross strut 25 is designed such that it forms two channels 7 and 8 separated from one another with the inner sides of the outer walls 10a and 10b. In the area of the channels 7 and 8, the outer walls 10a and 10b are provided with openings 11, 12. The channels 7 and 8 and the openings 11 and 12 extend over the entire height of the hollow profile 2. The channels 7 and 8 are sealed airtight at the mast base and at the mast tip by cover plates. The hollow profile 2 is enclosed by a shape-changing outer skin 3. The outer skin 3 is formed from a sheet-like material, such as plastic film, kevlar fabric, or canvas. The outer skin 3 is preferably made of an air-impermeable material.

The outer skin 3 is fastened over the entire height of the hollow profile 2 along fastening lines 28, 29 on the two outer sides of the profile wall 10c. The fastening lines 28, 29 preferably run in the region of the outer end 27 of the hollow profile 2, near the mast groove 18.

In the front area of the hollow profile 2, the outer skin is fastened to the outer wall 10 along a fastening surface 30, the fastening surface 30 being located in the center of the leading edge 23. Two separate chambers 5, 6 are formed between the outer skin 3 and the outer walls 10a, 10b and 10c by fastening the outer skin 3 to the hollow profile 2. The essentially airtight chambers 5 and 6 can be acted upon independently of one another by means of a pneumatic pump 9 (see FIG. 1) arranged in the area of the mast base 20 (see FIG. 1). The chambers 5, 6 are pressurized or depressurized via the channels 7 and 8, which are connected to the pump 9 and are connected to the chambers 5, 6 via openings 11, 12. By means of the pump 9, the two chambers 5, 6 can be pressurized either independently or alternately with pressure or vacuum.

In a preferred embodiment, 14 sensors are provided on the sailing vehicle, with which the current rotational position of the mast 1 with respect to the keel direction (K Fig. 3) can be detected. Inductive, capacitive, optical or mechanical sensors are preferably used. In Figure 3, the sailing vehicle 14 is shown in three different rotational positions of the mast 1. The rotational position of the mast 1 on the sailing vehicle 14 is preferably subdivided into a plurality of regions, for example left, right and center, and is accordingly detected and indicated by the sensors.

The use of the sail mast 1 according to the invention is described in more detail below with reference to FIG. 3. Figure 3b shows the sailboat 14 when sailing on the left bow and Figure 3c when sailing on the right bow. Figure 3a shows the rotational position of the mast on the sailboat when turning, whereby the keel direction K includes an angle of 180 ° with the wind direction W.

When sailing, the mast 1 is first placed on the desired side so that the wind coming from the wind direction W hits the leading edge 23, as shown for example in FIG. 3b for sailing on the left bow. The rotational position of the sail mast 1 chosen in this way with respect to the keel direction K is detected by the sensor for determining the rotational position of the mast and passed on to a control circuit for controlling the pump 9. The tree 21 is aligned in a known manner with respect to the wind direction W (true wind) and locked on the mast 1 in such a way that the main sail 16 is provided with the best possible inflow conditions in order to enable the largest possible travel component. In this position, the tree 21 forms an acute angle α with the longitudinal center plane 15 of the mast 1 (FIG. 3b).

The chamber 6 on the suction side S is pressurized by means of the pump 9 and the chamber 5 on the pressure side D is pressurized (FIG. 3b). By applying excess pressure, the outer skin 3 bulges out on the suction side S, while the outer skin 3 on the opposite pressure side, in the area of the chamber 5, is sucked into the outside 4 of the hollow profile due to the negative pressure prevailing there and comes to rest there , In this way, a cross-sectional profile that is asymmetrical with respect to the longitudinal center plane 15 is formed.

Due to the asymmetrical profile, which determines the aerodynamic properties of the mast 1, the effective sail area acting in the main sail 16 is increased compared to a symmetrical mast profile, because the wind coming from the direction W can flow better into the main sail 16. Furthermore, the asymmetrical profile prevents turbulence at the leading edge 23, which means that the sail 16 is fully functional from the luff. The sail area can therefore be chosen smaller while the propulsion remains the same, which reduces the offending forces. By avoiding the turbulence in the area of the leading edge 23, higher courses can also be taken on the wind because the sail does not come in until later.

When the sailboat turns (FIG. 3a), the tree 21 is first brought into the middle position in which the tree 21 is aligned with the longitudinal center plane 15 of the hollow profile 2. This position of the tree 21 and the sail mast 15 is detected by the sensor and passed on to the control circuit for controlling the pump 9. In this position, the pump 9 ensures pressure equalization between the chambers 5 and 6, so that the mast 1 assumes an aerodynamically neutral, ie symmetrical, profile. This symmetrical cross-sectional profile is achieved in that approximately the same overpressure is maintained in both chambers 5 and 6, so that the outer skin 3 inflates uniformly on both sides of the longitudinal median plane 15, whereby the entire aerodynamic shape of the mast 1 is a occupies an essential drop-shaped profile. When the mast 1 or the tree 21 is moved further, the corresponding position is again detected by the sensor and the pneumatic pump 9 is controlled in such a way that the chamber 5 on the suction side is pressurized and the chamber 6 on the pressure side D is pressurized (Figure 3c).

Compared to rotating masts with a rigid, symmetrical cross-section, this results in a significant increase in propulsive force for sailing on both bow sides (left bow or right bow) and an improvement in the inflow profile in every rotational position of the mast 1, because when sailing is from left on the right bow (and vice versa) the aerodynamic profile of the mast 1 can be adjusted so that the most favorable inflow conditions for the main sail 16 result in each rotational position of the mast 1.

FIG. 4 a shows the sailing vehicle 14 from FIG. 1 in the rear view with a preferred embodiment of the sailing mast 1. The sailing mast 1 has in its upper part and in its lower part spreaders 34, 35, 36, 37 attached transversely. The spreaders 34, 35 in the upper part of the mast are connected to the mast top 40 by shrouds 38, 39. Shrouds 41, 42 attached to the side wall 43 engage the mast top 40. In the area of the upper spreaders 34, 35 and in the area of the lower spreaders 36, 37, guide plates 31, 32, 33, 34 are attached to the hollow profile 2 on both sides of the hollow profile. The baffles 31, 32 can also be seen from the side view of FIG. 1.

FIG. 4b shows a detailed illustration of the sail mast 1 in the area of the upper spreaders 34, 35. FIG. 4c shows a cross section through the sail mast 1 according to FIG. 4b along the line II. The guide plates 31, 32, 33 and 34 are the shape of the outer skin when pressurized State adapted so that the outer skin 3 bears against the guide plates 31, 32, 33 and 34, if both chambers 5, 6 are pressurized. This state is shown in Figure 4c. The baffles 31, 32, 33 and 34 thus serve for the lateral stabilization of the outer skin 3 in the pressurized state. Maintaining the shape specified by the guide plates 31, 32, 33 and 34 is particularly important on the suction side over the entire height of the mast, since about two thirds of the driving force is generated on the suction side.

Claims

Expectations

1. sail mast (1), comprising a hollow profile (2) and means for influencing the aerodynamic shape of the sail mast (1), characterized in that the hollow profile (2) is rigid and the means for influencing the aerodynamic shape are formed by a Hollow profile (2) enclosing, changeable outer skin

(3) -

2. sail mast according to claim 1, characterized in that the outer skin (3) on the hollow profile (2) is attached such that between the outer skin (3) and the outside (4) of the hollow profile (2) two separate chambers ( 5, 6) form, which can be acted upon by pressure or vacuum.

3. sail mast according to claim 1, characterized in that in the interior of the hollow profile (2) channels (7, 8) are provided which are connected to a pump (9) and with the chambers (5, 6) are connected, wherein the two chambers (5, 6) can be acted upon independently of one another or alternately by means of the pump (9) with pressure or vacuum.

4. sail mast according to one of the preceding claims, characterized in that each channel (7, 8) with one chamber (5, 6) via openings (11, 12) is in communication.

5. sail mast according to one of the preceding claims, characterized in that the

Sail mast (1) is mounted on a sailing vehicle (14) so as to be rotatable about a vertically arranged axis (13).

6. sail mast according to one of the preceding claims, characterized in that the hollow profile (2) has a symmetrical cross-section with respect to its longitudinal center plane (15). Sail mast according to claim 5, characterized in that sensors are provided on the sailing vehicle (14) with which the rotational position of the sail mast can be detected.