FI90029C - PROPELLERNAV - Google Patents

Description

1 90029

Propeller hub

The present invention relates to a hub mounted on a hub at the rear of a propeller, the propeller comprising a plurality of propeller blades, each having a base along a hub base boundary extending from the leading edge of the hub to its trailing edge, the bases being along a line at an angle to the plane perpendicular to the axis of rotation of the propeller.

Extensive and intensive research has been done to improve the properties of the propeller, and in particular its power, especially regarding the number of blades, shape, spread area, pitch, etc., and now this research has borne fruit in the form of almost maximum development. Thus, it is unlikely that research in these areas will significantly improve the properties of propellers in the future.

On the other hand, it is known that the power of the propeller is low in the vicinity of the hub. For this reason, it has been proposed to place a small-diameter propeller behind the main propeller in order to increase the propeller power in the vicinity of the hub, as in e.g. Japanese Utility Model Publications 30,195/81 and 139,500/82. However, it seems that such an idea was not successful. This is probably due to the fact that ... the thrust does not increase as much as the torque and thus the propeller power does not improve as desired.

Thus, it is an object of the present invention to provide a new technique which makes it possible to significantly improve the characteristics of the propeller, and in particular the propeller power, by adding a fin hub to the propeller. As shown in the accompanying Figure 3 (prior art), a conventional propeller 31 comprises a plurality of blades 33 spaced evenly around the circumference of the hub 32 and connected via a hub 32 to a rotating drive shaft 34. A hub cap 35 is mounted at the opposite end of the hub 2 90029 32 to reduce as many vortices from the pole downstream as possible.

The present invention draws attention to the fact that a significant hub vortex (36) is also generated in the backflow of the hub of such a propeller, and bearing in mind that a smaller diameter additional propeller according to the prior art would increase such hub vortex, research has focused on finding ways to reduce such hub vortex. Finally, it has been found that adding a fin hub to a propeller can reduce such a hub vortex and thus increase propeller power.

Accordingly, the present invention is characterized in that the dome has a dome body and a plurality of fins mounted on said dome body spaced around the circumference of said dome body; the number of fins is equal to the number of propeller blades; the fins are inclined at an angle of -20 ° to + 30 ° to the line in which the base of the corresponding propeller blade is located and the angle is chosen so that the fins receive flow from the propeller blade on the side facing the propeller blades and the fins are tilted at an angle KK is -30 "s KK <0® with respect to the direction of rotation of the propeller, and the leading edges of the fins toward the propeller are between lines beginning at the leading and trailing edges of all propeller blades and extending toward the stern parallel to the axis of rotation of the propeller; and the fins are substantially smaller in area than the propeller blades, the outer diameter of the fins on the dome axis is greater than the diameter of the dome body at the rear of the propeller hub and up to 33% of the outer diameter of the propeller blades as measured from the propeller shaft.

The purpose of the fins according to the present invention is not to independently provide a thrust, but to direct the flow of water behind the hub in such a direction that the formation of a hub vortex is reduced. Due to this steering effect,

II

The hub vortex generated behind the 3 90029 hood disintegrates and thus the drag force exerted by the vortex on the propeller blade is reduced and as a result the propeller characteristics and especially the propeller power are significantly improved without a significant increase in torque.

Thus, in general, the present invention provides significantly higher power to a propeller with a high ascent ratio (H / D) that provides a stronger pole vortex.

As shown in the application examples of the present invention, the fins can be provided with an angle of inclination or a positive or negative plowing angle with respect to the pole piece.

Fig. 1 is a front view of a propeller mounted on a fin-powered propeller hub according to an embodiment of the present invention, and Fig. 2 is a side view of Fig. 1.

Fig. 3 is a side view similar to Fig. 2, but showing a prior art propeller and hub without fins, with hub vents formed behind the hub cap.

Figure 4 is a side view in partial section of the propeller characteristics measuring device used in the experiments.

Fig. 5 is a plan view showing the shape of the fins used in the experiments in the plane, and Fig. 6 is a side view showing the mounting locations of the fins in the propeller hub.

Fig. 7 shows curves illustrating the characteristics of the propeller obtained in Experiment 1, and Figs. 8-10 show diagrams which ... represent the relative positions of the propeller blade bases and fins in Experiments 2-4.

Fig. 11 is a side view showing the angle of inclination of the fins in Experiment 5, and Fig. 12 is a section along the line A-A in Fig. 11.

Fig. 13 is a diagram corresponding to Figs. 8-10, but showing the relative positions of the propeller blade bases and fins in Experiment 6.

Fig. 14 is a diagram showing the results of Experiment 7.

4,90029

Some embodiments of the present invention will be explained in detail with reference to the accompanying drawings. The tests are performed in a water tank on propeller models with the characteristics shown in Table 1. The water tank is a circular flow tank with a monitoring section measuring 5.0 m (length) x 2.0 m (width) x 1.0 m (depth). The maximum flow velocity is 2.0 m / s and the uniformity of the flow velocity is within 1.5%.

table 1

Type CP24 CP26

Diameter (mm) 220.0 220.0

Rise ratio 0.8 1.2

Spread-to-shoulder ratio 0.55 0.55

Pole ratio 0.18 0.18

Pallet thickness ratio 0.05 0.05

Cross - sectional shape of the platform MAU MAU

Number of blades 4 4

Figure 4 is a side view, partly in section, of a device for measuring propeller characteristics. This device is located in the monitoring section of the water tank by attaching its propeller boat 41 to a rigid carrier (not shown) located above the water tank. The boat 41 has a drive mechanism 43 for rotating a propeller 42, which propeller can be detachably attached to its tip end, a thrust detector 44 and a torque detector 45.

Although not shown in Figure 4, the propeller speed is measured with a digital calculator TM-225 (Ono Measurement Instruments Company, Japan) and the flow rate with a combination of a JIS-type Pitot tube and a differential pressure transducer DLPU-0.02 (Toyo Boldwin Company, Japan). The analog signals of thrust, torque, and flow rate, etc., represented by the differential position, are converted to digital signals through an AC-DC converter included in a microprocessor housed in a separate monitor, and then the signals are processed into physical data or printed by a writer. The thrust coefficient (KT) and the torque coefficient (KQ) are measured by different propagation coefficients (J), which are obtained by changing the flow rate while keeping the propeller rotation speed approximately the same, i.e. within 7.5-9.0 k / s. The center of the propeller is at a depth of 300 mm in the water and the direction of water flow is shown by the arrow in Figure 4.

The hood, which is in the shape of a rounded cone and has a base diameter of 35 mm and a height of 25.6 mm, is made as a hub for mounting on propeller models. The hood can be mounted on the propeller in any known manner and bolt nut mounting has been used in these tests. For the pole dome, the fins shown in Figure 5 in plan view, with six different triangular shapes (A) to (F), are made of flat plates 1 mm thick with the dimensions shown in Table 2 below.

Table 2

Stabilizer shape Width Height (X-axis direction) (Y-axis direction) (A) 20 mm 20 mm (B) 26 mm 16.5 mm (C) 26 mm 21 mm (D) 26 mm 28.5 mm .. . (E) 26 mm 34 mm (F) 26 mm 39.5 mm

Figure 6 shows the relative positions of the fins and the hood. In Fig. 6, the rear end 0 of the base 62 of the propeller blade 61 is marked on the propeller shaft 63 as a reference point. In this specification, referred to as the circumferential distance from the front end 64 of the fin plane which contains the reference point 0 and the propeller shaft 63 "a" hereinafter (presented by the positive direction of the arrow propeller pyörimissuunnas- 6 90029 SA). The surface spacing from the front end of the fin 64 to the circumference containing the vertex 0 is referred to as "b". The angle of the fin 64 with respect to the plane perpendicular to the propeller axis is "alpha". The geometric pitch of the propeller blade base 62 is "epsilon".

In this application, the geometric pitch angle of the propeller blade base is based on the cam-stern line of the "epsilon" propeller blade base. More specifically, two cylindrical surfaces whose axis is on the axis of the propeller and whose radius corresponds to the radius of the hub cap, and the surface of the propeller blade or its extension as the intended surface are taken into account. A cylindrical surface intersected by a transverse line running between the two surfaces, i.e. a cylindrical section, is applied to the plane. In the image thus applied, the angle between the cam-stern line of the blade section defined by the cylindrical section applied and the line perpendicular to the parent line of the cylindrical surface is "epsilon".

The fin 64 is mounted in a direction perpendicular to the pole hood against the plane of Figure 6 when the tilt angle is not indicated. The installation is carried out in these experiments by cutting a groove in the pole piece, placing the lower end of the fin in the groove and fixing it with glue, but it is of course possible and in some cases even advantageous to form the pole piece and the fins in one piece. The dashed lines in the lower parts of the fins in Fig. 5 show the intersection lines between the surface of the fins and the surface of the hub when the fins are mounted on the hub.

Test 1

Water tank tests have been performed using a CP26 type propeller (epsilon = 67.4 °) and fins according to Figure 5 (C). A total of 4 fins, one for each propeller blade, are mounted on the hub cap in positions a = 10 mm, b = 5 mm and alpha = 66 °. In this case, the maximum diameter of the fins, ie twice the distance (2r) of the fins furthest radially (from the propeller axis)

II

7 90029 between the head and the propeller shaft (when the fins are mounted on the na-exhaust) and the propeller diameter (2R) are in the ratio r / R = 0.23. Figure 1 shows a front view of the propeller 1, hub 2, propeller blades 3, shaft 4, hub 5 and fins 6 thus assembled; Figure 2 shows the same seen from the side. For comparison, experiments have also been performed without fins. Thrust coefficient (KT) and torque coefficient (KQ) have been measured with different propagation coefficients (J) between 0.0 and 1.1 and propeller power (eta = J.KT / 2PiKQ) has been calculated. The percentage increase in propeller power (d.eta) from the experiments without fins to the experiments with fins has then been calculated. The results are shown in Tables 3 and 4 below.

8 9 G O 2 9

Table 3 (without fins)

Well. J KT KQ x 10 eta 0 0.000 0.4816 0.9376 0.0000 1 0.050 0.4715 0.9092 0.0413 2 0.100 0.4606 0.8883 0.0831 3 0.150 0.4489 0.8565 0.1251 4 0.200 0.4363 0.8316 0.1670 5 0.250 0.4230 0.8071 0.2085 6 0.300 0.4088 0.7829 0.2493 7 0.350 0.3940 0.7586 0.2893 8 0.400 0.3785 0 , 7342 0,3282 9 0,450 0,3623 0,7094 0,3657 10 0,500 0,3454 0,6839 0,4019 11 0,550 0,3281 0,6578 0,4365 12 0,600 0,3102 0,6309 0,4695 13 0.650 0.2919 0.6031 0.5007 14 0.700 0.2731 0.5743 0.5299 15 0.750 0.2541 0.5445 0.5571 16 0.800 0.2349 0.5138 0.5820 17 0.850 0.2154 0, 4820 0.6046 18 0.900 0.1959 0.4944 0.6244 19 0.950 0.1764 0.4159 0.6413 20 1,000 0.1570 0.3817 0.6547 21 1.050 0.1378 0.3468 0.6639 22 1.100 0.1189 0.3115 0.6680 9 90029

Table 4 (with fins)

Well. J KT KQ x 10 eta d.eta <%> 0 0.000 0.4985 0.9154 0.0000 0.00 1 0.050 0.4894 0.8914 0.0437 5.55 2 0.100 0.4785 0.8677 0, 0878 5.35 3 0.150 0.4660 0.8440 0.1318 5.09 4 0.200 0.4522 0.8204 0.1755 4.81 5 0.250 0.4373 0.7965 0.2184 4.54 6 0.300 0, 4215 0.7724 0.2605 4.29 7 0.350 0.4050 0.7479 0.3016 4.09 8 0.400 0.3880 0.7229 0.3617 3.96 9 0.450 0.3705 0.6973 0.3806 3 .90 10 0.500 0.3528 0.6710 0.4184 3.95 11 0.550 0.3339 0.6441 0.4552 4.09 12 0.600 0.3168 0.6164 0.4909 4.35 13 0.650 0.2986 0 .5879 0.5255 4.73 14 0.700 0.2803 0.5585 0.5590 5.21 15 0.750 0.2617 0.5284 0.5913 5.78 16 0.800 0.2430 0.4974 0.6220 6.42 17 0.850 0.2239 0.4655 0.6506 7.07 18 0.900 0.2044 0.4328 0.662 7.66 19 0.950 0.1843 0.3994 0.6976 8.07 20 1,000 0.1634 0.3652 0.7123 8.09 21 1,050 0.1417 0.3303 0.7168 7.38 22 1,100 0.1187 0.2947 0.7053 5.29 10 90029

Figure 7 illustrates the results of Tables 3 and 4 and shows the propagation factor (J) on the horizontal axis and the thrust / factor (KT), the torque factor multiplied by ten (KQ x 10) and the propeller power (eta) on the vertical axis. In Figure 7, curves T2, Q2 and P2 show KT, KQ x 10 and eta in Table 3 and curves T3, Q3 and P3 show KT, KQ x 10 and eta in Table 4. Figure 7 and Table 4 show that propeller power increases from 4 to 8 X in the range J = 0.05 to 1.10 and in particular to 7.66 X with the commonly used value J = 0.9.

In addition, these experiments have manually lowered a capillary into the water from above the water tank near the aft end of the hood to conduct air bubbles. It has been found that in experiments without fins, a large number of air bubbles are generated and grouped along the propeller shaft, but in experiments with fins, the air bubbles disintegrate and disappear. From this it has been concluded that the na-vortex is significantly reduced due to the fins.

Test 2

Experiments similar to Experiment 1 were performed, but using different positions for the fins, i.e., different a, b, and alpha. The following Table 5 shows the increase in propeller power achieved with the generally used propagation factor (J) = 0.9.

Table 5

No ab alpha alpha r / R d.eta oo (mm) (mm) () epsilon () (X) 1 10 0 64 -3.4 0.25 5.49 2 15 0 61 -6.4 0.25 7.32 3 * 10 5 66 -1.4 0.23 7.66 4 14 5 59 -8.4 0.23 6.39 * ... from the data of Experiment 1

II

“90029

Fig. Ea illustrates the relative positions of the fins and the bases of the propeller blades, in which the rear end 0 of one of the propeller blade bases shown in Fig. 6 is placed on the x-axis and the blade position is shown as a line segment from the x-axis angle to the epsilon and its length t the length of the stern line. The base of the propeller blade adjacent to said propeller blade is shown in a similar manner, but there is a circumferential distance between their sterns in the x-axis direction. The positions of the fins are indicated by noting in Figure 6 "a" in the direction of the x-axis and in Figure 6 "b" in the direction of the y-axis passing through reference point 0 perpendicular to the x-axis. It can be seen from Table 5 and Figure Θ that a significant increase in propeller power can be achieved if the front ends of the fins are placed between the bases of adjacent propeller blades, i.e. in a space ® located between the extended tip-trays of the bases of adjacent propeller blades.

Experiment 3 Similar experiments were performed in which the alpha was changed. The following Table 6 shows the progress

The propeller power growth ratio achieved with Ql® (J) = 0.9.

‘2 90029

Table 6 o o

No alpha <) alpha-epsilon () r / R d.eta (X) 1 45 -22.4 0.24 0.34 2 50 -17.4 0.235 3.46 3 * 66 - 1.4 0.23 7.66 4 65 17.6 0.22 3.60 5 90 22.6 0.22 2.19 6 95 27.6 0.22 2.36 7 100 32.6 0.22 0.77 6 105 37 .6 0.22 0.47 * ... from Experiment 1 data

The results of Table 6 are shown in Figure 9 similarly to Experiment 2. Table 6 and Figure 9 show that a significant improvement in propeller power can be achieved in the range of -20 έ o alpha-epsilon 4 = 30.

Test 4

Experiments similar to Experiment 2 were performed, but a CP24 type propeller (epsilon - 57.4> and fins according to Figures 5 (A) and 5 (C) were used. The propeller power increase ratio provided by the propulsion factor (J) 0,0.6 generally used for such a propeller are shown in Table 7 below.

Il 13> '0 029

Table 7

Well. ab alpha alpha- r / R Fin d.eta oo (mm) (mm) () epsilon () shape (%) 1 0 5 80 22.6 0.21 (A) 2.03 2 10 17 63 5.6 0.18 (A) 3.02 3 5 12 63 5.6 0.20 (A) 2.06 4 5 9.5 63 5.6 0.21 (A) 2.32 5 5 7 63 5.6 0.215 (A) 2.84 6 10 7 63 5.6 0.23 (C) 3.93 7 10 7 57 - 0.4 0.22 (C) 2.32 8 6 7 63 5.6 0.22 (C) 2.57 9 4 5 35 -22.4 0.235 (C) -0.09 10 4 5 90 32.6 0.22 (C) -0.19

The results of Table 7 are shown in Figure 10 similarly to Experiment 2. It is understood that there is no significant difference between the shape of the fins (A) and (C) and that the fin locations should satisfy the condition that the front end of the fin is located on adjacent propeller blades. between the bases and the tilt of the fins within the range -20 ^ alpha- o epsilon ^ -30, as in the case of said Fig. 9. Test 5

Experiment 4 number 6 has been repeated and a tilt-o angle of - 30 has been added to the fins. The heeling angles are measured from a direction perpendicular to the plane of Figure 6 in the direction of rotation of the propeller. The results are shown in Table 8 below.

14 90029

Table 8

Well. ab alpha alpha- r / R Tilt d.eta ooo (mm) (mm) () epsilon () angle () (X) 6F 10 7 63 5.6 0.21 +30 1.46 6M * 10 7 63 5.6 0.23 0 3.93 6B 10 7 63 5.6 0.21 -30 4.47 * ... from the data of experiment 4

It can be seen from Table 8 that d.eta: 11a tends to improve further when the fins are mounted at an angle of inclination opposite to the direction of rotation of the propeller. The locations of the fins are shown in Fig. 11 as a side view corresponding to Fig. 6 and in Fig. 12, which is a section along the line A-A in Fig. 11.

Test 6

The number 7 of Experiment 4 has been repeated, but the number and position of the fins have been changed. The results are shown in Table 9 below.

Table 9

Well. ab alpha alpha- r / R Number of d.eta oo (mm) (mm) () number of epsilon () (X) 7-N2 10 ** 7 57 -0.4 0.22 2 -0.12 7-N3 10 ** 7 57 -0.4 0.22 3 0.49 7-N4 * 10 7 57 -0.4 0.22 4 2.32 7-N5 10 ** 7 57 -0.4 0.22 5 -1.12 * ... data from 4 experiments ** ... values for one specific fin; the values of the other fins correspond o to the positions obtained by dividing by the number of 360 fins.

It is 9 0 029

The relative positions of the bases and fins of the propeller blades are shown in Figure 13 by x-y axes as in Figures 8-10. In the case of fin number two, the fins are located relative to the four propeller blade bases B1-B4 in positions 1 / F and 2/2; fin number three in the case of positions 1 / F, 2/3 and 3/3; fin number four in the case of positions 1 / F, 2/4, 3/4 and 4/4; and fin number five in the case of positions 1 / F, 2/5, 3/5, 4/5 and 5/5, as shown in Fig. 13. It can be seen that in the case of fin number 2, no fin is placed between the bases B2 and B3 of the propeller blade and between the bases B4 and B1; fin number three in the case between bases B3 and B4. Further, in the case of fin number five, there are two fins between B3 and B4. Thus, the fins are not evenly spaced in the fin number two, three, and five cases.

Table 8 shows that the number of fins should be the same in each space between the bases of adjacent propeller blades.

Test 7

Experiments similar to Experiment 1 have been performed, but using different fins according to Figure 5 5 <B) -5 <F) that are the same width but different heights. A total of four fins of the same shape, one for each propeller blade, shall be installed in the positions defined by a = 10 mm, b - 5 mm and alpha = 66. The propeller power increase ratio achieved with a propagation factor (J) = 0.9 is shown in Table 10 below.

ie 9G029

Table 10

Well. ab alpha alpha- r / R Evan d.eta oo (mm) (mm) () epeilon () shape (X) 1 10 5 66 -1,4 0,2 (B) 4,12 2 * 10 5 66 - 1.4 0.23 (C) 7.66 3 10 5 66 -1.4 0.3 (D) 6.08 4 10 5 66 -1.4 0.35 (E) 0.87 5 10 5 66 -1.4 0.4 (F) -0.50 * ... from Experiment 1 data

The results in Table 10 are shown graphically in Figure 14, where r / R is on the x-axis and d.eta is on the vertical axis.

Given that the hub ratio of a CP26-type propeller is 0.18, it is clear that the maximum diameter of the fins must be larger than the diameter of the hub receiving hub end and must not be larger than 33 X of the propeller diameter in order to achieve a significant improvement in propeller power.

Test 8

Experiments similar to Experiment 1 have been performed, but the fins of Figure 5 (C) bent into an arc with a radius of 50 mm were used. Two types of fins were used, one bent into a convex arc in the direction of rotation of the propeller (= C-out) and the other a concave arc in the direction of rotation of the propeller (= C-in). A total of four fins of the same shape, one for each propeller blade, are installed at locations defined by a = 10 mm, b = 5 mm and alpha = 66 (= angle of arc ice direction). The propeller power growth ratio achieved with a propagation factor (J) = 0.9 is shown in Table 11 below.

Il 17 9 0 029

Table 11

Well. ab alpha alpha- r / R Form of fin d.eta oo <mm) (mm) <) shape of epilope () (%) 1 10 5 66 -1,4 0,23 C-uloe 6,46 2 * 10 5 66 - 1.4 0.23 <C) 7.66 3 10 5 66 -1.4 0.23 C to 6.94 * ... from the data of Experiment 1.

From the above information, it is clear that the shape of the fins is not limited to a plane and may have a positive or negative plowing angle.

As described in detail above, it is possible to improve the propeller characteristics and in particular the propeller power without increasing the torque by directing the water flow behind the hub of the propeller in a direction which reduces the generation of a hub vortex. This is achieved by arranging fins in the hub to be mounted on the propeller in accordance with the present invention.

According to the invention, other advantages are also achieved, for example the propeller characteristics can be considerably improved by slightly modifying the relatively small hub cap without having to change the propeller itself on which the hub cap is mounted, which would require cumbersome work and high costs. It can be seen that the present invention can be applied to propellers already installed on ships by simply replacing or machining the hub cap without high cost.

Claims (1)

ie 90029 Hub hub (5) to be mounted on the hub (2) at the rear of the propeller (1), the propeller (1) comprising a plurality of propeller blades (3; 61) each having a base (62) along the base boundary of the hub (2) extending to the blade from the leading edge to its trailing edge, the bases (62) being located along a line at an angle of inclination to a plane perpendicular to the axis of rotation of the propeller (1), characterized in that the hood (5) has a dome body and a plurality of fins (6; 64), mounted on said dome body spaced around the circumference of said dome body; the number of fins (6; 64) is equal to the number of propeller blades (3; 63); the fins (6; 64) are inclined at an angle of -20 * to + 30® relative to the line along which the base (62) of the corresponding propeller blade (3; 61) is located, and the angle is selected so that the fins (6; 64) receive the flow from the propeller blade (3; 61) on the side facing the propeller blades, and the fins (6; 64. are inclined at an angle of inclination KK of -30® £ KK <0® with respect to the direction of rotation of the propeller (1), and the fins (6; 64) the leading edges towards the propeller (1) are between lines starting from the leading and trailing edges of the bases (62) of all the blades (3; 61) of the propeller and extending towards the stern parallel to the axis of rotation of the propeller (1), and the fins (6; 64 ) are substantially smaller in area than the propeller blades (3; 61), the outer diameter of the fins (6; 64) from the axis of the dome (5) is larger than the diameter of the dome body at the rear of the propeller hub (2) and up to 33% of the propeller blades (3; 61) the rotation of the propeller (1) as measured by the outside diameter Il 19 90029 Navkapsel (5) for mounting on the base of the screw propeller (1), the propeller (1) of the propeller and the fly propeller (3; 61), with a light shield on the rotor (62) on the shank of the rotor (2) on the shank of the shoulder to the sheave, rotating the propellant rotation saxel, the cover is attached to the capsule (5) with a capsule and a ferrule (6; 64) mounted on the perpendicular pd interval with the perimeter of the periphery of the perimeter (6; 64) ) for the same time as the propellers (3; 63), but this time (6; 64) is at a temperature of -20 ° to + 30 ° to the ground line with the rotor (62) of the propellers (3). 61) ligger, och vinkein har valts pd sd sdtt att fenorna (6; 64) mottar ström-men frdn propellerbladet (3; 61) pd en sida som syns mot propellerns blad, och Bladen (6; 64) lutar i en sldppnings -inking KK, where dr -30 ° s KK <0 ° i is used for the screw-pellets (1) rotation restriction, and with the frame of the phenol (6; 64) a propeller according to the propeller (1) is provided with a line of propellant (62) of the propeller (3); 61) and the strikers are connected in parallel with the propellers (1) by a rotary saxel, and the drill (6; 64) is provided with all the propellers (3; 61), the dimensions of which are diameters of the phenol (6; 64) capsule (5) The shaft is arranged with a diameter of the capsule body of the propeller (2) with a dimension of 33% of the diameter of the propeller plate (3; 61) measured from the screw propellers (1) rotation saxel.