ZA200603033B - Piercing projectile - Google Patents

Description

x 3 d ® PIERCING PROJECTILE

The present invention relates to a method according to the precharacterising part of «claim 1, and to a device according to claim 3.

A so-called piercing detonating dart is known from WO -Al- 01/98728. It is self-propelled and, at speeds in the subsonic range, penetrates buildings, after which it is detonated with some delay, for example in the interior of a building or behind barricades. Also described is a non- lethal variant of a penetration core, in which the quantity of explosives stored in the core is only used to dismantle the core so that additional stored substances such as for example capsaicin, teargas etc. can issue. The fact that little damage results to buildings when the projectile enters is advantageous.

Depending on the particular tactical use, the above device is associated with disadvantages in that the apertures made in the building are often too small for further intervention, and the projectile can only be fired from a narrow selection of platforms (launching devices).

PCT/IB03/01139 describes a special improvement of a projectile with a ballistic hood. The projectile is intended for velocities of less than 600 m/s. The fuse, which is arranged in the sub-calibre penetration core, is set to delay-times of 1.2 ms to 3.4 ms so that detonation of the explosive charge takes place in the masonry, resulting in large openings. In order to achieve corresponding plugging or tamping and mass distribution, a massive tip that extends to about a third of the length is

< ® - 2 - provided. The effect of this projectile in concrete and masonry is very good: manholes are created which make it possible to engage in other tactical operations at the target.

The weapon is associated with a disadvantage in that it is limited to large-calibre platforms, without the ability of utilising the given cross section or the existing volume for transporting the explosives. Employing the projectile against lightly-armed targets, in particular ductile targets, has only shown little effect; the penetration behaviour of the core is poor, the effect of the explosive charge can be brought to bear only to a small degree at the target itself.

It is thus the object of the present invention to create a method and a universally deployable projectile which, having been accelerated with any desired means per se, at the target produces a penetration hole that is larger than the calibre of the projectile. It must be easy to adapt the projectile to the intended target and to the expected impact speed. In the target itself, optimal effect is to be created, i.e. the penetration holes have to be of a diameter that meets the requirements of the tactical operations, wherein nevertheless no avoidable collateral damage must result. The projectile is to be of modular construction, and prior to being fired must be able to be optimised without any special knowledge.

It must be possible to optionally design the projectile with a ballistic hood, but the projectile must not be limited to a sub-calibre effective part.

« ® 3 -

This object is met by the method-related characteristics of claim 1 and by the projectile according to claim 3.

The method according to the invention uses as a starting point the surprising findings that the shape of the tip of a penetration core that comprises an explosive charge is decisive in determining the effect on the target.

The method is based on the selection between two types of tips which are suitable for fundamentally different targets. As a rule it can be stated that hard targets are to be penetrated using a conical tip, preferably a tip comprising a stepped cone, while ductile targets are to be penetrated by a flattened tip.

For example in walls made of bricks or reinforced concrete © the selection, according to the invention, of the tip results in penetration holes the size of manholes. However, the same tip is unable to penetrate light armour made of steel or light metal. In contrast to this, with the use of a suitable tip a penetration hole that is larger than the calibre results in the same armour.

In an improvement the optimal tip is inserted in the jacket of the penetration core and is affixed therein before the projectile is deployed.

Designing the projectile with a receptacle according to claim 3 for an exchangeable tip is particularly advantageous, because it makes it possible to optimally use a projectile that is the same per se for a host of different targets. The suitable receptacle also makes it possible to exchange the tip, for example if during

Ce Tt tactical deployment new or different targets are to be attacked, i.e. penetrated.

The dependent claims show preferred improvements of the object according to claim 3.

Inserting and changing a tip is particularly easy if there is a receptacle designed according to claim 4.

With a suitable selection of the fit with the receptacle, a rear journal according to claim 5 makes it possible to produce axially-symmetrical projectiles that provide high accuracy.

From the point of view of production technology and kinetics, a stepped journal according to claim 6 is particularly favourable.

Simple axial securing of the journal by - one or several - split pins, pins or bolts has been shown to be advantageous, compare claim 7.

Incorporating air gaps between the individual steps of the journal, claim 8, helps distribute deformation energy without there being any premature massive outward buckling of the jacket of the penetration core.

Incorporating the fuse device according to claim 11 reduces the effect of shock waves during firing and in the target so that the system safety of the detonation process is enhanced.

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Also favourable is the incorporation of an insulation disc according to claim 12, which minimises the danger of self- ignition of the explosive material when the projectile impacts its target.

Surprisingly it has been shown that a pointed tip with a radius of a few tenths of millimetres in hard targets causes a through “crack path” so that the penetration core can easily penetrate, see claim 13.

The embodiment according to claim 14 with a surface that extends orthogonally in relation to the axis and a cone that tapers off towards the rear is well suited to “soft targets” such as light armour plating etc.

If a tip is designed in the manner of a stud bolt, it can be fully screwed into the jacket of the penetration core.

Offsetting said tip slightly in relation to the face of the jacket results in the effect of a hole punch in the target, and thus in an improved penetration effect in soft targets.

See claim 15.

In hard targets such as concrete or brick walls the angle range as stated in claim 16 is favourable for a tip, wherein the cone surface need not be smooth but instead it can be made from individual area segments that taper off towards the tip. In this way, comminuted material in the target can exit radially, without the following jacket being impeded by it.

A tip according to claim 17 is particularly advantageous and optimal in a wide range of applications.

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In practical application the materials-related details according to claim 18 have proven reliable.

According to claim 19 the fuse device can also be attached on both sides; however, placing elastomer film in between is recommended so that thermal expansion can be compensated for, and the transmission of vibration can be reduced.

The fuse chain, which according to claim 20 is arranged in the axis of the projectile, also supports high firing velocities as is experienced for example in mortars or cannon.

A weapons engineer can adapt the projectile to almost all imaginable systems. The only limit prescribed by system technology relates to the minimum calibre. In practical applications there is insufficient space to accommodate a sufficient quantity of explosives with adequate insulation in a calibre of less than 25 mm.

Below, by means of drawings, implemented embodiments of the invention are explained in more detail. In all figures identical reference characters have been used for identical functional parts.

The following are shown:

Fig. 1 a projectile of the type of a bazooka, for producing penetration holes, with a penetration core, a ballistic hood, drive and tail unit;

Fig. 2 an enlarged section view of the penetration core according to Fig. 1;

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Fig. 3 a tip with a double cone and a rear thread;

Fig. 4 a flattened tip based on a truncated cone that tapers off slightly towards the rear and that comprises a thread at the rear;

Fig. 5a a variant of a flattened tip with an outside thread, in longitudinal view;

Fig. 5b a frontal view of the tip shown in Fig. 5a, with its installation groove;

Fig. 6 a variant of a tip with a double cone and a rear stepped journal with an axial securing mechanism;

Fig. 7 an enlarged view of a variant of the fuse chain shown in Fig. 2;

Fig. 8a a penetration core with screwed-on sabots, designed to be fired from a cannon; and

Fig. 8b a front view of the penetration core Fig. 8a with its separate sabots.

In Figure 1 reference character 1 designates a projectile which in its basic configuration is known as a bazooka. By means of a threaded bush 11, a penetration core 2 with a tip 4, 4’, 4” is connected to an adapter 20 that carries a support 21 with joints 22 at its end as a tail unit 23. situated on the penetration core 2 is a support- and centring ring 28 which carries a ballistic hood 17, 19. The front part of the hood 17 is closed off by a closing cap

. ® - 8 - 18. Reference character H indicates a hollow space located in the penetration core 2.

The projectile 1 has the same external ballistic characteristics as a normal bazooka and can therefore be fired in the same way from the same platform. The characteristics of this arrangement are an external calibre of 70 mm and an external calibre of the core 2 of 37 mm.

The enlarged representation of the penetration core 2 in

Figure 2 in particular shows a section view of the details in the hollow space H. In a jacket M in various stepped hollow spaces the essential functional parts of the projectile are housed. The jacket M has a minimum thickness of 3 mm, wherein commercially available tool steel that has been hardened after processing is used as a material.

The tip 4 with its two cones 4’ and 4” and the flange-like shoulder 6 has been screwed into the thread 3’ of a receptacle 3 so that it has non-positive fit. The tip 4 ends in a point p. Behind this tip there is a two-part insulation disc 26 that has also been screwed into the thread 3’, adjacent to which insulation disc 26 there is a snugly fitting explosive charge 15 (high-performance explosives PBX N110).

On the rear, a threaded bush 11 has been inserted in the penetration core 2, which threaded bush 11 closes off an air space A in which a fuse device 12 extends in a self- contained manner. at the front end of the fuse device 12 there is a flange 27 with blind holes in which there is a fuse chain 13a, 13b,

- ® _ 9g - wherein the fuse amplifier 13b is in effective connection with the explosive charge 15 by way of a further chain link 14. The position of the detonator ZK is also indicated.

The fuse device 12 is of a commercially available type (Zzaugg Elektronik AG, Wassergasse 12, CH 4573 Lohn-

Ammannsegg, piezo fuse system type PEPZ-05). The delay time of the autonomous fuse device is set such that with a specified flight speed of the projectile 1, said projectile 1 is detonated in a time-delayed manner after impact in the target, such that maximum plugging or tamping of the penetration core 2 in the region of its explosive charge 15 takes place.

Figure 3 shows an enlarged view of the tip 4 shown in Figs 1 and 2. Apart from the fine thread 5 the two cone angles al and a2 are shown.

Tl designates a target that comprises reinforced concrete, towards which target the tip 4 with its optimally set angles al and o2 flies. In the present case al = 33° and a2 = 17°. The direction of flight of the tip 4 is indicated by an arrow.

Experiments have shown that the above configuration impeccably penetrates a wall made of bricks, even at an angle of impact of 40°, and at a fuse delay of 1.5 ms at an impact speed of approximately 180 m/s at the target generates a manhole.

The double cone shown breaks up (splits) the wall with the point p of its tip, Fig. 1, comminutes the masonry with its

- ® - 10 - front cone, after which the cleared-out material flows with little resistance over the rear cone. This significantly reduces the friction at the jacket M of the penetration core 2 and explains the excellent penetration characteristics.

Analogous to the above, the target T2, which is light armour comprising a metal plate, a layer of wood and a plastic plate is hit by the tip 4, Fig. 4. The diagram shows a truncated cone 4a, tapering off towards the rear, which is delimited by an orthogonal surface 4%’ - a flattened tip. The angle a3 is 3°.

According to Figs 5a and 5b the same target T2 is hit by a tip 4 that acts in the same way - a set screw with a chamber 9 on its face, and an installation groove 8.

If the tip 4 according to Figs 5a and 5b is screwed into the penetration core 2 until its face 6’, compare Fig. 6, projects, this results in improved penetration performance for ductile targets of the type TZ2.

In the case of thin armour, for example light-metal plates of a thickness of a few centimetres, it is recommended that a shorter fuse delay be set so that the plate has a plugging or tamping effect on the explosives stored in the penetration core so that the penetration performance of the projectile is considerably improved. Likewise, predetermined breaking points in the jacket M can locally optimise the fragmentation effect. Furthermore, it is recommended that friction on the jacket M be reduced, in that said jacket M is designed to taper off towards the rear (by approximately 2 mm).

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Fig. 6 shows a further embodiment of a tip 4. The part of the tip 4 that protrudes from the penetration core 2 is identical to that in Fig. 3; however, instead of a threaded journal it comprises a stepped journal 3a’. The receptacle 3 matches the stepped journal; in axial direction, between the steps of tip 4 and the receptacle 3, there are air gaps a which during impact serve as displacement paths, preventing outward buckling of the penetration core 2 in this region.

Furthermore, a radial pin 10 is shown which axially secures the tip in the penetration core 2.

The embodiment according to Fig. 6 can be varied in several variants; for example the cylindrical borehole 3a can be longer, and further steps can be done without. This results in a single journal 7 that is extended in relation to that shown in Fig. 6. Likewise, several pins or split pins that are arranged so as to be offset in relation to each other can replace the bolt 10.

The fuse chain shown in Figure 7 shows the detonator ZK, explosives 13 pressed into a carrier flange 29, as well as adjacent explosives 14 and 15. This fuse chain can cope with very high firing acceleration without its function being impeded. This diagram also clearly shows the stepped hollow spaces H, H’, H”. The radius at point p (Fig. 2 or

Fig. 8) is 0.4 mm. The optimal range is 0.3 to 0.8 mm for targets made of concrete or masonry.

Figure 8a shows a penetration core 2 that is suitable for being fired from a cannon. A three-part sabot 24 is screwed onto threaded grooves 25 (round thread) in the jacket of said penetration core 2. See Fig. 8b with the elements 24’ and point p of the tip 4.

The use of a sub-calibre projectile by means of a sabot 24 is known per se; after leaving the gun tube the sabot elements 24’ separate while the penetration core 2 flies with high energy to the target.

Numerous trials have resulted in the following findings:

In concrete, brickwork and armour made of glass a manhole can be made by means of a conical tip.

For example, holes of a diameter of up to a metre were produced in a prick wall 50 cm in thickness. This occurred at a speed of impact at the target of 230 m/s and impact angles of up to 30°.

In light-metal and steel armour, flattened tips result in penetration holes that are larger than the calibre of the projectile, wherein in addition the surrounding structural work is weakened.

For example, using the above-described projectile it has been possible to penetrate light metal armour of 7.5 cm thickness up to an impact angle of 30°. The explosives that were detonated in this process not only enlarged the penetration hole, but also caused a large pressure wave pehind the armour, which pressure wave would disable persons that are present behind said armour.

BY - 13 -

Massive loss of strength occurs in barricades made of timber, sand, earth etc., which barricades can subsequently be penetrated by conventional weapons.

The subject of the invention could also be adapted to very large calibres, for example to rocket systems. The penetration core can have any desired size, provided it has sufficient kinetic energy (drive); a ballistic hood is only necessary if the system is to comprise ballistics that are identical or similar to the ballistics of systems already in service. Likewise, combinations with other projectiles or parts thereof are imaginable which in steps follow the penetration achieved with the first penetration hole.

) ® - 14 -

List of reference characters: 1 Armour-piercing projectile 2 Penetration core 3 Receptacle : 37 Internal thread 3a Cylindrical borehole 3a’ Stepped journal 4 Tip 4’, 4” Tip with stepped cone qr Orthogonal surface / flattened tip 4a Conical tip (a3) / truncated cone

External thread (fine thread) 6 Flange-like shoulder 6’ Annular face 7 Journal 8 Installation groove 9 Chamfer

Split pin, bolt 11 Threaded bush for adapter 12 Fuse device 13a, 13b, 14 Fuse chain / explosives

Explosive charge 16 Centring sleeve 17 Ballistic hood (front) 18 Closing cap (end closure of 17) 19 Ballistic hood (rear)

Adapter of tail unit 21 Support for tail unit 22 Joints for tail unit 23 Tail unit

N ® - 15 - 24 Sabot 24’ Segments of 24

Round thread (thread grooves conically tapering) 26 Insulation disc (in two parts) 27 Flange 28 Support~ and centring ring for hood 17, 19 29 Carrier flange for 13 a Air gap

A Air space / gap

H-H" Hollow spaces in 2

M Jacket of 2 p Point (tip)

T1 Hard target

T2 Ductile target

ZK Detonator al-a3 Cone angle

Claims (20)

® CLAIMS

1. A method for producing penetration holes in targets such as masonry work; light armour plating made of steel, light-metal, ceramics, glass; barricades made of sand and/or wood and/or earth and the like; wherein the projectile comprises a penetration core with at jeast one axial hollow space in which an explosive charge and a fuse device with a time delay are provided, and wherein the time delay is set such that it initiates the explosive charge in the interior of the target, characterised in that the penetration core is matched to the intended target, wherein a conical tip is selected for walls made of bricks or concrete, for armour made of glass and/or ceramics, and for barricades; and a flattened tip is used for light armour made of ductile materials such as steel or light metal.

2. The method according to claim 1, characterised in that prior to the projectile being used, the tip is inserted in the jacket of the penetration core and is fixed.

3. A projectile for producing penetration holes in targets such as masonry work; light armour plating made of steel, light-metal, ceramics, glass; barricades made of sand and/or wood and/or earth and the like: wherein the projectile comprises a penetration core with at least one axial hollow space in which an explosive charge and a fuse device with a time delay are provided, and wherein the time delay is set such that it initiates the explosive charge in the

) ® - 17 - interior of the target, characterised in that the penetration core (2) comprises a receptacle (3) for an exchangeable tip (4), that the tip (4) of the penetration core (2) that is being used is matched to the intended target (T), wherein a conical tip (4) is used for walls made of bricks or concrete, for armour made of glass and/or ceramics, and for barricades; and a flattened tip (4”’) is used for light armour made of ductile materials such as steel or light metal.

4. The projectile according to claim 3, characterised in that at the rear the tip (4) comprises a screw thread (5) which is screwed into a receptacle (3) with an internal thread (3’) in the front hollow space (H) of the core jacket (M), and in that on the rear the tip (4) comprises a flange-like shoulder (6) which rests against pressure on the annular face (6’) of the hollow space (H).

5. The projectile according to claim 3, characterised in that at the rear the tip (4) comprises a journal (7) which is inserted in a receptacle (3) with a cylindrical borehole (3a) so as to fit, and in that on the rear the tip (4) comprises a flange-like shoulder (6) which rests on the annular face (6’) of the hollow space (H).

6. The projectile according to claim 3, characterised in that at the rear the tip (4) comprises a stepped journal (3a’) which is inserted in a receptacle (3) with cylindrical boreholes (3a) so as to fit radially, and in that on the rear the tip (4) comprises a

Ce or flange-like shoulder (6) which rests on the annular face (6’) of the hollow space (H).

7. The projectile according to one of claims 5 or 6, characterised in that on the rear the journal (3a) is axially secured by at least one pin or split pin (10).

8. The projectile according to claim 6, characterised in that the spacing in the steps (3a’) in the receptacle (3) is selected such that there is an air gap (a) between these individual steps (3a’) and the steps in the receptacle (3).

9. The projectile according to claim 3, characterised in that the axial hollow space (H) comprises regions (H’, H”) of different diameter.

10. The projectile according to claim 9, characterised in that the hollow space (H) is designed so as to be tubular and in that at the rear a threaded bush (11) is screwed in, which closes off an air space (A) in which the fuse device (12) is held at the rear so as to be axially movable.

11. The projectile according to claim 9, characterised in that the fuse device (12) is connected to a fuse chain (13a, 13b, 14) whose last link is in mechanical contact with the explosive charge (15).

12. The projectile according to claim 4, characterised in that in the front region an insulation disc (26) with an external thread is screwed into the internal thread (37) of the hollow space (H) and this frontal

® delimitation and support is for the explosive charge

13. A penetration projectile according to any one of claims 3 to 6, characterised in that the inserted tip (4”) ends in a point (p).

14. The projectile according to any one of claims 3 to 6, characterised in that the inserted tip (4) is cone- shaped (4a; a3) and ends in a surface (4”') that is orthogonal in relation to the axis of the projectile.

15. The projectile according to any one of claims 3 to 6, characterised in that the inserted tip (4) is a cylinder, and in that its front face (4”') is set back in relation to the front of the jacket (M) of the projectile (2).

16. The projectile according to one of claims 4 or 6, characterised in that the inserted tip (4) comprises a cone angle (al) of 20° to 36°.

17. The projectile according to one of claims 4 or 6, characterised in that the inserted tip (4) is a double cone whose tip angle (al) ranges from 20° to 36° and whose base angle (a2) ranges from 8° to 25°.

18. The projectile according to any one of claims 3 to 17, characterised in that the penetration core (2) has a calibre of at lest 25 mm, preferably of 37 mm; in that the jacket (M) comprises a hardened tool steel with a hardness of 500 to 650 HV 30; and in that the tip (4-

. i. 2 i om o RE 79 eo - 20 - £0 BEA 4”') comprises a hardened tool steel with a hardness of at least 400 HV 30.

19. The projectile according to claim 3, characterised in that the fuse device (12) is affixed in the hollow space (H) of the penetration core {2), on the rear, between two flanges (11; 27).

20. The projectile according to claim 19, characterised in that a central borehole is provided in the frontal flange (27), through which borehole a fuse amplifier (13a) of a fuse chain (13a, 13b, 14) protrudes.