GB2321950A

GB2321950A - Sub-calibre projectile

Info

Publication number: GB2321950A
Application number: GB9802550A
Authority: GB
Inventors: Fritz K Feldmann
Original assignee: NWM de Kruithoorn BV
Current assignee: NWM de Kruithoorn BV
Priority date: 1997-02-07
Filing date: 1998-02-05
Publication date: 1998-08-12
Anticipated expiration: 2018-02-05
Also published as: KR19980068388A; DE19704489C2; FR2759453B1; DE19704489A1; GB9802550D0; FR2759453A1; KR100211612B1; GB2321950B

Abstract

A sub-calibre projectile has a projectile core (1) of tungsten and a plastic projectile tip (2) and is surrounded by a feed hood (3) with internal preset rupturing points (7) and which is connected by an interlock (9) with a propulsion base (5) of light metal. The hood has a guide band (4) to generate spin on passage through a barrel and a groove (8) for connection to a propellant charge casing (15). A separate elastic sealing disc (11) is provided underneath the propulsion base (5) to ensure a reliable sealing effect during the passage of the projectile through the barrel. A rear zone of the feed hood (3) is plastically deformable under the effect of heat to form, in conjunction with peripheral grooves (9) of the propulsion base (5), and after the cooling process, a firm non-deformable connection, secured against rotation. A metal band (14) provided on the outside of the feed hood provides a reliable means for detection of projectiles.

Description

1 TITLE:

2321950 Sub-Calibre P ctie This invention relates to a sub-calibre projectile having a feed hood surrounding a penetrator which is mounted on a propulsion base, the assembly being connected with a cartridge case containing a propulsive charge.

US Patent 3,446,147 discloses a sub-calibre spin-stabilised projectile with a penetrator core comprising tungsten carbide, to the front of which is secured an aluminium tip or outer cone. The core and the tip of the projectile are embraced by a one piece feeder hood which is connected at the rear through an interlock with a propulsion base by means of a screw threading. At the interlock between the base and the feeder hood, a shoulder of the projectile core is secured in an axial direction by a radial projection of the said feeder hood. A rear zone of slightly increased diameter associated with the outer casing of the hood is formed as a barrel engaging guide band. During passage through the barrel of the weapon transmission of spin from the guide band of the feeder hood to the propulsion base is effected through the screw threading between the propulsion base and the hood. In this process the said screw threading undergoes a deformation as a result of the spin and an undesirable blow-by of the propulsion gases between the propulsion base and the hood may occur possibly leading to premature destruction of the hood during passage through the barrel.

A further disadvantage resides in the fact that the propulsion base surface is provided with a peripheral annular groove in which the propellant charge cartridge case is secured so that when the ammunition is fed into the loading chamber of the weapon the aforementioned screwthreaded zone of the feed hood is subject to high stresses which may shear-off the threading.

The rear shoulder on the core also has an increased diameter resulting in higher air resistance, thus causing considerable loss of velocity during flight and reducing the target penetrating power.

An additional disadvantage is that a projectile tip of aluminium loses some of its penetrating power when used against multi-plate targets because the aluminium tip, after making impact on the target, remains attached to the penetrator core for too long, resulting in disadvantageous oscillations on passage through the target.

When the aforesaid projectile is used in a gatling gun, moreover, there is no indication availabig to the operator of how, when the barrel has become heated up at the end of a sustained burst of fire, cartridges remaining in the cartridge case can be detected in preparation for their removal.

An object of this invention is to seek to provide a projectile with a propulsion base which will be simple to manufacture and in which disadvantages related to tightness, feed and firing resistance, speed loss and reduction of penetration capacity on multi-plate targets may be reduced or avoided and wherein presence of projectiles can be detected when the barrel has become heated.

According to this invention there is provided a sub-calibre projectile 3 unit having a core of a high density material connected with a tip of reinforced plastics material, the core being supported on a propulsion base and surrounded by a feed hood with an interlocking connection to the propulsion base formed by heat deformation of the hood around 0,5 formations on the base, the hood including a barrel engaging peripheral guide band and weakened zones forming pre-set rupturing points, a sealing member located beneath the base with a rearwardly directed propulsive gas sealing lip, a groove around the periphery of the hood at the rear forming a connection means with the lip of a cartridge case containing propellant charge.

According to this invention there is also provided a sub-calibre projectile unit with a projectile core of a high-density material, connected with a projectile tip and enclosed by a hood provided with an internal preset rupturing point to aid separation, the said hood being connected by 1.5 an interlock with a propulsion. base of light metal, the feed hood incorporating at the rear a barrel guide band to generate spin, the base of the unit having a groove for connection with a propellant charge casing, wherein:

(a) the propulsion base has peripheral grooves for connection with the hood, the said hood having a bore to receive the base and being deformable to produce the interlock under the effect of heat which after cooling firmly engages with the grooves to form the interlock; (b) a resilient sealing disc of plastic being located beneath the propulsion base and having a sealing lip directed 4 rearwardly; (c) the projectile tip comprising a plastic reinforced with fibre glass; (d) the outside of the feed hood having a continuous peripheral metal band forming a detection means, and (e) a groove on the rear part of the feed hood forming the means of securing the propellant charge casing.

The interlock connection between the propulsion base surface and the feeder hood can be produced very simply and provides a reliable nondetachable connection by which the required spin is transmitted to the core of the projectile body without difficulty. A packing disc forming a sealing member independent of the propulsion base ensures a gas seal so that particularly during the passage through the barrel, propulsive gases will not adversely affect the feed hood.

The choice of plastic einforced fibre glass as the material for the tip of the projectile not only ensures satisfactory stability and thus a high degree of accuracy in the trajectory of the projectile but also unimpeded passage of the penetrator core through a multi-plate target due to the instantaneous disintegration of the tip when impact is made on such a target, for example in the case of an attack on missiles.

The provision of a continuous peripheral metal band enables the ammunition to be accurately detected if it is required to count same or if it has to be removed from a gatling gun barrel which has become overheated during firing.

The provision of the groove on the feed hood prevents the aforementioned disadvantageous transmission of shock to the connection between the propulsion case surface and the said feed hood during the fee movement. The feed stress is thus satisfactorily transmitted directly to this latter.

Further preferred and advantageous features and embodiments of this invention will be described with reference to examples illustrated in the accompanying drawings and wherein:

Figure 1 shows a longitudinal section, along the line 1-1 of Figure 2 and through a sub-calibre projectile with a propulsion base and a propulsion charge casing connected thereto, Figure 2 shows a cross section along 1111 of Figure 1, through the propulsion base and feed hood, Figure 3 shows the projectile with propulsion casing in an enlarged longitudinal half section on the left, and in side view on the right, of the projectile shown in Figure 1, with tip, propulsion base, feed hood and sealing packing, Figure 4 shows the feed hood in longitudinal section along the line 1-1 of Figure 2, Figure 5 shows the propulsion base, half shown in a longitudinal cross section and half a side view, and Figure 6 shows a side view of an alternative projectile core with a projectile tip inserted therein. Figure 1, a sub-calibre projectile 1 is designed for spin As shown in 6 stabilisation and has a central longitudinal axis a with a projectile tip 2 in the front zone. The projectile comprises a core 1 of a high density material of about 18-19 g1CM3. The projectile tip is conical on the outside and merges into a frustum-shaped outer zone 23 of the projectile core 1.

The projectile tip consists of plastic, preferably polyamide 6 or 6.6, reinforced with fibre glass, the fibre glass part of the projectile tip 2 constituting between 37 and 43% of the latter.

A propulsion base 5 has a surface which supports the rear end surface of the projectile core 1 and which comprises a low-density high strength metal preferably of a high-strength aluminium alloy with a minimum tensile strength of 500 N/m M2. The propulsion base 5 contains, in the front lateral zone, grooves 9 (Figure 5) which are parallel and around the periphery and which provide an interlock connection with a feed hood 3 surrounding the projectile core 1 and the projectile tip 2.

At the rear the feed hood 3 bears against a radial projection 25 (Figure 5) of the propulsion base 5. The rear of the feed hood 3 is provided with a crimp groove 8 serving to secure a propellant charge casing 15 in a known manner and of which the interior contains a propellant charge 29. The rear zone of the casing 15 comprises a base 26 containing an ejector rim 27 and a firing cap 28.

The feed hood 3 is closed in the front zone 30. The front outer zone is frustum-shaped and the middle zone 32 continues in the form of a cylinder of somewhat greater diameter at the rear. This zone 33 of increased diameter forms a land serving as a guide band 4 and as a spin generating means on the passage of the projectile through the barrel. In 7 the middle zone 32 of the feed hood 3 a metal band 14 for the detection of projectiles is mounted on the outside 13. This metal band can be applied or sprayed on in a simple manner by a screen or other printing process of a known kind. It has been found that an excellent projectile detection means is provided by a metal band 14 (Figure 3) in the form of a silver band, the silver content being between 60 and 80%. The plastic feed hood is provided with four internal preset breaking points 7 (Figure 2) in the form of grooves produced at equal distances apart on the internal surface of the feed hood 3 and extending over the entire length or preferably at least over the end of the cylindrical zone 33 and the zone 34 by which the hood is secured to the propulsion base 5.

The provision of 4 preset rupturing points 7 (Figure 2) ensures a homogeneous structure for the production of the feed hood 3, which is not practicable in the case of three preset breaking points, for instance, for reasons connected with the production process. The internal positioning of the preset rupturing points 7 also determines the external location selected for the metal band 14, because the said metal band 14 must not be interrupted on the periphery if it is to function a trouble-free manner.

The rear zone 34 shown in Figure 4 and formed by the cavity 10 extending to the front zone 30 and the outer periphery of the projectile core 1 and extending to the projectile tip 2 is conically constructed before the production of the connection with the propulsion base 5. After the introduction of the projectile core 1 and the projectile tip 2 into the feed hood 3 the connection with the propulsion base is produced by plastically deforming the zone 34 by the application of heat and by introducing the 8 propulsion base 5, provided with the parallel grooves 9, into the boring 34, in which process the feed hood 3 is capable, in the heated state, of filling the free spaces in the grooves 9 to form a firm intimate connection with the propulsion base 5 after cooling. 05 To increase its resistance to rotation in relation to the feed hood 3 the propulsion base surface 5 can be provided with a knurling 35 in the zone of the grooves 9. The rear end face 36 of the propulsion base 5 forms a linear locating surface for an elastic packing 6 which takes the form of disc 11 10 with a sealing lip 12 directed towards the rear. This packing 6 may preferably consist of polycarbonate and due to the elastic deformability provides a reliable sealing against the barrel of a weapon (not shown), even at extremely high pressures, and also prevents any inflow of propu!sive gases into the interconnection zone between the propulsion base 5 and the feed hood 3.. The sealing disc 11 can be connected in a simple manner with the propulsion base 5 by means of a snap connection 16, this snap connection being formed by a conical spigot 17 on the propulsion base 5 and a complementary recess 18 on the sealing disc 11. The projectile tip 2 shown in Figure 1 can be connected in different 20 ways with the projectile core 1, as shown in Figures 3 and 6. Figure 3 shows the projectile core 1 with a front projection 21 pressed into a rear boring 22 of the projectile tip 2, the projectile tip 2 bearing through a rear internal surface against a conical surface 37 of the core 1.

Figure 6 illustrates a connection in which the projectile tip is 9 provided, at the rear, with a projection 19 pressed into a front boring 20 of the projectile core 1. In this example the projectile tip 2 bears against a flat surface 38 of the projectile core 1.

The configurations described above for the sub-calibre propulsion 0.5 base type of projectile according to this invention ensure a reliable transmission of spin from the feed hood 3 via the propulsion base 5 of the projectile core 1, the transmission from the propulsion base to the projectile core being effected by an interlock connection not shown in the drawing.

Premature destruction of the feed hood on the passage through the barrel is prevented by the sealing effect exerted by the sealing disc 11. The advantageous properties already mentioned as regards the feed hood 3, the propulsion base 5 and the projectile tip 2 make it possible, if the projectile core is made for example of a brittle tungsten alloy, for rapid 1.5 and manoeuvrable and at least partly armoured targets, such as attack helicopters and land vehicles to be engaged. In addition, the use of highstrength material for the projectile core, such as high-strength tungsten of high extensibility, enables multi-layer targets, such as missiles to be successfully combated.

Claims

1. A sub-calibre projectile unit having a core of a high density material connected with a tip of reinforced plastics material, the core being supported on a propulsion base and surrounded by a feed hood with an interlocking connection to the propulsion base formed by heat deformation of the hood around formations on the base, the hood including a barrel engaging peripheral guide band and weakened zones forming pre-set rupturing points, a sealing member located beneath the base with a rearwardly directed propulsive gas sealing lip, a groove around the periphery of the hood at the rear forming a connection means with the lip of a cartridge case containing propellant charge.

2. Sub-calibre projectile unit with a projectile core of a high-density 1-5 material, connected with a prpjectile tip and enclosed by a hood provided with an internal preset rupturing point to aid separation, the said hood being connected by an interlock with a propulsion base of light metal, the feed hood incorporating at the rear a barrel guide band to generate spin, the base of the unit having a groove for connection with a propellant charge casing, wherein:

(a) the propulsion base has peripheral grooves for connection with the hood, the said hood having a bore to receive the base and being deformable to produce the interlock under the effect of heat which after cooling firmly engages with the grooves to form the interlock; (b) a resilient seating disc of plastic being located beneath the propulsion base and having a sealing lip directed rearwardly., (c) the projectile tip comprising a plastic reinforced with fibre glass; (d) the outside of the feed hood having a continuous peripheral metal band forming a detection means, and (e) a groove on the rear part of the feed hood forming the means of securing the propellant charge casing.

3. Projectile in accordance with Claim 2 wherein the propulsion base and the boring in the feed hood are of conical shape in the zone of the cartridge case connecting groove.

1.5

4. Projectile in accordance with Claim 1, 2 or 3, wherein the propulsion base is made of a high-strength aluminium alloy.

5. Projectile in accordance with Claim 4, wherein the propulsion base has a minimum tensile strength of 500 N/m M2.

6. Projectile in accordance with any preceding claim, wherein the sealing member or disc is connected to the propulsion base by a snap connection.

12

7. Projectile in accordance with Claim 6, wherein the propulsion base has an external conical zone and the sealing member has an internal conical recess to enable a snap connection to be formed.

8. Projectile in accordance with any preceding claim, wherein the projectile tip is made of polyamide 6 or 6,6, reinforced with fibre glass.

9. Projectile in accordance with Claim 8 wherein the glass fibre part of the projectile tip amounts to between 37 and 34%.

10. Projectile in accordance with any one of Claims 1 to 9, wherein the projectile tip is provided at the rear with a projection press fitted into a front boring of the projectile core.

11. Projectile in accordanqe with any one of Claims 1 to 9, wherein the projectile core is provided a the front with a projection press fitted into a rear boring of the projectile tip.

12. Projectile in accordance with any preceding claim, wherein a metal 20 band, preferably a silver band, with a silver content of between 60 and 80% is provided around the outside of the feed hood.

13. Projectile in accordance with Claim 12, wherein the silver band is applied by a screen printing process or sprayed on.

14. Projectile in accordance with any preceding claim wherein the feed hood has four symmetrically positioned internal preset rupturing points extending over the entire length of the said feed hood.

15. A sub-calibre projectile unit substantially as described herein and exemplified with reference to the drawings.