GB2235274A

GB2235274A - Projectile

Info

Publication number: GB2235274A
Application number: GB8517904A
Authority: GB
Inventors: Wilfried Becker; Charlotte Schutkin; Bernhard Bisping
Original assignee: Rheinmetall GmbH
Current assignee: Rheinmetall Industrie AG
Priority date: 1981-11-10
Filing date: 1985-07-16
Publication date: 1991-02-27
Anticipated expiration: 2005-07-16
Also published as: GB2235274B; GB2235275A; GB2235275B

Abstract

A spin stabilized sub-calibre projectile of average density at least 17 g/cm<3> has a central column (12), 38 on to which a stack of discs 20 are mounted, or shrunk to produce pre-stressing, each disc having a weakened zone to assist disintegration on impact, and the column containing means to assist disintegration on impact. Exemplified means are a column (12) constructed as a penetrator with a rear disintegration-assisting conical surface (36); and a body 52 with a pin 56 directed on impact against bodies 68, 70, a stack of balls (60), or a primer (86) and disintegration composition (84), disposed in a hollow sleeve 38. A composition (84) may be activated in the absence of impact by a tracer (80). In one embodiment the projectile body is made in one piece from a tungsten alloy or depleted uranium and has zones (92) of weakened microstructure. The nose 14 may be pyrophoric. <IMAGE>

Description

TITLE Spin stabilized sub-calibre projectile.

This invention relates to a spin stabilized subcalibre projectile.

In prior patent application 81124Q1 there is disclosed a spin stabilized sub-calibre projectile which does not incorporate an explosive charge and which is intended to be embraced by a sabot. The projectile having a high proportion of a heavy me t a 1 and a small cross section so as to give it extended range with a flat trajectory. Such a projectile is especially useful for combating high speed moving targets such as low flying aircraft or helicopters. In this projectile, the disintegration on impact is effected througi retardation of the spinning motion as a result of which overloading occurs causing fracture along weakened zones of the projectile structure.It has been found that the initiation of the disintegration particularly with impact on thin walled targets, is influenced by the angle of impact and this may have an adverse effect upon efficiency.

This invention seeks to provide a projectile generally of the above mentioned kind but which is more effective on thin walled targets with the disintegration beingsubstantially independent of the angle of impact.

According to this invention there is provided a spin stablized sub-calibre projectile having an average density 3 of at least 17 g/cm , the projectile having a rear part surmounted by a central longitudinally extending axial element passing through the centre of the projectile and extending towards the nose thereof, the central part of the projectile through which the axial element passes being provided with weakened zones to assist disintegration on impact, the projectile being characterised by the central axial element incorporating a disintegration assisting means to enhance the disintegration effect following impact.

The invention is further described and explained in conjunction with the accompanying drawings showing preferred embodiments by way of example.

In the accompanying drawings Figure 1 shows a first embodiment in longitudinal cross section with a mounting support constructed as a penetrator and with a tail end having a conical disintegration assisting surface, Figure 2 shows a second embodiment in longitudinal cross section with a mounting support in the form of a sleeve containing disintegration assisting means, Figure 3 shows a third embodiment in longitudinal cross section with the mounting support in the form of a sleeve housing disintegration assisting means, Figure 4 shows a fourth embodiment with a disintegration assisting composition positioned within the mounting support which is in the form of a sleeve and with a single primer means at the forward end, and Figure 5 shows a fifth embodiment in longitudinal cross section having a central support again incorporating a disintegration assisting composition.

Referring to the drawings, a spin stablilized subcalibre projectile is of a kind which disintegrates on impact and not through the use of an explosive charge as the primary disintegration means. The projectile has a central axial mount 12 with a rear reinforcement element 18 having a rear end base surface 16 and a forward facing supporting surface 22. The holder 12 has positioned therearound a plurality of annular discs 20 in juxtaposed relationship and forming a stack. Each disc 20 has a central bore 34 which enables it to be located over the axial mount 12 and the discs include grooves or the like weakened zones which serve as fracture points to assist in the disintegration. The projectile includes a conical nose 14 made from a pyrophoric material 19.

Referring to Figure 1 of the drawings, the mounting holder 12 is of rod shape and is provided at the front end 23 with a nose 13 and constructed together with the rear reinforcement 18 as a penetrator. The rear reinforcement 18 is delimited at the forward end by a disintegration assisting surface 36 of conical shape. The annular discs 27 are shrunk onto the mounting holder 12 in order to produce a prestressing. The nose 14 is made in one piece of pyrophoric material 19 and in a blind hole 21 of the nose is received the front end 23 of the mounting holder 12.

In Figure 2 the mounting holder takes the form of a sleeve 38 onto which the annular discs 20 are mounted or shrunk stack-wise. The sleeve 38 is filled with balls 60 and is provided at the front with a mechanical disintegration assisting means 50 which has an impact body 52 and an impact pin 56 directed against the balls 60 in the sleeve 38. The impact body 52 has at the front an impact receiving surface 54 and the impact pin 56 has a rearward facing impact transmission surface 58, both surfaces are generally of rotationally symmetrical construction. The impact body 52 bears through a shouldered surface (not shown in detail) on an annular disc of plastically deformable material 76, which is in contact with the frontmost annular disc 20. A nose cone 29 surrounds the pyrophoric material 15'.

In Figure 3 the central axial mounting support takes the form of a sleeve 38 which is provided at the front with a mechanical disintegration assisting means 50 again with a plastically deformable annular disc 76. The sleeve 38 surrounds bodies 66 with a front cylindrical part 68 and a rear conical part 70. The latter part is partly embraced by an annular disc 72 having a funnel-shaped aperture 74.

The reinforcement 18 contains a boring 23. The annular discs 20 are shrunk onto the sleeve 38, this latter being provided with longitudinal axial preset breaking points in the nature of V-shape grooves. The tip 14 is again provided with a nose cone 29 containing a pyrophoric material 15'.

In the example shown in Figure 4, the annular discs 20 are again shrunk onto the sleeve 38, which contains a disintegration composition 84 and, at the front, a primer 86. At the rear the disintegration composition 84 is associated with a tracer composition 80 located in a recess 17 in the reinforcement 18. In the front the primer 86 faces the impact transmission surface 58 of the mechanical disintegration assisting means 50. The nose 14 again comprises a one piece pyrophoric material 19 and is connected with the impact receiving surface 54 in a manner not described in detail. The plastically deformable annular disc 76 supporting the disintegration assisting means 50 is provided on the peripheral zone 11 with a protective layer 77 not described in detail.

The example shown in Figure 5 is made mainly in one piece from depleted uranium but with zones 92 in which the microstructure of the material is weakened and which extend from the peripheral zone 11 to the zone 12'. A central axial boring 31 accommodates a disintegration composition 84 and a primer 86. The latter is connected with the tracer composition 80 which is situated in a container 94.

At the front the container 94 has projection 96 provided with a central boring 98 and bears agains an annular disc made of a plastically deformable material 76.

This projectile shown in Figure 5 is mainly made in one piece from heavy metal material of high density, e.g. a sinter alloy with a proportion of tungsten of at least 90% in a binding agent phase formed from iron and nickel or of depleted uranium. In the embodiments the circular discs 20, the central axial mounting support 12, (or in the form of a sleeve 38), reinforcement 18, balls 60, body 66, annular discs 72, mechanical disintegration assisting means 50 and container 94, are made of the relevant materials of high density. The pyrophoric material 19 preferably comprises depleted uranium having high density. The pyrophoric material 15 preferably comprises a fritted powder mixture of tungsten and depleted uranium, possibly in a binding agent phase, while for the material 15' tungsten may be supplemented by pyrophoric metals in a binding agent phase.The zones 92 of weakened microstructure, described in conjunction with example shown in Figure 5 can be produced by particle radiation, e.g.

from electrons.

In the examples the aim is to ensure that the kinetic energy inherent in the projectile is transferred as completely as possible to the target in question, which may be provided with bulkheads, i.e. to ensure complete disintegration after impact. The formation of a fragmentation cone with a preselectable spreading angle is in the first place provided by centrifugal forces, as a result of the spinning motion and this effect is assisted by mechanical measures, such as the disintegration surface 36 in the example shown in Figure 1 or the disintegration assisting means 50 in the examples shown in Figures 2 and 3. With the mounting support 12 shown in Figure 1, which forms together with the reinforcement 18 a penetrator, the splinters which form from the annular discs 20 are forced outwards by the surface 36 in a controlled manner.In this process at least the penetrator passes through the multi-layer wall of a target.

In the example shown in Figures 2 and 3 a wedgeforming radial thrust component is transmitted by the disintegration assisting means 50 and the balls 60 or the body 66 and the annular discs 72 to the annular discs 20, thus disintegrating the latter.

In the example shown in Figures 4 and 5 the sleeve 38 surrounds a disintegration composition 84, which after impact is intended to produce a preselectable radial acceleration of the splinters in order to obtain the narrowangle splinter cone. The method of operation in each case is as follows: On impact of a projectile as in Figure 4 on a target the impact receiving surface 54 absorbs energy. The annular disc 76 is plastically compressed and the impact transmission surface 58 transfer the absorbed energy in separate thrusts to the primer 86. The disintegration composition 84 is thus activated from the front surface.

If no impact is made with a target, then the disintegration composition 84 is activated from the rear as soon as the tracer composition 80 has burnt out. The projectile self disintegrates and can no longer cause any appreciable damage after flying past the latter.

When the projectile shown in Figure 5 makes impact on the target the bushing 94, as a result of its intertia, is moved suddenly against the annular disc 76, in which process the plastically deformable material of the latter is compressed and is able to yield in the radial direction.

The projection 96 thus transmits energy to the primer 86, which now actuates the disintegration composition 84. If the projectile flies past the target the tracer composition 80 burns through and acts through the boring 98 in order to actuate the primer 86, which in turn actuates the disintegration composition 84, in order to prevent any damage by the projectile.

The projectile can be employed against widely varying targets. With a suitable construction for the nose 14 the latter can be caused to act as a preliminary penetrator.

Claims

1. A spin stablized sub-calibre projectile having an average density of at least 17 /cam3 , the projectile having a rear part surmounted by a central longitudinally extending axial element passing through the centre of the projectile and extending towards the nose thereof, the central part of the projectile through which the axial element passes being provided with weakened zones to assist disintegration on impact, the projectile being characterised by the central axial element incorporating a disintegration assisting means to enhance the disintegration effect following impact.

2. A projectile in accordance with Claim 1, wherein the disintegration assisting means comprises a body which, on impact, moves in a longitudinal direction along the axis of the projectile.

3. A projectile in accordance with Claim 2, wherein the central axial element has an internal chamber, the body having a surface directed towards the internal chamber, the internal chamber housing a means which generates a radially outward force component following axial movement of the body.

4. A projectile in accordance with Claim 3, wherein the internal chamber houses a pyrotechnic charge having a primer on a surface facing the body, said surface being brought into contact with the primer to effect detonation.

5. A projectile in accordance with Claim 3, wherein the internal chamber houses a stacked arrangement of discrete bodies of conical shape and bodies of disc shape with a central aperture, each conical body having at least one disc associated therewith with the apex of the core entering the disc aperture, the conical body at the nose end of the projectile being connected through an end surface with the surface of the body.

6. A projectile in accordance with Claim 3, wherein the internal chamber contains a stack of balls , the forward end of the ball stack being in contact with the surface of the body.

7. A projectile in accordance with any one of Claims 3 to 5, wherein the surface of the body has an adjacently located conical element of which the larger diameter is greater than the diameter of the internal chamber.

8. A projectile in accordance with Claim 1 or 2, wherein the central axial element is rod-shaped and having at the rear a forward facing conical surface.

9. A projectile in accordance with Claim 4 or 7, wherein the pyrotechnic charge is operatively connected through a delay charge with a rear tracer composition.

10. A projectile in accordance with any preceding claim wherein the central part of the projectile comprises a stack of disc shaped elements positioned around the axial element and tightly engaging same through a central bore.

11. A projectile in accordance with Claim 10, wherein each disc shaped element has a weakened zone on a surface, said weakened zone comprising a groove.

12. A projectile constructed and arranged to function as described herein with reference to the drawings.

Amendments to the claims have been filed as follows

1. A spin stablized sub-calibre projectile having an average density of at least 17 g/cm3 , the projectile having a support structure comprising a rear part surmounted by a central longitudinally extending axial element passing through the centre of the projectile and extending towards the nose thereof, the central part of the projectile throngh which the axial element passes comprising a stack of disc shaped elements which disintegrate on impact, the support structure incorporating a mechanical means to assist disintegration of the discs following impact.

2. A projectile in accordance with Claim 1, wherein the means to assist disintegration comprises a body which, on impact, moves in a longitudinal direction along the axis of the projectile.

3. A projectile in accordance with Claim 2, wherein the central axial element has an internal chamber, the body having a surface directed towards the internal chamber, the internal chamber housing 2 further means which generates a radially outward force component following axial movement of the hody.

5. A projectile in accordance with Claim 3, wherein the internal chamber houses a stacked arrangement of discrete parts of conical shape and parts of disc shape with a central aperture, each conical part having at least one disc associated therewith with the apex of the part entering the disc aperture, the conical part at the nose end of the projectile being connected through an end surface with the surface of the body.

6. A projectile in accordance with Claim 3, wherein the internal chamber contains a stack of balls , the forward end of the ball stack being in contact with the surface of the.body.

7. A projectile in accordance with any one of Claims 3 to 5, wherein the surface of the body is in contact with an adjacently located conical element of which the larger diameter is greater than the diameter of the internal chamber.

9. A projectile in accordance with Claim 4 or 7, wherein the pyrotechnic charge is connected to a rear tracer composition forming a delay charge.

iC). A projectile in accordance with any preceding claim wherein the stack of disc shaped elements is shrunk onto the axial element.

11. A projectile in accordance with Claim 10, wherein each disc shaped element has a weakened zone on a surface, said weakened zone being formed by a groove.