GB2235275A - Projectile - Google Patents

Abstract

A spin stabilized subcalibre projectile of average density at least 17 g/cm<3> has a central column 12 on to which a stack of disc shaped elements 20 are mounted or shrunk. Each disc is weakened to assist disintegration on impact by recesses containing heavy metal powder which may have a pyrophoric effect: the recesses may be triangular cross-section radial grooves (26), annular recesses 42 or borings (44). Recesses containing powder can be defined by spaces (24) between discs, and a thin projectile casing (28). The discs may have conical end faces, so that they may either fit with an adjacent disc or define a space (24) therebetween. The nose 14 may be pyrophoric. <IMAGE>

Description

k 1 TITLE 39764Cjwpi Pin stabilized sub-calibre projectile cl This

Invention relates to a spin stabilized subcalibre projectile.

In prior patent application 8112401 there is disclosed a spin stabilized sub-calibre projectile which does not incorporate an explosive charge and which is intended to he embraced by a sabot. The projectile having a high proportion of heavy metal 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 through retardation of the spinning motion as a result of which overloading occurs causing fracture along weakened zones of the projectile structure. On impact with a target fragments are formed and initially they are of a size determined by the weakened zones along which fracture propagates. Further disintegration of the particles occurs as a result of direct interaction with the material of the target. In a target such as the wing of an aircraft having only a very limited thickness adequate disintegration into small fragments may fail to k KI-1 is occur so that #one of the kinetic energy inherent In the projectile is not dissipated in the target and the damage caused lathus severely restricted.

This invention seeks to provide a projectile generally of the above mentioned kind but in which a large number of comparatively small fragments already take effect on the target at the beginning of the disintegration process# According to this invention there is provided a spin stabilized sub- calibre projectile having an average density of at least 17 glcm3 0 and arranged to fragment on impact with a target without using an explosive means, 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 in the disintegration process on impact with a target, the projectile being characterised by the weakened zones at least in part comprising recesses with metallic particles within said recesses.

The invention is further described and explained in conjunction with the accompanying drawings showing preferred embodiments by way of example. In the accompanying drawingst 11 1 is Figure 1 shows a first embodiment with annular discs and bodies of heavy metal powder therebetweeng theprojectile being shown. In longitudinal section# Figure 2 shows one of the annular discs to a larger scale and In plan view.

Figure 3 shown an annular disc In section on the line III-III of Figure 2, Figure 4 shows a second embodiment of projectile In longitudinal section with annular portions to receive a heavy metal powder, Figure 5 shows a third embodiment in longitudinal cross section with bores to receive a heavy metal powder, and Figure 6 shows a fourth embodiment in longitudinal section with the annular discs segmented by cuts and weakened by preset breaking points with a heavy metal powder provided between the discs.

Referring to the drawings. in Figure 1 a sub-calibre projectile has a central axial mounting holder 12 with a rear reinforcement 18 which is delimited at the end by a base 16 and on a front opposite end by a supporting surface 22. Along a central longitudinal axis 30 of the projectile# Intermediate spaces 24 are left with annular Z1r - - 4 - discs 20 arranged to form a stack, one being shown in plan view In Figure 2 and in section In Figure 3. Each annular disc 20 has a central.boring 34 to enable It to be placed on the mounting holder 12, in addition to radial preset breaking points taking the form of grooves 26 of triangular cross section. Each triangular groove 26 forms part of the intermediate space 24& which is filled with heavy metal powder 40. A nose 14 is made in one piece from a pyrophoric material 19 (discussed later on) and Is provided with a blind hole 21 for the front end 23 of the mounting holder 12. A thin projectile casing 28 surrounds the arrangement in the zone In which this is required, this zone extending at least from the nose 14 as far as the reinforcement 18. The material 19 of which the tip 14 is made can be pre-treated for disintegration.

In the example shown in Figure 4 the annular discs 20 have annular recesses 42 filled with heavy metal powder.

The tip 14 is once again made In one piece from pyrophoric material 15# the blind hole 21 serving to acommodate the front e'nd 23 of the mounting support 12. The relevant parts are Interconnected In a conventional manner. e.g. by means of a screw thread.

In the example shown in Figure 5 the annular discs 20 situated in the cylindrical part of the projectile have receiving borings 44 for heavy metal powder 40, the number is of these borings and their diameter being preselected on a pitch circle 48 around the longitudinal axis 30 of the projectile In such a way that zones 46 of minimum wall thickness perform the function of preset breaking points. The annular discs 20 situated in the conical transition zone are shrunk onto the mounting holder 12. As regards the construction of the nose reference is made to Figure 4.

In the example shown In-Figure 6 the annular discs 20 have a doUbletropezoidal cross sectional profile in such a way that a concave shaped surface 27 follows onto a convex conical shaped surface 25. Where an intermediate space 24 is left between frustum surfaces 25 the said space is filled with heavy metal powder. Some of the annular discs 20 are alit to form segements 64. The front zone 23 of the mounting support is accommodated in the blind hole 21 of the nose 14 made in one piece from the pyrophoric material 19. The casing 26 extends at least over the peripheral zone 11 and the heavy metal powder fillings 40. The tail reinforcement 18 is delimited in the front by a disintegration surface 36.

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 bulkheades i.e, to ensure complete disintegration after impact. The formation of a splinter is cone with a preselectable angle for Its tip is in the first place ensured by centrifugal forces, as a result of the spiral movement This effect is assisted by mechanical -measures. much an the stripping surface 36 in the example shown in Figure 6.

In the examples shown In Figures 4 and 5 the annular discs 20 rupture. so that the resulting splinters are different sizes and the heavy metal powder 40 is released towards the target and can transmit energy.

In the example shown In Figure 6, a detonator can be provided, In order to ensure not only the automatic disintegration after the target has been missed but also the supporting action for the disintegration in the event of impact with the target.

The features provided in -the embodiments shown as examples can be combined with one another in various ways. with the advantage that any projectile can be used for a wide rangeof purposes. i.e. the projectile can be employed against widely varying targets. With a suitable construction for the nose 14 the latter can be caused to act an a preliminary penetrator. A single primer with an Impact mass for the Impact disintegration of the projectile and with a tracer composition for disintegration at a preselectable time is advantageously provided with parts made of the material of particularly high density# so that is any density loose which would detract from the flight properties of the projectile# particularly an extended flight path. are avoided.

The heavy metal powder 40 to advantageously provided in tablet form; high density Is obtained by a pre- selectable range of particle sizes (screening characteristic) with a lower limit in the range and an upper limit in the em range. In addition this system ensures ample transmission of energy to the target with a highly destructive effect; the small particles already transmit their energy to a target element in the surface range. If the material of which the target is made is sufficiently reactive under the impact conditions prevailing, which is the case with light metal alloys such as those customarily used in aircraft construction and particularly with the fuels carried on board, then a physical chemical effect is observed in addition to the mechanical effect. This renders the projectile according to the invention highly suitable for use against flying targets. If, on the other hand, the structure of the target Includes layers with considerable wall thickness, as In the case of armoured targets such as land vehicles, and attack helicopters, then the mechanical damage inflicted on them mainly takes the form of deformation, splitting and penetration, This renders the projectile according to the Invention highly suitable for use against the further targets mentioned likewise.

1 CLA IMS 1 A spin stabilized cub-calibre projectile having an average density of at least 17 S1cm3 # end arranged to fragment on impact with a target without using an explosive scan&& 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 in the disintegration process on impact with a target, the projectile being characterised by the weakened zones at least in part comprising recesses with metallic particles within said recesses.

Claims (1)

1. 2. A projectile in accordance with Claim 1 wherein the central pert of the

   projectile comprises a stack of disc shaped elements positioned about the central axial element.

   3.. A projectile In accordance with Claim 2 wherein the disc shaped elements are shrunk onto the central axial element.

   4. A projectile In accordance with Claim 2 or 3 wherein preset break points are provided on the surfaces of the annular discs.

   A projectile in accordance with Claim 4 wherein the preset breaking points are in the form of radially extending grooves on the surfaces of the discs.

   6. A projectile In accordance with any preceding claim wherein the recesses comprise a number of bores extendinglongitudinally.

   7. A projectile in accordance with any preceding claim wherein the metallic particles have a size from-a lower limit In the/,&-^ range to an upper limit in the mm range. the particles being of a heavy metal.

   i is 8. A projectile in accordance with Claim 7, wherein the heavy metal is In the form of a powder embedded in an incendiary composition.

   9. A projectile in accordance with any preceding claim wherein the recesses are defined between the central part of the projectile and the internal surface of a thin walled casing positioned about the periphery of the projectile.

   10. A projectile in accordance with any preceding claim wherein the central part of the projectile body to formed from a stack of discs, the metallic particles being located between adjacent discs come of which are spaced so as to define a cavity.

   11. A projectile in accordance with Claim 10 wherein the dine have conical end faces, some of the discs having opposite syminetry whereby the end surfaces may fit together# other adjacent discs having complementary symmetry surfaces whereby a cavity to receive the metallic particles is provided, a thin welled casing being provided around the discs to retain the metallic particles.

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

   is is ? 5 - I?- - Amendments to the claims have been filed as follows 1. A spin stabilized sub-calibre projectile having an average density of at least 17 g/cm3, and arranged to fragment on impact with a target without using an explosive means, 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 projectile being characterised by a central part comprising a stack of disc shaped elements positioned about the central axial element, with recesses between at least some of the adjacent discs, said recesses containing metallic particles.

   2. A projectile in accordance with Claim 1 wherein the disc shaped elements are shrunk onto the central axial element.

   3. A projectile in accordance with Claim 1 or 2 wherein preset break points are provided on the surfaces of the annular discs.

   4. A projectile in accordance with Claim 3 wherein the preset breaking points form the recesses and comprise radially extending grooves on the surfaces of the discs.

   c - 13 5. A projectile in accordance with any preceding claim wherein the recesses comprise a number of bores extending longitudinally.

   6. A projectile in accordance with any preceding claim wherein the metallic particles have a size from a lower limit in the,,JArrange to an upper limit in the mm range, the particles being of a heavy metal.

   7. A projectile in accordance with Claim 6, wherein the heavy metal is in the form of a powder embedded in an incendiary composition.

   8. A projectile in accordance with any preceding claim wherein the recesses are defined between the central part of the projectile and the internal surface of a thin walled casing positioned about the periphery of the projectile.

   9. A projectile in accordance with any preceding claim wherein the metallic particles are located between some at least of the adjacent discs which are spaced so as to define a cavity.

   10. A projectile in accordance with Claim 10 wherein the 25 discs have conical faces, some of the discs having k - - 1. - complementary shaped faces which may fit together, other adjacent discs having non-complementary faces defining a cavity to receive the metallic particles, a thin walled casing being provided around.the discs to retain the metallic particles.

   11. A projectile constructe.d and arranged to function a herein described with reference to the drawings.

   1 S; Published 1991 atThe Patent Office. State House. 66/71 High Holborn, IA)ndonWCIR4TP. Further copies may be obtained from Sales Branch, Unit 6. Nine Mile Point, Cwmfelinf2ch. Cross Keys. Newpor4 NPI 7HZ. Printed by Multiplex techniques ltd, St Mary Cray. Kent.