1. Field of the Invention
This invention relates to multi-charge munitions incorporating hole boring charge assemblies, in particular hole-boring charge assemblies capable of penetrating concrete targets.
2. Discussion of Prior Art
It is known that the attack, disruption, and destruction of fixed targets such as airfield runways, shelters, bunkers, bridges, roadways, railway marshalling yards and dockyards may be effected by first emplacing and then detonating relatively small quantities of high explosive within or under the target. The materials of construction of these targets are typically strong in compression and yet weak in tension, as exemplified by most forms of concrete. Such emplacement exploits both the inherent confining effect of the target material on the charge of emplaced explosive and the tensile weakness of the target material, and futhermore enhances the transmission of energy from the detonated explosive into the immediately adjacent confining medium and onwards into the outlying and underlying target structure.
One known technique of rapid implantation and detonation of explosive charges into fixed targets is to first breach the surface of the target with a hole-boring charge of explosive before driving a secondary charge of explosive into or through the hole so formed, and thereafter initiating detonation of the secondary charge. This technique has the advantage that it may be used in both the manual demolition of fixed targets, in which the hole boring and secondary charges will usually be brought separately and sequentially to the target, and in the attack of such structures by remotely-delivered munition systems such as aerially-deliverable bombs, missiles and shells which systems incorporate both types of charge and a suitable delay device for initiating detonation of the secondary charge.
The main requirement for a hole boring charge as applied to fixed targets is that it should be capable of producing a breach in the target of sufficient width and depth of penetration to permit subsequent emplacement of the secondary charge at a position which will cause enhanced damage to the structure once the secondary charge is detonated. The hole may be large enough to permit complete emplacement of the secondary charge within or even under the target. Alternatively, it may only be large enough to permit a remotely delivered secondary charge to lodge partly in the hole, but this at least has the advantage that it prevents ricochet of the secondary charge away from the target before detonation. In a remotely-delivered munition system in particular, the hole-boring charge should also preferably be of relatively small size and weight in comparison with that of the secondary charge because it is for the most part the latter charge which performs the task of destroying the target.
These requirements have in the past been met in part by the use of a hollow explosive charge having a conical concavity in one face lined with a non-explosive liner. The hollow and secondary charges are configured in what is known as a follow-through munition, in which the hollow charge is positioned axially in front of the secondary charge. When the hollow charge is detonated, the liner collapses upon its axis and is formed into a high velocity jet which upon impact with the target produces a hole. The secondary, follow-through charge is thrust into the hole so formed, either by virtue of its own forward momentum if sufficient to overcome blast-back forces from the hole, or under the influence of an auxiliary charge positioned to the rear of the follow-through charge. However, such known hollow charges fail to fulfil all the requirements for a variety of reasons.
Hollow charges with concavities having acutely-angled apexes generally collapse the liner into long, narrow, high speed jets. These are capable of penetrating both massive structures and armour to considerable depths. However the resulting holes bored in the target material tend to be narrow and tapered and so are not suitable for the subsequent emplacement of a blasting charge therein. The diameter of the hole can be increased by increasing the diameter of the hollow charge, but the corresponding increase in weight of the hollow charge is undesirable and furthermore the increase in target penetration in targets of finite thickness such as concrete walls, roads and runways may cause the secondary, follow-through charge to be emplaced beyond the depth at which it can cause maximum damage to that target.
Wider holes are also produced for the same calibre of hollow charge using shallower angled, lined concavities (ie concavities with large-angled apexes, of apex angles generally greater than 80°, especially greater than 100°) which generally form the liners into projectiles which tend towards lower velocity, non-jet penetrators. However, the shorter lengths and lower kinetic energies of these penetrators result in a significant reduction in performance especially against concrete targets, necessitating an undesirably large charge mass in order to excavate a hole of sufficient volume to permit emplacement of the secondary, follow-through charge to an optimum depth.
The need for a relatively large mass of explosive in the hole-boring hollow charge reduces the weight of explosive which can be used in the secondary, follow-through charge for a given overall weight of multi-charge munition, and when the hole-boring charge is detonated consequently gives rise to excessively large forces on the follow-through charge which may damage the follow-through charge and/or its fuzing system.
It is one of object of the present invention to provide a multi-charge munition incorporating a hole-boring charge assembly which can more adequately facilitate the emplacement of a follow-through charge within a target.
Accordingly, the present invention provides a multi-charge munition for attacking a target, comprising a secondary charge of explosive disposed on a fore-and-aft line of target penetration, a detonatable array of at least two hollow primary charges of explosive supported laterally about the line of target penetration, each primary charge having a recessed forward face, a liner of non-explosive material lining said forward face, and being geometrically configured, when detonated in the array, to project a penetrator derived from the liner along a line of tajectory extending forwards of the secondary charge, a fuze system arranged to initiate detonation of the array of primary charge and the secondary at appropriate times, and a primary detonation means for detonating the primary charges in the array in a temporal relationship with respect to one another such that the penetrators are projected forwards towards the target concurrently.
The effect of two or more linearly projected penetrators impacting concurrently on a target has been found to vary depending on whether the penetrators penetrate the target separately or as one. However, the present arrangement of hollow charges has been found to produce holes in a target material such as concrete of a volume which is significantly larger than that which could be produced by a single hollow charge of the same overall mass and linear geometry.
The mode of failure of a target material such as concrete and the subsequent formation of the borehole is complex but the following which does not in any way limit the scope of the invention provides an explanation of the possible mechanics involved.
If the primary charges of the array are geometrically arranged so that the penetrators converge and meet at a focal point before or, more preferably, soon after penetrating the target, it has been found that a single coalesced penetrator will form which surprisingly has little tendency to diverge from its resultant trajectory, especially if the array contains three or more, equispaced primary charges. The resultant penetrator tends to retain approximately the same energy density as the separate penetrators from which it is formed, so that a significant depth of target penetration in both high and low tensile strength materials is maintained. However the hole produced in target materials such as concrete is found to be very much wider than would have been expected from that produced by a single hollow charge of similar linear geometry and equivalent mass. Furthermore, the resultant, coalesced penetrator dissipates its energy rapidly when it comes into contact with softer material such as sand, soil, clay or gravel which may underlie a ground target such as an airfield runway or a roadway, leaving a bulbous cavity below the target which is ideally shaped for the subsequent emplacement of a secondary, cratering charge.
Ideally, the penetrators meet soon after penetrating the target and for this reason the fuze system preferably includes a primary fuze means arranged to initiate detonation of the primary charges when the focal point is located beneath the surface of the target.
It has been found that a coalesced penetrator of optimum penetration efficiency and hole boring characteristics is produced by so arranging the primary charges that the penetrators meet at a distance from the base of each charge recess (ie from the forward face of each charge) of between two and twenty times, preferably between two and ten times, particularly between three and seven times, the diameter of the liner. A distance of a minimum of two diameters is required adequately to form the collapsed liners into penetrators, whereas at a distance of greater than seven base diameters the penetrators tend to break up and become increasingly particulate and at a distance of greater than ten diameters, it becomes increasingly difficult to focus the charges in the array acurately. The most preferred upper limit of distance is therefore at the point at which the onset of particulation occurs for each single charge. In any event, unless a large and yet relatively shallow hole is required, the penetrators will collide at angles of preferably not greater than 90°, more preferably not greater than 60°, most preferably not greater than 30° to one another in order to prevent a significant reduction in kinetic energy transmission in the direction of target penetration.
If the primary charges in the array are not focussed, then the array must contain at least three primary charges. The initial effect of three or more non-focussed primary hollow charge penetrators impacting concurrently on a target is to bore a number of narrow, deep holes into the target equal to the number of hollow charges detonated. The collision of the penetrators with the target material produces intense shock waves which radiate outwards from the holes as they are formed. The strength of the shockwaves radiating from each penetrating jet is sufficiently large to cause material immediately adjacent the holes produced to fail in compression. In the case of impact by a single hollow charge jet, shock wave intensity decreases with distance of travel into the target, and damage is limited to the immediate vicinity of the hole. However, when three or more jets impact concurrently on the target, the transmitted shock waves from adjacent jets are reflected upon collision, and in the process of collision subject the target material to intense compression thus extending the region of failure to encompass the material bounded by the holes. This material may be ejected from the surface of the target upon its subsequent relaxation immediately following compression, an effect which may be assisted by gases generated during penetration by the jets, to leave behind a single and relatively wide resultant borehole encompassing the narrow holes initially formed by the individual penetrators. Thus, the present array of hollow charges exploits the efficient hole boring and rapid energy dissipation characteristics of explosively-formed penetrators, especially jet penetrators, but at the same time produces a much larger hole suitable for subsequent emplacement of the secondary charge.
For this effect to be produced, it is not essential that the primary charges should be arranged to produce penetrators which are projected along parallel pathways, although the arrangement should be such that the penetrators preferably produce a non-linear array of impact points on the surface of the target so that the lines of trajectory encompass a finite volume of target material. By appropriate geometric arrangement of the individual charges within the array, the penetrators may diverge or converge slightly, though preferably at an angle of not more than 30°, more preferably not more than 20°, to a line parallel to the line of target penetration. Divergent penetrators will produce a shorter, wider resultant hole because the relaxation effect will diminish with increasing distance into the target, whereas slightly convergent penetrators will tend to produce a deeper and slightly tapered hole which is more preferred for the purpose of secondary charge emplacement.
Since it will be understood that each of the individual penetrators do not by themselves contribute significantly to the width of the resultant hole produced by either of the effects described above in relation to focussed and non-focussed penetrators, it is therefore advantageous to provide a design of hollow charge which produces maximum depth rather than maximum width of penetration. Hollow charge and liner combinations which produce very long jet penetrators are therefore preferred. Hitherto, such combinations have not been employed in multi-charge munitions for attacking concrete targets because singly they normally produce deep, narrow, tapered holes of little use for the emplacement of secondary charges. In order to maximise the kinetic energies that can be attained by such jets, the non-explosive liners are preferably of relatively low density ductile materials having densities of less than 5 gm cm−3. Aluminium and alloys thereof are especially preferred, although plastics (such as polyethylene) and metal-loaded plastics may also be used, for example plastics loaded with up to 50% by weight of particulate aluminium or particulate aluminium alloy. Such low density materials can be formed into jet penetrators from much deeper recesses than traditional, high density shaped charge liner materials such as copper, so that within certain limits much higher penetrator velocities hence kinetic energies are possible with the former. The charges themselves are preferably axisymmetric with conical recesses which are commonly referred to as shaped charges, and using these low density liners the apex angle of the correspondingly conical liners is preferably from 15° to 70°, more preferably from 20° to 55°, most preferably from 25° to 50°.
The array preferably contains up to 6 hollow primary charges and is normally provided in a symmetrical form with the primary charges preferably equispaced about the line of target penetration and preferably lying in a plane normal to that line. For a non-focussed array of charges (which term also encompasses slightly convergent arrays), the most preferred number of charges is four, (especially if the charges are positioned in a substantially square array), since the hole produced by a triangular array of only three charges will significantly reduce the maximum diameter of the secondary charges which can be successfully emplaced. For a focussed array of charges, in which the charges are arranged such that the penetrators meet preferably before they particulate, the most preferred number of charges in the array is three, this being the minimum number required to produce a reasonably axisymmetrical, coalesced penetrator. In symmetrical arrangements the charges will normally be arranged to be detonated simultaneously, although in other arrangements a rapid succession of detonations may be advantageous. A relatively closely-spaced array is preferred especially when the charges are non-focussed, the centres of gravity of the primary charges being located within a pitch circle diameter of preferably less than 6 primary charge widths, more preferably less than 4 primary charge widths.
When the hollow charges are in a focussed configuration, at least two of the liners may be of different materials, especially of different materials which interreact exothermically when the penetrators coalesce. This can produce a significant pressure increase within the target during penetration, which can enhance the hole boring effect. An example of three different liner materials which when coalesced may together produce this effect are zirconium, titanium, and iron. In this particular case, the liner may comprise a hollow cone with an apex angle of between 20° and 120° or a hemispherical cap, the latter being commonly referred to as a Miznay Schardin dish.
In order to reduce the overall volume of the multi-charge munition for storage purposes, advantageously the primary charges are laterally displaceable on a moveable support mechanism from a confined, clustered configuration to their detonatable positions in the array. If the munition is aerially-deliverable, this arrangement can also be used to improve its flight characteristics since lateral deployment of the primary charges can be delayed until the munition approaches close to its target. An energising means such as a gas generator may be employed to deploy the primary charges. A latch means is preferably also provided for restraining the primary charges once displaced to their detonatable positions in the array by the moveable support mechanism. If the primary charges are retained in their own housing, then in order to facilitate deployment of the charge it is preferred that the housing is petalled. The housing petals are closed when the primary charges are in their clustered configuration, and open hingedly when the charge are laterally displaced outwards to their positions in the detonatable array.
The secondary charge will generally be of larger mass than each of the primary charges. It may comprise a blasting or cratering charge. Alternatively, it too may comprise a hollow charge have a recessed forward face lined with a non-explosive liner, especially if the primary charges are configured in a convergent or focussed array to provide an initial borehole for subsequent, further penetration by the secondary hollow charge.
The array of primary munitions may be arranged in a follow-through, lateral or reverse follow-through configuration with respect to the secondary charge.
In the follow-through configuration, the primary charges are located in front of the secondary charge. The munition may be provided with an auxilliary, thruster charge behind the secondary, follow-through charge in order to counteract the rearward blast from the detonated array of primary charges. Alternatively, if the follow through charge is very large in comparison to the size of the primary charges and comprises, for example, a free-fall bomb then its forward inertia may be high enough to carry it at least partly into the target without the need for a thruster charge.
In the reverse follow-through configuration the primary charges are located behind the secondary charge. The additional advantages of the present multi-charge munition in a reverse follow-through configuration is that detonation of the primary charges thrusts the secondary towards the hole produced by the penetrators, thus lessening the need for a rearward auxilliary charge. The secondary charge can be designed to take advantage of the geometrically dispersed nature of the array of primary charges, and is therefore preferably located within a volume defined by the trajectories of the penetrators. The penetrators will therefore travel past the outside surface of the secondary charge to reach the target. The primary charges will preferably be arranged to produce convergent, and most preferably focussed, penetrators. The secondary charge will therefore preferably be tapered towards its forward end to take maximum advantage of the space available in the volume defined by the penetrator trajectories, and is most preferably conical. The general shape of a conical secondary charge design offers a relatively large surface at its rearwardly-facing end upon which the blast effects from the detonated primary charges can act to drive it into the borehole. The shape also offers lower aerodynamic drag than a cylindrical design, is drag-stabilised in flight and is less likely to be inadvertently blown back out of the borehole once emplaced.
The present multi-charge munition may comprise a demolition munition suitable for static positioning at a target, for example at a concrete ground target. Alternatively, it may preferably comprise an aerially-deliverable munition. One such preferred munition is a dispensable submunition suitable for dispensing from a multi-submunition dispenser. Dispensers of this type can be carried on aircraft and are typically designed for the multiple attack of airfield runway surfaces. Another preferred munition is an aerially-deliverable bomb, whose secondary charge contained within the body of the bomb will generally be very much larger than the secondary charge in a dispensable submunition and so will usually carry its primary charges in a follow-through configuration. The aerially-deliverable munition may be fitted will stabilising fins and it may be desirable in some cases to fit a flight-retarding device such as a parachute to assist in adjusting the speed and angle of attack of approach to the target.
When the multi-charge munition is provided as a aerially deliverable bomb, the bomb may be provided with its own guidance system, such as a laser guidance system, located in front of the bomb. In this case, the primary charges are preferably supported about the axis of target penetration between the guidance system and secondary charge in order to prevent aerodynamic interference of the guidance system by the primary charges. The guidance system preferably includes a plurality of longitudinal, most preferably equispaced canards extending radially from a body member, and it is preferred that the primary charges are located detonatable array such that their lines of trajectory pass between these canards so as to prevent the canards from impairing the penetration performance of the primary charges. For the reason, the number of canards and primary charges are ideally the same and conveniently this number is four.
The primary charges on the bomb, which are preferably housed protected from damage in their own aerodynamic-shaped shielding, may be of a size which dictates that the outside diameter of the shielding is greater than that of the bomb body containing the secondary charge. In this instance, the shielding is preferably contoured around the primary charges and the primary charges are preferably alignable at a first position one behind each of the canards. This permits the bomb to be carried between adjacent canards as close as possible to its associated airborne carrier to minimize aerodynamic drag. Once the bomb is dropped, the primary charges are preferably alignable at a second position between adjacent canard in readines for attacking a target. In order to effect such alignment, the primary charges and guidance system body member are preferably rotatable relative to one another about the axis of target penetration, at least to a limited extent sufficient to permit relative rotation of the primary charges from the first to the second position.
In a further embodiment of the present invention a multi-charge munition suitable for defeating both concrete and armoured targets or combinations of the two is provided in which the primary charges in the array are arranged laterally about the secondary charge to produce focussed penetrators, and the follow-through charge comprises a secondary hollow (preferably shaped), charge having a recessed forward face lined with a second hollow charge liner. The mass of the secondary charge will preferably be greater than that of each primary charge. In this arrangement the secondary charge is detonated such that its penetrator either leads or follows the penetrators from the primary charges or combines with them at some point inside or outside the target. The primary penetrators will preferably be optimised to disrupt and clear interfering material between the target and secondary charge, thereby enhancing the performance potential of the latter. In general the primary charge liners will produce high velocity jet penetrators from low density material (usually less than 5 gm/cm−3) with conical liner apex angles of preferably between 20° and 60°. The secondary charge can be designed to form either a jet penetrator or non-stretching slug type penetrator from a liner of high density material (usually higher than 5 gm/cm−3) such as copper. Liner apex angles within the secondary, hollow charge may therefore range from 20° to 120° or the liners may be of geometries similar to hemispherical caps (usually termed Misznay Shardin dishes). An advantageous feature of this embodiment where the primary charges are arranged laterally of the secondary charge is that the detonation of the array will in most cases result in increased confinement of the secondary charge which will lead to a net increase performance of the latter. A prerequisite for this embodiment therefore is that detonation of the primary and secondary charges must be essentially simultaneous.
Embodiments of multi-charge munitions incorporating hole-boring charge assemblies in accordance with the present invention will now be described by way of example only with reference to the accompanying drawings in which
Referring first to the embodiment illustrated in
The support shaft 8 is attached at its rear end to a flat cylindrical housing 20 disposed to the rear of the primary munitions 6, which houses a folded parachute 22 attached to the shaft and a safety and arming unit 24. Flexible electric firing leads 25 extend from the unit to the detonators 17 in the primary munitions 6. At its forward end the shaft 8 is attached to a circular protective support plate 26 which extends across the entire width of and is attached to the secondary munition 10.
Referring now also to
At some point between the launch of the reverse follow-through munition dispensed from its airborne carrier and its arrival at the target, an annular gas generator charge 30 located centrally about the support shaft 8 between two support rings 32 is ignited (for example, by a delayed signal received from the unit 24) and the combustion gases produced simultaneously urge the support rings slideably apart along the shaft. The movement of the rings 32 causes forward and rearward linkages 34 pivotally connected between the rings and the casings 12 of the primary munitions 6 to rotate outwards from their initial positions parallel with the shaft, and so urge the primary munitions outwards from the axis AA′ until they collide with the walls of frangible canister 2. The force of the collision, which is augmented by the direct outward thrust of combustion gases from the gas generator charge 30, is sufficient to burst the canister 2 open at the regions of impact, allowing the primary munitions 6 to continue on their lateral trajectory from the axis AA′.
The rings 32 eventually collide and nest within the internal bases of cup-shaped stops 36 coaxially mounted on the shaft 8, which rings interact with the linkages 34 to arrest the primary munitions 6 at their required positions ready for detonation. Spring-loaded clips 38 emerge from the shaft 8 once the rings 32 have passed over them to lock the rings into positive engagement with the stops 36 and so prevent any further lateral movement of the primary munitions 6. The annular lips 36a of the cup-shaped stops 36 engage with the deployed linkages 34 to prevent any longitudinal or further rotational movement of the primary munitions 6. Thus during the flight of the reverse follow-through munition to its target, the shaft 8 supports the primary munitions 6 through the rings 32, stops 36 and linkages 34 and the secondary munition 10 through the protective support plate 26.
The secondary munition 10 is additionally suspended from the tapered inside support face 40 of an annular support 42 attached to the inside of the canister 2. An encased, annular auxilliary charge 44 is supported about the shaft 8 between the primary munitions 6 and the support plate 26. The secondary munition 10 is provided in two parts consisting of an encased rear portion 46 containing a main follow-through charge 48, and an encased nose portion 50 containing a secondary munition fuze 52. An annular primary munition fuze 54 is disposed within the frangible canister 2 about the nose portion 50, leaving a tapered, annular gap 56 between the two through which the axes of symmetry of the primary munitions 6 pass when deployed (see
Once the reverse follow-through munition is deployed in the arrangement shown in
In
It has been found that, against a 0.3 m thick concrete vehicle-supporting ground target (eg airfield runway), a triple focussed array of identical shaped charges each having a diameter of 85 mm and conical aluminium liner of 45° apex angle and arranged on a pitch circle diameter of 200 mm with their axes inclined at 8°56′ to a fore-and-aft line of target penetration, such that the forward faces of the charges are located at a distance of 425 mm above the surface of the target and the axes are focussed at a point 200 mm below the surface, will produce a bore-hole of similar throat dimension and penetration depth as a 180 mm diameter unitary shaped charge with an 85° conical aluminium liner and an all-up mass of twice that of the triple array.
A similar reverse follow-through sub-munition to that illustrated in
The parachute 22 and primary munitions 6 are deployed in the same manner as that described with reference to
The effect of these separate penetrators penetrating a hard, brittle target material such as concrete is shown in
The hole (Hb) extends for most of the depth of the holes (hb) bored initially by the individual penetrators, and its volume is generally considerably greater than that produced by a single shaped charge containing the same total mass of explosive as the four primary munitions 6. Since the position of the array of primary munitions 6 at detonation approximately defines the corner locations hence lateral shape and dimensions of the hole (Hb), these positions in turn approximately define the maximum diameter of secondary munition 70 which can be driven into the hole.
It has been found that a quadruple parallel array of identical shaped charges, each having a diameter of 85 mm and a conical aluminium liner of 45° apex angle, set on a pitch circle diameter of 300 mm and arranged such that the forward faces of the charges are separated from the surface of a 0.3 m thick concrete runway ground target by a distance of 510 mm, will produce a borehole of similar throat dimensions and penetration depth as a unitary shaped charge with an 85° conical aluminium liner and an all-up mass of 1.8 times that of the quadruple array.
It will be seen from
The secondary munition 70 is thrust into the hole (HB) by the combined blast effect from the detonated primary munitions 6. The shock effects produced by the blast primes the secondary fuze 90 which detonates the follow-through charge 86 soon after emplacement.
Referring next to
In each of the bombs illustrated in
Each primary munitions 6 is linked to the contact fuze within the sensor 116 by a flexible electric firing lead 124. When the sensor strikes a target, the fuze causes the primary munitions 6 to detonate immediately and simultaneously. If the target is a hard, brittle material such as concrete, the detonated primary munitions 6 will bore a hole in the target in the manner described above with reference to
Referring next to
The secondary munition 158, which is shown partly sectioned, is symmetrically disposed about the longitudinal axis. It consists of a cylindrical casing 160 open at its forward end, containing a hollow charge 162 of high explosive having a hemispherical recess 164 in its forward face which is lined with a mild steel Misznay-Shardin plate 166. The mass of the charge 162 is typically from 2 to 10 times that of the individual charges 14 within the primary munitions 6.
The use of the projectile illustrated in
Referring lastly to
Forward of the nose section 204 is located a cylindrical housing 212 supported by a tubular support member 214 extending between the housing and the nose section. The housing 212 and support member 214 are both coaxially located about the common axis EE′. The closed rear end 215 of the support member 214 is screwed into the nose section 204 and acts as a nose plug for the bomb body 202.
The housing 212 is divided into a fixed rearward housing 212b connected by a limited rotation bearing 216 to a rotatable housing 212a. At its front end, the forward housing 212a carries a sensor 218, for example a laser sensor, which incorporates a contact fuze. Four equispaced longitudinal canards 220 radiate outwards from the housing 212a along its length. The canards 220 are supported on bearings 222 which allow the canards a limited degree of rotation about axes radiating transversely from the axis EE′. The degree of rotation of the canards 220 is controlled by a motor (not shown) located within the forward housing 212a. The motor is in turn controlled by a guidance system (not shown), for example a laser guidance system.
The rearward housing 212b supports four equispaced, petalled bulbous cowlings 224 independently pivotable on hinges 226 attached to the rearward housing. Each cowling 224 houses one of the primary munitions 6. The cowlings 224 extend radially beyond the outside diameter of the bomb body 202, but are encompassed by the outside diameter of the array of canards 220 as can be seen from
Each of the equispaced primary munitions 6 housed within its associated cowling 224 is supported fore and aft by fore and aft articulated linkages 230 and 232 respectively which extend through longitudinal slots 234 in the tubular support member 214. The likages 230 and 232, which are shown folded in
The sensor 218 is electrically connected to the gas generator charge 240, and to the delay fuze 210. Four flexible, electric firing leads 246 extend from the fuze within the sensor 218 one to each of the detonators 17 in the primary munitions 6.
The forward housing 212a is, as shown in
Once the bomb 200 has been dropped from its carrier, the forward housing 212a is rotated on the bearing 216 a one-eighth turn (45°) to a new fixed position at which the cowlings 224, hence the primary munitions 6, are located in the quadrant spaces between the canards 220.
As the bomb 200 approaches its target towards the end of it guided flight path, a signal is transmitted from the sensor 218 to the ignite the gas generator charge 240. The gas pressure generated by the ignited gas generator charge 240 pushes the two pistons 236 and 238 apart within the support member 214, causing the articulated likages 230 and 232 to unfold. This in turn pushes the four primary munitions 6 outwards against the cowlings 224. The outward forces acting on the cowlings 224 ruptures the seal 227 and causes the cowlings to pivot outwards from the shell 228 about their respective hinges 226. The axial motion of the pistons 236 and 238 is eventually arrested by the stops 242 and 244 before the pistons reach positions at which pressure between them can exhaust through the slots 234. The abutment of the articulated linkages 230 and 232 against the stops 242 and 244 respectively and against the ends of the slots 234 prevent further movement of the primary munitions 6. The primary munitions 6 are arrested in a focussed array illustrated in
With the forward housing 212a and primary munitions 6 deployed in their respective positions shown in
If the target is a hard, brittle material such as concrete of considerable depth, then the jet penetrators will typically produce a funnel-shaped, approximately axisymmetric hole H in the surface S of the target T, as is shown in
Once lodged in the hole, the delay fuze 210 initiates detonation of the main charge 206 through the detonator 209. The acute taper of the inner region (r2) of the hole provides an ideal hole shape to ensure that the bomb lodges a sufficient distance above the bottom of the hole to provide adequate standoff for the collapsing conical liner 208 to form into an effective jet penetrator capable of penetrating a considerable distance into the target. Subsequent damage to the target is caused by the synergistic effect of shaped charge jet pentration produced by the collapsed liner 208 followed by axial pressure applied through the penetration hole by the detonation products of the main charge 206.
The delay fuze 210 may alternatively be set to detonate the main charge 206 just before the bomb body 202 is arrested by collision with the tapered inner region (r2) of the hole. This further reduces the probability of damage or disturbance to the main charge 206 before it is detonated.
Number | Date | Country | Kind |
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8901667 | Jan 1989 | GB | national |
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2984307 | Barnes | May 1961 | A |
3750582 | Kintish et al. | Aug 1973 | A |
4493260 | Foster | Jan 1985 | A |
4726297 | Bueno et al. | Feb 1988 | A |
4989517 | Adimari et al. | Feb 1991 | A |
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3010917 | Oct 1981 | DE |
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2629280 | Jul 1985 | DE |
3544528 | Apr 1987 | DE |
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Entry |
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Hunting Engineering sales brochure SG357, 1986 Aircraft Armament/UK. |