CA2583533A1

CA2583533A1 - Kinetic energy rod warhead with lower deployment angles

Info

Publication number: CA2583533A1
Application number: CA002583533A
Authority: CA
Inventors: Richard M. Lloyd
Original assignee: Individual
Current assignee: Raytheon Co
Priority date: 2004-09-10
Filing date: 2005-09-09
Publication date: 2006-11-30
Also published as: WO2006127027A3; EP1797392A2; JP2008512642A; US20050109234A1; WO2006127027B1; IL181803A0; WO2006127027A2

Abstract

This invention features a kinetic energy rod warhead including a projectile core including a plurality of different size projectiles, an explosive charge about the core, and at least one detonator for the explosive charge.

Description

KINETIC ENERGY ROD WARHEAD WITH LOWER DEPLOYMENT ANGLES
FIELD OF THE INVENTION

This invention relates to improvements in kinetic energy rod warheads.
BACKGROUND OF THE INVENTION

Destroying missiles, aircraft, re-entry vehicles and other targets falls into three primary classifications: "hit-to-kill" vehicles, blast fragmentation warheads, and kinetic energy rod warheads.

"Hit-to-kill" vehicles are typically launched into a position proximate a re-entry vehicle or other target via a missile such as the Patriot, THAAD or a standard Block IV missile. The kill vehicle is navigable and designed to strike the re-entry vehicle to render it inoperable. Countermeasures, however, can be used to avoid the "hit-to-kill" vehicle. Moreover, biological warfare bomblets and chemical warfare submunition payloads are carried by some threats and one or more of these bomblets or chemical submunition payloads can survive and cause heavy casualties even if the "hit-to-kill" vehicle accurately strikes the target.

Blast fragmentation type warheads are designed to be carried by existing missiles. Blast fragmentation type warheads, unlike "hit-to-kill" vehicles, are not navigable. Instead, when the missile carrier reaches a position close to an enemy missile or other target, a pre-made band of metal on the warhead is detonated and the pieces of metal are accelerated with high velocity and strike the target. The fragments, however, are not always effective at destroying the target and, again, biological bomblets and/or chemical submunition payloads survive and cause heavy casualties.

The textbook by the inventor hereof, R. Lloyd, "Conventional Warhead Systems Physics and Engineering Design," Progress in Astronautics and Aeronautics (AIAA) Book Series, Vol. 179, ISBN 1-56347-255-4, 1998, incorporated herein by this reference, provides additional details concerning "hit-to-kill" vehicles and blast fragmentation type warheads. Chapter 5 of that textbook, proposes a kinetic energy rod warhead.

The two primary advantages of a kinetic energy rod warheads is that 1) it does not rely on precise navigation as is the case with "hit-to-kill" vehicles and 2) it provides better penetration then blast fragmentation type warheads.

To date, however, kinetic energy rod warheads have not been widely accepted nor have they yet been deployed or fully designed. The primary components associated with a theoretical kinetic energy rod warhead is a hull, a projectile core or bay in the hull including a number of individual lengthy cylindrical projectiles, and an explosive charge in the hull about the projectile bay with sympthic explosive shields.
When the explosive charge is detonated, the projectiles are deployed.

The cylindrical shaped projectiles, however, may tend to break and/or tumble in their deployment. Still other projectiles may approach the target at such a high oblique angle that they do not effectively penetrate the target. See "Aligned Rod Lethality Enhanced Concept for Kill Vehicles," R. Lloyd "Aligned Rod Lethality Enhancement Concept For Kill Vehicles" 10'h AIAA/B1VIDD TECHNOLOGY
CONF., July 23-26, Williamsburg, Virginia, 2001 incorporated herein by this reference.

SUMMARY OF THE INVENTION

It is therefore an object of this invention to provide an improved kinetic energy rod warhead.

It is a further object of this invention to provide a higher lethality kinetic energy rod warhead.

It is a further object of this invention to provide a kinetic energy rod warhead with structure therein which aligns the projectiles when they are deployed.

It is a further object-of this invention to provide such a kinetic energy rod warhead which is capable of selectively directing the projectiles at a target.

It is a further object of this invention to provide such a kinetic energy rod warhead which prevents the projectiles from breaking when they are deployed.
It is a further object of this invention to provide such a kinetic energy rod warhead which prevents the projectiles from tumbling when they are deployed.
It is a further object of this invention to provide such a kinetic energy rod warhead which insures the projectiles approach the target at a better penetration angle.

It is a further object of this invention to provide such a kinetic energy rod warhead which can be deployed as part of a missile or as part of a "hit-to-kill"
vehicle.

It is a further object of this invention to provide such a kinetic energy rod warhead with projectile shapes which have a better chance of penetrating a target.
It is a further object of this invention to provide such a kinetic energy rod warhead with projectile shapes which can be packed more densely.

It is a further object of this invention to provide such a kinetic energy rod warhead which has a better chance of destroying all of the bomblets and chemical submunition payloads of a target to thereby better prevent casualties.

It is a further object of this invention to provide such a kinetic energy rod warhead which improves lethality against ballistic missiles having submunition or bomblet payloads.

This invention results from the realization that a higher lethality kinetic energy rod warhead which provides for high lethality of ballistic missiles having either submunition or bomblet payloads can be achieved by including a plurality of different size projectiles that are effective against destroying both submunition and bomblet payloads.

This invention features a kinetic energy rod warhead including a projectile core including a plurality of different size projectiles, an explosive charge about the core, and at least one detonator for the explosive charge.

In one embodiment, the plurality of different size projectiles may include a larger number of small projectiles and a smaller number of large projectiles.
The number of smaller projectiles may be chosen to increase lethality against submunition payloads. The number of larger projectiles may be chosen to increase lethality against bomblet payloads. The number of smaller projectiles may be chosen to increase the spray pattern density of the projectiles. The number of larger projectiles may be chosen to decrease the spray pattern density of the projectiles. The smaller projectiles may be located proximate an outer region of the core and the larger projectiles are located proximate the center region of the core. The plurality of different size projectiles may include about seventy percent smaller projectiles and about thirty percent larger projectiles. The mass of each large projectile may be greater than the mass of each of small projectile. All the projectiles may have a cruciform cross section. The large and small projectiles may be tightly packed in the core with minimal air spacing therebetween. All the projectiles may be made of tungsten.
Each of the small projectiles may weigh less than about 50 grams. Each of the small projectiles may weigh approximately 28 grams. The projectiles may have a hexagon shape, a cylindrical cross section, a non-cylindrical cross section, a star shape cross section, flat ends, a non-flat nose, a pointed nose, or a wedge-shape. The projectiles may be cube shaped or have a three-dimensional tetris shape.

This invention also features a kinetic energy rod warhead including a projectile core including a large number of smaller projectiles and a small number of larger projectiles, an explosive charge about the core, and at least one detonator for the explosive charge.

This invention further features a kinetic energy rod warhead including a projectile core including a large number of smaller projectiles for increasing the lethality against submunition payloads and a small number of larger projectiles for increasing lethality against bomblet payloads, an explosive charge about the core, and at least one detonator for the explosive charge.

BRIEF DESCRIPTION OF THE DRAWINGS

Other objects, features and advantages will occur to those skilled in the art from the following description of a preferred embodiment and the accompanying drawings, in which:

Fig. 1 is schematic view showing the typical deployment of a "hit-to-kill"
vehicle in accordance with the prior art;

Fig. 2 is schematic view showing the typical deployment of a prior art blast fragmentation type warhead;

Fig. 3 is schematic view showing the deployment of a kinetic energy rod warhead system incorporated with a "hit-to-kill" vehicle in accordance with the subject invention;

Fig. 4 is schematic view showing the deployment of a kinetic energy rod warhead as a replacement for a blast fragmentation type warhead in accordance with the subject invention;

Fig. 5 is a more detailed view showing the deployment of the projectiles of a kinetic energy rod warhead at a target in accordance with the subject invention;

Fig. 6 is three-dimensional partial cut-away view of one embodiment of the kinetic energy rod warhead system of the subject invention;

Fig. 7 is schematic cross-sectional view showing a tumbling projectile in accordance with prior kinetic energy rod warhead designs;

Fig. 8 is another schematic cross-sectional view showing how the use of multiple detonators aligns the projectiles to prevent tumbling thereof in accordance with the subject invention;

Fig. 9 is an exploded schematic three-dimensional view showing the use of a kinetic energy rod warhead core body used to align the projectiles in accordance with the subject invention;

Figs. 10 and 11 are schematic cut-away views showing the use of flux compression generators used to align the projectiles of the kinetic energy rod warhead in accordance with the subject invention;

Figs. 12-15 are schematic three-dimensional views showing how the projectiles of the kinetic energy rod warhead of the subject invention are aimed in a particular direction in accordance with the subject invention;

Fig. 16 is a three-dimensional schematic view showing another embodiment of the kinetic energy rod warhead of the subject invention;

Figs. 17-23 are three-dimensional views showing different projectile shapes useful in the kinetic energy rod warhead of the subject invention;

Fig. 24 is an end view showing a number of star-shaped projectiles in accordance with the subject invention and the higher packing density achieved by the use thereof;

Fig. 25 is another schematic three-dimensional partially cut-away view of another embodiment of the kinetic energy rod warhead system of the subject invention wherein there are a number of projectile bays;

Fig. 26 is another three-dimensional schematic view showing an embodiment of the kinetic energy rod warhead system of this invention wherein the explosive core is wedge shaped to provide a uniform projectile spray pattern in accordance with the subject invention;

Fig. 27 is a cross sectional view showing a wedge shaped explosive core and bays of projectiles adjacent it for the kinetic energy rod warhead system shown in Fig.
26; , Fig. 28 is a schematic depiction of a test version of a kinetic energy rod warhead in accordance with the subject invention with three separate rod bays;

Fig. 29 is a schematic depiction of the warhead of Fig. 28 after the explosive charge sections are added;

Fig. 30 is a schematic depiction of the rod warhead shown in Figs. 28 and 29 after the addition of the top end plate;

Fig. 31 is a schematic view of the kinetic energy rod warhead of Fig. 30 just before a test firing;

Fig. 32 is a schematic view showing the results of the impact of the individual rods after the test firing of the warhead showing in Fig. 31;

Fig. 33 is a schematic view showing a variety of individual penetrators rods after the test firing;

Fig. 34 is a schematic cross sectional view of a kinetic energy warhead with lower deployment angles in accordance with this invention;

Fig. 35 is an exploded view showing the use of buffer disks between the individual bays of projectiles in order to lower the deployment angles of the rods in accordance with this invention;

Fig. 36 is a schematic depiction showing the use of a glass filler around individual penetrators in order to lower the deployment angles in accordance with this invention;

Fig. 37 is a schematic three-dimensional view showing a different type of projectile in accordance with this invention including two frangible portions;

Fig. 38 is a schematic three-dimensional view of a kinetic energy rod warhead employing a plurality of different sized projectiles in accordance with this invention;
Fig. 39 is a schematic cross-sectional view showing in further detail one example of the different sized projectiles shown in Fig. 38;

Fig. 40 is a schematic three-dimensional view showing that a large number of small projectiles is more effective against a ballistic missile with a submunition payload;

Fig. 41 is a schematic three-dimensional view showing that a small number of larger projectiles is more effective against a ballistic missile with a bomblet payload;

Figs. 42A-42C are schematic side views showing the packing density of cruciform shaped projectiles and cylindrical rods in accordance with this invention;
Fig. 43A is a schematic three-dimensional view of a cube shaped projectile in accordance with this invention;

Fig. 43B is a schematic side view showing the packing density of the cube shaped projectile shown in Fig. 43A;

Fig. 44A is a three-dimensional view showing the tetris shaped projectile in accordance with this invention; and Fig. 44B is a schematic cross-sectional view showing the packing density of the tetris shaped projectile shown in Fig. 44A.

DISCLOSURE OF THE PREFERRED EMBODIMENT

As discussed in the Background section above, "hit-to-kill" vehicles are typically launched into a position proximate a re-entry vehicle 10, Fig. 1 or other target via a missile 12. "Hit-to-kill" vehicle 14 is navigable and designed to strike re-entry vehicle 10 to render it inoperable. Countermeasures, however, can be used to avoid the kill vehicle. Vector 16 shows kill vehicle 14 missing re-entry vehicle 10.
Moreover, biological bomblets and chemical submunition payloads 18 are carried by some threats and one or more of these bomblets or chemical submunition payloads 18 can survive, as shown at 20, and cause heavy casualties even if kill vehicle 14 does accurately strike target 10.

Turning to Fig. 2, blast fragmentation type warhead 32 is designed to be carried by missile 30. When the missile reaches a position close to an enemy re-entry vehicle (RV), missile, or other target 36, a pre-made band of metal or fragments on the warhead is detonated and the pieces of metal 34 strike target 36. The fragments, however, are not always effective at destroying the submunition target and, again, biological bomblets and/or chemical submunition payloads can survive and cause heavy casualties.

The textbook by the inventor hereof, R. Lloyd, "Conventional Warhead Systems Physics and Engineering Design," Progress in Astronautics and Aeronautics (AIAA) Book Series, Vol. 179, ISBN 1-56347-255-4, 1998, incorporated herein by this reference, provides additional details concerning "hit-to-kill" vehicles and blast fragmentation type warheads. Chapter 5 of that textbook, proposes a kinetic energy rod warhead.

In general, a kinetic energy rod warhead, in accordance with this invention, can be added to kill vehicle 14, Fig. 3 to deploy lengthy cylindrical projectiles 40 directed at re-entry vehicle 10 or another target. In addition, the prior art blast fragmentation type warhead shown in Fig. 2 can be replaced with or supplemented with a kinetic energy rod warhead 50, Fig. 4 to deploy projectiles 40 at target 36.

Two key advantages of kinetic energy rod warheads as theorized is that 1) they do not rely on precise navigation as is the case with "hit-to-kill"
vehicles and 2) they provide better penetration then blast fragmentation type warheads.

To date, however, kinetic energy rod warheads have not been widely accepted nor have they yet been deployed or fully designed. The primary components associated with a theoretical kinetic energy rod warhead 60, Fig. 5 is hull 62, projectile core or bay 64 in hull 62 including a number of individual lengthy cylindrical rod projectiles 66, sympethic shield 67, and explosive charge 68 in hull 62 about bay or core 64. When explosive charge 66 is detonated, projectiles 66 are deployed as shown by vectors 70, 72, 74, and 76.

Note, however, that in Fig. 5 the projectile shown at 78 is not specifically aimed or directed at re-entry vehicle 80. Note also that the cylindrical shaped projectiles may tend to break upon deployment as shown at 84. The projectiles may also tend to tumble in their deployment as shown at 82. Still other projectiles approach target 80 at such a high oblique angle that they do not penetrate target 80 effectively as shown at 90.

In this invention, the kinetic energy rod warhead includes, inter alia, means for aligning the individual projectiles when the explosive charge is detonated and deploys the projectiles to prevent them from tumbling and to insure the projectiles approach the target at a better penetration angle.

In one example, the means for aligning the individual projectiles include a plurality of detonators 100, Fig. 6 (typically chip slapper type detonators) spaced along the length of explosive charge 102 in hull 104 of kinetic energy rod warhead 106. As shown in Fig. 6, projectile core 108 includes many individual lengthy cylindrical projectiles 110 and, in this example, explosive charge 102 surrounds projectile core 108. By including detonators 100 spaced along the length of explosive charge 102, sweeping shock waves are prevented at the interface between projectile core 108 and explosive charge 102 which would otherwise cause the individual projectiles 110 to tumble.

As shown in Fig. 7, if only one detonator 116 is used to detonate explosive 118, a sweeping shockwave is created which causes projectile 120 to tumble.
When this happens, projectile 120 can fracture, break or fail to penetrate a target which lowers the lethality of the kinetic energy rod warhead.

By using a plurality of detonators 100 spaced along the length of explosive charge 108, a sweeping shock wave is prevented and the individual projectiles 100 do not tumble as shown at 122.

In another example, the means for aligning the individual projectiles includes low density material (e.g., foam) body 140, Fig. 9 disposed in core 144 of kinetic energy rod warhead 146 which, again, includes hull 148 and explosive charge 150.
Body 140 includes orifices 152 therein which receive projectiles 156 as shown.
The foam matrix acts as a rigid support to hold all the rods together after initial deployment. The explosive accelerates the foam and rods toward the RV or other target. The foam body holds the rods stable for a short period of time keeping the rods aligned. The rods stay aligned because the foam reduces the explosive gases venting through the packaged rods.

In one embodiment, foam body 140, Fig. 9 maybe combined with the multiple detonator design of Figs. 6 and 8 for improved projectile alignment.

In still another example, the means for aligning the individual projectiles to prevent tumbling thereof includes flux compression generators 160 and 162, Fig. 10, one on each end of projectile core 164 each of which generate a magnetic alignment field to align the projectiles. Each flux compression generator includes magnetic core element 166 as shown for flux compression generator 160, a number of coils 168 about core element 166, and explosive charge 170 which implodes magnetic core element when explosive charge 170 is detonated. The specific design of flux compression generators is known to those skilled in the art and therefore no further details need be provided here.

As shown in Fig. 11, kinetic energy rod warhead 180 includes flux compression generators 160 and 162 which generate the alignment fields shown at 182 and 184 and also multiple detonators 186 along the length of explosive charge 190 which generate a flat shock wave front as shown at 192 to align the projectiles at 194. As stated above, foam body 140 may also be included in this embodiment to assist with projectile alignment.

In Fig. 12, kinetic energy rod warhead 200 includes an explosive charge divided into a number of sections 202, 204, 206, and 208. Shields such as shield 225 separates explosive charge sections 204 and 206. Shield 225 maybe made of a composite material such as a steel core sandwiched between inner and outer lexan layers to prevent the detonation of one explosive charge section from detonating the other explosive charge sections. Detonation cord resides between hull sections 210, 212, and 214 each having a jettison explosive pack 220, 224, and 226. High density tungsten rods 216 reside in the core or bay of warhead 200 as shown. To aim all of the rods 216 in a specific direction and therefore avoid the situation shown at 78 in Fig. 5, the detonation cord on each side of hull sections 210, 212, and 214 is initiated as are jettison explosive packs 220, 222, and 224 as shown in Figs. 13-14 to eject hull sections 210, 212, and 214 away from the intended travel direction of projectiles 216.
Explosive charge section 202, Fig. 14 is then detonated as shown in Fig. 15 using a number of detonators as discussed with reference to Figs. 6 and 8 to deploy projectiles 216 in the direction of the target as shown in Fig. 15. Thus, by selectively detonating one or more explosive charge sections, the projectiles are specifically aimed at the target in addition to being aligned using the aligning structures shown and discussed with reference to Figs. 6 and 8 and/or Fig. 9 and/or Fig. 10.

In addition, the structure shown in Figs. 12-15 assists in controlling the spread pattern of the projectiles. In one example, the kinetic energy rod warhead of this invention employs all of the alignment techniques shown in Figs. 6 and 8-10 in addition to the aiming techniques shown in Figs. 12-15.

Typically, the hull portion referred to in Figs. 6-9 and 12-15 is either the skin of a missile (see Fig. 4) or a portion added to a "hit-to-kill" vehicle (see Fig. 3).
Further details of the frangible skin employed in the kinetic energy rod warhead of this invention are discussed in detail below.

Thus far, the explosive charge is shown disposed about the outside of the projectile or rod core. In another example, however, explosive charge 230, Fig. 16 is disposed inside rod core 232 within hu11234. Further included may be low density material (e.g., foam) buffer material 236 between core 232 and explosive charge 230 to prevent breakage of the projectile rods when explosive charge 230 is detonated.

Thus far, the rods and projectiles disclosed herein have been shown as lengthy cylindrical members made of tungsten, for example, and having opposing flat ends.

In another example, however, the rods have a non-cylindrical cross section and non-flat noses. As shown in Figs. 17-24, these different rod shapes provide higher strength, less weight, and increased packaging efficiency. They also decrease the chance of a ricochet off a target to increase target penetration especially when used in conjunction with the alignment and aiming methods discussed above.

Typically, the preferred projectiles do not have a cylindrical cross section and instead may have a star-shaped cross section, a cruciform cross section, or the like.
Also, the projectiles may have a pointed nose or at least a non-flat nose such as a wedge-shaped nose. Projectile 240, Fig. 17 has a pointed nose while projectile 242, Fig. 18 has a star-shaped nose. Other projectile shapes are shown at 244, Fig.
19 (a star-shaped pointed nose); projectile 246, Fig. 20; projectile 248, Fig. 21;
and projectile 250, Fig. 22. Projectiles 252, Fig. 23 have a star-shaped cross section, pointed noses, and flat distal ends. The increased packaging efficiency of these specially shaped projectiles is shown in Fig. 24 where sixteen star-shaped projectiles can be packaged in the same space previously occupied by nine penetrators or projectiles with a cylindrical shape.

Thus far, it is assumed there is only one set of projectiles. In another example, however, the projectile core is divided into a plurality of bays 300 and 302, Fig. 25.
Again, this embodiment may be combined with the embodiments shown in Figs. 6 and 8-24. In Figs. 26 and 27, there are eight projectile bays 310-324 and cone shaped explosive core 328 which deploys the rods of all the bays at different velocities to provide a uniform spray pattern. Also shown in Fig. 26 is wedged shaped explosive charge sections 330 with narrower proximal surface 334 abutting projectile core 332 and broader distal surface 336 abutting the hull of the kinetic energy rod warhead.
Distal surface 336 is tapered as shown at 338 and 340 to reduce the weight of the kinetic energy rod warhead.

In one test example, the projectile core included three bays 400, 402 and 404, Fig. 28 of hexagon shaped tungsten projectiles 406. The other projectile shapes shown in Figs. 17-24 may also be used. Each bay was held together by fiberglass wrap 408 as shown for bay 400. The bays 400, 402 and 404 rest on steel end plate 410. Buffer 407 is inserted around the rod core. This buffer reduces the explosive edge effects acting against the outer rods. By mitigating the energy acting on the edge rods it will reduce the spray angle from the explosive shock waves.

Next, explosive charge sections 412, 414, 416 and 418, Fig. 29 were disposed on end plate 410 about the projectile core. Thus, the primary firing direction of the projectiles in this test example was along vector 420. Clay sections 422, 424, 426 and 428 simulated the additional explosive sections that would be used in a deployed warhead. Between each explosive charge section is sympathetic shield 430 typically comprising steel layer 432 sandwiched between layers of Lexan 434 and 436.
Each explosive charge section is wedge shaped as shown with proximal surface 440 of explosive charge section 412 abutting the projectile core and distal surface 442 which is tapered as shown at 444 and 446 to reduce weight.

Top end plate 431, Fig. 30 completes the assembly. End plates 410 and 431 could also be made of aluminum. The total weight of the projectile rods 406 was 65 pounds, the weight of the C4 explosive charge sections 412, 414, 416, and 418 was 10 pounds. Each rod weighed 35 grams and had a length to diameter ratio of 4. 271 rods were packaged in each bay with 823 rods total. The total weight of the assembly was 30.118 pounds.

Fig. 31 shows the addition of detonators as shown at 450 just before test firing.
There was one detonator per explosive charge section and all the detonators were fired'simultaneously. Fig. 32-33 shows the results after test firing. The individual projectiles struck test surface 452 as shown in Fig. 32 and the condition of certain recovered projectiles is shown in Fig. 33.

To reduce the deployment angles of the projectiles when the detonators detonate the explosive charge sections thereby providing a tighter spray pattern useful for higher lethality in certain cases, several additional structures were added in the modified warhead of Fig. 34.

One means for reducing the deployment angles of projectiles 406 is the addition of buffer 500 between the explosive charge sections and the core.
Buffer 500 is preferably a thin layer of poly foam 1/2 inch thick which also preferably extends beyond the core to plates 430 and 412. Buffer 500 reduces the edge effects of the explosive shock waves during deployment so that no individual rod experiences any edge effects.

Another means for reducing the deployment angles of the rods is the addition of poly foam buffer disks 510 also shown in Fig. 35. The disks are typically 1/8 inch thick and are placed between each end plate and the core and between each core bay as shown to reduce slap or shock interactions in the rod core.

Momentum traps 520 and 522 are preferably a thin layer of glass applied to the outer surface of each end plate 410 and 430. Also, thin aluminum absorbing layers 530 and 532 between each end plate and the core help to absorb edge effects and thus constitute a further means for tightening the spray pattern of the rods.

In some examples, selected rods 406a, 406b, 406c, and 406d extend continuously through all the bays to help focus the remaining rods and to reduce the angle of deployment of all the rods. Another idea is to add an encapsulant 540, which fills the voids between the rods 406, Fig. 36. The encapsulant may be glass and/or grease coating each rod. Preferably, there are a plurality of spaced detonators 450a, 450b, and 450c, Fig. 32 for each explosive charge section each detonator typically aligned with a bay 400, 402, and 404, respectively, to provide a flatter explosive front and to further reduce the deployment angles of rods 406. Another initiation technique could be used to reduce edge effects by generating a softer push against the rods.

This concept would utilize backward initiation where the multiple detonators 450a', 450b', and 450c' are moved from their traditional location on the outer explosive to the inner base proximate buffer 500. The explosive initiators are inserted at the explosive/foam interface which generates a flat shock wave traveling away from the rod core. This initiation logic generates a softer push against the rod core reducing all lateral edge effects.

Another idea is to use rod 406e, Fig. 37 at select locations or even for all the rods. Rod 406e extends through all the bays but includes frangible portions of reduced diameter 560 and 562 at the intersection of the bays, which break upon deployment dividing rod 406e into three separate portions 564, 566, and 568.

The result with all, a select few, or even just one of these exemplary structural means for reducing the deployment angles of the rods or projectiles when the detonator(s) detonate the explosive charge sections is a tighter, more focused rod spray pattern. Also, the means for aligning the projectiles discussed above with reference to Figs. 6-11 and/or the means for aiming the projectiles discussed above with reference to Figs. 12-15 may be incorporated with the warhead configuration shown in Figs. 34-35 in accordance with this invention.

In one preferred embodiment, the kinetic energy rod warhead of this invention includes a plurality of different size projectiles which are effective against ballistic missiles having submunition or bomblet payloads. The different size projectiles typically include a large number of small projectiles which are effective against destroying submunition payloads and a small number of larger, typically heavier projectiles which are effective against destroying bomblet payloads.

For example, kinetic energy rod warhead 600, Fig. 38, includes projectile core 602 including plurality 604 of different size projectiles. The projectiles ideally include a larger number of small projectiles 606 and a smaller number of large projectiles 608. The large projectiles are typically heavier than the small projectiles, typically weighing about 113.7 g compared to about 28.6 g for the small projectiles.
Warhead 600 also includes an explosive charge divided into a number of sections 610, 612, 614, 616, 618, 620, 622 and 624. Shields, such as shield 626, separate explosive charge sections 610 and 612. Warhead 600 also includes a plurality of detonators, such as detonators 628, 630, 632, 634, 636, 638, 640 and 642. Selected detonators 628-640 (typically chip slapper-type detonators) are used to initiate selected explosive charge sections 610-624 and deploy the plurality of different size projectiles. Foam body 603, similar to foam body 140, Fig. 9, as discussed above, may be employed to surround core 602, Fig. 38, for improved projectile alignment. The smaller projectiles 606 are effective at destroying ballistic missiles having submunition payload and the larger, heavier projectiles 608 are effective at destroying bomblet payloads.
The result is that kinetic energy rod warhead 600 of this invention effectively destroys ballistic missiles having either submunition or bomblet payloads, as discussed in further detail below.

Fig. 39, where like parts have been given like numbers, shows an enlarged view of projectile core 602 including smaller projectiles 606 and larger projectiles 608. In this example, all the projectiles have a cruciform cross section. The projectiles may also include cube shaped projectiles, such as cube shaped projectiles 652 and tetris shaped projectiles, such as tetris shaped projectiles 654.

Typically, smaller projectiles 606 are located proximate outer region 802 of core 602 while the larger projectiles 608 are located proximate the center region 804 of core 602.

In one design, the projectiles include about 70% smaller projectiles 606 and about 30% larger projectiles 608. The mass of each of the large projectiles 608 is typically greater than the mass of each of the small projectiles 606. In one example, the mass of each small projectiles 606 in core 602 is about 28 grams and the mass of each of the large projectiles 608 is about 114 grams. The plurality of different size projectiles may be made of tungsten or similar materials.

A simulation showing that a larger number of smaller projectiles is more effective against a ballistic missile having a submunition payload is shown in Fig. 40.
In this example, the smaller projectiles, e.g., 128 projectiles, indicated at 758, are effective at destroying submunition payloads, as shown by the destroyed submunitions indicated at 760. In contrast, when a fewer number of projectiles were deployed, e.g., 32 projectiles, as indicated at 762, fewer submunitions were destroyed, as shown by the destroyed submunitions indicated at 764. When four large projectiles were deployed, as indicated at 766, only three submunitions were destroyed, as indicated at 768. A large number of smaller projectiles or rods is also shown at 770 impacting submunition payload 772. As shown at 774, the large number of small projectiles or rods created substantial damage to the submunition payload 772.
In contrast, when a small number of large projectiles indicated at 776 were deployed against submunition payload 772, only minimal damage resulted to submunition payload 772, as indicated at 778.

Fig. 41 is a simulation showing that a few larger, heavier projectiles are very effective against ballistic missiles having bomblet payloads. In this example, when a small number of larger projectiles, e.g., four heavier projectiles or rods each weighing about 2273 grams, as indicated at 780 are deployed the large projectiles penetrated bomblet payload 782 and destroyed almost all the bomblets therein, as indicated by destroyed bomblets 784. However, when a larger number of rods were used, e.g., rods each weighing about 276 grams, as indicated at 784, the larger number of smaller projectiles or rods did not destroy the aft bomblets, as indicated by live bomblets 788.
When an even larger number of smaller projectiles or rods where deployed, e.g., 1024 rods each weighing about 31 grams, as indicated at 790 a substantial portion of the aft bomblets were not destroyed, as shown by the live bomblets 792. Hence, a small number of larger and heavier penetrators are more effective at destroying ballistic missiles having bomblet payloads.

Because kinetic energy rod warhead 600, Fig. 38 of this invention deploys both a large number of small projectiles and a small number of larger and heavier projectiles or rods at the same time, warhead 600 effectively destroys ballistic missiles having submunition and/or bomblet payloads.

As discussed above, the different size rods ideally have a cruciform cross section. The cruciform shaped rods provide for tight packing of the projectiles within core 602 with minimal air space therebetween. Tight packing of the cruciform cross-sectional shaped projectiles provides for a larger number of projectiles to be packed within core 602 than cylindrical shaped rods. For example, as shown in Fig.
42A the packing density of the cruciform shaped rods 660 allows about 80 projectiles to be packed projectile core 602. In contrast, cylindrical shaped rods 662 Fig. 42B
allows only about 56 rods or projectiles to be packed in core 602. The cruciform shaped rods can be even more tightly packed, as shown in Fig. 42C, where, in this example, cruciform projectiles 662 were packed within the core 602. The higher number of projectiles that can be packed within core 602 provide a higher spray pattern density on the enemy target. In this example, the larger cruciform shaped rods 660 have a diameter of about 0.75 inches and each weigh about 34.4 grams and cruciform shaped rods 662 have a diameter of about 0.375 inches and each weigh about 25.2 grams.
Moreover, the use of cruciform projectiles or penetrators are effective against bulk or liquid filled tanks because they enhance the transfer of kinetic energy causing hydraulic ram effects. This process is caused by high shock pressure with projectile drag causing sub-explosive forces on the tank wall.

As discussed above, the preferred projectiles do not have a cylindrical cross-section and instead have cruciform cross-section. Also, the projectiles may have a pointed nose or at least a non-flat nose such as a wedge-shaped nose.
Projectile 240, Fig. 17 has a pointed nose while projectile 242, Fig. 18 has a star-shaped nose. Other projectile shapes are shown at 244, Fig. 19 (a star-shaped pointed nose);
projectile 246, Fig. 20; projectile 248, Fig. 21; and projectile 250, Fig. 22.
Projectiles 252, Fig.
.23 have a star-shaped cross section, pointed noses, and flat distal ends. The increased packaging efficiency of these specially shaped projectiles is shown in Fig. 24 where sixteen star-shaped projectiles can be packaged in the same space previously occupied by nine penetrators or projectiles with a cylindrical shape. The projectiles or rods may also be cube shaped, as shown in Fig. 43A. The cube shape also provides for a tightly packed density, as shown in Fig. 43B. Typically each cube has a mass of about 50 grams and about 48 cubes may be packed in core 602. The plurality of projectiles may have a three-dimensional tetris shape as shown in Fig. 44A.
The tetris shaped rods also provide for a tightly packed density in core 602, as shown in Fig.
44B.

Although specific features of the invention are shown in some drawings and not in others, this is for convenience only as each feature may be combined with any or all of the other features in accordance with the invention. The words "including", "comprising", "having", and "with" as used herein are to be interpreted broadly and comprehensively and are not limited to any physical interconnection. Moreover, any embodiments disclosed in the subject application are not to be taken as the only possible embodiments.

Other embodiments will occur to those skilled in the art and are within the following claims:

What is claimed is:

Claims

1. A kinetic energy rod warhead comprising:

a projectile core including a plurality of different size projectiles;
an explosive charge about the core; and at least one detonator for the explosive charge.

2. The kinetic energy rod warhead of claim 1 in which the plurality of different size projectiles includes a larger number of small projectiles and a smaller number of large projectiles.

3. The kinetic energy rod warhead of claim 2 in which the number of smaller projectiles is chosen to increase lethality against submunition payloads.

4. The kinetic energy rod warhead of claim 2 in which the number of larger projectiles is chosen to increase lethality against bomblet payloads.

5. The kinetic energy rod warhead of claim 2 in which the number of smaller projectiles is chosen to increase the spray pattern density of the projectiles.

6. The kinetic energy rod warhead of claim 3 in which the number of larger projectiles is chosen to decrease the spray pattern density of the projectiles.

7. The kinetic energy rod warhead of claim 2 in which the smaller projectiles are located proximate an outer region of the core and the larger projectiles are located proximate the center region of the core.

8. The kinetic energy rod warhead of claim 2 in which the plurality of different size projectiles includes about seventy percent smaller projectiles and about thirty percent larger projectiles.

9. The kinetic energy rod warhead of claim 2 in which the mass of each large projectile is greater than the mass of each of small projectile.

10. The kinetic energy rod warhead of claim 2 in which all the projectiles have a cruciform cross section.

11. The kinetic energy rod warhead of claim 10 in which the large and small projectiles are tightly packed in the core with minimal air spacing therebetween.

12. The kinetic energy rod warhead of claim 1 in which the all the projectiles are made of tungsten.

13. The kinetic energy rod warhead of claim 10 in which each of the small projectiles weigh less than about 50 grams.

14. The kinetic energy rod warhead of claim 13 in which each of the small projectiles weigh approximately 28 grams.

15. The kinetic energy rod warhead of claim 1 in which the projectiles have a hexagon shape.

16. The kinetic energy rod warhead of claim 1 in which the projectiles have a cylindrical cross section.

17. The kinetic energy rod warhead of claim 1 in which the projectiles have a non-cylindrical cross section.

18. The kinetic energy rod warhead of claim 1 in which the projectiles have a star shape cross section.

19. The kinetic energy rod warhead of claim 1 in which the projectiles have flat ends.

20. The kinetic energy rod warhead of claim 1 in which the projectiles have a non-flat nose.

21. The kinetic energy rod warhead of claim 1 in which the projectiles have a pointed nose.

22. The kinetic energy rod warhead of claim 1 in which the projectiles have a wedge-shape.

23. The kinetic energy rod warhead of claim 1 in which the projectiles are cube shaped.

24. The kinetic energy rod warhead of claim 1 in which the projectiles have a three-dimensional tetris shape.

25. A kinetic energy rod warhead comprising:

a projectile core including a large number of smaller projectiles and a small number of larger projectiles;

an explosive charge about the core; and at least one detonator for the explosive charge.

26. A kinetic energy rod warhead comprising:

a projectile core including a large number of smaller projectiles for increasing the lethality against submunition payloads and a small number of larger projectiles for increasing lethality against bomblet payloads;

an explosive charge about the core; and at least one detonator for the explosive charge.