ARTILLERY ROCKET KINETIC ENERGY ROD WARHEAD
 The invention described herein may be manufactured, used and licensed by or for the Government for U.S. governmental purposes; provisions of 15 U.S.C. section 3710c apply.
BACKGROUND OF THE INVENTION
 The prior art for artillery rocket lethal warhead packaging includes unitary high explosive bombs, autonomous or semi-autonomous submunitions designed to attack armor, and anti-personnel payloads comprised of hundreds of fragmenting, explosive filled cluster munition bomblets. In order to construct the cluster munition warheads, cylindrical cluster munitions are installed into longitudinal holes in large cylindrical foam overpacks. Multiplicities of overpacks are installed, one at a time, into the warhead bay of the rocket.
 The rocket dispenses its payload by means of an explosive bursting charge in the warhead bay that splits the warhead skin along pre-scored longitudinal lines, disintegrates the cylindrical foam overpacks, and scatters the cluster munitions into the airstream around the rocket. The explosive bursting charge is black powder contained in a plastic cylinder that extends the entire length of the warhead bay. The artillery rocket payload dispense event is extremely violent and energetic, since the burster must rip apart the metal warhead skin and widely disperse the payload of cluster munitions.
 Kinetic energy (KE) rods have been used in the past in artillery shells and in small (2.75") direct fire rockets, but never in an indirect fire artillery rocket. The prior art artillery shells used a large number of extremely small rods that were dispensed by a central bursting charge for effect within a short distance of the dispense point. The rods lost velocity and effectiveness very quickly, due to their low mass and random orientation dispense method.
 The aforementioned direct fire rocket utilized an explosive charge behind the rod payload cavity to dislodge the warhead nose and dispense the single cluster of KE rods into the airstreara ahead of the rocket body. Neither of these techniques is applicable for use in an indirect fire artillery rocket.
 KE rods are currently fielded in a US Air Force delivered dispenser weapon system. However, this weapon operates in a much lower velocity regime than a supersonic artillery rocket; thus, its payload dispensing system is not applicable to the present invention.
 No currently utilized munition packaging techniques are appropriate for use with artillery rocket KE rod payloads. If the rods are placed directly into the rocket warhead bay, they are dispensed in random orientations and quickly lose their velocity and lethality due to air drag. Installing them into foam packs and then installing the foam packs one at a time into the rocket is labor intensive. The explosive forces needed to break up the foam packs and expel the rods from the rocket would result in many rods being damaged during dispense and cause many rods to be dispensed in random and ineffective orientations.  Additionally, the dispensed rods would form large numbers of tightly packed small clusters. The clusters would be dispensed along an axis several feet in length, so that poorly oriented rods and random foam fragments from the forward clusters would cause fratricide in the following clusters. Thus, the effectiveness of the warhead payload would be severely degraded.
 This invention, which includes a novel packaging arrangement specifically designed for KE rod rocket payloads along with a new payload dispensing technique, yields benefits in both assembly cost and in terminal performance. Assembly costs are reduced because the laborious task of filling the foam packs with KE rod packs is eliminated. All of the KE rods are pre-assembled into tier packs that are inserted as units into the rocket warhead bay.
 Once the tier packs of rods are in place they are secured by a retaining band that is severed during the skin severance event. The technical performance of the warhead is improved because the tightly packed rods can be dispensed in a well defined radial ejection event that minimizes rod tumbling or excessive angular oscillations. Additionally, no packing material or dunnage is used between the rods, so that dunnage fragments cannot damage the rods or disturb their orientation during dispense.  The result is a KE rod cloud that forms a predictable and repeatable expanding elliptical pattern over the target area. Holes in the rod cloud and fratricide between KE rods are minimized.
SUMMARY OF THE INVENTION
 Accordingly, one object of the present invention is to realize a highly accurate KE rod warhead.
 Still another object is to provide an easily assembled KE rod warhead.  Yet another object is to provide a warhead that removes the problems inherent with unexploded ordnance.
 These and other objects are provided by a warhead having a plurality of tier pack bulkheads arranged in a stacked formation around a center column to form a plurality of tier packs. A plurality of skin severance trays are connected to the plurality of tier pack bulkheads. A bulkhead collar and an aft bulkhead are connected to the center column with the plurality of tier packs being positioned between the bulkhead collar and the aft bulkhead. A plurality of holding trays, separated by dividers, are positioned within the plurality of tier packs, the holding trays being positioned between respective tier pack bulkheads. The holding trays are filled with KE rods.
DESCRIFΠON OF THE DRAWINGS
 Figure 1 is a cutaway side view of the KE rod payload assembly of the present invention.
 Figure 2 is a perspective illustration showing one of the multiplicity of tier packs which are loaded into an artillery rocket warhead bay according to the present invention.
 Figure 3 is a perspective illustration of one of the tier pack holding trays filled with KE rods.
 Figure 4 is a perspective illustration of one of the tier packs according to the present invention completely assembled into the artillery rocket warhead bay.
 Figure 5 is a perspective illustration showing how the tier pack dividers and tier pack bulkheads are assembled on the artillery rocket center column according to the present invention.
 With respect to Figure 1 , KE rods 202 in warhead 100 are visible in that the straps and dunnage over the KE rod packs or tier packs 104 have been removed. The forward portion of the warhead bay 109 contains ballast weights 101A and 101B that tailor the mass, center of mass location, and inertia properties of the rocket. A rocket center column 102 runs down the center of the warhead bay 109.  The ballast weights are designed to ensure that the overall mass and inertia properties of the KE rod payload matches the prior art cluster munition payload that the present invention is designed to replace so that no changes will be required in the prior art trajectory simulations and firing tables.
 The rocket center column 102 serves as the attachment point for the ballast weights 101A, 101B, the warhead bay bulkhead collar 103, and the stages of tier packs 104A, 104B, 104C, 104D, 104E, 104F, etc. The center column 102 and the warhead bay skin 105 are the primary structural components of the KE rod warhead. The KE rods are tightly nested together in a multiplicity of tier packs inside the artillery rocket warhead bay.
 The present invention utilizes a KE rod payload concept such that the skin severance system has been separated from the rod distribution function so that each can be optimally calibrated for its intended purpose. The warhead skin 105 is separated from the artillery rocket just prior to dispense of the KE rods. Skin severance trays 106 containing flexible linear shaped charge (FLSC) lines 305 are placed at four equally spaced radial locations just beneath the warhead skin.
 The FLSC lines 305 (Figure 4), which are initiated by a conventional artillery rocket fuze, sever the warhead bay skin away from the artillery rocket. Inflatable gas bags can be placed beneath the skin panels to initiate their separation from the rocket body, if so required by the aerodynamics of the particular implementation. The bags are required in some cases to ensure that the skin panels do not strike the rocket body or tailfins after severance. In most applications, the rocket spin rate is sufficient to discard the skin panels and the gas bags are not necessary.
 In Figure 2, one of the multiplicity of tier packs is shown as it would be packed into the artillery rocket warhead bay. The tier pack as shown is divided into segments, with tier pack dividers 201A, 201B between them. KE rods 202 are tightly packaged together into tier pack trays 205 inside the tier dividers with all of them pointing forward toward the nose of the artillery rocket.
 The tier pack bulkheads 204 are slotted for and attached to the skin severance trays 106. The distance between the bulkheads is slightly greater than the rod length, so that the rods can be dispensed from the rocket without dragging against the bulkheads. It should be noted that although Figure 2 shows four tier pack trays in a tier pack, the tier pack can be comprised of either less than or greater than four tier pack trays.  A single tier pack holding tray 205 filled with KE rods 202 is shown in Figure 3. In the configuration shown, two sizes of KE rods are packed into the same tier pack holding tray 205. A single tier pack holding tray can contain a single size or type of KE rods, or a multiplicity of sizes and types of KE rods. All of the tier pack trays to be inserted into a single tier pack will be filled with the same mix of sizes and types of KE rods. Adjacent tier packs can be filled with different mixes of sizes and types of KE rods, so that the rocket payload effects can be optimized.
 In Figure 4, one of the tier packs is shown completely assembled into the warhead bay 109. The flexible dunnage 301 prevents damage to the rods caused by skin contact during transportation and handling of the rocket. The restraining strap 302 wraps around the tier pack and passes over the skin severance trays 106. Quadrant or tier pack divider 201 is attached to the center column 102.
 The restraining strap 302 compresses the tier packs so that the rods do not vibrate or chafe against each other during transportation and handling of the rocket or during flight. Operation of the FLSC when the warhead skins are cut separates the restraining strap into four pieces and releases the rods from the rocket.  The KE rod warhead utilizes the spin rate of the rocket to dispense the rods from the warhead and disperse them into the airstream without excessive pitching or tumbling. The dispense technique, in conjunction with the nose-forward packaging arrangement, ensures that a dense and repeatable pattern of rods is delivered to the artillery rocket target area.
 The present invention provides that different tier packs can contain different types or sizes of KE rods. Since each type and size of rod is effective against a defined range of targets, constructing the payload from a mix of rods yields excellent broad spectrum lethality for the overall payload. Conversely, constructing payload assemblies from a single type of rods gives optimized lethal results against more narrowly defined target sets. The present invention can contain both homogeneous and heterogeneous arrangements of KE rod configurations.
 With reference to Figure 1 , the major structural components of the artillery rocket KE rod warhead are the center column 102, the skin severance trays 106, and the warhead skin 105. The components are rigidly attached to the warhead bay forward bulkhead 108 and the warhead bay aft bulkhead 107. The reinforcement provided to the assembly by the bulkheads and center column ensures that it will withstand all ground handling and flight loading conditions. The ballast weights 101A, 101B are rigidly attached to the center column 102 and are securely fastened into the artillery rocket.  In Figure S, the warhead bay tier pack dividers 201A, 201B and tier pack bulkhead 204 are assembled onto the center column 102. The center column is longitudinally slotted with slots 404A, 404B to allow the quadrant or tier pack dividers 201A, 201B to be placed into position. The tier pack bulkheads are not attached to the warhead skin. The skin severance trays 106 fit within cutouts 203 (Figure 2) in the tier pack bulkheads 204 and are securely attached to them. The skin severance trays 106 are securely attached to the forward warhead bay bulkhead 106 and the aft warhead bay bulkhead 107.
 The skin severance trays 106 hold the FLSC lines 305 in close proximity to the warhead skin in the locations where the skin is to be cut. Finally, the KE rods are packed into the tier pack holding trays 205 as shown in Figure 2 and Figure 3, using the flexible dunnage material 301 and restraining strap 302 to hold them securely in position (Figure 4). All of the KE rods are packaged in a nose-forward orientation.
 All of the components with the exception of the FLSC, KE rods, tier pack trays and flexible dunnage can be constructed from either aluminum or corrosion resisting steel as required for their specific strength and weight properties. The FLSC lines are energetic pyrotechnic devices. The tier pack trays can be constructed from the many plastic based materials that combine low cost manufacturing, reasonable strength and flexibility properties, and light weight. The KE rods can be constructed from steel or tungsten, depending upon the loadout that best addresses the full target set for the rocket.
 The KE rods are KE rod penetrators, sometimes known as flechettes. Other payloads, such as smoke canisters, informational leaflets, or illumination devices can be packaged in the same fashion using the invented packaging arrangement. The flexible dunnage can be made from any type of currently available protective packaging material.
 The operation cycle begins when an artillery rocket carrying a KE rod payload enters its target area and its fuze initiates the payload dispense event. The artillery rocket fuze initiates the FLSC lines 305 contained in the skin severance trays 106. The FLSC severs the skin longitudinally into four panels and cuts the KE rod pack restraining straps 302. The spin of the rocket throws the panels away from the rocket body so that they do not strike either the rocket airframe or the tailfins.
 The removal of the warhead skin and severance of the restraining straps frees the KE rods from their tier packs. The KE rods are then ejected away from the rocket by the centripetal acceleration resulting from the rocket spin rate. Dispense of the KE rods in this way results in their entering the airstream with a minimum of pitching or tumbling. The completion of the operation cycle occurs when a dense and repeatable pattern of KE rods engages the artillery rocket target area.
 In prior art artillery rockets, when the rocket was used against a target, large numbers of cluster munitions were scattered in and around the target area. Typically some of the munitions failed to explode, making the area hazardous to friendly troops and to civilians for an indefinite period of time. Use of the cluster munitions has drawn increasing international criticism, with some organizations and countries advocating complete bans on the use of cluster munitions. A further drawback of prior art artillery rockets is that they have limited effectiveness against certain types of targets.  In the present invention, the artillery rocket target area is attacked with a lethal and effective pattern of KE rod penetrators that leaves no unexploded ordnance (UXO) contamination after the attack. Thus, friendly troops can enter the target area without danger, civilians in the area can pursue their daily activities without the lingering danger of injury or death from UXO hazards, and no battlefield cleanup costs will be incurred by the United States Government from the use of artillery rockets.  Still further, in the present invention, the KE rod payload has broad spectrum effectiveness against most artillery rocket targets. Its lethality against the target set is equal to or greater than the prior art cluster munition payload, and it can be used without incurring condemnation from the international community.
 Modifications of the above teachings are possible without deviating from the teachings of the present invention. Accordingly, the scope of the invention is only limited to the claims which follow hereafter.