Abstract
Apparatus and methods relating to a missile canister that utilizes a variable obturator assembly. The variable obturator assembly can include a plurality of gates that adjust based upon canister pressure at a base plate. In a maximum pressure situation experienced during successful missile egress from the canister, one or more of the gates can open in response to canister flyout pressure so as to increase flow area through the base plate, thereby reducing canister pressure. In a restrained firing scenario, the plurality of gates remain closed thereby preventing missile exhaust gases from flow up past the base plate which could lead to heating of a rocket motor and warhead. The variable obturator assembly can have multiple individual gates that are mounted to the base plate with a hinge assembly, with the gates held in a closed position against the base plate with a spring assembly.
Claims
1. A missile canister for a vertical launch missile system, said canister comprising a forward end and an aft end and a central axis extending from the forward end to the aft end, said forward end disposed approximate a missile nose while the aft end is disposed proximate a missile exhaust nozzle, the canister comprising a canister shell, a canister forward closure disposed at said forward end, a canister aft closure disposed at said aft end, an obturator plate mounted adjacent to the missile exhaust nozzle and spaced apart from the canister aft closure, said obturator plate disposed transverse to the central axis of the missile canister, wherein said obturator plate defines a main opening and at least one peripheral obturator opening, said peripheral obturator opening covered by at least one rotatable obturator gate, the peripheral obturator opening disposed between the canister shell and the main opening wherein the obturator plate includes a spring assembly, said spring assembly attaching the peripheral obturator plate to the obturator gate.
2. The missile canister of claim 1 wherein the obturator plate is adjacent at its periphery to the canister shell.
3. The missile canister of claim 1 wherein the obturator plate includes 6 peripheral obturator openings.
4. The missile canister of claim 1 wherein the obturator gate is sized to cover more than one peripheral obturator opening.
5. The missile canister of claim 1 wherein the spring assembly is set to a desired spring force so that after firing the missile, flyout pressure from the missile overcomes the spring force thus opening the obturator gate and reducing pressure within canister shell.
6. The missile canister of claim 5 wherein multiple obturator gates are disposed about multiple obturator openings and the spring force is different for each individual obturator gate.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
(1) The invention can be more completely understood and appreciated by referring to the following more detailed description of the presently preferred exemplary embodiments of the invention in conjunction with the accompanying drawings, of which:
(2) FIG. 1 is a top, perspective view of a naval ship of the prior art having a pair of Vertical Launch System mounted in a ship deck.
(3) FIG. 2 is a top, perspective view of a ship deck of the prior art including a deck mounted Vertical Launch System.
(4) FIG. 3 is a top, perspective view of a vertical launch cell of the prior art.
(5) FIG. 4 is a partially hidden, perspective view of a missile canister according to an embodiment of the present invention.
(6) FIG. 5 is a bottom, perspective view of an obturator assembly in a closed gate position according to an embodiment of the present invention.
(7) FIG. 6 is a bottom, perspective view of the obturator assembly of FIG. 5 in an open gate position according to an embodiment of the present invention.
(8) FIG. 7 is a top, perspective view of the vertical launch cell of FIG. 3 illustrating a gas containment system.
(9) FIG. 8 is a top, perspective, partially hidden view of the vertical launch cell of FIG. 3 illustrating a successful missile egress.
DETAILED DESCRIPTION OF THE DRAWINGS
(10) As illustrated in FIG. 1, a ship 50 can comprise a hull 51 and a deck 52. Ship 50 can comprise a wide variety of variants including for example, an Arleigh Burke class destroyer as depicted in FIG. 1 or alternative, various classes of destroyers, frigates, cruisers, littoral zone ships, transport ships and even attack submarines. As part of the armament of ship 50, one or more Vertical Launch Systems (VLS) 100 can be mounted within deck 52. Depending upon the size and mission requirements for ship 50, ship 50 can be equipped two or more batteries of VLS 100, such as, for example, a fore VLS 100a and an aft VLS 100b.
(11) As seen in FIGS. 2 and 3, VLS 100 can comprise a deck mount 102 for positioning and mounting the VLS 100 in the deck 52. Generally, VLS 100 comprises one or more cells 104 that are individually positionable within the deck mount 102. For example, the VLS 100 as illustrated in FIG. 2 includes eight cells 104. Cells 104 generally comprise a plurality of missile canisters 106. One advantage of VLS 100 is that each cell 104 can be uniquely configured both in the number of missile canisters 106 per cell 104 (for example, a 24 arrangement as shown in FIGS. 2 and 3 with 2 rows of 4 missile canisters 106 per cell) and missile types within each cell 104. For example, within a single cell 104, a VLS 100 can include anti-aircraft, anti-submarine, strike, naval surface fire support and ballistic missile defense missiles.
(12) Referring to FIGS. 2 and 3, each cell 104 generally comprises a cell frame 110 having an upper deck structure 112, a lower base structure 114 and an outboard structure 116 extending there between. Upper deck structure 112 generally comprises a cell hatch 118 having a plurality of upwardly rotatable canister doors 120. The number of canister doors 120 generally corresponds to the number of individual missile canisters 106 in cell 104, for example eight canister doors 120 as seen in FIGS. 2 and 3. Cell 104 further comprises a gas management system 122 including a base plenum 124 (located in the lower base structure 114), an uptake plenum 126 (extending the height of the outboard structure 116 between the lower base structure 114 and the upper deck structure 112) and an upwardly rotatable uptake hatch 128 (mounted in the cell hatch 118 between the rows of upwardly rotatable canister doors 120). Directly below each canister door 120, the outboard structure 116 defines individual canister cells 122 for receiving the missile canisters 106. Each canister cell 122 includes a canister latch assembly 124 for physically coupling and restraining the associated missile canister 106. Though not necessary for the understanding of the present invention, it will be understood that cell frame 110 includes additional features and systems relating to operational control and safety including, for example, electrical power and control systems, missile restraining systems and deluge systems.
(13) As illustrated in FIG. 4, each missile canister 106 comprise a four sided canister shell structure 130, a forward (or top) closure 132 and an aft (or bottom) closure 134. Within the shell structure 130, a variety of structures are used to support, restrain, store, control, power and potentially quench missiles. These include missile guide surfaces 136, guide rails 138, deluge assembly 140, electrical assembly 142, desiccant assembly 144 and lateral support assemblies 145. A variable obturator assembly 146 is located proximate the aft closure 134. The variable obturator assembly 146 manages exhaust gas flow following ignition of a rocket engine within individual missiles.
(14) As seen in FIGS. 5 and 6, a representative embodiment of the variable obturator assembly 146 of the present invention comprises an obturator plate 148 and a plurality of obturator gates 150. Obturator plate 148 generally has a plate surface 152 defined by a plate perimeter 154. Plate perimeter 154 generally matches and snugly fits across an internal shell cross-section 156 of the canister shell structure 130. Plate surface 152 includes a central obturator opening 158 and one or more peripheral obturator openings 160. Central obturator opening 158 is selectively sized to have a desired central opening area 162. Peripheral obturator openings 160 are selectively sized to have a desired peripheral opening area 164. Obturator plate 148 can be designed and constructed to include any number of peripheral obturator openings 160, for example, two peripheral obturator openings 160 along three sides of the obturator plate 148 and one side lacking any peripheral obturator openings 160. In choosing a particular layout for obturator plate 148 including, for example, the number of obturator gates 150, size and shape of central opening area 162 and the number and shape of peripheral opening areas 164, the obturator plate 148 is designed to maximize ignition, firing and egress characteristics of particular missile designs.
(15) As seen in FIGS. 5 and 6, variable obturator assembly 146 will have obturator gates 150 that correspond to the arrangement of peripheral obturator openings 160 on the obturator plate 148. For example three obturator gates 150 are rotatably opened and closed to either expose or cover the six peripheral obturator openings 160 located on three sides of the obturator plate 148. In some non illustrated embodiments, it will be understood that multiple obturator gates 150 can be utilized on each side of the obturator plate 148, for example, two obturator gates 150, each covering a single peripheral obturator opening 160. Each obturator gate 150 generally comprises a gate body 166 having a gate body area 168. The gate body 166 includes a hinge attachment end 170, a pair of gate sides 172a, 172b and a forward end 174. Attached to hinge attachment end 170 is one or more spring hinges 176 that rotatably couple the gate body 166 to the obturator plate 148 proximate the plate perimeter 154. Spring hinges 176 generally function to hold the gate body 166 against the obturator plate 148 in a closed gate disposition 179 as shown in FIG. 5 such that the obturator gates 150 block off or otherwise restrict air flow through the covered peripheral obturator openings 160. Each spring hinge 176, used either individually or combined in pairs, is selected to have a desired spring force . When gas flow having a pressure exceeding spring force is directed through the peripheral obturator openings 160, each obturator gate 150 begins to rotate around the corresponding spring hinge 176 such that the peripheral obturator openings 160 are uncovered, thereby assuming an open gate disposition 180 as shown in FIG. 6, which allows for gas flow through the peripheral obturator openings 160. The obturator plate 148 further includes rods 182 mounted approximate the corner of the plate to control travel of the obturator plate.
(16) In a successful missile deployment from missile canister 106, a variety of events unfold as shown in FIGS. 7 and 8. Generally, a missile selection and ignition command is transmitted to the VLS, whereby a particular missile 200 is selected and prepared for deployment. Generally, the canister door 120 corresponding to missile 200 is opened and a rocket motor in the missile 200 is ignited causing missile exhaust gases to be directed downward toward the lower base structure 114 and out the gas management system 122. Within missile canister 106, the missile exhaust gases generate a pressure exceeding spring force , such that the obturator gates 150 rotate from the closed gate disposition 178 to the open gate disposition 180. As the obturator gates 150 reach the open gate disposition 180, a canister flyout pressure experienced by canister shell structure 130 is reduced as the missile 200 egresses the missile canister 106. Canister flyout pressure is the highest pressure condition typically experienced by missile canister 106 and thus, canister flyout pressure is the primary design criteria utilized for safely designing canister shell structure 130. By reducing canister flyout pressure , it is possible to reduce the size and weight of the materials used in constructing the canister shell structure 130. Reducing the size and weight of the materials used in constructing canister shell structure 130 has a number of benefits including reducing the overall weight of VLS 100, reducing the weight of individual missile canisters 106, reducing the material costs for individual missile canisters 106 and making it easier to reload cell 104 with missile canisters 106.
(17) In the event of an unsuccessful missile deployment or restrained firing scenario, the rocket motor is ignited but for whatever reason, missile 200 fails to egress from missile canister 106. Even with the rocket motor ignited, restraining features on the cell frame 110 and within missile canister 106 retain missile 200 and prevent it from egressing the missile canister 106. As the missile 200 does not egress the missile canister 106, canister flyout pressure is never achieved such that obturator gates 150 remain in the closed gate disposition 178. As such, the exhaust gases are directed solely through the central obturator opening 158 and vented out gas management system 122. In a restrained firing scenario, the rocket motor can be ignited for up to six seconds before the deluge system quenches missile 200. Throughout the restrained firing scenario, the obturator gates 150 remain in closed gate disposition 178.
(18) While the invention is amenable to various modifications and alternative forms, specifics thereof have been shown by way of example in the drawings and will be described in detail. It should be understood, however, that the intention is not to limit the invention to the particular embodiments described. On the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the invention as defined by the appended claims.
