The present invention is generally related to the field of missile canisters. More specifically, the present invention is directed to a missile canister having a variable obturator system that provides for sealed obturation during restrained firing events while also allowing for reduced canister pressures during missile egress.
Modern warships use missiles as offensive and defensive weapons. Vertical Launch Systems (“VLS”) provide a missile firing platform for surface ships and submarines throughout the world. Generally, a VLS is made up of a number of cells, wherein each cell includes at least one individual missile canister. Loaded within each missile canister is an individually firable missile. Within each cell, a variety of different missile designs can be included so as allow for the performance of various missions including for example, anti-aircraft, anti-submarine, strike, naval surface fire support and ballistic missile defense missions. The individual cells are located below a ship's deck providing increased system survivability while reducing the ship's radar cross-section as compared to prior deck mounted systems.
Encapsulating missiles within a canister is desirable because it provides a convenient and safe way to ship, handle and launch the missiles. The operation of the missile within the canister and in firing must be managed due to the potential hazards. In designing a VLS, missiles can be ejected from their individual canisters by ignition within the canister, i.e. a hot launch, or using a non-missile gas followed by ignition of the missile outside the canister, i.e. a cold launch. One advantage of a hot launch system is that the missile is expelled by its own means and thus, an additional ejection mechanism such as, for example, a gas generator and associated structure, is unnecessary. This allows hot launch systems to be smaller and more lightweight as compared to cold launch systems. However, the individual canisters of a hot launch system must be designed to withstand the temperature and pressure associate with igniting the missile within the canister.
Not only must the canisters be designed to withstand the canister flyout pressure during a successful missile egress but in addition, the canister must be able to withstand an unsuccessful missile egress or restrained firing scenario in which the missile is ignited but otherwise fails to exit the canister. The restraint means for the missile, i.e. the means for securing the missile in its associated canister, could fail when the missile was fired. Protection against the hazards associated with such restrained firings was provided in the prior art launchers in the form of a deluge and drain system. Provision for such a system undesirably added to the complexity, cost, maintenance and weight of the launcher. Increased weight is particularly undesirable when the launcher is to be installed aboard a ship.
In order to further reduce both manufacturing costs and cell weight, it would be advantageous to improve upon existing canister design such that the weight of individual canisters can be reduced while still providing exceptional performance in both restrained firing and successful missile egress situations.
The present invention is directed to a missile canister for use in a VLS that utilizes a variable obturator assembly. The missile canister is generally rectangular in shape although may be circular. The canister has a forward closure aligned with the nose of a missile and an aft closure, aligned with the exhaust nozzles of the missile. The canister generally includes internal missile guide surfaces and booster lateral support assemblies for directing the missile from the canister. The canister is defined by an outer wall which maybe rectangular, square of circular. The canister will also include an electrical assembly for connection of the firing and control system to the missile within the canister.
At the aft closure end of the canister is an obturator. The obturator is typically a plate like structure with a central opening. The central opening seals around the missile exhaust nozzle while the edges of the plate seal to the sides of the canister. The obturator is positioned to control the flow of the exhaust gas from the missile.
In the present invention, the obturator has a plurality of gates. The variable obturator assembly can comprise 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.
In one representative embodiment, the variable obturator assembly can comprise three individual gates that are mounted to the base plate with a hinge assembly. Each gate can be forcibly held in a closed position against the base plate with a spring assembly. Each spring assembly can be selected to have a spring force sufficient to hold the gate closed against the base plate during a restrained firing event. At the same time, the spring force is selected to be less than the canister flyout pressure such that each gate rotatably opens with respect to the base plate during missile egress.
In one aspect, the present invention is directed to a VLS filled with missile canisters having a variable obturator assembly.
In another aspect, the present invention is directed to a missile canister comprising a variable obturator assembly.
In another aspect, the present invention is directed a variable obturator assembly.
In another aspect, the present invention is directed to a method of fabricating a missile canister having a variable obturator assembly.
In another aspect, the present invention is directed to a method of reducing canister flyout pressure with a variable obturator assembly during missile egress from a VLS.
The above summary of the various representative embodiments of the invention is not intended to describe each illustrated embodiment or every implementation of the invention. Rather, the embodiments are chosen and described so that others skilled in the art can appreciate and understand the principles and practices of the invention. The figures in the detailed description that follow more particularly exemplify these embodiments.
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:
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In a successful missile deployment from missile canister 106, a variety of events unfold as shown in
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 β 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.
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.
The present application is a Divisional of U.S. patent application Ser. No. 14/586,414, filed Dec. 30, 2014, entitled “MISSILE CANISTER GATED OBTURATOR” which claims the benefit of U.S. Provisional Application No. 61/921,920 entitled “MISSILE CANISTER GATED OBTURATOR”, filed Dec. 20, 2013, which are incorporated herein by reference in their entirety.
Number | Date | Country | |
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61921920 | Dec 2013 | US |
Number | Date | Country | |
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Parent | 14586414 | Dec 2014 | US |
Child | 15839211 | US |