Abstract:
A &#34;float-up&#34; launching system for launching missiles from submerged submarines or other submerged launchers utilizing a lightweight rigid cylindrical tube telescoped over the missile while stored in the launcher so as to not take up additional volume. On launching, the tube is extended forward of the missile by a gas generator to form a floatation chamber which creates extra buoyance forward of the missile center of gravity, but still connected to the water surface, nose upwardly, where it is disconnected and the missile booster is ignited.

Description:
BACKGROUND OF THE INVENTION 
     This invention relates, in general, to missile launching systems and related, specifically, to systems for launching missiles from submerged submarines or other submerged launchers. 
     Submarine torpedo tubes and other launchers have limited volume and the missiles that they contain are dense and have a negative buoyancy. Therefore, the missiles are boosted to the surface by rocket motors. Underwater booster motors are, of necessity, of special design having low thrust and low expansion ratio. These underwater boost requirements tend to be incompatible with the subsequent in-air boost phase and this incompatability leads to complex designs requiring dual thrust boosters. Furthermore, the boost motors become more complex as launch depth flexibility (shallow and deep) requirements increase. 
     Floatation systems to simplify the underwater boost requirements have been proposed by which the missile is floated to the surface where the in-air booster motors are ignited and the missile launched. These prior art floatation systems have either been rigid floatation capsule systems which took up too much volume, were heavy and complex, and resisted deep submergence pressures, or fabric floatation devices which did not provide the rigidity needed to maintain good missile control especially during high speed torpedo tube ejection. 
     Accordingly, it is a primary object of this invention to improve the prior art floatation systems by providing a float up system which is compact and lightweight for launching missiles from submerged submarines or other launchers. 
     SUMMARY OF THE INVENTION 
     The launching system which meets the foregoing principle object comprises a float up system which utilizes a simple lightweight rigid cylindrical tube which fits the missile closely while in storage so as to not take up additional volume and which is extended forward of the missile on launching by a small gas generator, either in the float assembly or in the missile nose, to form a floatation chamber which creates an extra buoyance well forward of the missile center of gravity but still connected to the missile nose thus causing the missile to rise to the surface nose upward in a very controlled manner. At or near the surface the float capsule is disconnected and either jettisoned or retracted on to the missile. 
     The foregoing system, as will be seen from the more detailed description hereinafter, is quiet and thus minimizes the possibility of alerting enemy submarines. The rocket motor necessary to boost the missile from the shallow depth to which the float up system has brought the missile is optimized for in-air performance. Many of these missiles must also operate from surface ships, and the shallow depth booster is directly applicable to such a surface launch. Thus, the same type missiles can be used for surface as well as deep or shallow submerged launch. 
     Other and additional advantages and objects of the invention will become apparent to those skilled in the art after a study of the following drawings and detailed description set forth hereinafter. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. A represents the trajectory of the launched missile and floatation capsule of the invention; 
     FIGS. 1-5 illustrates the operation of the float-up system constructed in accordance with the teachings of the invention; 
     FIG. 6 is a cross-sectional view of a portion of the float-up system, enlarged over FIGS. 1-5 to illustrate certain details more clearly; 
     FIG. 7 illustrates an alternative form of float-up system from that of FIGS. 1-5; and 
     FIG. 8 illustrates the extended position of the floatation chamber of FIG. 7. 
    
    
     DETAILED DESCRIPTION 
     FIG. A and FIGS. 1-5 should be considered together since FIG. A shows the trajectory of the float-up system comprising this invention launched from a submerged launcher, such as in a submerged submarine, with the numbers in FIG. A representing the various stages of the launch and represented by corresponding Figure numbers. 
     Thus, before describing the details of the invention, it can be seen that FIG. 1 shows a missile encapsulated in a floatation chamber as it would be stored for launching from a submarine torpedo tube or other launchers. The entire system requires substantially the same volume as would be taken up by the normal missile without such a floatation system which, it can be appreciated, is a definite advantage of the invention. 
     FIG. 2 shows the missile and floatation chamber launched together from the launcher. 
     FIG. 3 illustrates the expanded floatation chamber extending beyond the nose of the missile so as to direct the nose of the missile upward toward the surface. 
     FIG. 4 illustrates the detachment of the floatation chamber from the missile with floatation chamber changing it&#39;s direction so as to not interfere with the missile path of travel. 
     And finally FIG. 5 illustrates the floatation chamber separate from the missile and floating on the surface with the missile now being launched from a shallow depth and airborne as shown in FIG. A. 
     To accomplish the foregoing float-up launch of the invention, attention is now directed more specifically to FIGS. 1-6 which contain the details of the system and the manner in which the encapsulated missile and floatation chamber act together. 
     The float-up system comprises a floatation chamber 12, shown retracted in FIGS. 1 and 2, telescoped over a missile 14 and thereby completely encapsulating the missile nose both of which are installed in a capsule or launching tube 16. The floatation chamber 12 is formed by an elongated rigid tube 18 which terminates in a concavo-convex front end wall 20 closing the front end of said tube and which generally conforms to the blunt front end or nose 22 of the missile 14. The outer peripheral area of said end wall is spaced out from the nose, as at 24, to accomodate a rigid support ring 26 which supports a flexible diaphragm 28 located between the inner side of the front wall 20 and the nose 22. This flexible diaphragm 28 conforms to the nose 22. This flexible diaphragm 28 and its supporting ring 26 remain contiguous to the nose of the missile while stored in the capsule or launching tube yet forms, effectively, a movable back wall of the floatation chamber and, as such, allows the floatation chamber comprising the front wall 20, the tube 18 and the back wall (flexible diaphragm) to be telescoped over the missile while stored, thus permitting the system to be stored in approximately the same volume as would be taken up by the missile alone. 
     After launching from the capsule, as shown in FIG. 2, a source of gas under pressure, such as from gas generator 32, (in this embodiment located within the missile) provides gas pressure through an orifice 34 in the diaphragm sufficient to extend the tube 18, that is, move the front end wall forward of the nose of the missile separating it from the nose and diaphragm until the ring 26 supporting the diaphragm engages a stop means (ring) 36 located near the end of the floatation chamber tube 18. Of course, at the same time the gas generator 32 is activated, the floatation chamber nose release mechanism 30 is actuated to allow the front end wall 20 to separate from the missile nose 22. This actuation is accomplished through a guidance logic means 38 connected thereto. 
     Also located within the missile nose 22 are a plurality of floatation restraint assemblies 40 or attachment means 40 which engage the supporting ring 26 and allow the gas pressure to build up within the chamber 12 to a predetermine level after the supporting ring 26 engages the stop means. This relationship or condition exists while the floatation chamber and missile are traveling missile nose upwardly, toward the water surface. The guidance logic means 38, to which the restraint assemblies are connected, senses the depth of the missile, among other things. The assemblies are then actuated and, under the influence of the pressure in the floatation chambers, the flexible diaphragm 28 reverses its curvature and the chamber is separated from the missile. Note that the missile&#39;s negative buoyancy is overcome by the positive buoyancy of the floatation chamber and when the floatation chamber is extended, the missile&#39;s center of gravity is such that the missile nose is directed upwardly. The floatation chamber 12 is attached to the missile nose in the three places around the periphery of the stop ring. There attachments are released under the control of the guidance logic which effectively determines depth. Orifices 34 and 42 in the diaphragm direct the released float assembly away from the missile. Since the missile is at or near the surface of the water and the floatation chamber is clear of the path of travel of the missile travel, the missile booster motors are ignited to boost the missile into its aerodynamic flight. 
     Turning now specifically to FIG. 6, where the details of the system are more fully disclosed, it can be seen that the floatation restraint assembly 40 includes a pin and the nose release assembly 30 includes a piston both of which are actuated by the guidance logic 38. These assemblies 30 and 40 as well as the means to actuate the pressure chamber 32 are not described in detail since any suitable assemblies which would perform their function could be selected by those skilled in the art once having understood this invention. 
     FIG. 7 shows an alternative embodiment with the pressure source 32a located outside the missile but inside the floatation chamber 12a. In this embodiment, also the stop means 36a is in the form of a plurality of cables of suitable length to stop the support ring 26a at the preselected position, as shown in FIG. 8, rather than engaging the stop means in the form shown in the preceding embodiment. It is to be noted that a plurality of O-ring type seals 50 are used between the outer tube 18a and the forward end wall and this system also has the restraint system 40a which is connected to the support ring 26a and which is under the control of the guidance logic means 38a as in the prior configurations. 
     Again, at the appropriate time after launching, the gas pressure chamber 32a is actuated to emit gas into the floatation chamber 12a to cause the frontwall 28a to move from the missile nose 22a thereby forming a floatation chamber 12a as in the prior embodiments until the stop means (cables) 36a are fully extended. Thereafter, the guidance logic means actuates the restraint assemblies as in the prior embodiment to accomplish the launch near the surface.