Patent Publication Number: US-4730561-A

Title: Subcaliber projectile

Description:
BACKGROUND OF THE INVENTION 
     The invention relates to a subcaliber projectile of the type which includes a penetrator and a guide assembly which coaxially surrounds the penetrator over part of its length. 
     Subcaliber projectiles of this type are known from British Patent No. 1,256,740. They are advisably used with cartridged ammunition and prefeably serve to combat armored targets in direct fire. Subcaliber projectiles of this type are manufactured for the most varied caliber ranges; they have already been introduced for armored cannons and automatic cannons. 
     For the purpose of increasing their terminal ballistic performance, the projectiles, which are also called penetrators and are frequently made of tungsten heavy metal, are made as long as possible. In this way, sufficient projectile material is available for penetration of the target. The extension of these projectiles is generally limited by the fact that the maximum cartridge length of in-service tubular weapons is limited and by the fact that that a guide assembly must be provided at the tail of the subcaliber projectile for the purpose of stabilization, which also takes up part of the space available in the cartridge case. 
     In order to obtain the longest possible penetrator, attempts have already been made to also make the core of the guide assembly itself of the penetrator material. If, however, the subcaliber projectile hits the target and ultimately penetrates it, the guide assembly exerts a very great transverse force on the penetrator, thus causing it to break. The broken-off part, however, generally no longer contributes to penetration of the target. Thus the terminal ballistic effect of the projectile is reduced. 
     SUMMARY OF THE INVENTION 
     It is the object of the invention to improve the terminal ballistic performance of a subcaliber projectile. 
     Based on a projectile of the type discussed in detail above, this is accomplished by providing a region with a conically configured surface adjacent the tail end of the penetrator, and by providing a recess with a conically configured surface in the guide assembly, the region of the penetrator with the conically configured surface being seated in the recess. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is an enlarged detail view of the tail section of a subcaliber projectile; and 
     FIG. 2 is a partial sectional view of the schematic representation of cartridged ammunition and a subcaliber projectile. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     FIG. 2 shows, partially in section, a schematic representation of a piece of cartridged ammunition 10 for an armored cannon. Ammunition 10 includes a cartridge case 11, in which a propelling charge igniter 12 and the propelling charge 13 are disposed. Connected with cartridge case 11 is the discarding sabot 14 which is composed of a plurality of segments and coaxially surrounds the subcaliber projectile 15 over part of its length. A fin-including guide assembly 16 is disposed at the tail of subcaliber projectile 15. After firing the cartridge, discarding sabot 14 and projectile 15 are accelerated in the gun barrel (not illustrated). After leaving the gun barrel, discarding sabot 14 is separated from projectile 15 so that the latter, stabilized by guide assembly 16, speeds toward the target. After hitting the surface of the target, projectile 15 penetrates into the target material. However, as soon as the tail guide assembly 16 comes in contact with the already partially penetrated wall of the target, a large transverse force is exerted on projectile 15 and causes projectile 15 to break, preferably in its region 15a, i.e. shortly before the start of tail guide assembly 16. The broken-off part of projectile 15 becomes positioned at an angle with respect to the longitudinal axis of the projectile and does not participate in the penetration of the target, thus considerably reducing the terminal ballistic performance of projectile 15. The invention now overcomes this drawback in that it makes it possible to prevent a noticeably larger region of the tail section of projectile 15 encased by guide assembly 16 from breaking off and thus enables it to participate in the penetration of the target. This then increases the terminal ballistic performance of projectile 15. The significant features of the invention will be described in connection with FIG. 1, which is an enlarged detail view of the tail section of subcaliber projectile 15. In the figure, penetrator 15b of projectile 15 is shown only in part. Tail section 15a of penetrator 15b has a conical configuration and is seated in a recess 16a of tail guide assembly 16 which is likewise provided with a conical jacket surface. Recess 16a has a length which is preferably between one third and two thirds of the length of section 15a. The slopes are here selected in such a manner that the angle β of recess 16a is noticeably larger (preferably at least 2° larger) than the angle α of the penetrator cone. The conical region 15a of penetrator 15b is followed by a threaded cylindrical pin 15c which finally is delimited by a cone frustum 15d having a jacket surface extending at an angle of 45°. By means of pin 15c, penetrator 15b is screwed into an internally threaded recess 16b in guide assembly 16, with this recess 16b following conical recess 16a. Recess 16b opens into a blind bore 16c which has a conical jacket surface. The slope of the jacket surface is 45° so that, when penetrator 15b is screwed in, its cone 15d causes penetrator 15b and guide assembly 16 to be centered. 
     The above-described type of connection assures that transverse stresses occurring during the penetrating action of projectile 15 cannot have any effect in the conical region 15a of penetrator 15b. Thus, at most the externally threaded pin 15c of penetrator 15b will be sheared off, so that a considerable portion of penetrator 15b coaxially surrounded by guide assembly 16 is able to participate in the penetration of the target. 
     In a preferred embodiment of the invention, the conical region 15a of penetrator 15b had a length of about 70 mm; the conical recess 16a in guide assembly 16 had a length of about 40 mm. The angle α was 5°, while the angle β was 7°.