Open railgun with steel barrel sections

Abstract

An elongated electromagnetic railgun ( 1 ) adapted to propel a moving armature ( 30 ) through a bore ( 11 ) along the length of the railgun ( 1 ) from its breech end ( 21 ) to its muzzle end ( 22 ). The railgun ( 1 ) comprises two elongated mechanically rigid electrically conductive barrel sections ( 13 ), said sections ( 13 ) being spaced apart from each other along the length of the railgun ( 1 ). Mechanically coupled via a dielectric ( 18 ) to each barrel section ( 13 ) is an elongated current carrying rail ( 14 ) for providing electromagnetic propulsive force to the armature ( 30 ). The two rails ( 14 ) face each other across an elongated open channel, defining the bore ( 11 ). The two barrel sections ( 13 ) are electrically connected to each other at a maximum of one location of the railgun ( 1 ).

What is claimed is: 
     
         1 . An elongated electromagnetic railgun adapted to propel a moving armature through a bore along the length of the railgun from its breech end to its muzzle end, said railgun comprising:
 two elongated mechanically rigid electrically conductive barrel sections, said sections being spaced apart from each other along the length of the railgun; and   mechanically coupled via a dielectric to each barrel section and electrically insulated therefrom, an elongated current carrying rail for providing electromagnetic propulsive force to the armature, said two rails facing each other across an elongated open channel defining the bore; wherein:   the two barrel sections are electrically connected to each other at a maximum of one location of the railgun, said barrel sections not providing any positive electromagnetic force to the armature.   
     
     
         2 . The railgun of  claim 1  wherein the two barrel sections are substantially identical to each other, and the two rails are substantially identical to each other. 
     
     
         3 . The railgun of  claim 1  wherein the barrel sections are fabricated of steel. 
     
     
         4 . The railgun of  claim 1  further comprising an elongated dielectric shell surrounding and spaced apart from the barrel sections and rails, said dielectric shell adapted to provide containment for an inert gas. 
     
     
         5 . The railgun of  claim 4  wherein the inert gas is from the group consisting of helium, nitrogen, and argon. 
     
     
         6 . The railgun of  claim 1  wherein the barrel sections are uniformly spaced apart from each other throughout the length of each railgun. 
     
     
         7 . The railgun of  claim 1  wherein the rails are fabricated of a material from the group consisting of copper, copper alloy, tungsten copper eutectic, and tungsten copper alloy. 
     
     
         8 . The railgun of  claim 1  wherein each barrel section has a generally rectangular cross section. 
     
     
         9 . The railgun of  claim 1  further comprising an elongated electrically conductive wear-resistant plate fabricated on a bore-facing outer surface of each rail. 
     
     
         10 . The railgun of  claim 9  wherein the plates are fabricated of a material from the group consisting of steel, tungsten alloy, tungsten copper eutectic, and tungsten copper alloy. 
     
     
         11 . The railgun of  claim 9  wherein several expansion slots are cut in each plate along the length of said plate, said slots adapted to compensate for different thermal expansion coefficients of the plate and its corresponding rail. 
     
     
         12 . The railgun of  claim 1  wherein each rail is recessed within its corresponding barrel section. 
     
     
         13 . The railgun of  claim 1  wherein each rail comprises an elongated internal channel adapted to deliver coolant to interior surfaces of the rail. 
     
     
         14 . The railgun of  claim 13  wherein each coolant channel is segmented along the length of its corresponding rail into regions, permitting cooling of the rail on a region-by-region basis. 
     
     
         15 . The railgun of  claim 13  further comprising an elongated mechanically wear-resistant plate attached to an outer surface of each rail, wherein said plate has a concave shape with respect to the bore. 
     
     
         16 . The railgun of  claim 1  further comprising an electrically insulative material positioned between each rail and its corresponding barrel section. 
     
     
         17 . The railgun of  claim 16  wherein the electrically insulative material is fabricated of a material from the group consisting of Kevlar, ceramic, ceramic composite, and Phenolic. 
     
     
         18 . The railgun of  claim 1  wherein outer edges of the insulation material are open to ambient gases, and there is no direct line of sight between the electrically insulative material/ambient gas interface and the rail/armature interface. 
     
     
         19 . The railgun of  claim 1  further comprising electrically conductive linings on outer surfaces of the barrel sections, said linings fabricated of a material from the group consisting of copper and copper alloy. 
     
     
         20 . The railgun of  claim 1  further comprising several rigid retention frames positioned around the two barrel sections, said retention frames spaced apart along the length of the railgun. 
     
     
         21 . The railgun of  claim 20  wherein the retention frames are fabricated of steel. 
     
     
         22 . The railgun of  claim 20  further comprising a dielectric positioned between inner surfaces of the retention frames and outer surfaces of the barrel sections. 
     
     
         23 . The railgun of  claim 20  wherein inner surfaces of the retention frames that are positioned proximate the bore are beveled into sharp edges. 
     
     
         24 . The railgun of  claim 20  wherein the distance between adjacent retention frames is large compared to the thickness of each frame. 
     
     
         25 . The railgun of  claim 20  wherein a slot is cut completely through each retention frame. 
     
     
         26 . The railgun of  claim 1  wherein each rail has a generally triangular cross section, with an apex of the triangle facing towards the bore. 
     
     
         27 . The railgun of  claim 26  further comprising an electrically insulated pad coupled between a portion of each rail and its corresponding barrel section. 
     
     
         28 . The railgun of  claim 27  wherein the insulative pad is fabricated of a material from the group consisting of Kevlar, ceramic, ceramic composite, and Phenolic. 
     
     
         29 . The railgun of  claim 26  further comprising an electrically conductive lining on outer surfaces of the barrel sections, wherein the lining is thicker on surfaces of the barrel sections that have associated rails than on surfaces of the barrel sections that do not have associated rails. 
     
     
         30 . The railgun of  claim 26  wherein surfaces of the rails facing the bore are capped with an electrically conductive mechanically wear-resistant material. 
     
     
         31 . The railgun of  claim 30  wherein the wear-resistant material is from the group consisting of steel, tungsten alloy, tungsten copper eutectic, and tungsten copper alloy. 
     
     
         32 . The railgun of  claim 26  further comprising a plurality of cooling nozzles positioned on at least one outer surface of the barrel sections. 
     
     
         33 . An elongated electromagnetic railgun adapted to propel a moving armature through a bore along the length of the railgun from its breech end to its muzzle end, said railgun comprising:
 two elongated mechanically rigid electrically conductive barrel sections, said sections being spaced apart from each other along the length of the railgun; and   mechanically coupled via a dielectric to each barrel section and electrically insulated therefrom, an elongated current carrying rail for providing electromagnetic propulsive force to the armature, said two rails facing each other across an elongated open channel defining the bore; wherein:   the two barrel sections are electrically connected to each other at a maximum of one location of the railgun, said barrel sections not providing any positive electromagnetic force to the armature;   each rail is recessed within its corresponding barrel section; and   each rail comprises an elongated internal channel adapted to deliver coolant to interior surfaces of the rail.   
     
     
         34 . An elongated electromagnetic railgun adapted to propel a moving armature through a bore along the length of the railgun from its breech end to its muzzle end, said railgun comprising:
 two elongated mechanically rigid electrically conductive barrel sections, said sections being spaced apart from each other along the length of the railgun; and   mechanically coupled via a dieletric to each barrel section, an elongated current carrying rail for providing electromagnetic propulsive force to the armature, said two rails facing each other across an elongated open channel defining the bore; wherein:   the two barrel sections are electrically connected to each other at a maximum of one location of the railgun;   each rail has a generally triangular cross-section, with an apex of the triangle facing towards the bore; and   surfaces of the rails facing the bore are capped with an electrically conductive mechanically wear-resistant material.