Deployable boat-tail device for use on projectiles

Abstract

In accordance with one aspect of the invention, a system, method and apparatus for a boat-tail device is described herein. A body section for a projectile having a deployable portion is provided. Gun gases may pass through an orifice at an aft end of a piston and pressurize a volume in a plenum within the body section. Depressurization at muzzle exit may allow the gas pressurized in the plenum to push the piston aft deploying the deployable portion. A stopping and locking mechanism such as a complementarily tapered piston and opening may engage at the end of the stroke of the piston to stop and lock the piston at a predetermined location. A releasable protective cover may be used to protect the structure of the deployable element and other elements from gun gases and launch loads.

1 . A boat-tail deployment device for a projectile having an aft end, comprising:
 a body section having an internal passage and a distal end;   a piston having a proximal end and the distal end, wherein the piston is located in the internal passage; and   a support attached to the distal end of the piston; and   a deployable element having a first end and a second end, wherein the first end is in connection with distal aft end of the body section and the second end is in connection with the support, whereby a boat-tail is formed on the distal end of the body section upon deployment of the deployable element.   
     
     
         2 . The device of  claim 1 , wherein the support is disk-shaped. 
     
     
         3 . The device of  claim 1 , wherein the piston includes a stopping mechanism. 
     
     
         4 . The device of  claim 3 , wherein the stopping mechanism includes a taper to the proximal end of the piston and complementary taper to the distal end of the internal passage. 
     
     
         5 . The device of  claim 1 , wherein the second end of the deployable element is in connection with the support at a circumference of the support. 
     
     
         6 . The device of  claim 1 , further comprising a releasable cover located at the distal end of the body. 
     
     
         7 . The device of  claim 1 , wherein the piston includes an orifice from the proximal end to the distal end. 
     
     
         8 . The device of  claim 6 , wherein the deployment element is stowable between the support and the cover. 
     
     
         9 . The device of  claim 1 , wherein the deployable element is generally frustum-shaped when deployed. 
     
     
         10 . The device of  claim 1 , wherein the body section includes at least one plenum in connection with the internal passage, whereby a gas collected in the plenum may act upon the proximal end of the piston. 
     
     
         11 . The device of  claim 10 , wherein the proximal end of the piston includes gas flow elements. 
     
     
         12 . The device of  claim 11 , wherein the gas flow elements include one or more castellations. 
     
     
         13 . The device of  claim 6 , wherein the support comprises an inner support and an outer support having a greater diameter than the inner support. 
     
     
         14 . The device of  claim 10 , wherein the internal passage includes at least one void into the plenum. 
     
     
         15 . The device of  claim 1 , further comprising a restriction having an aperture connected to the internal passage. 
     
     
         16 . The device of  claim 10 , further comprising at least one channel from the outside of the body to the plenum. 
     
     
         17 . A projectile having a boat tail deployment device at a distal end, comprising:
 a body section having an internal passage and a distal end;   a piston having a proximal end and the distal end, wherein the piston is located in the internal passage; and   a support attached to the distal end of the piston; and   a deployable element having a first end and a second end, wherein the first end is in connection with the distal end of the body section and the second end is in connection with the support.   
     
     
         18 . The projectile of  claim 17 , wherein the body section includes at least one plenum in connection with the internal passage, whereby a gas collected in the plenum may act upon the proximal end of the piston. 
     
     
         19 . The projectile of  claim 17 , further comprising a restriction having an aperture connected to the internal passage. 
     
     
         20 . The projectile of  claim 17 , wherein the piston includes a stopping mechanism. 
     
     
         21 . The projectile of  claim 17 , wherein the piston includes gas flow elements. 
     
     
         22 . An assembly kit for modifying a projectile, comprising:
 a body section connectable to a distal end of the projectile, having the distal end and an internal passage;   a piston having a proximal end and a distal end, wherein the piston is located in the internal passage; and   a support attached to the distal end of the piston; and   a deployable element having a first end and a second end, wherein the first end is in connection with an aft end of the body section and the second end is in connection with the support, whereby a boat-tail is formed on the distal end of the body section upon deployment of the deployable element.