Tuning saboted projectile performance through bourrelet modification

Abstract

Kinetic energy projectiles including sabots having stiffened bourrelets which tune and improve shot performance. Shot dispersion for the projectiles is decreased by reducing adverse dynamic perturbations imparted to the projectiles during projectile launch. Reducing dynamic perturbations is accomplished by better controlling interior ballistics by changing the stiffness of the sabot bourrelets.

What is claimed is:  
     
       1. A method of tuning the performance of saboted projectiles, said sabot including at least one bourrelet, said bourrelet having a forward inner surface and an aft outer surface, said method comprising attaching a stiffening means to said at least one bourrelet so that adverse dynamic perturbations to said projectile during projectile launch are decreased. 
     
     
       2. The method of claim  1 , wherein said stiffening means comprises a disk-shaped insert and wherein said insert is attached to the forward inner surface of said bourrelet. 
     
     
       3. The method of claim  2 , wherein said sabot comprises a plurality of petals and said disk-shaped insert comprises segments equal in number to the petals of said sabot so that each of said segments can be individually attached to each of said petals. 
     
     
       4. The method of claim  1 , wherein said stiffening means comprises a disk-shaped insert and wherein said insert is attached to the aft outer surface of said bourrelet. 
     
     
       5. The method of claim  4 , wherein said sabot comprises a plurality of petals and said disk-shaped insert comprises segments equal in number to the petals of said sabot so that each of said segments can be individually attached to each of said petals. 
     
     
       6. The method of claim  1 , wherein said sabot includes a forward ramp and wherein said stiffening means comprises spokes, said spokes attached to the inner surface of said bourrelet and said forward ramp of said sabot. 
     
     
       7. The method of claim  6 , wherein said spokes further include one concentric ring connected to an end of each spoke so that said spokes extend radially from said ring and are substantially coplanar. 
     
     
       8. The method of claim  6 , wherein said spokes further include two concentric rings, each of said rings connected to an end of each spoke so that said spokes are substantially coplanar. 
     
     
       9. The method of claim  1 , wherein said bourrelet includes an inner circumferential surface and an outer circumferential surface, and said stiffening means comprises a ring attached to said inner circumferential surface. 
     
     
       10. The method of claim  9 , wherein said ring is slotted so that it easily breaks upon sabot discard during projectile flight. 
     
     
       11. The method of claim  9 , wherein said ring is made of a reinforced composite material having fibers oriented in a circumferential direction. 
     
     
       12. The method of claim  1 , wherein said bourrelet includes an inner circumferential surface and an outer circumferential surface, and said stiffening means comprises a ring attached to said outer circumferential surface. 
     
     
       13. The method of claim  12 , wherein said ring is slotted so that it easily breaks upon sabot discard during projectile flight. 
     
     
       14. The method of claim  12 , wherein said ring is made of a reinforced composite material having fibers oriented in a circumferential direction. 
     
     
       15. The method of claim  1 , wherein said stiffening means is made of a material selected from the group consisting of plastics, metals, ceramics, and composite materials. 
     
     
       16. The method of claim  1 , wherein said attaching is accomplished by a technique selected from the group consisting of welding, using adhesives, using mechanical fasteners, and using a friction-interference snug fit. 
     
     
       17. A projectile, comprising; 
       (a) a penetrator rod;  
       (b) a sabot affixed to and surrounding a portion of said penetrator rod, said sabot including at least one bourrelet, said bourrelet having a forward inner surface and an aft outer surface; and  
       (c) means for stiffening said bourrelet so that adverse dynamic perturbations to said projectile during projectile launch are reduced and thus shot accuracy is improved.  
     
     
       18. The projectile of claim  17 , wherein said stiffening member is selected form the group consisting of a disk-shaped member, a ring member, and a spoked member. 
     
     
       19. The projectile of claim  17 , wherein said stiffening means comprises a separate insert attached to said bourrelet. 
     
     
       20. The projectile of claim  19 , wherein said insert is selected from the group consisting of a disk-shaped insert, a ring insert, and a spoked insert. 
     
     
       21. The projectile of claim  20 , wherein said disk-shaped insert is attached to said forward inner surface of said bourrelet. 
     
     
       22. The projectile of claim  20 , wherein said disk-shaped insert is attached to said aft outer surface of said bourrelet. 
     
     
       23. The projectile of claim  20 , wherein said sabot comprises a plurality of petals and said disk-shaped insert comprises segments equal in number to the petals of said sabot, each of said segments being individually attached to each of said petals. 
     
     
       24. The projectile of claim  20 , wherein said bourrelet includes an inner circumferential surface and an outer circumferential surface, and said ring insert is attached to said inner circumferential surface. 
     
     
       25. The projectile of claim  20 , wherein said bourrelet includes an inner circumferential surface and an outer circumferentail surface, and said ring insert is attached to said outer circumferential surface. 
     
     
       26. The projectile of claim  20 , wherein said ring is slotted so that it easily breaks upon sabot discard during projectile flight. 
     
     
       27. The projectile of claim  20 , wherein said ring is made of a reinforced composite material having fibers oriented in a circumferential direction. 
     
     
       28. The projectile of claim  20 , wherein said sabot includes a forward ramp and wherein said spoked insert is attached to the inner surface of said bourrelet and said forward ramp of said sabot. 
     
     
       29. The projectile of claim  27 , wherein said spoked insert further includes concentric rings, each of said rings connected to an end of each spoke so that said spokes are substantially coplanar. 
     
     
       30. The projectile of claim  19 , wherein said insert is made of a material selected form the group consisting of plastics, metals, ceramics, and composite materials. 
     
     
       31. The projectile of claim  19 , wherein said attachment is accomplished by a technique selected from the group consisting of welding, using adhesives, using mechanical fasteners, and using a friction-interference snug fit. 
     
     
       32. A method of tuning the performance of saboted projectiles, said sabot including at least one bourrelet, said method comprising removing material from the bourrelet structure so that the stiffness of the bourrelet is decreased. 
     
     
       33. The method of claim  32 , wherein said removal of material is accomplished by machining material away from the bourrelet surface.