Supercavitating water-entry projectile

Abstract

A supercavitating water-entry projectile having empennage on the aft end which provides both aerodynamic and hydrodynamic stability and a supercavitating nose section is provided. A representative projectile is a subcaliber munition adapted for use in a 25 mm weapon using a sabot currently in use with the M919 round. The projectile has circumferential grooves around its center section to match these sabots. A key feature in the invention is the size and shape of the nose section. The projectile has a novel high strength extended blunt nose section followed by a truncated conical section which angles towards the body of the projectile in the range of five degrees. During underwater trajectory, the entire projectile is contained within the cavitation bubble formed by the blunt nose tip. The projectile's aft empennage, which provides both aerodynamic and hydrodynamic stability, fits within the bore of the weapon.

What is claimed as new and desired to be secured by Letters Patent of the United States is:  
     
       1. An air-launched, supercavitating water-entry projectile comprising: 
       a cylindrical long body having forward and aft sections;  
       a plurality of aerodynamic and hydrodynamic stabilizing fins attached to the aft section of said cylindrical body; and  
       a supercavitating nose section attached forward and integral of said cylindrical body comprising a truncated conical section with a supercavitating blunt nose tip in the front.  
     
     
       2. An air-launched, supercavitating water-entry projectile as in claim  1  wherein said cylindrical body further comprises a cylindrical aft section having a payload cavity on a rearward end and a threaded aperture on a forward end. 
     
     
       3. An air-launched, supercavitating water-entry projectile as in claim  1  wherein said plurality of stabilizing fins comprise four fins equally spaced around the aft section of said cylindrical body. 
     
     
       4. An air-launched, supercavitating water-entry projectile as in claim  3  wherein said fins are fabricated of steel. 
     
     
       5. An air-launched, supercavitating water-entry projectile as in claim  1  wherein said supercavitating nose section is fabricated using a tungsten alloy. 
     
     
       6. An air-launched, supercavitating water-entry projectile as in claim  1  wherein said cylindrical body is fabricated using tungsten alloy. 
     
     
       7. An air-launched, supercavitating water-entry long body projectile comprising: 
       a cylindrical aft section having a payload cavity on a rearward end and a bored aperture on a forward end;  
       a plurality of aerodynamic and hydrodynamic stabilizing fins attached to said cylindrical aft section;  
       a cylindrical center section attached to the bored aperture of said cylindrical aft section; and,  
       a nose section attached to said center section, said nose section including an extended blunt nose tip to generate an underwater cavitation bubble larger at all longitudinal location than the diameter of the projectile body at the corresponding longitudinal position.  
     
     
       8. An air-launched, supercavitating water-entry projectile as in claim  7  wherein said plurality of stabilizing fins are fabricated of steel. 
     
     
       9. An air-launched, supercavitating water-entry projectile as in claim  7  wherein said plurality of stabilizing fins comprise four stabilizing fins. 
     
     
       10. An air-launched, supercavitating water-entry projectile as in claim  7  wherein said cylindrical center section further comprises a center section having circumferential grooves adapted to interface with existing standard sabots. 
     
     
       11. An air-launched, supercavitating water-entry projectile as in claim  7  wherein said cylindrical center section is fabricated from tungsten alloy. 
     
     
       12. An air-launched, supercavitating water-entry projectile as in claim  7  wherein said nose tip has a diameter of approximately 0.10 inches. 
     
     
       13. An air-launched, supercavitating water-entry projectile as in claim  7  wherein said nose section is capable of achieving aerodynamic and hydrodynamic stabilization when used with said plurality of stabilizing fins. 
     
     
       14. A method for destroying water objects, comprising the steps of: 
       providing an aerodynamically and hydrodynamically stable air-launched, supercavitating water-entry long body projectile comprising a cylindrical body having forward and aft sections, a plurality of aerodynamic and hydrodynamic stabilizing fins attached to the aft section of said cylindrical body, and a supercavitating nose section attached forward and integral of said cylindrical body comprising a truncated conical section with a supercavitating blunt nose tip in the front, wherein said projectile enters the water at a supercavitating velocity, and,  
       air-launching said projectile from above the water with sufficient kinetic energy to enter a body of water and destroy the underwater object.  
     
     
       15. A method for removing water objects as in claim  14  wherein said projectile has sufficient kinetic energy to impart a velocity of approximately 4300 feet per second to the projectile at the surface of the water.