Ring airfoil glider with augmented stability

Abstract

In one embodiment, a less lethal munition including a ring airfoil projectile. The flight trajectory of the projectile has increased accuracy resulting from the aerodynamic stabilization of the projectile. In some embodiments, the projectile is both aerodynamically stabilized and spin stabilized.

1 - 9 . (canceled) 
     
     
         10 . A munition for a gun having a barrel, comprising:
 a ring airfoil projectile having a substantially open inner flowpath and a ring-shaped wall with an airfoil cross-sectional shape, the center of pressure of the airfoil being aft of the center of gravity of the projectile, the projectile having an outer diameter greater than about 35 mm and less than about 45 mm, the projectile having a blunt leading edge and a trailing edge with a distance therebetween of more than about 20 mm and less than about 35 mm;   an explosive charge adapted and configured to propel said projectile from the barrel with a velocity greater than about 50 m/s and less than about 150 m/s.   
     
     
         11 . The munition of  claim 10  wherein the projectile has a mass for more than about 5 grams and less than about 20 grams. 
     
     
         12 . The munition of  claim 10  wherein the barrel is rifled, and the rifling spins the projectile at more than about 1000 rpm and less than about 8000 rpm. 
     
     
         13 . The munition of  claim 10  wherein the gun is a Mk 19 machine gun. 
     
     
         14 . The munition of  claim 10  wherein the projectile is fabricated from Delrin or Noryl. 
     
     
         15 - 17 . (canceled) 
     
     
         18 . The method of  claim 10  wherein the airfoil has a chord line, and said placing is by providing an angle of attack to the chord line. 
     
     
         19 . The method of  claim 10  wherein the airfoil has a chord line and a mean camber line, the chord line and the camber line being non-coincident, and the central portion of the camber line is inward to the chord line. 
     
     
         20 . The method of  claim 12  wherein the barrel is rifled, the projectile is supported by a sabot, and the sabot engages the rifling.