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A deployable fairing is driven off of high-pressure gun gases to reduce aerodynamic drag and extend the range of the artillery shell. An artillery shell is provided with a fabric fairing and a piston attached thereto in a rear section of the shell in a stowed state and a chamber. During launch high-

A deployable fairing is driven off of high-pressure gun gases to reduce aerodynamic drag and extend the range of the artillery shell. An artillery shell is provided with a fabric fairing and a piston attached thereto in a rear section of the shell in a stowed state and a chamber. During launch high-pressure gun gasses are captured and stored in the chamber. Once the shell clears the end of the artillery tube, the pressure aft of the shell drops from the high pressure inside the tube to atmospheric pressure outside the tube. The high pressure gun gasses stored in the chamber act over the top surface of the piston to drive the piston aft against the much lower pressure behind the projectile to deploy the fabric fairing attached thereto to reduce the base area of the projectile creating or extending the boat-tail of the shell, hence reduce aerodynamic drag. The aft driven piston engages a locking mechanism that locks the piston in a deployed position.

대표청구항 ▼

1. A gun-launched artillery shell for launch from an artillery gun tube, comprising: a payload;a fabric fairing fitted in a rear section of the shell in a stowed state;a chamber in a rear section of the shell;a plate attached to a rear section of the fabric fairing;a piston attached to the plate;a l

1. A gun-launched artillery shell for launch from an artillery gun tube, comprising: a payload;a fabric fairing fitted in a rear section of the shell in a stowed state;a chamber in a rear section of the shell;a plate attached to a rear section of the fabric fairing;a piston attached to the plate;a locking mechanism; anda gas intake path to store high pressure gun gases in said chamber upon firing of the artillery shell from an artillery tube, said stored high pressure gun gases driving the piston aft into the locking mechanism to deploy the fairing once the shell clears the gun tube. 2. The artillery shell of claim 1, further comprising: a cylinder along a long axis of the shell that extends into the chamber, said cylinder including one or more holes formed therein, said piston disposed within said cylinder,wherein the holes in the cylinder form a gas outlet path to expel the stored high-pressure gun gas from the chamber into the cylinder to drive the piston aft into the locking mechanism to deploy the fairing. 3. The artillery shell of claim 2, wherein the gas intake path comprises an orifice that extends through the plate, axially through the piston and through holes in the piston and the cylinder in the stowed state. 4. The artillery shell of claim 3, wherein the orifice extends axially through the piston to its top surface, further comprising: a plurality of castellations arranged on the top surface of the piston about the orifice, void spaces between adjacent castellations coupling high pressure gun gases from the orifice through the holes in the cylinder to store the gases in the chamber in the stowed state, said high-pressure gases expelled from the chamber through the holes in the cylinder and through the castellations to apply pressure to a top surface of the piston to drive the piston aft. 5. The artillery shell of claim 2, wherein the locking mechanism comprises complementary tapers of the internal diameter of the cylinder and the external diameter of the piston. 6. The artillery shell of claim 2, wherein the diameter of the plate is less than the diameter of the rear section of the shell to reduce that base area and form or extend a boat-tail on the shell once deployed. 7. The artillery shell of claim 1, further comprising a base assembly that holds an obturator in place around the rear section of the warhead to engage an inner diameter of the artillery tube, said fabric fairing fitted in and attached to a rear section of the base assembly in the stowed state. 8. The artillery shell of claim 7, wherein a rear section of the warhead has a void space, said chamber positioned forward of the base assembly to engage said void space. 9. The artillery shell of claim 7, wherein said chamber is contained within the base assembly. 10. The artillery shell of claim 9, wherein the piston comprises a telescoping mechanism that extends beyond its stowed length when driven aft to deploy the fairing. 11. A base assembly kit for a gun-launched artillery shell launched from an artillery tube, comprising: a base assembly;a fabric fairing fitted in and attached to the aft end of the base assembly in a stowed state;a chamber;a plate attached to a rear section of the fabric fairing;a piston having an aft surface attached to the plate and having a top surface;a locking mechanism; anda gas intake path to store high pressure gun gases in said chamber upon firing of the artillery shell from an artillery tube, said stored high pressure gun gases acting on the top surface of the piston driving the piston aft into the locking mechanism to deploy the fairing once the shell clears the artillery tube. 12. The base assembly kit of claim 11, further comprising: a cylinder along an axis of the base assembly that extends into the chamber, said cylinder including one or more holes formed therein, said piston disposed within said cylinder,wherein the holes in the cylinder form a gas outlet path to expel the stored high-pressure gun gas from the chamber into the cylinder to drive the piston aft into the locking mechanism to deploy the fairing. 13. The base assembly kit of claim 12, wherein the gas intake path comprises an orifice that extends through the plate, axially through the piston and through holes in the piston and the cylinder in the stowed state. 14. The base assembly kit of claim 13, wherein the orifice extends axially through the piston to its top surface, further comprising: a plurality of castellations arranged on the top surface of the piston about the orifice, void spaces between adjacent castellations coupling high pressure gun gases from the orifice through the holes in the cylinder to store the gases in the chamber in the stowed state, said high-pressure gases expelled from the chamber through the holes in the cylinder and through the castellations to apply pressure to the top surface of the piston to drive the piston aft. 15. The base assembly kit of claim 13, wherein the holes in the piston are arranged in the sidewalls of the piston nominally aligned to holes in the cylinder in the stowed state to direct high-pressure gun gases into the chamber, once the shell clears the artillery tube said high-pressure gun gases are expelled from the chamber through holes in the cylinder to apply pressure to the top surface of the piston to drive the piston aft. 16. The base assembly kit of claim 12, wherein said chamber is positioned forward of the base assembly. 17. The base assembly kit of claim 12, wherein said chamber is contained within the base assembly. 18. A gun-launched artillery shell for launch from a gun tube, comprising: a nose section including a fuze;a warhead, said warhead having a threaded rear section that defines a void space;an obturator around the rear section of the warhead to engage an inner diameter of the artillery tube; anda base assembly kit comprising: a base assembly threaded onto the threaded rear section of the warhead holding the obturator in place;a chamber positioned on the base assembly forward into the warhead's void space;a cylinder that extends axially through the base assembly into the chamber, said cylinder including one or more holes formed therein;a piston within the cylinder, said piston having an axial orifice along its length, said piston having one or more holes formed therein;an end plate attached to the aft end of the piston, said plate having an orifice aligned with the axial orifice in the piston;a fabric fairing fitted in the aft end of the base assembly in the stowed state, one end of the fairing secured to the base assembly and the other end of the fairing secured to the end plate; anda locking mechanism to lock the piston in a deployed state,wherein the plate orifice, along the piston axial orifice and through the holes in the piston and cylinder form a gas intake path to store high pressure gun gas in the chamber in the stowed state, andwherein the holes in the cylinder form a gas outlet path to expel the stored high-pressure gun gas from the chamber into the cylinder to produce a high pressure that drives the piston aft into the locking mechanism to deploy the fairing to the deployed state. 19. The artillery shell of claim 18, wherein the orifice extends axially through the piston to its top surface, further comprising: a plurality of castellations arranged on the top surface of the piston about the orifice, void spaces between adjacent castellations coupling high pressure gun gases from the orifice through the holes in the cylinder to store the gases in the chamber in the stowed state, said high-pressure gases expelled from the chamber through the holes in the cylinder and through the castellations to apply pressure to the top surface of the piston to drive the piston aft. 20. A method of reducing aerodynamic drag on a gun-launched artillery shell, comprising: providing an artillery shell having a fabric fairing and a piston attached thereto in a rear section of the shell in a stowed state and having a chamber;loading the artillery shell into an artillery tube;deflagrating a propellant inside the artillery tube to produce high-pressure gun gases to launch the shell from the artillery tube;during launch of the artillery shell from the artillery tube, capturing and storing high-pressure gun gases in the chamber;once the shell clears the end of the artillery tube, said stored high-pressure gun gases driving the piston aft to deploy the fabric fairing attached thereto to reduce the boat-tail area of the shell; andengaging a locking mechanism to lock the piston in a deployed position.