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A projectile, such as a guided mortar projectile, has both a front obturator and an aft obturating device. The aft obturating device is located aft of the front obturator, and serves to trap pressurized gases behind the aft obturating device, so as to provide further propulsion to the projectile wit

A projectile, such as a guided mortar projectile, has both a front obturator and an aft obturating device. The aft obturating device is located aft of the front obturator, and serves to trap pressurized gases behind the aft obturating device, so as to provide further propulsion to the projectile with the trapped pressurized gases, even after the front obturator has cleared the muzzle of a launcher. The aft obturating device provides less resistance to movement of pressurized gases across the aft obturating device in the aft direction, than to movement of pressurized gases across the aft obturating device in the forward direction, and may act as a check valve with regard to such gas flows. The aft obturating device may be part of a cap that is coupled to a tail boom of the projectile, and that drops away from the projectile after launch.

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1. A projectile launchable from a launcher comprising: a projectile body;a propellant on the body;a forward obturator on the body, wherein the forward obturator is forward of the propellant; andan aft obturating device that is aft of the propellant;wherein the aft obturating device contains pressuri

1. A projectile launchable from a launcher comprising: a projectile body;a propellant on the body;a forward obturator on the body, wherein the forward obturator is forward of the propellant; andan aft obturating device that is aft of the propellant;wherein the aft obturating device contains pressurized gas that is behind the projectile in the launcher, after the forward obturator has cleared the launcher;wherein the aft obturating device reversibly provides greater resistance to flow of pressurized gas from aft of the aft obturating device to forward of the aft obturating device, than to flow of pressurized gas from forward of the aft obturating device to aft of the aft obturating device. 2. The projectile of claim 1, wherein the aft obturating device acts as a check valve, allowing flow of pressurized gas from forward of the aft obturating device to aft of the aft obturating device, while substantially blocking flow of pressurized gas from aft of the aft obturating device to forward of the aft obturating device. 3. The projectile of claim 1, wherein an outer portion of the aft obturating device forms a seal with a muzzle of the launcher during launching. 4. The projectile of claim 3, wherein the outer portion forms the seal only after the forward obturator clears the muzzle. 5. The projectile of claim 1, wherein the aft obturating device changes shape from a shape which allows flow in the aft direction, when pressure in front of the aft obturating device is higher than pressure in back of the aft obturating device, to a shape that at least in part blocks flow in the forward direction, when the pressure in back of the aft obturating device is higher than the pressure in front of the aft obturating device. 6. The projectile of claim 1, wherein the aft obturating device has a fixed shape that provides different flow resistance for flows in the forward direction and the aft direction. 7. The projectile of claim 1, wherein the aft obturating device separates from a remainder of the projectile during flight. 8. The projectile of claim 7, wherein the aft obturating device is part of a cap that fits over at least part of fins of the projectile. 9. The projectile of claim 1, wherein the aft obturating device includes reed valves hingedly coupled to an aft obturating device body of the aft obturating device. 10. The projectile of claim 1, wherein the projectile is a guided projectile. 11. The projectile of claim 10, wherein the projectile includes control surfaces that deploy from the body during flight of the projectile, and that are usable to control flight of the projectile. 12. A projectile launchable from a launcher comprising: a projectile body;a propellant on the body;a forward obturator on the body, wherein the forward obturator is forward of the propellant; andan aft obturating device that is aft of the propellant;wherein the aft obturating device contains pressurized gas that is behind the projectile in the launcher, after the forward obturator has cleared the launcher;wherein the aft obturating device includes one or more movable parts that reversibly shift position to allow flow in an aft direction, while at least in part preventing flow in a forward direction. 13. The projectile of claim 12, wherein the aft obturating device acts as a check valve, allowing flow of pressurized gas from forward of the aft obturating device to aft of the aft obturating device, while substantially blocking flow of pressurized gas from aft of the aft obturating device to forward of the aft obturating device. 14. The projectile of claim 12, wherein the aft obturating device includes reed valves hingedly coupled to an aft obturating device body of the aft obturating device. 15. The projectile of claim 12, wherein the aft obturating device changes shape from a shape which allows flow in the aft direction, when pressure in front of the aft obturating device is higher than pressure in back of the aft obturating device, to a shape that at least in part blocks flow in the forward direction, when the pressure in back of the aft obturating device is higher than the pressure in front of the aft obturating device. 16. A projectile launchable from a launcher comprising: a projectile body;a propellant on the body;a forward obturator on the body, wherein the forward obturator is forward of the propellant; andan aft obturating device that is aft of the propellant;wherein the aft obturating device contains pressurized gas that is behind the projectile in the launcher, after the forward obturator has cleared the launcher;wherein the body includes a main body and a tail boom attached to the main body; andwherein the aft obturating device is mounted on the tail boom. 17. The projectile of claim 16, wherein the aft obturating device acts as a check valve, allowing flow of pressurized gas from forward of the aft obturating device to aft of the aft obturating device, while substantially blocking flow of pressurized gas from aft of the aft obturating device to forward of the aft obturating device. 18. The projectile of claim 16, wherein the aft obturating device includes reed valves hingedly coupled to an aft obturating device body of the aft obturating device. 19. The projectile of claim 16, wherein the aft obturating device changes shape from a shape which allows flow in the aft direction, when pressure in front of the aft obturating device is higher than pressure in back of the aft obturating device, to a shape that at least in part blocks flow in the forward direction, when the pressure in back of the aft obturating device is higher than the pressure in front of the aft obturating device. 20. The projectile of claim 16, wherein the aft obturating device has a fixed shape that provides different flow resistance for flows in the forward direction and the aft direction.