The present invention is directed to propellant grains having multiple layers consisting of an outer, slow burning, layer composition and an inner, fast burning, layer with desirable progressivity burn rates. The outer, slow burning, layer comprising a first energetic material, a first plasticizer and a first binder and an inner, fast burning, layer comprising a second energetic material, and the same plasticizer as the outer layer, and a second binder. The compositions in the propellant grain provided herein provides for a burn rate energy differential between the outer, slow burning, layer and inner, fast burning, layer of at least 2.

The invention is directed to a propellant charge, to a method of preparing a propellant charge, and to uses of the propellant charge. The propellant charge or grain of the invention comprises two or more energetic materials with different linear burn rate, wherein the two or more energetic materials are distributed within the charge or grain such that two perpendicular cross-sections of said propellant charge or grain have at least two linear burn rate gradients in non-parallel directions, wherein said propellant charge or grain is layered with layers having a layer thickness in the range of 1-10 000 m, wherein, if the propellant charge or grain has a longitudinal axis, at least one of said perpendicular cross-sections is along said longitudinal axis, and wherein said propellant charge or grain further comprises one or more perforations.

The invention is directed to a propellant charge, to a method of preparing a propellant charge, and to uses of the propellant charge. The propellant charge or grain of the invention comprises two or more energetic materials with different linear burn rate, wherein the two or more energetic materials are distributed within the charge or grain such that two perpendicular cross-sections of said propellant charge or grain have at least two linear burn rate gradients in non-parallel directions, wherein said propellant charge or grain is layered with layers having a layer thickness in the range of 1-10 000 m, wherein, if the propellant charge or grain has a longitudinal axis, at least one of said perpendicular cross-sections is along said longitudinal axis, and wherein said propellant charge or grain further comprises one or more perforations.

A propellant in the form of a pellet includes adjoining pellet sections. Each pellet section includes a smokeless powder, a burnable metal, and a polymer. The smokeless powder in each pellet section will in many examples be different from the burn rate of the smokeless powder in other pellet sections. A nonignitable tube passes through the center of the pellet. When the pellet is used within a firearm cartridge, the ignition products from the primer travel through the nonburnable tube, igniting the pellet sections sequentially from the front to the rear of the cartridge. The pressure generated by the propellant within a cartridge casing can be maximized and controlled through the selection of the burn rate for each pellet section.

A composite explosive product, wherein its composition expressed as percentages by weight includes 85% to 92% of organic energetic charges; the organic energetic charges a) being selected from charges of octogen (HMX), hexogen (RDX), hexanitrohexaazaisowurtzitane (CL20), penthrite (PETN), and mixtures thereof, and b) presenting a grain size distribution with a value for D90 less than 15 m and a value for D50 less than or equal to 5 m; and 7% to 12% of a polymer gum selected from polyurethane-polyester gums, polyurethane-polyether gums, and mixtures thereof, of number average molecular weight greater than 20,000 g/mol and of Mooney viscosity lying in the range 20 to 70 ML (5+4) at 100 C.; and wherein the composite explosive product has a thickness lying in the range 0.4 mm to 5 mm.

A cylindrically-shaped hybrid rocket engine solid fuel grain defines an axial combustion port. A fuel grain material comprises a compounded blend of thermoplastic fuel and aluminum. The fuel grain comprises fused stack layers, each layer comprising a plurality of fused abutting concentric beaded structures arrayed to define the combustion port; the port exhibits a rifling pattern or rifling inducing geometry along the port wall. When an oxidizer is introduced into the combustion port combustion occurs along the exposed port wall. Each beaded structure defines a geometry that increases the combustion surface area while inducing a vortex flow of oxidizer and fuel gas. As each layer ablates, an abutting layer exhibiting a similar geometry, is revealed, undergoes a gas phase change, and ablates. This process repeats and persists until oxidizer flow is terminated or the fuel grain material is exhausted. The fuel grain may be manufactured by an additive manufacturing process.

A munition, such as a projectile formed of at least one reactive material. In one embodiment, the projectile includes a body portion formed of at least one reactive material composition wherein the at least one reactive material composition defines at least a portion of an exterior surface of the projectile. In other words, a portion of the reactive material may be left unbuffered or exposed to the barrel of a gun or weapon from which it is launched and similarly exposed to a target with which the projectile subsequently impacts. In one embodiment, the projectile may be formed with a jacket surrounding a portion of the reactive material to provide additional structural integrity. The projectile may be formed by casting or pressing the reactive material into a desired shape, or the reactive material may be extruded into a near-net shape and then machined into the desired shape.

A munition, such as a projectile formed of at least one reactive material. In one embodiment, the projectile includes a body portion formed of at least one reactive material composition wherein the at least one reactive material composition defines at least a portion of an exterior surface of the projectile. In other words, a portion of the reactive material may be left unbuffered or exposed to the barrel of a gun or weapon from which it is launched and similarly exposed to a target with which the projectile subsequently impacts. In one embodiment, the projectile may be formed with a jacket surrounding a portion of the reactive material to provide additional structural integrity. The projectile may be formed by casting or pressing the reactive material into a desired shape, or the reactive material may be extruded into a near-net shape and then machined into the desired shape.

A solid rocket motor includes a first solid propellant and a second solid propellant at least partially surrounding the first solid propellant. The second solid propellant is resistant to fragment impact and the first solid propellant has a higher impulse than the second solid propellant.

An additively manufactured solid fuel grain for a hybrid rocket engine having a cylindrical shape, defining a center combustion port and comprising a stack of fused layers of polymeric material suitable for hybrid rocket fuel. Each layer is formed as a plurality of fused abutting concentric beads of solidified material arrayed around the center port. An oxidizer is introduced into the solid fuel grain through the center port, with combustion occurring along the exposed surface area of the solid fuel grain center port wall. Each concentric bead possesses a surface pattern that increases the combustion surface area and when stacked forms a rifling pattern of undulations that induces oxidizer-fuel gas axial flow to improve combustion efficiency. The port wall surface pattern persists during the rocket engine's operation as the fuel phase changes from solid to gas and is ablated.