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 hybrid rocket solid fuel grain having a cylindrical shape and defining a center port is additive manufactured from a compound of thermoplastic fuel and passivated nanocomposite aluminum additive. The fuel grain comprises a stack of fused layers, each layer formed as a plurality of fused abutting concentric circular beaded structures arrayed to define a center port. During operation, an oxidizer is introduced along the center port, with combustion occurring along the exposed port wall. Each circular beaded structure defines geometry that increases the surface area available for combustion. As each layer ablates the next 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. To safely achieve this construction, a fused deposition additive manufacturing apparatus, modified to shield the nanocomposite material from the atmosphere, is used.

A hybrid rocket solid fuel grain having a cylindrical shape and defining a center port is additive manufactured from a compound of thermoplastic fuel and passivated nanocomposite aluminum additive. The fuel grain comprises a stack of fused layers, each layer formed as a plurality of fused abutting concentric circular beaded structures arrayed to define a center port. During operation, an oxidizer is introduced along the center port, with combustion occurring along the exposed port wall. Each circular beaded structure defines geometry that increases the surface area available for combustion. As each layer ablates the next 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. To safely achieve this construction, a fused deposition additive manufacturing apparatus, modified to shield the nanocomposite material from the atmosphere, is used.

A solid rocket motor includes a propellant grain structure defining an axial bore and a vortex inducing feature.

A solid rocket motor includes a propellant grain structure defining an axial bore and a vortex inducing feature.

A method for manufacturing a solid propellant includes: forming a tool of layers of a first material wherein cuts in the layers form a first interior chamber in the tool; using the tool to mold a second material in the first interior chamber; removing the molded second material from the tool; using the molded second material to mold an interior chamber in a rocket propellant grain; and removing the molded second material from the rocket propellant grain.

A method for non-destructively determining a mechanical property of a solid rocket motor propellant grain may comprise applying a force to a surface of the solid rocket motor propellant grain, wherein a deformation is formed on the surface of the solid rocket motor propellant grain in response to the applying, and calculating a value of the mechanical property of the solid rocket motor propellant grain based on the deformation. This process may be performed over time to determine a lifespan of the propellant grain.

A method for non-destructively determining a mechanical property of a solid rocket motor propellant grain may comprise applying, via a gas, a force to a surface of the solid rocket motor propellant grain, wherein a deformation is formed on the surface of the solid rocket motor propellant grain in response to the applying, and measuring a pressure of the gas. This process may be performed over time to determine a lifespan of the propellant grain.

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.

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.