A method of making a fuel grain for a hybrid rocket engine includes deposing beads of fuel grain material onto mandrel using additive manufacturing to form a cylindrical fuel grain, each bead including a polymer based rocket fuel material and a nanoscale metallic material. The deposing includes deposing multiple, adjacent beads to form concentric layers of beads, wherein a composition of the beads of the fuel grain material differs between the beads of a first layer and the beads of a second layer of the fuel grain.

Solid propellant systems include a main propellant and a secondary propellant in contact with the first propellant that exhibits autoignition temperatures of at least about 100° F. lower than the autoignition temperature of the main propellant. The secondary propellant of the present invention is most advantageously employed with conventional AP-containing solid propellant formulations as the main propellant, especially formulations containing both AP, an energetic solid, and a binder. In especially preferred forms, the secondary propellant will include a nitramine which is at least one selected from nitroguanidine (NQ), cyclotrimethylene trinitramine (RDX) and cyclotetramethylenetetranitramine (HMX), and a binder which is at least one selected from HTPB, HTPE or glycidyl azide polymer (GAP). Most preferably, the secondary propellant will include a combination of nitramines which includes NQ and one of RDX or HMX.

Solid propellant systems include a main propellant and a secondary propellant in contact with the first propellant that exhibits autoignition temperatures of at least about 100° F. lower than the autoignition temperature of the main propellant. The secondary propellant of the present invention is most advantageously employed with conventional AP-containing solid propellant formulations as the main propellant, especially formulations containing both AP, an energetic solid, and a binder. In especially preferred forms, the secondary propellant will include a nitramine which is at least one selected from nitroguanidine (NQ), cyclotrimethylene trinitramine (RDX) and cyclotetramethylenetetranitramine (HMX), and a binder which is at least one selected from HTPB, HTPE or glycidyl azide polymer (GAP). Most preferably, the secondary propellant will include a combination of nitramines which includes NQ and one of RDX or HMX.

Solid-fuel rocket propellants comprising an oxidizer, an oxophilic metal-halophilic metal formulation, and a binder are described herein. Further described are processes for preparing such propellants and methods of reducing hydrogen chloride production via the combustion of such propellants. Non-limiting examples of such formulations include aluminum-lithium alloys.

Solid-fuel rocket propellants comprising an oxidizer, an oxophilic metal-halophilic metal formulation, and a binder are described herein. Further described are processes for preparing such propellants and methods of reducing hydrogen chloride production via the combustion of such propellants. Non-limiting examples of such formulations include aluminum-lithium alloys.

A composite pyrotechnic product containing energetic charges in a plasticized binder includes a cured energetic polymer and at least one energetic plasticizer, wherein: the cured energetic polymer consists of a glycidyl azide polymer (GAP) having a number average molecular weight (Mn) lying in the range 700 g/mol to 3000 g/mol and cured via its hydroxyl terminal functions with at least one curing agent of polyisocyanate type; and the energetic charges present at a content in the range 50% to 70% by weight consisting, for at least 95% of their weight, of large crystals of ammonium dinitramide (ADN) and of small crystals of hexogen (RDX): the large crystals of ammonium dinitramide (ADN) being present at a content in the range 8% to 65% by weight; and the small crystals of hexogen (RDX) being present at a content in the range 5% to 55% by weight.

A combustible solid propellant composition is disclosed that includes an oxidizer of the reaction product under vacuum of potassium periodate and isocyanate, a polymer binder, a plasticizer, and a fuel.

A combustible solid propellant composition is disclosed that includes an oxidizer of the reaction product under vacuum of potassium periodate and isocyanate, a polymer binder, a plasticizer, and a fuel.

Solid propellant systems include a main propellant and a secondary propellant in contact with the first propellant that exhibits autoignition temperatures of at least about 100° F. lower than the autoignition temperature of the main propellant. The secondary propellant of the present invention is most advantageously employed with conventional AP-containing solid propellant formulations as the main propellant, especially formulations containing both AP, an energetic solid, and a binder. In especially preferred forms, the secondary propellant will include a nitramine which is at least one selected from nitroguanidine (NQ), cyclotrimethylene trinitramine (RDX) and cyclotetramethylenetetranitramine (HMX), and a binder which is at least one selected from HTPB, HTPE or glycidyl azide polymer (GAP). Most preferably, the secondary propellant will include a combination of nitramines which includes NQ and one of RDX or HMX.

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.