Solid Rocket Motor Propellant Manufacture and Configurations
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.
1 . A method for manufacturing a solid propellant, the method comprising:
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.
2 . The method of claim 1 wherein:
the first material is metallic.
3 . The method of claim 2 wherein:
the second material is a silicone.
4 . The method of claim 1 wherein:
the second material is a silicone.
5 . The method of claim 1 wherein:
the removing the molded second material from the rocket propellant grain stretches the second material.
6 . The method of claim 1 wherein:
the molded second material molds a Helmholtz resonator in the rocket propellant grain.
7 . The method of claim 1 wherein the forming the tool comprises:
forming the layers with the cuts; and
bonding the layers to each other.
8 . The method of claim 7 wherein the forming the layers comprises:
photomasking and etching.
9 . The method of claim 7 wherein the forming the layers comprises:
laser cutting.
10 . The method of claim 1 wherein:
the layers have thickness of 0.001 inch to 0.003 inch.
11 . A method for manufacturing a solid propellant, the method comprising:
using an elastic mandrel to mold an interior chamber in a rocket propellant grain; and
removing the molded elastic mandrel from the rocket propellant grain via stretching of the elastomeric mandrel.
12 . The method of claim 11 wherein the elastic mandrel comprises:
a shaft; and
at least one radial protrusion from the shaft, the at least one radial protrusion casting at least one radial extension of the interior chamber.
13 . The method of claim 12 wherein the at least one radial extension of the interior chamber comprises:
a full annulus.
14 . The method of claim 12 wherein the at least one radial extension of the interior chamber comprises:
a proximal portion; and
an axially protuberant distal portion.
15 . The method of claim 12 wherein the at least one radial extension of the interior chamber is a single off-center extension at a given axial position.
16 . The method of claim 12 wherein:
the at least one radial extension of the interior chamber forms a Helmholtz resonator in the rocket propellant grain.
17 . The method of claim 11 wherein the mandrel is formed of silicone.
18 . The method of claim 11 repeated with the same mandrel to mold a second rocket propellant grain.
19 . A solid propellant grain extending along a length from a first end to a second end and comprising:
an interior chamber open to the second end; and
at least one radial extension of the interior chamber at an intermediate portion of the length.
20 . The solid propellant grain of claim 19 wherein at least one of:
the interior chamber is open to the first end; and
the at least one radial extension of the interior chamber forms a Helmholtz resonator in the solid propellant grain.