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A hollow grain propellant for use in a lightweight training round. The hollow grain propellant incorporates multi-perforation propellant grain geometry. The hollow grain propellant is configured as a propellant grain having a center hole surrounded by uniform perforations. The center hole is larger

A hollow grain propellant for use in a lightweight training round. The hollow grain propellant incorporates multi-perforation propellant grain geometry. The hollow grain propellant is configured as a propellant grain having a center hole surrounded by uniform perforations. The center hole is larger than any one of the uniform perforations. The placement of the uniform perforations forms webs of equal length. The hollow grain propellant may include seven or more perforations. The perforations are arranged in a single ring around the center hole. The size of the center hole may be controlled to produce a wide range of bulk densities. The number of perforations may be dependant on the size of the center hole. The number of perforations may be controlled to vary with the size of the center hole to provide for a desired bulk density. The large center hole improves flame permeability through a propellant bed by increasing the porosity of the propellent bed and increasing grain diameter. The hollow grain geometry maintains good progressive burning characteristics at low bulk densities while retaining low mass fraction at slivering. The hollow grain propellant further eliminates the need to reduce ullage with costly spacers, fillers, or liners.

대표청구항 ▼

[ What is claimed is:] [1.] A multiperforated propellant grain geometry comprising a center perforation surrounded by a concentric ring having at least 7 perforations arranged and sized so as to form a plurality of webs having substantially equal length, wherein each of the at least 7 perforations i

[ What is claimed is:] [1.] A multiperforated propellant grain geometry comprising a center perforation surrounded by a concentric ring having at least 7 perforations arranged and sized so as to form a plurality of webs having substantially equal length, wherein each of the at least 7 perforations includes a perforation diameter (d), and wherein the propellant grain includes an inner diameter (ID) related to the number of the at least 7 perforations (n), the perforation diameter (d), and by a desired web size (w) by the following equation ]EQU2 ]