Main-stage solid-propellant rocket motor design

Abstract

A ballistic missile main-stage solid-propellant rocket motor; including a propellant grain configuration tailored to provide required missile ballistic performance, having a center bore, major and minor rear fin slots, and a silver eliminator bore enlargement; utilizing a forward pressure equalizing flap; and designed to accommodate severe operating conditions.

That which is claimed is: 
     
       1. A rocket motor comprising: a case which includes a cylindrical chamber having domed front and rear ends wherein said domed front end has a centrally located front opening and said domed rear end has a centrally located rear opening;   an insulator having a first surface and an opposite second surface, said insulator first surface bonded to and covering the interior surface of said chamber;   an open netting positioned against and covering said insulator second surface in the region of said domed front end;   a pressure equalizing flap having a first surface and an opposite second surface, said flap first surface positioned against and covering said netting, the outer periphery of said flap extending sufficiently beyond the periphery of said netting so that direct bonding is made between said flap first surface and said insulator second surface;   an embedded-granule/adhesive coating the second surfaces of said flap and said insulator where said second surfaces are exposed to said chamber interior;   a propellant grain positioned within the interior of said chamber, and against and bonded to said embedded-granule/adhesive coated flap and insulator second surfaces, said grain including a longitudinal bore that extends from said front opening to said rear opening;   a sliver eliminator means for ensuring that no unburned propellant remains after first-stage separation;   a local enlargement at the rearmost end of said bore defining a nozzle cavity, said cavity being adapted to receive a nozzle and associated flexible seal means between said nozzle and said domed rear end, said cavity being fluidly connected at the rearmost periphery to an annular stress relief groove at said groove inner periphery; and   a plurality of major fin slots and an equal number of minor fin slots, said fin slots located at the rear section of said grain and extending radially outward from the bore in a radiosymmetric pattern alternating sequentially from major fin slot to minor fin slot.   
     
     
       2. A rocket motor as recited in claim 1, wherein said silver eliminator means includes a uniquely shaped enlargement of a forward portion of said longitudinal bore, the volume of said shaped enlargement being equal to the volume of propellant that would remain unburned after first stage separation if the bore were not so enlarged. 
     
     
       3. A rocket motor as recited in claim 2, wherein there are five major and five minor fin slots.