Propellant grain

Claim 1

A PROPELLANT GRAIN OF COMPOSITE MATERIAL COMPRISING A PROPELLANT MIXTURE CONSISTING OF AN ORGANIC CHEMICAL FUEL AND AN INORGANIC OXIDANT, AND A MULTIPLICITY OF HIGH-BURNING-RATE EXPLOSIVE STICKS OF RELATIVELY SHORT LENGTH AND SMALL VOLUME IN PRECISE PREDETERMINED SPACED RELATION WITH EACH OTHER IN THE DIRECTION OF BURNING WITHIN SAID PROPELLANT MIXTURE ALONG THE LONGITUDINAL AXIS THEREOF, SAID HIGH-BURNING-RATE EXPLOSIVE BEING CONSTITUTED BY A MIXTURE OF CHARCOAL, SULFUR AND SALTPETER, SAID HIGH-BURNING-RATE EXPLOSIVE HAVING A BURNING RATE EXCEEDING 1000 MM./SEC. AND MORE THAN 50 TIMES AS GREAT AS THAT OF SAID SURROUNDING PROPELLANT MIXTURE, SAID PROPELLANT GRAIN BEING ADAPTED FOR BEING COVERED BY A RESTRICTOR WHICH IS OPEN AT ONE END, AT WHICH BURNING STARTS, THE PROPELLANT GRAIN FORMING A BURNING SURFACE OF PROGRESSIVELY LENGTHENING U-SHAPE THAT IS A COMBINATION OF A CYLINDRICAL SURFACE AND AN APPROXIMATE PARTIAL SPHERICAL SURFACE WHEN THE GRAIN ACHIEVES A STEADY BURNING STATE, THE BURNING RATE UNDERGOING INTERMITTENT INCREASES UPON THE BURNING OF SAID STICKS AS THE BURNING SURFACE REACHES THE SAME.