Solid propellant rocket motor

Claim 1

A ROCKET MOTOR COMPRISING A MOTOR CASING, AN APERTURE FORMED IN SAID CASING, AN EXHAUST NOZZLE CONNECTED TO SAID CASING ABOUT SAID APERTURE, A FOAMED RIGID PLASTIC MANDREL HAVING A DIAMETER GREATER THAN SAID APERTURE PERMANENTLY DISPOSED WITHIN SAID CASING UNTIL COMBUSTION OCCURES TO FORM A PROPELLANT-RECEIVING CAVITY BETWEEN THE CASING AND THE MANDRELL, SAID MANDRELL HAVING A PLURALITY OF PROJECTIONS EXTENDING RADIALLY OUTWARDLY TOWARD SAID CASING, EACH SAID PROJECTION INCORPORATING A STRING IGNITER-RECEIVING SLOT THEREIN, A STRING IGNITER DISPOSED WITHIN THE SLOT OF EACH MANDREL PROJECTION BELOW THE SURFACE THEREOF, IGNITER MEANS CARRIED BY SAID MANDREL ADJACENT THE RADIAL EXTREMITIES OF SAID PROJECTIONS ELECTRICALLY CONNECTED TO EACH OF SAID STRING IGNITERS ADJACENT THE CASING APERTURE, A POLYSULPHIDE PERCHLORATE PROPELLANT DISPOSED IN THE CAVITY FORMED BETWEEN SAID CASING AND SAID MANDREL IN SEALED RELATION TO THE MANDREL BODY AND MANDREL RADIAL PROJECTIONS, SAID PROPELLANT PROVIDING A PLURALITY OF RELATIVELY ENLARGED, CONCAVITY-SHAPED PROPELLANT BURNING SURFACES CONFORMING RESPECTIVELY TO THE BODY AND RADIAL PROJECTION PORTIONS OF THE MANDREL AND IN PROXIMITY TO THE STRING IGNITERS INCORPORATED IN THE RADIAL PROJECTIONS; SAID MANDREL BEING INITIALLY SEALED TO THE PROPELLANT ADJACENT THE RADIAL EXTREMITIES OF THE PROJECTIONS AND THE APERTURE OF THE CASING AND SUBSEQUENTLY DEMOLISHED BY COMBUSTION AND SAID PROPELLANT IGNITED UPON IGNITION OF SAID IGNITER MEANS.