Thiokol Corporation

Morton Thiokol Inc.

C Max White

Roger A Grosgebauer

James D Rozanski

An igniter for full head-end web rocket motors comprises two molded urethane hemispherical shells, each of which is lined with a layer of solid propellant fuel, joined together to form a solid propellant-lined spherical pressure vessel, which spherical pressure vessel is strengthened by a wrapping fiberglass around the girth, includes an igniter initiator having an elongated tubular urethane housing that contains ignition material and serves also as a structural tie between the hemispherical shells, and a mounting foot incorporated in the lower portion of the spherical shell to facilitate bonding to the rocket motor's propellant grain, nozzle ports located in the lower portion of the spherical shell being provided for igniter flaming gas discharge and subsequent rocket motor ignition.

Spherical igniter for full head-end web rocket motors

A radial pulse rocket motor having a nozzle at the aft end includes longitudinally spaced hollow boost and sustain propellant grains in the combustion chamber thereof with an elongated tubular thermal barrier covering substantially the whole of the interior surface of the sustain grain to enable the production of separate boost and sustain pulses. At the forward end of the motor, mounted within a reentrant motor bulkhead position, is a multiple pulse arm-fire device which, when commanded, produces an igniting signal that is transmitted to a boost igniter for igniting the boost grain and a subsequent igniting signal that is transmitted to a sustain igniter for igniting the sustain grain. The sustain igniter is positioned in surrounding relation to the motor forward bulkhead reentrant portion, the multiple pulse arm-fire device, and the forward end of the tubular barrier, and comprises a consumable, molded, polyurethane case having two interlocking tubes with a thin 0.10 inch (2.5 mm.) wide annulus therebetween which contains a thin sheet of igniter propellant wrapped around and bonded to the inner tube. Upon completion of the burning of the boost grain and subsequent initiation of the sustain igniter, the operation of the sustain igniter produces a pressure of flaming gases externally of the forward end of the thermal barrier that is effective to turn the barrier inside out to expose the sustain grain to the flaming gases and to deposit the thermal barrier in the space previously occupied by the boost grain.

Radial pulse motor igniter-sustain grain

An igniter for high-performance rocket motors having a full head-end web of propellant in the forward end of the motor includes a shallow cup-shaped fiberglass reinforced urethane container, dual rubber orifice arrangement in a plurality (12) of peripherally spaced exhaust ports, a shear key or lip for interlocking into the rocket motor propellant, and a saddle arrangement for initiator tube retention.

Consumable wafer igniter

A consumable wafer-like igniter for high-performance rocket motors having a full, head-end web of propellant in the forward end of the motor includes a hat-shaped urethane housing. The housing comprises a flat disk attached to one end of a short cylinder, a flange being attached to the other end for attachment of the igniter directly to the rocket motor propellant. A disk of solid propellant attached to the inside of the housing disk has holes formed therein and has radial grooves in the surface facing the rocket motor propellant for directing gases from the burning propellant through holes that are provided in the peripheral surface of the cylinder. A liner on the inside surface of the cylinder has holes that are in alignment with the holes in the cylinder but which, normally, are smaller. An igniter initiator having a tubular urethane housing is positioned adjacent the solid propellant disk. Upon ignition of the solid propellant disk, as the internal pressure within the igniter becomes greater, the holes in the liner expand, releasing the hot gases in a smoothly increasing volume thereby to provide rapid and reliable ignition of the rocket motor propellant before the igniter is consumed by combustion or becomes detached from the rocket motor propellant due to erosion of the latter.

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Brigham City, UT, United States of America

C Max White