SOLID PROPELLANT ROCKET MOTOR

• US 3,729,935 A
• Filed: 05/28/1971
• Issued: 05/01/1973
• Est. Priority Date: 05/28/1971
• Status: Expired due to Term

• Current Assignee: John I. Shafer, John W. Behm, Leon D. Strand, Warren L. Dowler
• Original Assignee: John I. Shafer, John W. Behm, Leon D. Strand, Warren L. Dowler
• Inventors: Dowler, Warren L., Shafer, John I., Behm, John W., Strand, Leon D.
• Primary Examiner(s): Croyle, Carlton R.
• Assistant Examiner(s): Garrett, Robert E.
• Application Number:
  US05/147,996
• Time in Patent Office: 704 Days
• Field of Search: 60/256,254,39.82 102/49.3,49.7,49.8,103
• US Class Current: 60/256
• CPC Class Codes: F02K 9/95 characterised by starting or ignition means or arrangements safety devices F02K9/38

Abstract

A solid propellant rocket motor having a controlled rate of thrust buildup to a desired thrust level by the combined utilization of a regressive-burning controlled flow solid propellant igniter and a progressive-burning main solid propellant charge wherein the igniter is capable of operating in a vacuum and sustaining the burning of the propellant below its normal L* combustion limit until the burning propellant surface and motor chamber pressure has increased sufficiently to provide a stable motor chamber pressure.

Claims

1. A solid propellant motor capable of controlled acceleration comprising:

a motor chamber, having a nozzle affixed thereto;

a main solid propellant grain within said chamber having a progressive burning surface and an inhibited end burning design such that the burning area of the end of said grain during an initial ignition interval generates pressure below the extinction pressure of said motor chamber and would not initially sustain stable combustion when ignited and said progressive burning surface when sufficiently ignited after said interval provides a chamber pressure above the extinction pressure which is independently capable of sustaining stable combustion; and

at least one solid propellant igniter connected to said chamber, said igniter being capable of supplying sufficient mass flow to said motor chamber at a controlled rate for a period no longer than said interval to raise the chamber pressure above the extinction pressure whereby said motor will maintain stable combustion conditions during and after said interval.

2. The motor of claim 1 wherein:

said igniter is disposed externally of said motor chamber.

3. The motor of claim 1 wherein:

said igniter is disposed within said motor chamber.

4. The motor of claim 3 wherein:

said toroidal igniter has a plurality of nozzles therein for directing said gas to said grain.

5. A solid propellant motor capable of a controlled rate of acceleration comprising:

a motor chamber, having a nozzle affixed thereto;

a main solid propellant grain within said chamber having a progressive burning surface such that said grain would not initially sustain stable combustion when ignited; and

at least one solid toroidal propellant igniter disposed in said chamber for directing gas to said main propellant grain, said igniter being capable of supplying sufficient mass flow to said motor chamber at a controlled rate whereby said motor will maintain stable combustion conditions.