Abstract Means for grounding an electrostatic charge from within a fiberglass case of a solid propellant rocket motor are provided. The rocket motor utilizes a solid propellant grain within a fiberglass case which is provided with a metalic dome ring at the forward end of the case. A metallic aft retainer ring for the grain is positioned between the grain and an exhaust nozzle which is affixed to the aft-end of the case. The exhaust nozzle is in electrical contact with the retainer ring and the case. A conductive path to ground is established by a conductive material (e.g., conductive plastic or metallic screen) which is positioned between the propellant grain and the fiberglass case and in electrical contact with an aft-end metallic retainer ring and a forward end metallic-dome ring. The conductive path to ground is established through the fiberglass case itself by employing a conductive material (e.g., powdered carbon or powdered metal) in the epoxy resin used to coat the fiberglass threads in a filament wound fiberglass case. The outside of the motor case is coated with a conductive paint.
The rocket motor as set forth in claim 1 and wherein said conductive material means for grounding consists of a metallic screen for establishing a conductive path to ground, said metallic screen being in electrical contact with said aft-end metallic closure ring, said fiberglass case, and said metallic dome ring, said metallic screen being positioned between said fiberglass case and said propellant grain, said metallic dome ring being in electrical contact with said propellant grain, said metallic dome ring extending to the outside of said motor case, and said case being covered with a conductive paint; and a suitable conductor secured to said metallic dome ring and attached to a suitable ground for completing said conductive path to ground.
Claim 2
Dependent Claim
119 words
The rocket motor as set forth in claim 1 and wherein said conductive material means for grounding consists of a conductive plastic for establishing a conductive path to ground, said conductive plastic being in electrical contact with said aft-end metallic closure ring, said fiberglass case, and said metalic dome ring, said conductive plastic being positioned between said fiberglass case and said propellant grain, said metallic dome ring being in electrical contact with said propellant grain, said metallic dome ring extending to the outside of said motor case, and said case being covered with a conductive paint; and a suitable conductor secured to said metallic dome ring and attached to a suitable ground for completing said conductive path to ground.
Claim 3
Dependent Claim
144 words
The rocket motor as set forth in claim 1 and wherein said conductive material means for grounding consists of a conductive fiberglass case for establishing a conductive path to ground, said conductive fiberglass case being conductive by means of an additive selected from powdered carbon and powdered metals, said additive being added to epoxy resin used in coating the fiberglass threads employed in the making of said conductive fiberglass case, and said case being in electrical contact with said aft-end metallic closure ring and said metallic dome ring, said metallic dome ring being in electrical contact with said propellant grain, said metallic dome ring extending to the outside of said motor case, and said case being covered with a conductive paint; and a suitable conductor secured to said metallic dome ring and attached to a suitable ground for completing said conductive path to ground.