The Boeing Company

John A Ward

John Richard Porter

Jeffrey A Wilkerson

Russell Joe Heeter

Thu A Nguyen

Daniel James Kovach

Arlene McKeeman Brown

Donald K Dabelstein

Kari L Stromsland

Diane L Heidlebaugh

Russell J Heeter

Edge seals for composite structure fuel tanks are disclosed herein. One disclosed apparatus includes a seal covering an exposed edge of a carbon fiber reinforced composite fuel tank, where the seal comprises a layer of dielectric material to insulate carbon fibers at the exposed edge from fuel in the tank.

Edge seals for composite structure fuel tanks

A conductive fastener assembly, system, and method are described. The fastener assembly includes a nut having a counterbore formed therein. The counterbore is formed to maintain a sufficient gap between the nut and the protruding end of a fastener sleeve. The nut with the counterbore improves the conductive fastener system such that the need for a solid copper grid and a cap seal is reduced or eliminated.

Sleeved fastener assembly

A conductive fastener assembly, system, and method, wherein the fastener assembly includes a fastener, a fastener sleeve, a nut, and a lubricant coating. The lubricant coating is deposited on a distal portion of a fastener shank and is omitted from the rest of the fastener. To overcome the stresses placed on the fastener sleeve by the insertion of the fastener shank largely devoid of a lubricant coating, the fastener sleeve is reinforced by one or more of an increased thickness, a high-strength alloy, and a soft metal coating.

Conductive sleeved fastener assembly

The present disclosure describes a conductive fastener assembly, system, and method, wherein the fastener assembly comprises a nut having a counterbore formed therein. The counterbore is formed to maintain a sufficient gap between the nut and the protruding end of a fastener sleeve. The nut with the counterbore improves the conductive fastener system such that the need for a solid copper grid and a cap seal is reduced or eliminated.

The present disclosure describes a conductive fastener assembly, system, and method, wherein the fastener assembly comprises a fastener, a fastener sleeve, a nut, and a lubricant coating. The lubricant coating is deposited on a distal portion of a fastener shank and is omitted from the rest of the fastener. To overcome the stresses placed on the fastener sleeve by the insertion of the fastener shank largely devoid of a lubricant coating, the fastener sleeve is reinforced by one or more of an increased thickness, a high-strength alloy, and a soft metal coating.

The cut laminate edges of aircraft fuel tanks formed of carbon fiber reinforced polymers are sealed to prevent the exposure of carbon fibers to combustible fuel. The edge seal is produced from a prepreg form using a thermosetting resin matched to the characteristics of the resin used in the laminate. The prepreg form can be applied to the cut laminate edges either before or after the laminate is cured. The edge seal acts as a dielectric layer that both electrically insulates the cut laminate edges from the fuel and mechanically contains energetic particles produced at the edges due to lightning strikes or other sources of electrical charges.

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Bonney Lake, WA, United States of America

John A Ward