Abstract: A method of protecting an air vehicle against lightning strikes includes inserting a fastener through a hole in conjoined structures, the fastener defining an axis along its length and having a threaded end and a sleeve, and installing a washer assembly over the threaded end and the sleeve, the washer assembly having a metallic washer and a polymer seal radially inward of the metallic washer. The seal includes a lower seal portion defining a counter-bore, and an upper seal portion extending axially from the lower seal portion. The method includes installing a counter-bored nut on the threaded end, and applying torque to the nut to compress the lower seal portion against a surface of the conjoined structures and around the sleeve at the counter-bore of the seal, and to compress the upper seal portion of the seal into a counter-bore of the nut and around the threaded end.

Abstract: A washer assembly including a metallic washer and a polymer seal. The metallic washer defines a cylindrical void and an axis therethrough. The polymer seal is attached to the metallic washer and is positioned radially inward thereof. The polymer seal includes a lower seal portion positioned at least partially within the cylindrical void and defining a counter-bore, and an upper seal portion extending axially from the lower seal portion. The lower seal portion is configured to engage, at the counter-bore, a fastener to form a seal to reduce escape of energized particles. The upper seal portion is configured to engage a counter-bore of a counter-bored nut to form a seal inside the counter-bored nut to reduce escape of energized particles.

Abstract: A method of protecting an air vehicle against lightning strikes includes inserting a fastener through a hole in conjoined structures, the fastener defining an axis along its length and having a threaded end and a sleeve, and installing a washer assembly over the threaded end and the sleeve, the washer assembly having a metallic washer and a polymer seal radially inward of the metallic washer. The seal includes a lower seal portion defining a counter-bore, and an upper seal portion extending axially from the lower seal portion. The method includes installing a counter-bored nut on the threaded end, and applying torque to the nut to compress the lower seal portion against a surface of the conjoined structures and around the sleeve at the counter-bore of the seal, and to compress the upper seal portion of the seal into a counter-bore of the nut and around the threaded end.

Abstract: A washer assembly including a metallic washer and a polymer seal. The metallic washer defines a cylindrical void and an axis therethrough. The polymer seal is attached to the metallic washer and is positioned radially inward thereof. The polymer seal includes a lower seal portion positioned at least partially within the cylindrical void and defining a counter-bore, and an upper seal portion extending axially from the lower seal portion. The lower seal portion is configured to engage, at the counter-bore, a fastener to form a seal to reduce escape of energized particles. The upper seal portion is configured to engage a counter-bore of a counter-bored nut to form a seal inside the counter-bored nut to reduce escape of energized particles.

Abstract: Blind inserts for use with sandwich panels and methods for manufacturing the same. A blind insert can include a nut arranged in an insert. The insert can include a cavity at an end of the nut. When a screw is screwed into the nut, the screw can enter the cavity and dig into the insert. The interference between the insert and the screw can provide friction that prevents the screw from loosening in a vibrating environment. The blind insert can be made by placing a mandrel into the nut. The mandrel includes a nose that extends past the end of the nut. When the insert is molded around the nut, the mandrel prevents mold material from entering a threaded aperture of the nut and forms the cavity in the insert. The blind insert can also be made by placing a cap that defines the cavity on the end of the nut. The insert can be molded around the cap and the nut.

Abstract: Blind inserts for use with sandwich panels and methods for manufacturing the same. A blind insert can include a nut arranged in an insert. The insert can include a cavity at an end of the nut. When a screw is screwed into the nut, the screw can enter the cavity and dig into the insert. The interference between the insert and the screw can provide friction that prevents the screw from loosening in a vibrating environment. The blind insert can be made by placing a mandrel into the nut. The mandrel includes a nose that extends past the end of the nut. When the insert is molded around the nut, the mandrel prevents mold material from entering a threaded aperture of the nut and forms the cavity in the insert. The blind insert can also be made by placing a cap that defines the cavity on the end of the nut. The insert can be molded around the cap and the nut.

Abstract: Blind inserts for use with sandwich panels and methods for manufacturing the same. A blind insert can include a nut arranged in an insert. The insert can include a cavity at an end of the nut. When a screw is screwed into the nut, the screw can enter the cavity and dig into the insert. The interference between the insert and the screw can provide friction that prevents the screw from loosening in a vibrating environment. The blind insert can be made by placing a mandrel into the nut. The mandrel includes a nose that extends past the end of the nut. When the insert is molded around the nut, the mandrel prevents mold material from entering a threaded aperture of the nut and forms the cavity in the insert. The blind insert can also be made by placing a cap that defines the cavity on the end of the nut. The insert can be molded around the cap and the nut.

Abstract: Blind inserts for use with sandwich panels and methods for manufacturing the same. A blind insert can include a nut arranged in an insert. The insert can include a cavity at an end of the nut. When a screw is screwed into the nut, the screw can enter the cavity and dig into the insert. The interference between the insert and the screw can provide friction that prevents the screw from loosening in a vibrating environment. The blind insert can be made by placing a mandrel into the nut. The mandrel includes a nose that extends past the end of the nut. When the insert is molded around the nut, the mandrel prevents mold material from entering a threaded aperture of the nut and forms the cavity in the insert. The blind insert can also be made by placing a cap that defines the cavity on the end of the nut. The insert can be molded around the cap and the nut.