Frangible fasteners with flexible connectors for unmanned aircraft, and associated systems and methods

A frangible fastener for coupling a first component to a second component, the frangible fastener comprising:

• an outer body having:
• a first portion terminating at a first end of the outer body, the first portion including a head integrally formed at the first end of the outer body and positionable to contact the first component;
• a second portion terminating at a second end of the outer body opposite the first end of the outer body, the second portion including external threads positionable to contact the second component;
• and
• a frangible portion located between the first and second portions;
• a flexible member positioned at least partially within the outer body, the flexible member having a first end oriented toward the first end of the outer body, and a second end oriented toward the second end of the outer body, the first end of the flexible member fixedly connected to the first portion, the flexible member extending through the second portion such that the second end of the flexible member is located outside of the outer body;
• and
• a stop element fixedly connected to the second end of the flexible member and spaced apart from the second end of the outer body, the stop element being configured to contact the second end of the outer body when the second portion separates from the first portion in response to the frangible portion breaking.

A method for manufacturing an unmanned aircraft, the method comprising:

• attaching a first component of the unmanned aircraft to a second component of the unmanned aircraft with a frangible fastener, the frangible fastener including:
• an outer body having a first portion terminating at a first end of the outer body, a second portion terminating at a second end of the outer body opposite the first end of the outer body, and a frangible portion located between the first and second portions, the first portion including a head integrally formed at the first end of the outer body, the second portion including external threads;
• a flexible member positioned at least partially within the outer body, the flexible member having a first end oriented toward the first end of the outer body, and a second end oriented toward the second end of the outer body, the first end of the flexible member fixedly connected to the first portion, the second end of the flexible member extending through the second portion such that the second end of the flexible member is located outside of the outer body;
• and
• a stop element fixedly connected to the second end of the flexible member and spaced apart from the second end of the outer body, the stop element being configured to contact the second end of the outer body when the second portion separates from the first portion in response to the frangible portion breaking;
• and
• wherein attaching the first aircraft component to the second aircraft component includes:
• threadably engaging the second portion of the outer body to the second aircraft component;
• and
• operably engaging the first portion of the outer body with the first aircraft component.

A method for operating an unmanned aircraft, the method comprising:

• launching the unmanned aircraft, the unmanned aircraft having a first component and a second component connected to the first component with a frangible fastener, the frangible fastener including:
• an outer body having a first portion terminating at a first end of the outer body, a second portion terminating at a second end of the outer body opposite the first end of the outer body, and a frangible portion located between the first and second portions, the first portion including a head integrally formed at the first end of the outer body, the second portion including external threads, the first portion being operably engaged to the first component, the second portion being threadably engaged to the second component;
• a flexible member positioned at least partially within the outer body, the flexible member having a first end oriented toward the first end of the outer body, and a second end oriented toward the second end of the outer body, the first end of the flexible member fixedly connected to the first portion, the second end of the flexible member extending through the second portion such that the second end of the flexible member is located outside of the outer body;
• and
• a stop element fixedly connected to the second end of the flexible member and spaced apart from the second end of the outer body, the stop element being configured to contact the second end of the outer body when the second portion separates from the first portion in response to the frangible portion breaking;
• and
• placing a load on the unmanned aircraft, the load breaking the frangible portion, the first component remaining connected to the second component by the flexible member following the breaking of the frangible portion, the flexible member allowing movement of the first component relative to the second component following the breaking of the frangible portion, the movement being limited by the stop element.