What is a Coupler?

A coupler is an internal support component used to join two body tubes.

How to Design a Coupler?

Before designing a coupler, the body tubes of the rocket need to be designed. The general shape is similar to that of the body tubes, allowing it to fit snugly between them. Once the body tubes are designed, if the coupler is joining two body tubes that will separate in flight, it should be designed to fit tightly onto the bodies using an interference fit method. For a safe flight, the length of the integration structure should be at least 1.5 times the diameter of the rocket body. To increase the strength during flight, holes can be drilled into the body tubes and coupler, and pins can be inserted into these holes. This ensures that the body tubes remain firmly together during flight and can easily separate when the pins are broken. If the integration structure will join two body tubes that will not separate, the bodies can be screwed together to increase strength. When considering the rocket’s center of gravity, the integration structure can be produced with various thicknesses and materials to optimize the rocket’s center of gravity.

Coupler Materials

Various alternative materials can be used for the integration structure. These materials should be selected based on properties such as strength and density. The material should be chosen based on the design for suitable production. For model rockets, the main materials are cardboard, aluminum, and composite materials. For more detailed information on these materials and production methods, you can refer to the page on Materials Used in Model Rocketry.