is developing a fully reusable sounding rocket named WIRES (WInged REusable Sounding rocket). The winged rocket incorporates many novel technologies, including a full composite structure and a navigation, guidance, and control system. It is also equipped with an innovative hybrid rocket engine named CAMUI (CAscaded MUltistage Impinging-jet). In such a complex rocket, system integration is difficult to achieve and innovation is imperative. The laboratory is therefore also developing a subscale model of the rocket named WIRES#014 to assess the new navigation, guidance, and control system. This paper describes the procedure and results of a trial and error approach, comprising three ground combustion tests, to integrating the systems of the rocket. In the first and second try of the combustion test, the tests had some troubles mainly about ground support system and avionics. Authors eliminated these errors after the cause analysis; the third combustion test was finally succeeded.