A supersonic combustion apparatus including a fixed geometric nozzle having a converging area, throat, and a diverging area, at least one movable combination of a fuel injector and an oxygen injector where the combined fuel injector and the oxygen injector is located within the divergent area of the fixed geometric nozzle, and an exit plane adjacent and downstream to the diverging area. The exit plane Mach speed is varied by heat addition in the diverging area by introduction of a combustible fuel through the fuel injector and oxygen through the oxygen injector and then axially aligning and positioning the combination of the fuel injector and the oxygen injector along the length of the diverging area to obtain a stabilized flame at the exit plane.