Analysis of efficiency of using hybrid propulsion for accelerating small-size rockets starting from the Earth surface

The flight trajectories of a hypothetical small-size rocket starting from the Earth surface and driven by hybrid propulsion, which involves a solid-propellant rocket motor (SRM) and a ramjet-type air-breathing engine (ramjet), are calculated and analyzed. The basic varied parameter is the ratio of the fuel masses used for operation of various engine types with the total fuel mass being unchanged. The objective function is the flight range of the rocket under different initial conditions. Based on a model problem considered as an example, it is demonstrated that the flight range can be substantially increased by using hybrid propulsion (SRM and ramjet), as compared with the vehicle having identical mass and size characteristics and using the SRM only.