Abstract: A method of propulsion includes providing a high-speed-launch ramjet boost (HSLRB) stage and HSLRB engine attached to a launch aircraft providing a speed ?1.5 Mach. The HSLRB engine includes a combustion system and inlet(s) for air flow to the fuel injectors. A variable geometry (VG) nozzle having a nozzle actuator exhausts gas from combustion. A processor receives sensing signals from sensor(s) during flight that provides control signals to the nozzle actuator for dynamically controlling an aperture size of the VG nozzle, and if the inlet is a VG inlet to an inlet actuator to dynamically control the VG inlet shape. The HSLRB engine is ignited while attached to the aircraft at 1.5 to 1.99 Mach if assisting the aircraft to accelerate to 2.0 Mach, or at a speed of ?2.0 Mach if the aircraft can accelerate to 2.0 Mach autonomously, then the HSLRB stage is separated from the aircraft.

Abstract: A method of propulsion includes providing a high-speed-launch ramjet boost (HSLRB) stage and HSLRB engine attached to a launch aircraft providing a speed ?1.5 Mach. The HSLRB engine includes a combustion system and inlet(s) for air flow to the fuel injectors. A variable geometry (VG) nozzle having a nozzle actuator exhausts gas from combustion. A processor receives sensing signals from sensor(s) during flight that provides control signals to the nozzle actuator for dynamically controlling an aperture size of the VG nozzle, and if the inlet is a VG inlet to an inlet actuator to dynamically control the VG inlet shape. The HSLRB engine is ignited while attached to the aircraft at 1.5 to 1.99 Mach if assisting the aircraft to accelerate to 2.0 Mach, or at a speed of ?2.0 Mach if the aircraft can accelerate to 2.0 Mach autonomously, then the HSLRB stage is separated from the aircraft.