Design and control of solid-fuel ramjet for pseudovacuum trajectories

ii ballistic trajectory in air of a powered projectile where the thrust alw ays balances the drag is termed as a pseudovacuum trajectory. For a solid-f uel-ramjet (SFRJ)-powered gun-launched projectile this trajectory can be ac hieved by the control of engine mass-flow rate, either by a bypass control of inlet air or by a regression rate control of fuel. Based on one-dimensio nal considerations, the procedures for a preliminary design of the propulsi on system for an SFRJ-assisted gun-launched projectile and the methods to c alculate the control requirements are presented. Using these, typical confi gurations of SFRJ suitable for 155-mm gun-launched projectiles are analyzed for different launch angles. The results indicate that the control require ments by either method are minimal and thus, demonstrate the self-throttlin g characteristics of SFRJ.