Increasing the stable operating range of a Mach 2.5 inlet

Abstract

The results of an experimental investigation to increase the stable operating range of a supersonic mixedcompression inlet a r e presented. Large stability margins were obtained with inlet throat bleed systems utilizing controlled bleed plenum pressure. These throat bypass systems removed airflow through either distributed normal holes, distributed educated slots, o r a single forward-facing slot. Control of the bleed plenum pressure was provided by variable choked exits, vortex valves, o r self-acting mechanical valves. Stability limits were determined for steady-state operation and transient internal airflow disturbances. Mechanical valve instability was encountered at some discrete inlet operating conditions.