Analytical and experimental investigation of inlet-engine matching for turbojet-powered aircraft at Mach numbers up to 2.0

Fred T. Esenwein, Carl F. Schueller
naca-rm-e51k20
Feb 1952


An analysis of inlet-turbojet-engine matching for a range of Mach numbers up to 2.0 indicates large performance penalties when fixed-geometry inlets are used. The analysis was confirmed experimentally by investigating at Mach numbers of 0, 0.63, and 1.5 to 2.0 two single oblique-shock-type inlets of different compression-ramp angles, which simulated a variable-geometry configuration. The experimental investigation indicated that total-pressure recoveries comparable with those attainable with well designed nose inlets were obtained with the side inlets when all the boundary layer ahead of the inlets was removed. 2.0 from the use of blunt-cowl leading edges. However, sharp-lip inlets produced large losses in thrust for the take-off condition. These thrust penalties which are associated with the the low-speed operation of the sharp-lip inlet designs can probably be avoided without impairing the supersonic performance of the inlet by the use of auxiliary inlets or blow-in doors.

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