Performance of supersonic scoop inlets

A brief summary is made of the performance of a series of variable-geometry type scoop inlets investigated at the Lewis Laboratory on a model of the X-3 airplane fuselage. Data are presented for a range of inlet mass-flow ratios over a Mach number range from 0 to 2 and from 0 degrees to 12 degrees angle of attack. Rounded-lip inlets are found to give satisfactory performance to a Mach number of 1.5. Use of sharp rather than blunt lip configurations is shown to provide considerable gains in available thrust at Mach number 2.0 but penalize take-off performance to the extent that auxiliary air intakes may be required. No one inlet type was found to be superior over the entire range of operating variables. Thus, the choice of a specific inlet design will be influenced by structural and mechanical as well as aerodynamic considerations.