Inlet Performance Characteristics of a Generalized 1/5.2-Scale Aircraft Model at Transonic and Supersonic Mach Numbers

Abstract : A wind tunnel investigation was conducted at free-stream Mach numbers from 0.55 to 2.0 on a 1/5.2-scale composite inlet model to evaluate configuration factors which affected inlet performance. In addition, flow-field surveys were made at the inlet throat and on the fuselage, forward of the inlet cowl lip. Inlet performance parameters in terms of total-pressure recovery, distortion, and turbulence at the simulated compressor face, as well as compressor face and throat station total-pressure contours and diffuser duct static-pressure distributions are presented for various Mach numbers and angles of attack and sideslip. The basic air induction system consisted of a normal-shock-type inlet with a long splitter plate assembly and was located beneath the wing glove in proximity to the fuselage. The total-pressure recovery for the basic inlet system was slightly better than normal shock recovery for cruise attitudes at supersonic Mach numbers. At Mach numbers approaching 2.0, the basic inlet system was operating close to the buzz limit at design engine airflow. Reductions in total-pressure distortion were achieved by increasing the fuselage-to-inlet standoff distance and by inlet duct boundary-layer blowing.