NACA-RM-L57B07

Abstract

INTRODUCTION <br>The growing complexity of modern aircraft with much electronic equipment which requires air for cooling, increased requirements for cabin or cockpit ventilation, problems of matching engine and inlet airflow rates, and the increased use of suction slots for boundary-layer control systems has created a demand for information on the flow characteristics of auxiliary inlets in the transonic speed range. Numerous large-scale inlet investigations have been conducted in this speed range, but except at low subsonic speeds there is little experimental material available whereby the designer may obtain the necessary mass-flow and pressure recovery characteristics of inlets which must induct large amounts of air from with in the boundary layer. <br>The inlet models of the present investigation ranged from flush thin plate inlets to a scoop. Flush circular inlets followed by straight ducts the length-diameter ratios of which varied from 0 to 10 were inclined to the surface at angles from 15&#176; to 90&#176;; the yaw angle far several of the inlets was varied from 0&#176; to 60&#176;. Rectangular inlets with various inclination angles, width-depth ratios, and ramp approaches were also tested. The Mach number range was from 0.55 to 1.3 and mass-flow rates were varied from 0 to choke. Inlet mass-flow ratios are presented as a function of the required pressure drop and of the total pressure recovery.