Application of circulation control to advanced subsonic transport aircraft. Part II - Transport application

Abstract

An experimental/ analytical research program was undertaken to develop advanced versions of circulation control wing (CCW) airfoils and to address specific issues related to the application of these blown high-lift devices to subsonic transport aircraft. The primary goal was to determine the feasibility and potential of these pneumatic configurations to increase high-lift system performance in the terminal area while reducing system complexity and aircraft noise. A four-phase program was completed, including 1) experimental development and evaluation of advanced CCW high-lift configurations; 2) development of effective pneumatic leading-edge devices; 3) computational evaluation of CCW airfoil designs plus high-lift and cruise capabilities; and 4) the investigation of the terminal-area performance of transport aircraft employing these airfoils. The first three phases were presented in Part I of this article. This segment, Part II, describes the fourth phase of the program. Experimental lift coefficient values approaching 8.0 at zero incidence were demonstrated by two-dimension al CCW configurations and were reported in Part I. These were used to predict 70-80% reductions in takeoff and landing distances for a three-dimensional advanced subsonic transport configuration employing a simplified pneumatic high-lift system. These results and the methodology used to obtain them will be presented in greater detail in the following discussions.