The objective of this research is to investigate the efficacy of circulation control (CC) at low Reynolds numbers () with relatively low and high blowing rates on a circulation control wing (CCW). Four dual-radius flap geometries are developed and tested by varying specific flap parameters from a previously studied baseline configuration. A two-dimensional low-speed wind-tunnel experimental study is undertaken to evaluate the effect of trailing edge upper slot blowing at cruise flight and takeoff (0° and 30° flap deflection). The wind tunnel tests are conducted at Mach numbers of 0.03, with momentum coefficients of blowing () ranging from 0.0 to 0.3. The research presented in this paper is the natural outgrowth of results reported in previous work related to the wind tunnel testing of a CCW with dual-radius flaps. This investigation explores the design of CC dual-radius flaps to improve the performance of existing CC flap configurations. This research also provides insight into how the characteristics of the CC flap geometry affect CC performance.