An experimental study was conducted to determine the effect of wall angle, wall offset, and power jet pressure on the control signal required to switch the flow in a Coanda wall attachment device. A stability parameter was defined as the ratio of the power jet pressor to the change in control pressure required for switching to occur. When this ratio is a minimum, maximum stability has been attained. Data was obtained for wall angles from zero to fifty degrees; wall offsets from one-half to none inches; and power jet pressures in the range from 0.7 to 4.0 inches of mercury. Comparisons were made between the stability parameter, the wall angle, and the wall offset to find the most stable configuration of the wall. This configuration was a wall angle of thirty degrees and a wall offset of one inch. The stability parameter remained approximately constant for different power jet pressures at each geometric configuration.