An experimental investigation was performed to study the characteristics of the flow in a two-dimensional air ejector in which the center stream entered the mixing chamber at a Mach number of 1.90 while the velocity of the secondary flow was varied from zero to Mach 0.7. Mass flow ratios of the ejector were approximately equal when the pressures of the two streams were equal at the entrance to the mixing chamber. The chamber had a rectangular cross section and converged slightly; its length was equal to 16 times the width. Pressures measured at the walls and the centerline of the flow indicated that a maximum static pressure was reached at 8 widths of the chamber downstream of the nozzle when the flow was completely expanded at the nozzle exit. The maximum static pressure was achieved in less distance for the overexpanded condition and took longer for the underexpanded condition. The flow was always subsonic by the time the maximum pressure position was reached except in the underexpanded case, where the flow remained supersonic throughout the chamber and the maximum pressure was located at the exit to the chamber. (Author).