A six-stage axial-flow compressor with a tip speed of 550 feet per second and a flat operating characteristics at constant speed has been designed and tested. It was designed for a constant power input per pound of flow in expectation that this would result in a wider mass-flow operating range at a given stagnation-presssure ratio. The design specific weight flow was 21.3 pounds per second per square foot of frontal area at atmospheric discharge with a stagnation-pressure ratio of 3.25 and an inlet hub-tip radius ratio of 0.7. Several configurations consisting of various blade setting angles and solidities were tested. Tests showed that the design flow, pressure ratio, and flat operating characteristic were obtained over a range of 10 percent of design flow at a peak efficiency of 82 percent for design conditions. The compressor had a possible immediate application for air removal from a large slotted-throat transonic wind tunnel, but the design theory could apply to any low-speed industrial compressor or second spool of a turbojet engine.