 Along with some other minor design changes to the wings, the design was finalized on January 10, 1922.The Army expressed interest in the new design, and agreed to provide armament, powerplants, and test the aircraft, while leaving Boeing the rights to the aircraft and design.The contract was signed on April 4, 1923 and the first prototype, designated "XPW-9" for "Experimental Pursuit, Water-cooled engine", flew on June 2, 1923.