The Curtiss P-1 Hawk was the first US Army aircraft to be assigned the P (Pursuit) designation which replaced the PW (Pursuit, single seat, Water-cooled engine) designation. The P-1 was the production version of the Curtiss XPW-8B which won a fly-off against the Boeing XPW-9 in July 1924. The first production P-1, serial number 25-410, was delivered on 17 August, 1925.