Curtiss P-1B Hawk, 17th Aero Squadron, 1926  The first model of pursuit category aircraft to be named Hawk.  Improved PW-8, the radiator was slightly more rounded and the wheels were slightly larger in diameter. The cowling was redesigned. Flares were added for night landings and controls were improved. Equipment changes increased the weight still further, and reduced the performance still more.
United States Air Force
1926
Maurer Maurer, 1987, Aviation in the US. Army, 1919-1938, United States Air Force Historical Research Center, Office of Air Force History,  United States Air Force, Washington, D.C.