The Curtiss P-36 Hawk was an American fighter aircraft developed in the late 1930s. It was notable for its all-metal construction and was one of the first U.S. fighters to feature a retractable landing gear. The P-36 was powered by a single Pratt & Whitney R-1830 engine, which allowed it to reach speeds of around 300 miles per hour. The P-36 served primarily during the early years of World War II and was used by the United States Army Air Forces as well as several other nations. Although it was eventually outclassed by newer aircraft, the P-36 played a significant role in the development of American fighter design.