The Military Aircraft HM-1 was a unique American landplane that originated as the Hawks Miller HM-1, a high-speed racing aircraft commissioned by aviator Frank Hawks and designed by Howell W. “Pete” Miller. Miller, who had previously served as the chief engineer for the Curtiss-Wright Corporation, developed the original racer for speed record attempts between 1936 and 1937. In 1936, Hawks sold the engineering data and rights to Tri-American Aviation, which sought to adapt the streamlined airframe into a two-seat attack and observation aircraft. This redesign process, which took place between 1937 and 1938, added a rear cockpit and armament provisions, and the project eventually fell under the management of the Miller Aviation Corporation (also known as the Miller Aircraft Co.).
Technically, the HM-1 was a compact low-wing monoplane with a wingspan of 30 feet and a length of 23 feet 6 inches. It was powered by a single 14-cylinder, two-row, air-cooled Pratt & Whitney R-1830 “Twin Wasp” radial piston engine producing 1,150 hp. This powerful powerplant, combined with a refined aerodynamic profile and retractable landing gear, allowed the aircraft to reach an estimated maximum speed of 375 mph (604 km/h). The military configuration included two fixed, forward-firing machine guns in the wings and one flexible machine gun in the rear cockpit for defensive fire.
Although intended for foreign military export, the HM-1 never entered operational service. It served primarily as a demonstrator, most notably appearing in the 1938 Thompson Trophy race. Flown by Leigh Wade, the aircraft finished fourth in the competition while equipped with dummy machine guns to highlight its combat potential. Later, test pilot Earl Ortman conducted demonstration flights for foreign representatives near East Hartford, Connecticut. During one such flight, the aircraft suffered a cowling failure, leading to a crash that destroyed the sole prototype. Ortman bailed out safely, but the accident resulted in the immediate abandonment of the project. No further aircraft were produced, and the companies associated with the project, including Tri-American Aviation and Miller Aviation Corporation, are now defunct.