Photograph of a United States Army Air Corps Douglas YO-31B aircraft parked by a hangar, likely at the National Air Races in Ohio, circa 1930s.Inscription: "U.S. Army. Douglas YO-31B."Inscription on verso: "Douglas YO-31B observation."Inscription…
Photograph of a United States Army Air Corps Douglas YO-31B aircraft parked by a hangar, likely at the National Air Races in Ohio, circa 1930s.Inscription: "U.S. Army. Douglas YO-31B."Inscription on verso: "Douglas YO-31B observation."Inscription…
Photograph of a United States Army Air Corps Douglas YO-31B aircraft parked by a hangar, likely at the National Air Races in Ohio, circa 1930s.Inscription: "U.S. Army. Douglas YO-31B."Inscription on verso: "Douglas O-31B. Conqueror G1-1570-C, 600…