B-6

The Keystone B‑6 was the last biplane bomber ordered by the United States Army Air Corps, entering service in 1930. Developed from the earlier LB‑6 model, the aircraft was built by the Keystone Aircraft Corporation in Columbus, Ohio, and represented the culmination of a series of light bombers that the company had produced throughout the 1920s. Powered by a single Wright R‑1820 Cyclone radial engine delivering 575 horsepower, the B‑6 could carry up to 2,000 pounds of mixed ordnance and achieved a top speed of roughly 130 mph with a service ceiling of 13,000 feet. Its fixed, split‑axle undercarriage and open‑cockpit layout were typical of the era, while the dual‑seat configuration allowed a pilot and an observer/gunner to operate a defensive .30‑caliber machine gun. Although quickly eclipsed by more modern monoplane designs such as the Boeing B‑17, the B‑6 served an important transitional role, giving aircrews valuable experience in coordinated bombing tactics and night‑time navigation. The aircraft’s brief but active career, ending in 1934, underscored the rapid technological advances of the interwar period and marked the end of biplane bombers in U.S. military aviation.