North American Aviation

North American XB-21

The North American XB‑21 was a twin‑engine bomber conceived in the late 1930s by North American Aviation as a potential replacement for the aging B‑17 and B‑18 fleets. First flown on 17 July 1939, the prototype demonstrated a high‑speed, long‑range capability that surpassed many contemporary designs. Powered by two Pratt & Whitney R‑2800 Double Wasp engines, the XB‑21 could reach a top speed of 340 mph and a service ceiling of 28,000 feet, while carrying a bomb load of up to 4,000 pounds. Its all‑metal, semi‑monocoque construction featured a streamlined nose, retractable landing gear, and a crew of five with advanced defensive armament, including powered turrets in the nose and dorsal positions. Although the aircraft performed well in tests, the United States Army Air Corps chose the Boeing B‑17 and later the Consolidated B‑24 for mass production, limiting the XB‑21 to a single prototype. The project nonetheless provided valuable data on high‑performance twin‑engine aerodynamics, influencing later North American designs such as the B‑25 Mitchell. Today the XB‑21 is remembered as a transitional step that showcased the rapid technological advances preceding World War II.

Classification

Production & History

First Flight
1936

Design & Classification

Country of Origin
Manufacturer
North American Aviation
Wikidata ID
Q2711415