The Martin XB-13 was the designation given to a version of the Martin B-10 that would have been powered by the Hornet B radial engine.
The B-10 was the first modern monoplane bomber to enter USAAC service in the 1930s, and was a mid wing twin engine monoplane with a crew of three or four, and a top speed higher than that of the standard US fighter types when it first entered service. It was powered by a Wright Cyclone radial engine.
Three variants of the B-10 were planned, each using a different Pratt & Whitney radial engine. The XB-13 was to have been powered by two 575hp Pratt & Whitney R-1860-17 Hornet B single row air cooled radial engine, a larger version of the Hornet A used in the B-12. At one point it was planned to built twelve B-13s, but in the end none were constructed.
Engine: Pratt & Whitney R-1860-17 Hornet B radial engines
Crew: 3 or 4 (nose gunner, pilot, radio operator/ rear gunner)
Span: 70ft 6in
Length: 44ft 9in
Height: 15ft 5in
Guns: Three 0.3in machine guns, in nose and rear turrets and ventral position
Bomb load: 2,260lb