The XB-19 was modified in 1943 by replacing the original Wright R-3350 radials with Allison V-3420 inline engines. The aircraft was then redesignated XB-19A. With the more powerful Allison engines, the aircraft's top speed increased to 265 mph, and the cruising speed went from 135 mph to 185 mph. The XB-19A, like the XB-19, was used as a test bed for very large aircraft design, construction and flight characteristics.
The Air Corps contracted for the construction of the Northrop XB-35 and Consolidated XB-36 in November 1941, just five months after the XB-19 flew for the first time. In fact, the design competition for these large bombers was completed more than two months before the XB-19 ever flew.
After completing flight testing, the XB-19A was used as a cargo/transport until it was scrapped in 1949.
XB-19 with V-3420-11 engines
TECHNICAL NOTES: Armament: Two .37mm cannon, five .50-cal. and six .30-cal. machine guns; 18,700 lbs. of bombs (maximum load) Engines: Four Allison V-3420-11 of 2600 hp each Maximum speed: 265 mph at 20,000 ft. Cruising speed: 185 mph Service ceiling: 39,000 ft. Range: 7,710 miles with 2,500 lbs. of bombs Span: 212 ft. 0 in. Length: 132 ft. 2 in. Height: 42 ft. 9 in. Weight: 140,230 lbs. gross weight Crew: 11 (normal); 18 (maximum) Serial number: 38-471