In April 14, 1934, the Army Air Corps issued a request for a long-range bomber. A 5000 mile range with a 2000-pound bombload was envisaged.
The Glenn L. Martin Company of Baltimore, Maryland submitted its Model 145 in response to this request. This design was in competition with the Boeing Model 294 project which eventually emerged as the XB-15. Originally, the Model 145 was to have been very similar to the Boeing Model 294, being a large cantilever monoplane powered by four Allison V-1710 liquid-cooled V-12 engines.
On May 12, 1934, the Chief of Staff authorized negotiations with both Boeing and Martin for preliminary designs. In the meantime, the Martin design had undergone a major redesign, having been enlarged to a 173-foot wingspan. Six Allison V-1710-2 engines were to have been utilized, four of them operating as tractors and two as pushers. Twin rudders were to have been mounted behind two tail booms. A tricycle landing gear was to be used. The maximum weight was to have been 105,000 pounds. The range was estimated to be 3300 miles carrying 2500 pounds of bombs. The crew was to be 11.
The Martin XB-16 was considered as being too large and expensive, and the project was cancelled before anything could be built.