The Boeing XB-15 experimental four-engined long-range bomber of 1937 proved to be seriously underpowered and was never ordered into production. In March of 1938, in an attempt to remedy some of the deficiencies of the basic design, the Boeing company offered a more advanced version of the XB-15. It was known by the company as the Model 316, and was approximately the same size as the XB-15. However, in an attempt to provide more power, the Model 316 was to have been powered by four 1400 hp Pratt & Whitney R-2180 Twin Hornet air cooled radials.
The Model 316 was offered to the Army in several different forms. The Model 316D version, which featured a high-winged design with an 80,000 pound gross weight, 152-foot wingspan, seven machine guns, and a pressurized canopy, attracted sufficient attention so that two examples were ordered by the Army in June of 1938 under the designation Y1B-20.
Shortly after the order, the Army concluded that the Y1B-20 was simply too expensive and that they really did not require bombers with range or carrying capability beyond those of the B-17. Consequently, both Y1B-20 prototypes were cancelled before anything could be built.
Specification of the Boeing Y1B-20:
Four Pratt & Whitney R-2180 Twin Hornet air cooled radials, rated at 1400 hp each. Weights: 80,000 pounds gross Dimensions: wingspan 152 feet Armed with seven machine guns.
Source:
- Boeing Aircraft Since 1916, Peter M. Bowers, Naval Institute Press, 1989.
