B-47C (XB-56)
The B-47C was redesignated the XB-56 and subsequently cancelled because of problems with development and a shift of interest towards the budding B-52 program. However, during its existence, the B-47C program was based closely off of the design of the B-47B. The difference was that the B-47C was to recieve Allison J35-A-23 turbojets in place of the six General Electric J47s. Besides the engines, the only other significant difference was with the inboard engine nacelles, one J35 was to be mounted in place of the two J47s on the production B-47B model. The first flight date of April 1951 was delayed because of problems with the new engine system. They did not produce as much thrust as first estimated (Preliminary estimates were 9,700lbs, but testing showed the actual thrust was 7,400lbs). Other engines were considered for the needed power boost. The Allison J71-A-5 and the Pratt & Whitney J57 were the engines considered, but by the time testing came about, the interest in the program died due to shifted interest in the B-52 program (the B-52 eventually recieved the Pratt & Whitney J57 engines).
XB-56 Specifications
| Specifications | ||
|---|---|---|
| Span | 116ft. | |
| Length | 106ft. 7in. | |
| Height | 27ft. 9in. | |
| Armament | Two radar directed .50-cal. machine guns with 1,200 rounds ammunition in a tail turret up to 25,000 lbs. of conventional or nuclear bombs. (max. bomb load was one 25,000 lb. bomb) | |
| Engines | Four Allison J35-A-23 axial flow turbojet engines of 9,700 lbs. thrust each (estimated) or four Allison J71-A-5 axial flow turbojet engines of 10,700 lbs. thrust each or four Pratt & Whitney J57 dual-rotor axial flow turbojets of 10,000+ lbs. thrust | |
| Cruising speed | 426 knots | |
| Range | 4,225 nautical miles | |
| Service Ceiling | 42,200 | |
