06/30/2011. A pilot order for ten B-47As, essentially service test versions of the XB-47 to be used for the training of factory and Air Force personnel alike, was placed with the Boeing Wichita, Kansas plant. Powered with 5,200 lb (2,359 kg) thrust J-47-GE-11 engines and retaining the built-in JATO feature of the prototypes, the first B-47A flew on June 25, 1950.
Empty weight was 73,240 lb (33,226 kg) and maximum take-off weight was 151,324 lb (68,639 kg). The tail armament of two 0.50 in (12.7 mm) machineguns was tested with an A-2 fire control system on one machine
(49-1906) and an A-5 on another (49-1908). Speed was 521 knots (600 mls, 965 kmh) at 8,800 ft (2,682 m) .
Since the production B-47s were built at Wichita, they used the Stearman system of factory serial numbers keyed to the aircraft model number that had been continued on the Model 75s after Stearman became a Boeing division, and the ten B-47As had c/n 450001 to 450010 and s/n 49-1900 to 49-1909.