The B-29 was the original production version of the Superfortress. Since the new bomber was urgently needed, the production design was developed in tandem with the service testing. In fact, the first B-29 was completed only two months after the delivery of the first YB-29. 46 B-29s of this variant built by the Glenn L. Martin Company at its Omaha plant were used as the aircraft for the atomic bomb missions, modified to Silverplate specifications. 2,513 B-29s were manufactured by Boeing-Wichita (1,620), Bell-Atlanta (357), and Martin-Omaha (536).
Read more about this topic: Boeing B-29 Superfortress Variants