The B-47 Stratojet, the world's first swept-wing bomber, made its initial flight on December 17, 1947, and quantity deliveries began in 1951. Oklahoma City was the designated site for maintenance and modification of the Stratojet in the 1950s, and had weapon system management responsibility for the aircraft until 1969. More than 2,000 B-47s were produced by Douglas and Lockheed aircraft companies. This RB-47 was a photo reconnaissance version. Its characteristics were a span of 116 feet, a length of 110 feet, a height of 28 feet, a gross weight of 206,700 pounds, a top speed of 606 miles per hour, a range of 4,000 miles, and ordnance of 20,000 pounds.