Boeing B-52 Stratofortress B-52A

Encouraged by the promise of the XB-52 and YB-52, and with the Korean War under way, the US Air Force placed the first production contract for the Stratofortress in early 1951 as a replacement for the Convair B-36. The contract, dated 14 February 1951 and secured after several direct interventions by General LeMay, covered thirteen B-52As and seventeen detachable reconnaissance pods. It was updated on 9 June 1952 to reflect new specifications and, such was the pace of the programme, soon cut back to just three aircraft; the remainder were completed as RB-52Bs. There was nothing wrong with the B-52A; the next version was simply ready.

The B-52A was the first Stratofortress to look like the aeroplane everyone now recognises. The forward fuselage was redesigned from scratch: the tandem cockpit under a bubble canopy, carried over from the B-47, gave way to a conventional flight deck with the two pilots side by side, a change LeMay insisted upon to make the co-pilot more effective and reduce crew fatigue. The nose was lengthened by 53 cm to house additional avionics and a sixth crew member, the electronic warfare officer, seated behind the pilot and facing aft.

At the tail a turret with four .50-calibre machine guns and a fire-control system appeared for the first time; the first RB-52Bs inherited it before switching to a pair of 20-mm cannon. The engines were now Pratt & Whitney J57-P-1W turbojets delivering 10,000 pounds-force dry, rising to 11,000 pounds-force for short periods with water injection fed from a 360-gallon (1,363 l) tank. A 1,000-gallon (3,785 l) external fuel tank could be hung under each wing; besides extending range, the tanks acted as dampers on the flexible wing and kept the tips close to the ground for easier maintenance.

The first B-52A flew in August 1954. The three aircraft, built at Seattle like the prototypes and every A, B and C model, never reached a bomb wing: they were loaned to Boeing and used exclusively for tests on behalf of the manufacturer and the Air Force, including the development of the new four-gun tail turret. Nominally the first production variant, the B-52A was in practice a third set of prototypes, the bridge between the demonstrators and the B-52B with which operational service began.

The most celebrated of the three was the last built, 52-0003. In 1959 it was modified and redesignated NB-52A as the mothership for the North American X-15. A pylon was fitted under the right wing between the fuselage and the inboard engine pod, a section of flap measuring 1.8 by 2.4 metres was cut away to clear the rocket plane's tail, and liquid oxygen and hydrogen peroxide tanks were installed in the bomb bays to top up the X-15 before release. Operating from Edwards, the NB-52A carried the X-15 to launch altitude throughout the high-speed research programme, joined in the task by a former B-52B converted as the NB-52B.

52-0003 is today the oldest B-52 in existence. It is preserved at the Pima Air & Space Museum in Tucson in the markings of the Air Force Flight Test Center at Edwards in the 1960s, carrying the name "The High and Mighty One". The museum's data card lists a 185 ft wingspan, a length of 156 ft, a height of 48 ft, a loaded weight of 450,000 lbs, a maximum speed of 650 MPH, a service ceiling of 50,000 ft, a range of 6,000 miles and a crew of six.

Of the 744 Stratofortresses built by 1962, the three B-52As were the ones that fixed the definitive formula: side-by-side cockpit, six crew, manned tail turret, water injection and underwing tanks. Everything that followed, from the B-52B to the B-52H, was built on those decisions, and the only one of the three that survives did so not as a bomber but as the aircraft that launched the X-15.