The first three were B-52As, whose tests began August 5, 1954. None had bombing-navigation gear, and all stayed with Boeing for tests. In 1959, the third A was a carrier plane for the X-15 research program. The B-52 became the most thoroughly tested aircraft in the USAF. Since its design required three million engineering hours, compared to 153,000 for the B-29, it was well-prepared for its long service life.
The next 17 were originally designated RB-52B in a June 17, 1953, contract, because their bomb bay was fitted for an interchangeable pressurized capsule with cameras for reconnaissance and room for two additional crewmen. Seventeen capsules were actually built, but only once was one test flown. The others remained in storage after a January 7, 1955, order, and all of the next 50 Boeings were delivered as B-52B bombers.
First flown January 25, 1955, the B-52B had a Sperry K-3A bombing system, plus five transmitters and two receivers for radar countermeasures. An MA-6A system later replaced the K-3A. While the first 11 had J57-P-1Ws, the rest used J57-P-19W or 29W engines.
The crew included two pilots and an ECM operator in the pressurized top deck, two bombardier-navigators in the lower deck behind the radar, and a lonely gunner in the tail. Armament included four .50-caliber M-3 guns with 2,400 rounds and both optical and A-3A radar fire control. A pair of 20-mm M24A1 guns and MD-5 fire control was fitted to 33 B-52Bs.
The 28-foot long bomb bay could include twenty-seven 1,000-pound bombs, or up to 43,000 pounds of various sizes. When the B-52B appeared, a 8,500-pound Mk 6 was the common nuclear load, until two 7,600-pound thermonuclear Mk 15s became standard. That was the 3.75 megaton yield weapon dropped from 40,000' in the Cherokee test on May 21, 1956. The larger 15,000-pound Mk 21 became available by 1957
Boeing’s B-52B joined SAC’s 93rd Heavy Bomb Wing at Castle AFB, Calif. in June 1955, replacing B-47s. Deliveries were completed in August 1956, and the B model would be retired in 1966.
Over half the Stratofortress takeoff weight consisted of fuel carried in the fuselage and wings, mostly in self-sealing tanks. But the receptacle for an inflight refueling boom was the key to long-range operations. Three B-52Bs completed a 24,325-mile nonstop, round-the-world flight in 45 hours, 19 minutes, on January 18, 1957.
Relays of 78 KC-97 tankers had met the bombers at five refueling points on the route. Boeing KC-135 tankers began arriving at Castle AFB in June 1957. Jet-propelled, and carrying some 31,000 gallons of fuel, they were far more effective than the propeller-driven KC-97s they replaced.
Larger 3,000-gallon drop tanks, and an MA-6A bombing system by International Business Machines Corporation (IBM) was provided on the B-52C, first flown March 9, 1956. Thirty-five B-52Cs built at Seattle by December 1956 replaced the B-36s of the 22nd Bomb Wing at March AFB. Tail defense remained four .50-caliber M-3 guns with A-3A fire control, and white thermal reflecting paint underneath would reduce blast heat.
Boeing’s Wichita factory was added to the Stratofortress program by an August 1954 contract, and the first of B-52Ds was flown there on June 4, 1956, with MD-9 fire control and omission of the recon capsule capability. There were 69 B-52D-BWs from Wichita and 101 B-52D-BOs from Seattle delivered by November 1957. They replaced the B-36s of the 42nd Bomb Wing at Loring AFB, Maine, in 1956, the 92nd BW at Fairchild AFB, Washington, and the 28th Bomb Wing at Ellsworth AFB, South Dakota, in 1957. War in Vietnam required B-52D modification in 1966 to carry 42 750-pound or 84 500-pound bombs in the internal bay, and improved ECM fittings were essential.
A more advanced ASQ-38 bombing-navigation system was used on the B-52E flown at Seattle on October 3, 1957. Forty-two B-52E-BOs and 58 B-52E-BWs were built by June 1958. New J57-P-43As were used on 44 B-52F-BOs, first flown May 6, 1958, and completed when production in Seattle ceased in November 1958. Concurrently, Wichita built 45 B-52F-BWs.
The long-lived B-52G/H models
The B-52G began with a letter contract dated August 29, 1957, for a “super-B-52” with range extended by a new wing structure allowing enlarged integral wing tanks, and fixed 700-gallon external tanks. Other B-52G innovations included the elimination of ailerons in favor of control by spoilers, and a shortened fin.
All six crewmen sat in the pressurized front cabin, including the gunner who was moved forward. He and the ECM operator faced backwards, with ASG-15 remote fire control for the four .50-caliber tail guns. Hostile radar could be detected and confused by four ECM sensors, 14 ECM jammers, 400 pounds of chaff, and up to four McDonnell ADM-20A (formerly GAM-72) Quail decoy missiles carried in the bomb bay. The 13-foot, 1,200-pound Quail reflected a radar image resembling a B-52.