Boeing RB-52B/B-52B Stratofortress

Last revised June 30, 2000



The B-52B was the first truly operational version of the Stratofortress. The B-52B was outwardly identical to the B-52A, but featured an enhanced reconnaissance capability and was fitted with a bombing/navigation system. A total of 50 were built, with 23 being pure bomber B-52Bs and 27 being dual-capable reconnaissance/bomber RB-52Bs. All of them were built at Seattle.

Letter Contract AF33(038)-21096 of February 1951 originally specified 13 B-52As but was changed on June 9, 1952 to include only 3 B-52As, with the remainder to be delivered as B-52Bs. Another seven aircraft were added to the contract at this time. As it turned out, all 17 of these aircraft were actually completed as RB-52Bs. Serials were 52-0004/0013 and 52-8710/8716

Further B-52Bs were ordered later. Letter Contract AF33(600)-22119 was initially drawn up in September of 1952 and formally signed on April 15, 1953. The contract called for 43 RB-52Bs. In April 1954, the contract was amended and the number of RB-52Bs was cut to 33, with the remaining ten machines to be completed as B-52Cs. As it turned out, only ten of these aircraft were actually built as RB-52Bs, with the rest being delivered as B-52Bs. Serials were 53-0366/0398.

The RB-52B had been the result of an earlier disagreement among Air Force officers about what the true role of the B-52 should be--a pure bomber or a pure reconnaissance aircraft. Although bearing an R prefix, the RB-52B could be reconfigured in a matter of hours for either a reconnaissance or a bombardment mission. The RB-52Bs carried out its reconnaissance mission via a two-man pressurized capsule installed in the bomb bay which could perform electronic countermeasures or photographic reconnaissance work. Downward-firing ejector seats were provided for the crew in the case of an inflight emergency. Equipment inside the capsule could be optimized for different types of intelligence-gathering missions and included long-focal length and panoramic camers, plus photoflash bombs, mapping radars, receivers, pulse analyzers and recorders. For search operations, the pod had one AN/APR-14 low-frequency radar receiver and two AN/APR-9 high-frequency radar receivers. Each station had two AN/APA-11A pulse analyzers. The station also had three AN/ARR-88 panoramic receivers and all electronic data was recorded on an AN/ANQ-1A wire recorder. Photographic equipment could include 4 K-38 cameras at the multi-camera station plus one T-11 or K-36 at the vertical camera station. The pod could also carry three T-11 cartographic cameras. The reconfiguring of the aircraft was a fairly straightforward process and the pod could usually be installed in about four hours. Although the pods were retained in USAF inventory, these pods were never actually employed operationally.

At the beginning, the engines of the B-52B/RB-52B were J57-P-1W, -1WA or -1WB turbojets with water injection, the same engines which had powered the B-52A. These were rated at 10,000 lb.s.t. dry and 11,000 lb.s.t. with water injection. About half of the B-52B/RB-52Bs were delivered with these engines. In the meantime, there were attempts to correct problems which had been encountered with the water injection system. These efforts were expected to lead to the J57-P-9W engine with titanium compressor blades. Unfortunately, problems with the manufacture of the blades forced a return to steel blades in the J57-P-29W and J57-P-29WA engines which were installed in the bulk of the remaining B-52B/RB-52Bs. The -29W was rated at 10,500 lb.s.t dry and 11,000 lb.s.t wet. The -29WA had twice the water flow rate as the -29W, and had a 12,100 lb.s.t wet rating. The problems with the titanium blades were finally overcome in the summer of 1956, which led to the J57-P-19W version, which was installed in the final five aircraft delivered.

The first B-52B took off on its maiden flight on January 25, 1955. The first B-52B (52-8711) was delivered to the 93rd Bombardment Wing at Castle AFB in California on June 29, 1955. Over the next few months, the 93rd BW traded in its B-47s for B-52Bs, and changed its name to the 93rd Bombardment Wing (Heavy). The 93rd BW was declared combat ready on March 12, 1956, but its primary mission was the training of future B-52 crews. The initial teething troubles with the B-52 were not nearly as severe as those encountered with the early B-47. However there were difficulties with the fuel system, imperfect water injection pumps, faulty alternators, and especially with deficient bombing and fire control systems.

The B-52B had originally been intended to carry the MA-2 bombing/navigation system, which combined an optical bombsight, a radar presentation of target, and an automatic computer, together with radar modifications designed for use in a high-speed aircraft. However, the development of this package had been delayed. Consequently, SAC had decided to equip some of the early production B-52 aircraft with the Sperry K-3A system that was used by the B-36. Unfortunately, at heights of 45,000 feet where the B-52B typically operated, the K-3A system was found to be almost totally ineffective--poor resolution qualities and a loss of definition made it almost impossible to identify targets with any degree of certainty. The Philco Corporation developed a temporary fix in which power output was increased by about 50 percent, but this was not really much of a solution and things really did not improve very much until the IBM MA-6A system was finally available during the latter stages of the B-model production run.

There were also problems experienced with the fire control system for the tail-mounted defensive armament. Nine of the first ten RB-52Bs (52-004/008 and 52-010/013 used a A-3A fire control system which operated a quartet of 0.50-inch machine guns. However, one early RB-52B (52-0009) was fitted with the alternative MD-5 fire control system which incorporated a pair of M24A-1 20-mm cannon. This system was adopted as standard equipment on the remaining 17 RB-52Bs and 16 B-52Bs (52-8710/8716 and 53-0366/0391). However, the new system proved to offer no real improvement, and the last seven B-52Bs reverted to the original system of four machine guns with a supposedly improved A-3A fire control system. However, in reality, many of the problems remained.

The original electrical system of the B-52 consisted of four air turbine-driven 60 KVA alternators furnishing 200/115 volt three-phase 400 cycle alternating current. The first fatal B-52 crash in February 1956 was blamed on a faulty alternator. This caused the immediate grounding of 20 B-52Bs and the halting in delivery of further B-52Bs while the problem was addressed. In mid-May, deliveries were resumed, but the alternator problem later reappeared.

In July 1956, there was another temporary grounding of the B-52B fleet, this time because of fuel system and hydraulic pack deficiencies. Although this grounding did not last long, the 93rd BW's training program was adversely affected, and by mid-year there were still no combat-ready B-52 crews.

The last B-52B was delivered in August of 1956. The B-models remained in service into the mid-1960s when they were traded in for more modern B-52s.

A program known as Sunflower brought 7 early B-52Bs up to B-52C standards. B-52Bs also went through many other modifications in subsequent programs such as Harvest Moon, Blue Band, and Quickclip, which were initially intended for the benefit of subsequent B-52 models.

RB-52B serial number 52-008 was modified for use as a carrier aircraft for the X-15 and Lifting Body flight research programs, and was redesignated NB-52B.

Serials of B-52B/RB-52B

 
52-004/006 	Boeing RB-52B-5-BO Stratofortress
		 c/n 16494/16496 
52-007/013 	Boeing RB-52B-10-BO Stratofortress 
		c/n 16497/16503 
52-8710/8715 	Boeing RB-52B-15-BO Stratofortress 
		c/n 16838/16843 
52-8716 		Boeing RB-52B-20-BO Stratofortress 
		c/n 16844 
53-366/372 	Boeing RB-52B-25-BO Stratofortress 
		c/n 16845/16851 
53-373/376 	Boeing B-52B-25-BO Stratofortress 
c/n 16852/16855 
53-377/379 	Boeing RB-52B-30-BO Stratofortress 
c/n 16856/16858 
53-380/387 	Boeing B-52B-30-BO Stratofortress 
c/n 16859/16866 
53-388/398 	Boeing B-52B-35-BO Stratofortress 
c/n 16867/16877 

Specification of Boeing B-52B Stratofortress:

Engines: Eight Pratt & Whitney J57-P-1W, -1WA, or -1WB turbojets, each rated at 11,400 lb.s.t with water injection. Later, Eight Pratt & Whitney J57-P-29W or -29WA turbojets, each rated at 10,500 lb.s.t dry and 12,100 lb.s.t. with water injection. Last five were fitted with eight Pratt & Whitney J57-P-19W turbojets, each rated at 10,500 lb.s.t dry and 12,100 lb.s.t. with water injection. Performance: Maximum speed 630 mph at 19,800 feet, 598 mph at 35,000 feet, 571 mph at 45,750 feet. Cruising speed 523 mph Service ceiling at combat weight 47,300 feet. Initial climb rate 4750 feet per minute. Combat radius 3590 miles with 10,000 pound bombload. Ferry range 7343 miles. Takeoff ground run 8200 feet. Takeoff over a 50-foot obstacle 10,500 feet. Dimensions: Length 156 feet 6.9 inches, wingspan 185 feet 0 inches, height 48 feet 3.6 inches, wing area 4000 square feet. Weights: 164,081 pounds empty, 272,000 pounds combat, 420,000 pounds maximum takeoff. Armament: Two 20-mm M24A1 cannon with 400 rpg or four 0.50-inch M3 machine guns with 600 rpg in tail turret. Maximum offensive payload 43,000 pounds.

Sources:


  1. American Combat Planes, Third Enlarged Edition, Ray Wagner, Doubleday, 1982.

  2. Post World War II Bombers, Marcelle Size Knaack, Office of Air Force History, 1988.

  3. Boeing Aircraft Since 1916, Peter M. Bowers, Naval Institute Press, 1989.

  4. United States Military Aircraft Since 1909, Gordon Swanborough and Peter M. Bowers, Smithsonian, 1989.

  5. Boeing B-52--A Documentary History, Walter Boyne, Smithsonian Institution Press, 1981.

  6. Boeing's Cold War Warrior--B-52 Stratofortress, Robert F. Dorr and Lindsay Peacock, Osprey Aerospace, 1995.

  7. USAF Museum website, http://www.nationalmuseum.af.mil/factsheets/factsheet.asp?id=2646