The upgraded RB-47H included a number of new features: a separate pressurized compartment in the area formerly occupied by the short bomb bay housed the aircraft's new electronic reconnaissance and electronic countermeasures equipment as well as 3 operators, bringing the RB-47H's crew to a total of 6.
General requirements for electronic countermeasures were established in mid 1951. A detailed configuration was made firm in 1952 because, as Lt. Gen. Lawrence C. Craigie, Deputy Chief of Staff for Development, put it, "losses to the potential enemy air defense system would be very high;' unless the B-47 possessed the capability to counter them. As initially set up, the Air Force's electronic countermeasures program reflected postwar technological advancements as well as state of the art limits. Five phases were planned. Phases I through IV would provide successively more effective self protection equipment, such as transmitters and chaff for jamming enemy signals. Phase V would install a 2 man pod in the B-47's bomb bay for escort protection. This beginning, as modest as it might seem, would not come easily. Yet, the urgency was great. On 29 December 1952, General Twining, Air Force Vice Chief of Staff, wrote Boeing's President, William M. Allen, to urge that "the necessary engineering leading to an effective capability be accomplished as speedily as possible." SAC, nonetheless, kept on believing that procuring the desired B-47, specially equipped for electronic countermeasures would take several years. In any case, other requirements needed to be addressed.
On 25 June 1953, General Power, SAC's Vice Commander, stressed that the command actually needed more advanced technology than promised by Phase V In short, a so called Phase VII electronic reconnaissance apparatus had to be permanently installed in a number of B-47s in place of the planned 2 man pod. These electronic B-47s would ferret out enemy radar defenses and would replace the RB-50s, RB-36s, and modified B-29s which lacked the speed to do such work.
As requested by SAC, the RB-47H program was amended. The RB-47H's initial 2 man pod was replaced by a permanent pressurized compartment that enclosed equipment and 3 additional crew members then referred to as electronic countermeasures observers. In 1955, the number of aircraft in the program was brought to 35-a 5 aircraft increase.
The first RB-47H reached the 55th Strategic Reconnaissance Wing, Forbes AFB, Kansas, on 9 August 1955, after considerable slippage due to production difficulties. Although most of the RB-47Hs had been received by the end of 1956, the 55th Wing still had problems. Besides its operational commitments, the 55th was responsible for "organizing and training a force capable of immediate and sustained strategic electronic reconnaissance and air to air refueling on short notice in any part of the world, utilizing the latest technical knowledge, equipment, and techniques." Combat crew training was delayed from the start by the aircraft's late deliveries. Faulty engines in the first available RB-47Hs and the fuel leaks of subsequent aircraft likewise hampered training. Excessive noise in the aircraft's pressurized compartment did not help either. By the end of 1956, many of these problems had been ironed out, but none of the RB-47Hs was fully and effectively equipped.
The absence of an automatic electronic direction finder was the RB-47H's most crucial deficiency. Two pioneer productions of the required direction finder finally became available in December 1956. Each was immediately installed by Douglas (at the company's Tulsa plant), and the 2 newly equipped RB-4714s reached the 55th Wing in January 1957. As could be expected, the many relatively untested components in these direction finders caused more problems. Their seriousness resulted in the establishment of a joint military and civilian committee to assist testing and operation. Additional direction finders were received in March and the RB-47H's first modification program began. Basically, it called for the installation of 1 automatic electronic direction finder in each RB-47H. Numerous related adjustments were necessary, however. Just the same, the work was done promptly, on base, by Douglas personnel.
The Flyaway Cost Per Production Aircraft was $2.1 million. Airframe, $1,588,723; engines (installed), $273,449; electronics, $54,877; ordnance, $8,271; armament, $201,597.
The Air Force took delivery of its last 2 RB-47Hs in January 1957.
Although the RB-47H's post production modifications of 1957 were satisfactory and the aircraft was practically unique, SAC had to keep pace with incessant technological advances. New requirements and the development of more sophisticated equipment soon required a reconfiguration of the RB-47H's special compartment. A mockup inspection in September 1959 was followed in August 1960 by the first flight of a refitted RB-47H. The plane, besides its 6 radar sets, carried some of the most modern electronics. The RB-47H prototype of 1960 was put together by Boeing, but other RB-47Hs were retrofitted by Douglas. The first reconfigured aircraft was returned to the 55th Wing in November 1961.
The EB-47H, for a time designated ERB-47H, was an RB-47H that carried special electronic "ferret" equipment. As such, the 3 planes so modified by Boeing before the end of 1957 were able to detect, locate, record, and analyze electromagnetic radiations.
On 29 December, SAC's last B-47 type aircraft, an RB-47H (Serial No. 53 4296) of the 55th Wing, was flown to Davis Monthan AFB for storage. Completion of the RB-47H phaseout came exactly 20 years after the initial flight of the experimental B-47.
In all, a total of 35 were produced. Phaseout was completed in 1967.
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