The RB-66B at first closely resembled the improved RB-66A. Differences emerged over the years, as the B-model received better cameras and electronic countermeasures equipment. Some changes were made on the production lines; others, long after completion of the entire program. The J71-A-13 engine, an important feature of the aircraft, appeared on the last 17 RB-66Bs, earlier productions acquiring the higher-thrust engines through retrofit.
Even though the improved RB-66A had been thoroughly tested, the Air Force Flight Test Center conducted extensive qualifying flight tests on one of the initial RB-66Bs. In contrast to the reworked RB-66A, which had been refitted with J71-A-1 this plane and 19 other early RB-66Bs carried the less powerful -9 engines. Nevertheless, the flight center's tests and subsequent RB-66B acceptance flights were generally successful. Electronic interference disturbed the image on the aircraft's AN/ARC-21 radar receiver, but Air Research and Development Command engineers soon found out that the ionization of particles in the jet engine exhaust caused the problem. This helped the contractor to swiftly devise an effective production modification.
The first truly official flight of the RB-66B occurred on 29 October 1955, after 8 of the aircraft had already been accepted by the Air Force. The flight, which was considered satisfactory, confirmed earlier test-flight results.
The first RB-66Bs joined the 9th Tactical Reconnaissance Squadron of the 363d Tactical Reconnaissance Wing (TRW), at Shaw AFB, South Carolina. Although the aircraft's initial all-weather capability was limited, arrival of the RB-66Bs permitted the long overdue replacement of the obsolescent RB-26s, and speeded phaseout in early 1957 of the problem-ridden RB-57As. The RB-66B program was a year behind schedule, but by the end of 1956 two-thirds of the RB-66Bs on order had been delivered, allowing activation of 2 other squadrons within the 363d TRW, the 41st and 43d, both located at Shaw AFB. The RB-66B in time became the primary night photographic weapon system of the Tactical Air Command.
A special development engineering inspection verified the proper installation of active defense electronic countermeasures equipment in forthcoming RB-66Bs. Several new devices were involved, most of which were intended to jam hostile radars. The 2-day development engineering inspection also covered retrofit of the 46 RB-66Bs, already accepted from Douglas. Even though attendees submitted 32 requests for alteration, the inspection board only approved 22 of them. The endorsed changes represented no extra expenses for the Air Force, since they all fell under the purview of Douglas's contract.
While the bulk of the B/RB-66 contingent was earmarked for TAC, the Air Force originally wanted some of the delivered aircraft to be deployed overseas immediately. Slippage of the program changed this planning. Still, the 12th Tactical Reconnaissance Squadron, at Itami, Japan, a unit of the Pacific Air Forces (PACAF), received its RB-66Bs in late 1956, at about the same time that TAC activated 2 additional RB-66B squadrons. The United States Air Forces in Europe (USAFE), however, did not get any of the new aircraft until the fall of 1957. The 2 RB-66B squadrons, first assigned to the USAFE's 66th Wing, were later transferred to the 10th Tactical Reconnaissance Wing, another USAFE unit.
The fact that the RB-66Bs were operational, at home and overseas, did not mean that all was well with the aircraft. To begin with, the program's near-cancellation and subsequent indefinite slippage, combined with overall financial restrictions, had created troublesome setbacks. TAC's 363d TRW was ill-prepared to support its first aircraft. The wing did not have enough MA-3 all-purpose servicing units and had too few of the MA-1 air conditioners that were necessary to preflight the RB-66s. There were also serious shortages of personal equipment, helmets in particular. The RB-66Bs themselves were encountering some of the problems often experienced during the early operational life of a new aircraft. Cautious, the Air Force grounded all RB-66Bs in mid-1956 after an incident at Shaw in which an aircraft suffered engine failure because bolts or screws either worked loose or sheared from the alternator. The grounding did not last, but similar restrictions were imposed in September, following the discovery of cracks on the horizontal stabilizer of a B-66B. The grounding this time affected both the B-66Bs and the RB-66Bs and remained in effect until all aircraft had been inspected and repaired, as necessary.
Slow acceleration, flameout, stall, and surge were malfunctions that characterized the performance of the J71-A-9 engines that originally equipped 20 RB-66Bs and 17 B-66Bs. Allison improved the engine's bleed air system (reduced from the 16th to the 8th stage), and this with other minor changes led to the production of the J71-A-11. The new engine reached the Douglas plants promptly, equipping most B/RB-66s from the start. But the J71-A-14, despite its 9,700 pounds of thrust, proved disappointing. Tb begin with, the engine was still underpowered. In addition, like its predecessor, the J71-A-11 often stalled under high acceleration because of sticking compressor bleed valves and poorly designed electrical relays. Even though the most serious stall problems were solved without delay, TAC kept on insisting that better engines were needed. The command had in mind still another version of the Allison J71, namely, the 10,200-pound thrust J71-A-13, which could be injected with a mixture of water and alcohol. TAC believed, rightly as it turned out, that the higher-thrust engines would decrease takeoff roll by nearly 40 percent, would ensure a range increase of 10 percent, and would guarantee a 5-percent improvement of the aircraft's maximum speed. The Air Staff, in the fall of 1956, finally endorsed TAC's request. This meant that nearly 200 aircraft had to be retrofitted with J71-A-13s, while the B/RB-66s that had yet to clear the Douglas production lines would receive the new engines directly. Unforeseen by all parties-the Air Force, Douglas, as well as Allison- were the many difficulties that the new engines would soon create.
Operational difficulties and forthcoming engine changes notwithstanding, the RB-66B by mid-1957 seemed to have shed most of its developmental flaws, and for all practical purposes the incorporation of production fixes had ceased. The aircraft, in addition, contributed to the successful development of a rain removal system that would serve the entire program, and other Air Force jet bombers. This system used a stream of engine bleed air, which was blown over the aircraft's windshield. Tested by the Wright Air Development Center under both artificial and natural conditions, the new development appeared to be the most effective and reliable means thus far devised to control a visibility problem of long standing. Indicative of the system's importance, the Air Force by mid-1957 had already initiated the procurement of retrofit kits for installing the new rain removal system on all B/RB-66s. The kits were geared to the J71-A-13s, since these engines were now due to appear on every B/RB-66 aircraft.
Unforeseen problems were caused by the J71-A-13s, whether production installed or retrofitted on the B/RB-66s, because the new engines' higher thrust was accompanied by greater noise. Evidences of acoustically induced sonic fatigue were immediately noted, as skin cracks and stress breaks increasingly appeared in the ailerons, flaps, dive brakes, elevators, stabilizers, and rudders of the J71-A-13-equipped aircraft. Remedial procedures, undertaken without delay, consisted of pouring a powdered substance, known as Sta-Foam, into the aircraft's control surfaces that were subject to stresses. The powdered Sta-Foam, subsequently combined with chemicals causing it to foam up and solidify, promised to be a counteracting stress agent in the aircraft's most vulnerable surfaces. The B/RB-66s predated metallic honeycombing, an industrial technique used to absorb the higher acoustical disturbances caused by the higher thrusts of later engines. TAC was greatly concerned by the stress problems besetting its new aircraft, particularly because the Sta-Foaming program, as initiated in 1957, would be lengthy. In effect, the most exacting work was assigned to Douglas, while tactical units would accomplish the simpler tasks. Yet TAC insisted that whether the B/RB-66s were flown to the manufacturer for rework, or whether Douglas shipped Sta-Foamed surfaces to the tactical units, its new aircraft would be kept out of operation for an excessive period. In mid-1957, TAC again protested the program's pace, and suggested to save time that its RB-66s be flown to the San Bernardino Air Materiel Area where reworked surfaces would be exchanged for damaged and unmodified surfaces. Once flight tested, the modified planes would fly back to their bases. The Air Staff endorsed the TAC proposal, but new problems arose within a month. In August 1957, the command was informed that the B/RB-66 overall modernization program had to be curtailed for lack of money The cut would be drastic, up to 80 percent if possible, and the entire inspectand-repair-as-necessary (IRAN) program was eliminated. However, neither the aircraft conversion to J71-A-13 engines, nor the Sta-Foaming of fixed and movable surfaces were affected. The irony of the latter exemption came to light in February 1958, when the Sta-Foaming program was stopped. 7b some degree, 98 percent of the TAC B/RB-66s carried Sta-Foamed surfaces. Unfortunately, there was now clear evidence that the Sta-Foaming technique was a failure. The compound promoted corrosion and could eventually absorb up to 180 percent of its own weight in moisture, thus affecting aircraft balance. Although Douglas estimated that it would take some 8 months to fabricate new B/RB-66 control surfaces, the Air Force stated categorically that the work had to be done in little more than half that time.
Not only was the so-called all-weather RB-66B incapable of performing under adverse weather conditions, but it could not take photographs at night from high altitudes. Obvious from the start, the lack of proper tactical reconnaissance equipment was an increasingly crucial problem. 1b remedy the deficiency, Headquarters USAF in mid-1957 approved a TAC request for replacement of the aircraft's 12-inch cone K-37 camera by two 24-inch K-47s. However, the funding restrictions of the new fiscal year (FY 1958) postponed procurement of the more efficient cameras until mid1958-fiscal year 1959. This would be in time to prevent Fairchild from shutting down its K-47 production lines, thereby saving the expense of re-establishing production, a financial burden that Air Force would have had to bear. Just the same, while this timing was a plus, the postponed camera procurement presented TAC with another delay, since the installation of K-47 cameras on all RB-66Bs would require nearly 1 year. Meanwhile, the acquisition of a high-resolution radar, to give the aircraft the capability to navigate in all types of weather, was almost at standstill. In late 1957, various radars were being considered and some testing was being done, but no solution was in sight.
The B/RB-66 overall modernization program, postponed because of the FY 58 funding restrictions, finally got under way in May 1958. Tagged as "Little Barney," the $29 million project encompassed a myriad of technical order compliances, which had been delayed for lack of money. It covered the installation of J71-A-13 engines in the aircraft still equipped with J71-A-1 is and the improvement of all PACAF and USAFE B/RB-66s which, in contrast to the TAC aircraft, had never benefitted from any type of modification. Of necessity, Little Barney also had to deal with the metal fatigue and corrosion problems encountered in all varieties of the B/RB-66s. Although Douglas provided sufficient newly designed control surfaces to allow all needed substitutions, Little Barney was not completed until August 1959, a slippage of several months. The delay was caused by a contractor-labor dispute, which prevented Douglas from sending field teams to the Air Force as soon as expected. Still, the project's results were satisfactory, and "Big Tom" which succeeded Little Barney at the Mobile Air Materiel Area in Alabama, also proved successful. The managerial logistics support of the B/RB--66 program was transferred from the San Bernardino to the Mobile Air Materiel Area on 31 July 1959. The 2 projects were closely related, since both centered on the yearly IRAN program of the weapon system. TAC delivered 5 percent of its RB-66s to Mobile each month and, as a rule, received its aircraft back within 30 days. The arrangement, while it lasted, worked well. Meanwhile, there were other problems, and frustrating incertitudes would soon follow.
TAC grounded all its RB-66s in February 1959, after discovering cracks in the aircraft's nose gear attaching lugs. The repair of this flaw as well as other design deficiencies was guaranteed to be corrected by the contractor. The Air Force returned all available spares to Douglas for rework, and modifications to strengthen the nose gear strut assemblies were done at field and depot levels. Three Douglas teams arrived at Shaw, where they worked on 24-hour schedules so that all aircraft resumed flying before March. But another vexatious problem arose in mid-year, putting a new burden on the
Big Tom project. The fuel tanks of all B/RB-66s had to be inspected, and most of them resealed, to prevent fuel leaks attributed to deterioration of the original sealant. When another sealant was applied, a different problem developed. Various areas of the resealed tanks started leaking under pressurization, which tended to indicate that the tanks were nearing the end of their useful lives.
In 1960, the long-awaited installation of K-47 cameras, having been canceled for lack of money, was reinstated (On the other hand, Headquarters USAF in 1960 also recommended that TAC drop its requirement for putting a high resolution radar on the RB-66Bs. The cost involved, about $100,000 per aircraft, seemed no longer justifiable in view of the RB-66B's near phaseout, then programmed to take place in fiscal year 1964.). However, the RB-66B's new K-47 camera system again became a cause of concern in early 1961. Camera magazines did not function properly. They could be fixed for $178,000 or replaced for $268,000, two expensive propositions considering the Air Force's continuing penury. In addition, while efficient for night photography, the cameras still needed to be upgraded for daytime operation, a modification finally approved in October.
Since its introduction into the TAC inventory the RB-66B had failed to achieve the desired level of operational readiness, often due to maintenance and supply shortcomings. In fact, the same failings were experienced Air Force-wide by every version of the plane and persistent funding limitations did not help. While unwelcome by any command, support deficiencies made the Tactical Air Command's many tasks especially onerous. In the last months of 1961, TAC possessed an average of 20 RB-66s for combat crew training, but only 12 of them were flyable. Similar conditions compounded the difficulty of training replacement aircrews for all USAF RB-66 units, another responsibility of the command. Furthermore, B/RB-66 support problems might restrict TAC's ability to reinforce other major command units during contingencies. Although great improvements were realized in early 1962, the general support outlook was not optimistic. Subsystems of the RB-66 aircraft were past their normal life expectancy and were almost certain to cause further unexpected maintenance. Planning changes, again intricately related to tight budgets, aggravated the overall situation. Previous phaseout schedules had spurred the end of the aircraft's IRAN program, but retention of the RB-66s was now programmed to extend through fiscal year 1965, because there was no replacement. In 1962, this meant bringing back some kind of IRAN program, on a one-time basis, in view of the aircraft's forthcoming retirement. As approved by the Air Force, this $7.1 million project (About Time) covered 145 RB-66s, 32 of them belonging to TAC. The project was at once affected by fund shortages. To make sure that as many aircraft as possible would be repaired, without reducing the scope of the work to be performed, TAC agreed to a sizable commitment of its own resources.
In January 1963, a corrosion-induced failure of one aircraft's nose struts engendered a complete retrofit of the fleet by the Mobile Air Materiel Area. During the same period, overhaul of the RB-66's J71-A13 engines began. Done under contract at the Naval Air Station at Quonset Point, Rhode Island, this crucial task proved time-consuming, prompting TAC to wonder if some kind of arrangement enabling engine repair at Shaw AFB would not be more effective. On the other hand, Shaw had retained its full share of problems. Despite every effort, the overall maintenance of the RB-66s remained difficult. Parts shortages did not abate throughout the year, contributing to high cannibalization rates within the 363d Wing and 4411th Combat Crew Training Group of the Tactical Air Command.
As of 30 June 1964, only 100 RB-66Bs remained in the Air Force inventory and within 12 months, this total had dipped to 79. Still, phaseout of the entire B/RB-66 fleet was becoming less likely. The Air Force's increasing involvement in Southeast Asia affected all planning. The primary question no longer seemed to be how long a given model's retirement would be postponed, but rather to assess how retained aircraft would cope with their extended commitments. Obviously, some modifications would be needed. Yet, experience showed that the best modifications would not necessarily work from the start. For example, 3 RB-66Bs had been equipped in 1963 with infrared sensors, electronic strobes, and side-looking radars, but the performance of the strobes and infrared sensors, as demonstrated during a 1964 exercise, did not satisfy TAC. In any case, retention of the RB-66s, however probable, could not be taken for granted. This posed another dilemma by preventing reinstatment of a formal IRAN program. Wanting to be ready for an early IRAN program, should the Department of Defense approve the aircraft's retention, Headquarters USAF in April 1965 directed a "minimum prudent work package for IRAN of RB-66 aircraft during FY 66." Developed by TAC and endorsed by Air Force Logistics Command, this program made allowances for the fact that previous work on the RB-66 consisted of a series of short-term actions, none intended to keep the plane in service for more than 2 additional years.
The October 1957 delivery of the last RB-B66B reflected the end of the aircraft's production. The Air Force accepted 4 RB-66Bs in FY 55, 46 in FY 56, 87 in FY 57, and 8inFY58. Cost per aircraft was: $2.55 million: Airframe, $1,563,671; engines (installed), $6%,034; electronics, $155,000; ordnance, $10,081; armament (and others), $166,137.'6
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