The Convair RB-58 Recce Hustler’s Short But Fascinating Career
On more than one occasion, the Air Force attempted to turn its Mach-2-capable B-58 Hustler bomber into a reconnaissance platform.
The Convair B-58 Hustler is widely remembered today as the most spectacular Cold War bomber to make it into service with the U.S. Air Force’s Strategic Air Command. But as well as being a nuclear bomber, the delta-winged Hustler was also adapted as a spy plane and, 60 years ago this month even flew a mission during the Cuban Missile Crisis, using its pod-mounted radar reconnaissance system.
Blessed with a top speed of Mach 2.2 and a ceiling of over 63,000 feet, the B-58 was an obvious candidate for reconnaissance flights, as well as its primary mission of delivering freefall nuclear bombs as part of Strategic Air Command’s deterrent forces. Also in its favor was the modular nature of its ‘mission pods’ — a variety of streamlined stores on the jet’s centerline that could carry different combinations of weapons, fuel, defensive electronics, and sensors.
As early as April 1956, seven months before the B-58’s first flight, a surveillance payload was proposed for what would be the RB-58A reconnaissance version. At this time, like the bomber, the RB-58 was expected to fly unmolested at high altitudes and its mission pods would be notably advanced for the time. Instead of optical sensors, it was to contain a Hughes AN/APQ-69 side-looking airborne radar, or SLAR. This used an enormous 50-foot antenna that would use radio-frequency emissions to scan the terrain to the side of the aircraft, providing a detailed ground picture.
Studies of the AN/APQ-69 pod for the Hustler began in September 1956, and the store proved so large that it was no longer able to accommodate any fuel, severely reducing the aircraft’s range. At the same time, the pod was longer and more angular than the standard MB-1 store (carrying fuel and weapons) and restricted the RB-58 to subsonic operations.
Despite the potential of the AN/APQ-69 as a sensor, the pod for the RB-58 was not judged to be worth pursuing and was canceled in 1958. Nevertheless, work on the program continued and Hughes completed one of the pods, which was delivered to Convair in February 1959, and then flight-tested it aboard B-58A 55-0668. It flew with the recce store for the first time on December 24, 1959, and then reportedly. 25 test flights were completed with the pod.
According to Peter E Davies in his authoritative B-58 Hustler Units, the pod achieved “satisfactory results at ranges of up to 50 miles.” The resolution was in the order of 10 feet. While this was an impressive sensor performance for the time, the reduction in speed and range that came as a result of adding the pod would have removed much of the advantages of installing it on a B-58 in the first place.
Also canceled in 1958 was a proposal to develop an electronic reconnaissance version of the B-58, with the Melpar ALD-4 electronic intelligence (ELINT) equipment installed. This would have provided an automatic means of hoovering up enemy electronic transmissions for analysis, but instead, it found its way into SAC’s RB-47 bombers, plenty of which were available for modifications like these, but which offered nothing like the space-age performance of the B-58.
Undaunted, the Air Force continued to look at ways to exploit the Hustler for reconnaissance work. In June 1958, the Aerial Reconnaissance Laboratories of the Wright Air Development Center issued a request for an all-weather reconnaissance ‘system,’ and this led Convair to approach Goodyear Aircraft Corporation seeking proposals. This project was given the name Quick Check.
Quick Check led to Hustler 55-0668, the ninth aircraft to be built, being converted as a testbed. This aircraft had been built as a YB-58A pre-production machine, and later became a TB-58A trainer, but for this test work, it was designated RB-58A, appropriately nicknamed Peeping Tom.
In June 1960, RB-58A Peeping Tom was converted under Project Quick Check, receiving a much-modified MB-1 pod the front of which contained Goodyear’s AN/APS-73, a synthetic aperture radar (SAR) working in the X band. This scanned on both sides of the aircraft at a range of up to 80 nautical miles. Imagery from the pod was collected and stored on five-inch film for later analysis. Unlike the AN/APQ-69 pod, this version also had space for fuel. The aircraft itself received a reprofiled nose radome behind which was a Raytheon forward-looking radar, and a new stellar tracking device was installed above the navigator’s cockpit.
It was during the Cuban Missile Crisis, with the two superpowers teetering on the brink of nuclear conflict, that Peeping Tom flew its only operational mission — as far as is known — in its Quick Check configuration. On October 30, 1962, a General Dynamics crew took the specially modified Hustler along Cuba’s northern coast, its AN/APS-73 mapping the terrain of the Caribbean island, now home to Soviet R-12 medium-range ballistic missile (MRBMs), R-14 intermediate-range ballistic missiles (IRBMs), as well as cruise missiles, and Il-28 Beagle jet bombers. All were capable of delivering nuclear payloads against U.S. targets.
“The AN/APS-73 was effective in providing detailed, all-weather terrain mapping at supersonic speeds over an 80-mile range, and the Cuba flight was duly performed at high speed,” Davies writes. “The results achieved with the pod proved to be better at subsonic speeds, however.”
Despite the little-known cameo in the Cuban Missile Crisis, the Air Force decided to abandon Project Quick Check before the end of the year. From now on, the strategic reconnaissance mission would increasingly be handled by other, more specialized types. While these lacked the performance of the Hustler (at least until the arrival of the SR-71 toward the end of the 1960s), it seems the radar sensors of the time were generally more effective when operated from subsonic platforms. Once the idea of recce overflights of the Soviet Union was abandoned, larger airframes, too, like the RC-135, began to operate along its borders. Standoff platforms like these offered key advantages, not least the space for more and more diverse intelligence-gathering equipment, but also dedicated operators to monitor the ‘product’ in real-time.
With the B-58A bomber established in SAC service, in 1963 the Air Force turned again to the idea of a recce Hustler, perhaps inspired by its performance off the coast of Cuba. Under Project Main Line, ten existing MB-1C mission pods were adapted to become LA-1 pods with a single KA-56 forward-facing panoramic camera for low-altitude photography. In all, 45 B-58As received the modifications to use the pod, which involved a mission profile flown at 500 feet and Mach 0.9. While a well-trained crew was able to achieve good results, the Main Line B-58s were never seriously considered for strategic reconnaissance work. Instead, they were mainly used for monitoring natural disasters, the camera being controlled by the navigator in the second cockpit.
Somewhat confusingly, a full 17 of planned service test YB-58As were completed under the RB-58A designation, with plans to carry a reconnaissance pod, but most were instead used in various test programs alongside the XB-58 and YB-58A aircraft. Thereafter, they were brought up to B-58A production standards and issued to operational units.
As it was, the story of the reconnaissance Hustler was destined to be a brief one. Even the B-58 bomber version proved to be short-lived, with a combination of steep operating costs and advances in Soviet air defenses, paired with the advent of intercontinental ballistic missiles, ensuring that it was retired after only a decade in service.
As dramatic and ground-breaking as the B-58 was in terms of performance and technology, it’s also worth taking a look at what might have been. In the late 1950s, studies were underway on what would have been an even more capable and exotic B-58 derivative, the so-called ‘Super Hustler.’ Intended to fly at 90,000 feet over a range of 4,000 miles, this concept was apparently schemed by Convair following a request from the CIA, and, not surprisingly, it would have been a strategic reconnaissance platform, although strike versions were also envisioned.
The original ‘Super Hustler’ would have used a three-stage concept, with a more or less standard B-58A being used to haul a ramjet-powered parasite second-stage aircraft and an unmanned third stage, also with ramjet engines.
Eventually, the studies yielded the Kingfish design, now a single-stage vehicle, with little of the B-58 DNA remaining, and the same twin J58 turbojet powerplant as used in Lockheed’s A-12. A reconnaissance version of the Kingfish was expected to clock an astonishing Mach 6 at a height of 125,000 feet.
The promise of the A-12 ensured that Kingfish would remain a dead end, and Convair would not provide the CIA or the Air Force with a high-altitude, high-Mach reconnaissance aircraft.
However, the story of the recce Hustler would, in a way, come full circle. When the Air Force began to introduce the SR-71 strategic reconnaissance aircraft, it needed suitable crews. While some of these men came from the U-2 program, others were aviators with suitable high-speed experience from the B-58 community. Indeed, of the 26 SR-71 crews assigned to the initial 9th Strategic Reconnaissance Wing, a full half had previous B-58 experience. While the Hustler would soon be confined to the boneyard, some of those that had operated it would fulfill vital roles in the strategic reconnaissance world for some years to come.
Update: The original article stated that the Project Main Line B-58As were able to fly their reconnaissance mission at 500 feet and Mach 1. A former B-58A pilot has since gotten in touch to clarify that the Hustler was operationally limited to Mach 0.9 below 26,500 feet. The typical maximum low-level speed was 600 knots.
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