Why was the A-5 Vigilante forgotten?

In 1961, the US Navy would receive the first of a new series of Mach 2-capable, carrier-launched, nuclear bombers. The A3J Vigilante – as it was initially called – was one of several new designs the Navy was being equipped with, to bring it up to a new standard.

It had been designed to replace the quickly outdated A-3 Skywarrior – or Whale – as a carrier-capable bomber. As time went on, due to similar operational expectations and capabilities, the A-5 – as it was later redesignated – would go on to serve many of the same supplementary roles as the A-3 did; from dedicated reconnaissance to aerial refuelling, and so on.

For whatever reason, no one really remembers the Vigilante. In fact, its level of obscurity is surprising, given that it was a production aircraft deployed with the US Navy, and it’s one of those recurring planes in old Navy footage. Regardless, the Vigilante was an impressive design, and one that would influence future Navy designs, whether people remember it or not.

Background

As a nuclear bomber, the Vigilante was the product of a long series of concepts dating back to the late 1940s.

At the time, the pressure was on to develop increasingly fast, long-range bombers. The first demonstration of nuclear weapons had put a check on any Soviet attempt to open new hostilities against the western powers in Europe. With a nuclear project of their own, it was only a matter of time before the Soviets would field nuclear weapons as well.

The job of checking Soviet power thus fell to Strategic Air CommandThe U.S. Air Force’s primary organization for long-range nuclear deterrence during the Cold War, responsible for maintaining and, if necessary, delive... More, but to do so, they had to guarantee to the Soviets that they could reliably project air power into Europe again and again, whenever necessary. If a gap existed, it could be exploited.

By the late 40s, such gaps were beginning to form. In 1945, the Soviets had undertaken Operation August StormOperation August Storm was the codename for the large-scale Soviet strategic offensive launched against Japanese forces in Manchuria in August 1945, d... More, an offensive against the Japanese in Manchuria. American analysts had noted the impressive speed at which the Soviets captured the region. US forces in the Pacific had entered battles with a three-to-one numerical advantage or greater – August Storm was done with just under a two to one advantage, and was completed in one and a half weeks. While the Americans had gone up against better-trained forces, a key lesson learned was that the Soviets had drastically improved since the start of the war, and relied heavily on tanks and artillery. Likewise, new jet concepts – culminating in the MiG-15 – would make easy work of older bombers, aided to target by new early-warning radars like the P-8 Knife Rest.

Put simply, to avoid a power disparity in which the Soviets would have not only dominance on land but also a fighter umbrella against SAC bombers, new alternatives had to be developed. One potential solution was to compliment the strategic bomber fleet with faster strike aircraft.

The US Air Force had many such concepts on the drawing board; however, a carrier-capable alternative was also attractive. The Korean War broke out in the midst of this, and during the conflict, the need for newer, faster jet bombers only became clearer. In some ways, this would lay the groundwork for what would become the Vigilante.

A-5 Development

Following the Korean War, a team at North American AviationNorth American Aviation (NAA, United States; 1928–1967) North American Aviation was a major American aerospace manufacturer that played a central role... More, under Frank G Compton, reviewed existing proposals drawn up over the years. A new preliminary design was then developed. A radical concept for its time, it featured a swept airframe, a twin-engine design, and variable intakes.

It was an ambitious project, not just because the Navy had only recently adopted jet aircraft like the Panther and Fury, but also because this new design was going to be a genuine bomber with impressive specs. In essence, the Vigilante aimed to have everything Air Force designers were talking about at the time; all-weather, long-range, and high-speed.

In 1954, the Navy reviewed a proposal and issued new requirements. It needed to be Mach 2-capable, carry a large payload, and be able to launch without a headwind from the carrier. Through rapid redesigns, the team met these requirements, adding a larger wing area and new blown flaps. By mid-1955, the Navy had approved the design and funded the production of a mock-up, and a follow-up contract in late 1956 called for two working prototypes.

Meeting these impressive goals, the aircraft would take its maiden flight on August 31st, 1958. Thereafter, further alterations were requested, including a new, unconventional bomb bay. The Navy, while liking the core design, now wanted a direct replacement for the Skywarrior in the nuclear strike role.

Production begins

By the late 50s, production had begun on the initial variant, later designated the A-5A, while a second model – later the A-5B – was on the drawing board.

The final product was impressive; arguably the most advanced and complex aircraft the Navy had ever received. Powered by two readily available J79 engines and with good aerodynamic handling, it performed as expected. It was also massive, 76 feet long with a 53-foot wingspan, albeit with foldable components to fit in the hangar. Internally, it was equally impressive; it ran on the first digital computer ever installed in a bomber – known as VERDANVERDAN (Versatile Digital Analyzer, United States Air Force; early 1960s) An early airborne digital computer developed for integration into U.S. strat... More – and a suite of systems was available to the two-man crew of pilot and radar navigator. An early HUDHUD (Head-Up Display): A transparent display system that presents critical information directly in a user's line of sight, eliminating the need to loo... More, known as the PPDIThe Pilot’s Projected Display Indicator (PPDI) was an early form of head-up display (HUD) developed during the late 1950s and early 1960s to improve p... More (Pilot’s Projected Display Indicator), showed information from the AN/ASB-12 suite, which also included a multimode radar and a low-drift INSINS (Inertial Navigation System): A self-contained navigation system used in military aircraft that calculates position, velocity, and orientation wit... More based on the Navaho missiles’ N6A autonavigator, offering both navigational and target information. This was aided by a camera mounted under the nose and by an early form of fly-by-wire. A variety of exotic materials were also used in production, including gold coating for better heat conductivity.

On top of this, the later recon model would add further cameras, including the AAS-21 infrared system and the AN/ALQ-61 ELINTELINT (Electronic Intelligence) – A subcategory of signals intelligence (SIGINT) involving the collection, analysis, and exploitation of non-communica... More system, an ECM pod in the bomb bay, flare-like illuminator strobes on the wings, and a side-looking airborne radar,the APD-7.

The method of nuclear delivery was equally interesting, although less technologically reliable. Designed to overfly the target at supersonic speed, the aircraft avoided a downward bay with doors in favour of an internal tunnel-like bay, the ‘stores train’. Inside, a B27 nuclear bomb would be kept, followed by two 275-gallon fuel tanks, all on rails, and finally a fairing below the vertical fin. Over the target, the fairing would jettison, and a charge would eject the payload.

In theory, this method was better for high-speed release, but in practice its reliability was questionable, especially given the detonation required to actually shoot the nuclear projectile out of the plane. Alternatively, weapons could simply be held on hardpoints, either nuclear, like the B28 or B43, or conventional bombs, like the Mark 84.

Bomb Delivery Methods

As described by pilot Leroy Heath, once it became obvious that the high and fast method of delivery was prone to shootdowns by SAMSurface-to-Air Missile: A ground-based or ship-launched guided missile system designed to detect, track, and destroy enemy aircraft, helicopters, crui... More sites, other bombing methods were devised. Thanks to the advanced internal systems, pilots could use the new preferred method – low and fast – instead, aided to target by the computer. Just like the lofting method later popularised in the Phantom, the crew could use the INSINS (Inertial Navigation System): A self-contained navigation system used in military aircraft that calculates position, velocity, and orientation wit... More to set the targets location, altitude, and an IP (or initial point) for the run-in. Picking a set speed and altitude for the run-in, the computer would calculate exactly when to pull up into a preset angle at a preset G load – simple in theory, but quite advanced for its time. Once over the IP, the crew could hand the run in to an automated system or fly it manually. Then, once the parameters were met, the computer would indicate pull up, and if all went well, the bomb would accurately be lofted to target. Another, stranger method, was also used known as ‘over the shoulder’. This method – popularised by B-47 crews in the late 50s – used the same basic run in method, but with the release angle set far higher, when coming over the top of the loop. The original method had the IP set past, and at an offset, to the target. The crew would begin the pull-up sequence, the bomb would release after coming round the top, while at an offset angle, hence ‘over the shoulder’, then they’d finish the loop and escape. The method described by Leroy Heath was a direct overhead release, when the plane hit 90 degrees. Either way, with a chute, this gave crews ample time to run. In both delivery profiles, if they had good INSINS (Inertial Navigation System): A self-contained navigation system used in military aircraft that calculates position, velocity, and orientation wit... More alignment, good target information, and flew the parameters, Vigilante crews could accurately put bombs on target, all through computer guidance – something quite special in the late 50s.

In terms of raw capabilities, the aircraft had a top speed of Mach 2.1, a service ceiling of 52000 feet, a combat radius of 1800 kilometres (974 nautical miles), and a maximum take-off weight of 63000 pounds.

Overall, while the bombing approach was questionable, the design itself was highly advanced. Interestingly, during this period, the Royal Australian Air Force considered the design as a possible interim solution to the delayed F-111Cs, although nothing eventuated from this.

A-5 In Service

The aircraft was now ready for service, and in June 1961 the first deliveries of the A-5A would begin. Off to a rough start, the design proved difficult for crews to maintain. Then, with impeccably bad timing, right after its introduction, the project was halted in 1963, with 57 aircraft and two improved B models produced.

The latter models, which had been drawn up while the A-5A was still on the production line, had been an attempt to turn the aircraft into a long range bomber. For what it’s worth, the B model actually was a substantial improvement; with four, rather than two hard-points, and a larger redesigned wing, it was claimed to have possessed a range almost twice that of the A, or alternatively, could be loaded up with double the payload under the wing. Regardless, this was all forced to a halt.

With ample nuclear missile tech now available, and under increasing pressure from the air force via congress that the Navy should not have a strategic bombing mission, the decision was made to move the nuclear delivery role away from the platform.

Recon Role

In June 1962, a reconnaissance variant first flew. The RA-5C – as it was later designated – was almost five tons heavier, integrating the additional suites mentioned earlier. This platform would become the definitive model of the Vigilante, with more being built or converted from earlier models. Nine squadrons and one transitional squadron would be established, designated Reconnaissance Attack Wings, or RVAHThe Reconnaissance Attack Wing (RVAH) designation referred to a category of U.S. Navy aviation units tasked with both nuclear strike and, subsequently... More.

From 1964 onward, eight of these squadrons were deployed to Vietnam, serving in a fast-recon role. Although 18 were lost – giving it the highest loss rate of the war – it was important. Returning to the carrier, the aircraft would offload its film for analysis, while other signals were recorded on magnetic tape. This was all sent to the Integrated Operational Intelligence Center – a new facility on carriers. From there, the data could be transmitted to other ships.

The aircraft would also begin, alongside recon and ELINTELINT (Electronic Intelligence) – A subcategory of signals intelligence (SIGINT) involving the collection, analysis, and exploitation of non-communica... More, to fly aerial refuelling missions.

End of A-5 Service

Following the end of the Vietnam War, the Vigilantes’ carer would come to an end. Despite its impressive capabilities, the aircraft’s large design took up a lot of space, at a time when carriers were attempting to house more and more aircraft. It was also increasingly costly and time-consuming to keep in the air.

What’s more, by the 1970s, the specific roles the Vigilante filled were no longer exclusive and could be performed by an increasing number of newer or cheaper aircraft. In Vietnam, the Marines had begun using RF-4B Phantoms for reconnaissance, while the Navy was supplementing the A-5 with modified F-8 Crusaders for photo reconnaissance, EA-3Bs for electronic intelligenceELINT (Electronic Intelligence) – A subcategory of signals intelligence (SIGINT) involving the collection, analysis, and exploitation of non-communica... More, and Intruders for reconnaissance and electronic warfare.

Newer designs would also fill similar roles; the new F-14 would allow for reconnaissance using TARPSThe Tactical Airborne Reconnaissance Pod System (TARPS) was a modular, high-performance reconnaissance pod developed for the United States Navy to pro... More – a highly advanced camera pod under development – while the F/A-18 was on order as a multirole platform.

While the Vigilante still held some advantages over these alternatives, the disparity wasn’t significant enough to justify keeping the fleet in the air. Unlike the A-3 it had replaced, the A-5 was simply too costly to be assigned to a support role.

In a final bid to keep the platform alive, North American presented a heavily modified alternative in 1972, this time to the air force. Designated NR-349, it would have featured a third engine and carried six AIM-54 Phoenix missiles under the fuselage. Despite an improved speed of Mach 2.5 and a new service ceiling of 80000 feet, the concept was never pursued.

Thus, the decision was made to phase out the aircraft from 1974 to 1979, with the eventual goal of transferring some reconnaissance duties to TARPS-capable F-14s by the early 80s. Until then, fast reconnaissance missions would be carried out by Marine RF-4 crews, sent to supplement carrier air wings, or by other Navy aircraft.

Conclusion

The Vigilante would serve for 18 years, finally retiring on November 20, 1979, following RVAH-7’s return from deployment and a final take-off from NAS Key West that day.

Despite its obscurity, the Vigilante was an impressive design. It set several records and would probably have served well as a bomber if called upon. As a reconnaissance platform, it never fired a shot, serving for almost two decades.