In January of 1954 the North American Aviation Company begun to work on a new aircraft, designated as NAGPAW - North American General Purpose Attack Weapon. It boasted a modern design and many breakthrough features, previously unused in the construction of aircraft. The machine was to be powered by two engines and have a ground target acquisition radar. The US Navy recognized the usability of the new design to give the new aircraft carriers then under construction means to deliver nuclear weapons. North American’s new model was submitted to the US Navy in 1954 under the designation NA-233. US Navy requested changes in the design, and after they were made it was re–submitted in April of 1955. A preliminary agreement to manufacture the new aircraft was reached on the 29th June, 1956.
The design of the new machine emphasized the reduction of its cross-section, to minimize drag and optimize its performance. A side-effect of this was the reduction of the radar cross-section of the aircraft. Big flaps allowed for favorable take-off and landing characteristics. There were no ailerons – the roll of the aircraft was controlled by the differentially actuated elevators. Many other breakthrough solutions were introduced, like the one-piece, all moving rudder, variable-geometry engine intakes or one-piece wing skins machined from aluminum-lithium alloy. Many parts utilized titanium as a material, and in the hottest areas of the airframe pure nitrogen replaced the hydraulic fluid to drive some actuators. The new aircraft also featured one of the first digital computers to calculate navigational and bomb drop data, and also one of the first fly-by-wire systems. Further development of the aircraft was influenced by its so-called linear bomb bay – basically a tube running along the fuselage between the engines, it could hold the nuclear weapon and/or additional fuel cells to be ejected to the rear through a small opening. In praxis this solution wasn’t reliable enough and didn’t allow the aircraft to carry conventional weapons internally.All the A-5 aircraft and their variants were manufactured at North American aviation plant in Columbus, Ohio.
The prototype, designated YA3J-1 was rolled out on 16 May 1958 and officially named Vigilante. Its first flight took place on 31 August 1958. Despite good results of the flight tests and lack of major problems the aircraft didn’t enter production before the beginning of 1959. The Vigilante’s first carrier landing was made on 22 July 1960. In the production aircraft, designated A3J-1, and later, in 1962, A-5A, the engines were changed from J79-GE-2 to J79-GE-8. Just the same engines were used to power the F-4 Phantom, in service at that time, which greatly enhanced the logistics, especially on board of an aircraft carrier.
To convince the Congress to fund the Vigilante program, the early production aircraft were used to establish new speed and altitude records. For example in 1960, in an aircraft of this type Jacqueline Cochran became the first woman to fly over Mach 2.
The Vigilante entered service on 25 January 1962. Shortly after that their designation was changed to A-5A. In service some problems with the aircraft became evident – for example during the carrier take off the acceleration from the catapult could rupture the fuel lines from the bomb bay carried fuel tanks, or even break loose the tanks themselves, which led a few times to a spectacular fire.
The rapid development of the surface to air missiles prevented the combat use of the A-5 as a strategic bomber, making its mission – high altitude bomb delivery – impossible to conduct. This, in conjunction with the problems with the linear bomb bay, led to the decision to adapt the A-5 to conduct tactical reconnaissance missions.
In the beginning of 1963 the production of A-5A was finished and the new variant – A-5B was already being prepared. The improvements to the aircraft aimed to increase its payload and range. There were two variants considered – bomber and reconnaissance. The most visible from outside change to the aircraft was the addition of a substantial “hump” to the fuselage spine, which allowed to sharply increase the amount of fuel that the aircraft could carry. The wing was redesigned with bigger flaps and hardpoints to carry external stores – an option never used practically. The undercarriage wheel brakes were also strengthened to handle the increased weight and the engine intakes were redesigned for high speed and high altitude operation. Before the A-5B production could start for good, it was decided to convert all the A-5 aircraft to the reconnaissance RA-5C variant. As result, only two A-5Bs were delivered and they didn’t enter operational service.
The first RA-5C flew on the 30 June 1962. The experience with the A-5B was used on this variant, with few changes. The main difference was the addition of a long external underfuselage pod called the “canoe”. The pod didn’t negatively affect the speed of the aircraft and housed an extensive array of reconnaissance gear – a SLAR (Side Looking Airborne Radar), many different photo cameras, infra-red and low light level sensors. The recon gear also consisted of passive electronic counter measures (PECM) – receivers used to gather data about the enemy’s radar and radio networks. Some of the gear was mounted in the bomb bay, the aircraft also retained the capability to carry external stores, although this option was never used in praxis. The first RA-5C was delivered on 27 June 1963. The new aircraft provided the US Navy with the long range tactical reconnaissance capability, supplementing shorter range types, like the RF-8G.
The RA-5C aircraft constituted the airborne component of the Integrated Operational Intelligence System (IOIS). It’s every mission brought back kilometers of magnetic tape from the electronic gear and similar quantity of exposed film from the cameras, that were subsequently processed in the aircraft carrier’s Integrated Operational Intelligence Center (IOIC). That center had, among other devices, a high speed film processor – highly classified in the beginning of the sixties, but the same type of a device became very common in the shopping malls in the end of the seventies to process “one hour photos”. After processing the photos were read-out and analyzed by specialists. Other specialists analyzed the recorded radio and radar transmissions gathered by the aircraft.
The great success of the reconnaissance variant justified further production of the aircraft. 43 RA-5C’s were built, then the 18 A-5B’s (unfinished) were converted to RA-5C standard. This concluded the production of the aircraft, the tooling and hardware were put in storage and the company went on to bring the remaining 43 A-5A’s and A-5B’s to RA-5C standards. But the heavy toll the Vietnam War took on existing aircraft resulted in Navy’s interest to reopen the production. In a very rare occurrence the production of the Vigilante was restarted in 1968 and 36 additional aircraft were built until 10 August 1970. The new-built RA-5C’s were powered by J79-GE-10 engines and could be identified from outside by straight outside engine intake edges and wing leading edge root extensions (LERX).
The RA-5C’s were introduced to South-East Asia in 1964. At first they were only used over South Vietnam for fear of losing such a modern aircraft over enemy territory. Eventually the Vigilantes went north, and there were losses – 18 aircraft were lost in total. Nevertheless their combat use was a great success. One of the first tasks of the RA-5C’s in Vietnam was to completely map the whole country. This was completed under two weeks, proving the value of the new equipment type. Usually, over land the RA-5Cs went on full power, flying with a supersonic speed and low. They were normally escorted by F-4 fighters to protect them from MiGs – this shows how important the RA-5C was to the Navy. Despite this, Vigilantes took heavy losses over North Vietnam. This was directly linked to the mission they were conducting. Especially the bomb damage assessment (BDA) mission was dangerous, as the enemy gunners quickly learned that after a strike the reconnaissance aircraft is guaranteed to show up – and they made taking it down their goal.
After the end of the Vietnam War the RA-5C started to be pulled out of service. The last time the RA-5C flew in service in the end of 1979. Taking it out of service left a substantial gap in the Navy’s reconnaissance capability that took many years to fill.
|Length:||23 330 mm|
|Height:||5 900 mm|
|Wing span:||16 210 mm|
|Empty weight:||17 005 kg|
|Maximum takeoff weight:||36 101 kg|
|Propulsion:||Two 48 kN/76 kN (with afterburner) J79-GE-8 or 53 kN/80 kN (with afterburner) J79-GE-10 turbojet engines|
|Range:||3 299 km|
|Max speed:||2 124 km/h|