In November of 1953, the Columbus, Ohio Division of North American Aviation began work on a privately-funded design project for a carrier-based aircraft that would be a more capable platform for the delivery of a nuclear weapon than the Douglas A3D Skywarrior. The company gave its project the internal name of North American General Purpose Attack Weapon (NAGPAW). The aircraft was to be capable of delivering a nuclear weapon at speeds of up to Mach 2. In 1954, the NAGPAW was offered to the Navy in an unsolicited proposal.
The Navy was suitably impressed, but added some conditions. The original NAGPAW proposal called for a low-altitude penetrator which dictated an aircraft with a small wing area with a high loading to give an acceptable low-altitude ride at high speeds. However, the Navy wanted the aircraft to have the ability to launch from a carrier even in zero wind conditions, which requires a larger wing area. The obvious solution for this problem would be a variable-sweep wing, but the Navy had gotten cold feet about variable geometry aircraft in general after the failure of the Grumman XF10F-1 Jaguar, and decided that it would be a better idea to abandon the low-altitude penetrator mission in favor of better carrier landing and takeoff characteristics. Consequently, in January of 1955, the Navy changed the requirements, making a high-altitude Mach 2 dash capability primary and a low-altitude penetration capability only secondary.
The wing that was finally adopted was mounted high on the fuselage and had a sweep of 37.5 degrees and an area of of 769 square feet. The wing did not have ailerons--lateral control was via a series of spoilers hinged along the leading edges of the wing and deflectors arranged along the trailing edges. The inner wing trailing edges were fitted with large flaps, and the leading edges were fitted with extendible slats. The outer wing panels had hinges outboard of the control surfaces and flaps for folding for stowage aboard carriers.
The wing was fitted with a boundary layer control system on the trailing edge, which was automatically coordinated with the operation of the wing flaps. When the flaps began lowering, the system directed high-velocity air over them, which increased the lift and lowered the angle of attack required for landing. A external pylon could be mounted underneath each wing for the carriage of an external store or a drop tank.
The original design had twin vertical stabilizers, and this was actually how the mockup was configured when it was reviewed in March of 1956. However this was changed to a single vertical stabilizer shortly thereafter. The tailfin was a single piece pivoting slab. The amount of tail travel was restricted to 2 degrees left or right with flaps up and 8 degrees with flaps lowered to 25 degrees or more.. The vertical tail was sufficiently tall that it had to be fitted with a hinge so that the top could be folded to the left for stowage aboard aircraft carriers. An electronic countermeasures antenna, formation lights, and a fuel vent were installed in a fairing that extended from the trailing edge of the vertical fin at about 40 percent height. A radio antenna was installed inside a dielectric fairing at the extreme tip of the fin.
The horizontal tailplanes were of the all-flying variety and were hinged at a single pivot on each side of the extreme rear fuselage. The horizontal tail could perform a limited amount of asymmetrical deflection for roll trim, but could not actually provide roll control, which was the responsibility of the wing spoilers.
The fuselage was rather long and thin, with a radome at the very tip of the nose. For storage aboard carriers, the radome could be folded back. The aircraft was powered by a pair of afterburning General Electric J79 turbojets, mounted side-by-side in the rear of the fuselage. They were fed by individual air intakes on the sides of the fuselage. A unique feature was the use of variable geometry engine air intakes, the Vigilante being one of the first production aircraft to have this feature. They were designed to decelerate supersonic air to subsonic speed before it reached the engine air compressor.
In order to protect against the aerodynamic heating generated by flight at Mach 2, much of the internal structure was made of titanium.
The main landing gear members were attached to the fuselage sides, with the wheels retracting forward and rotating through 90 degrees to fit into fuselage wells. The nosegear also retracted forward. The advantage of forward retraction was that the landing gear would automatically be locked into place by the force of the airstream in the event of a hydraulic failure.
The aircraft carried a crew of two--a pilot and a bombardier-navigator, seated in tandem underneath separate clamshell-type canopies. The pilot had a frameless, wraparound windshield, and his canopy was sufficiently transparent to provide him with a fairly good view. The bombardier/navigator had only a tiny transparent window on either side. In the mockup, the bombardier/navigator was provided with a completely transparent canopy. However, it was felt that a completely blacked-out cockpit would be more effective for viewing a radar display or for protection against the glare of a nuclear blast, and the bombardier/navigator's canopy was completely solid in later designs. Prospective bombardier/navigators protested that a completely solid canopy would cause claustrophobia, and a compromise was worked out in which a small window would be cut into each side of the canopy. The bombardier/navigator had no forward view and he had no flight controls.
The aircraft was to be fitted with a HS-1/1A emergency escape system. The two crew members sat on individual ejector seats. The pilot could initiate the ejection sequence for both crewmen, which could be done by either pulling a face curtain or by pulling a handgrip underneath the seat. After activated, the seat would automatically pull the crewman into ejection position, after which both canopies would be blown away and a catapult-rocket system would fire and blast the crewmen up and out of the aircraft. A drogue chute then was opened to stabilize the seat, and shortly thereafter the crewman was separated from the seat and the crewman's parachute automatically deployed. The entire sequence took only 3 seconds. In the event the pilot was incapacitated, the navigator/bombardier could eject on his own. The HS-1 ejection seats were effective only at speeds above 100 knots, and were superseded in late production A-5As by the HA-1A with zero-zero capability.
The nuclear weapon was to be stored in an internal weapons bay. The weapons bay did not have a conventional bomb bay with doors opening underneath the bottom of the aircraft, since this would make it impossible to release the weapon at supersonic speeds. Instead, the Mk 28 nuclear weapon was mounted at the end of a long duct which extended rearward between the two engines and was ejected to the rear during release. The duct exit at the rear of the aircraft was capped by a clamshell-opening door, which was later replaced by a blow-away tailcone. The weapon was integrated with two jettisonable fuel storage tanks, which were generally emptied before the target was reached. The weapon and the associated fuel tanks were released as a unit by rearward ejection through the opening at the rear. As the bomb fell toward the target, the attached fuel tanks provided stability. In addition, a countermeasures device was included in the bomb bay that could be ejected before the release of the nuclear weapon.
The aircraft was to be equipped with a North American Autonetics AN/ASB-12 bomb direction system. It provided basic navigation and aircraft positioning. The nose was fitted with a GE Electronics multi mode radar, a North American NASARR radar computer, CCTV for daytime visual identification, a Radar-Equipped Inertial Navigation System, aand a Versatile Digital Analyzer. There was a TV optical scanner housed in a small bulge underneath the forward fuselage, just behind the radome.
The aircraft was capable of being refueled in midair, via a retractable probe on the port side of the fuselage ahead of the pilot's cockpit.
The aircraft had a primitive fly-by-wire flight control system in which stick movements of the stick were converted into electrical signals which fed into actuators that controlled lateral and l longitudinal movements. The actuators then mechanically positioned the control valves, the horizontal stabilizer, and the spoiler activators. There was a mechanical backup system in case this system failed.
On June 29, 1956, North American received a letter of intent from the Navy. On August 29, 1956, a formal contract was issued for two prototypes under the designation XA3J-1, which was later changed to YA3J-1. It took about two years for the first prototype to be ready. The first YA3J-1 (BuNo 145157) was rolled out of the factory on May 16, 1958. During the rollout ceremony, it was announced that the plane was officially named Vigilante.
The first flight of the YA3J-1 took place on August 31, 1958, North American chief test pilot Richard Wenzel being at the controls. Only a few relatively minor problems were encountered. The Vigilante went supersonic for the first time on September 5. The second prototype joined the flight test program in November.
The first production contract was issued in January of 1959. On June 3, 1959, the second prototype (BuNo 145158) crashed when a hydraulic and electrical system failure caused the pilot to lose control of the aircraft.
The initial A3J-1 production batches soon followed. 14 of them were employed in test flights. The 6th Vigilante made 14 launches and landings on the USS Saratoga (CVA-60) in July of 1960. Additional tests were made of the deck handling of the Vigilante.
Initial production A3J-1s were powered by a pair of J79-GE-2 turbojets, each rated at 15,150 lb.s.t. with afterburning. Very early on, the J79-GE-4 was introduced on the production line, followed very soon by the J79-GE-8, both of which were rated at 16,500 lb.st. with afterburning.
On December 13, 1960, an A3J-1 crewed by Cdr Leroy Heath and Lt Larry Monroe set a new altitude record of 91,450.8 feet.
The first A3Js were assigned in June of 1961 to VAH-3 at NAS Sanford, Florida. This was a Replacement Air Group (RAG), which was used to train aircrews and ground crew maintenance people for the Vigilantes that would be operating with the fleet. The operational debut of the Vigilante was in August of 1962 when VAH-7 deployed aboard the USS Enterprise (CVAN-65) for a short cruise in the Mediterranean. Deliveries to VAH-1 and VAH-3 followed shortly thereafter.
The linear bomb bay release method was never very reliable. The release often did not work properly, electrical connections were faulty, the ejection gun was unreliable, and there was poor separation and post-ejection stability of the store train of the bomb and two fuel tanks. In addition, it was not uncommon for the entire load to slide out of the bomb bay during a catapult launch, leaving the fuel tanks and bomb sitting on the carrier deck. Such were the difficulties encountered that the linear bomb bay system would never be used aboard aircraft carriers in fleet service.
In September of 1962, the A3J-1 was redesignated A-5A under the new Tri-Service designation system.
The A-5A could be equipped with a hose-and -drogue inflight refueling system using a buddy tank system housed in the linear weapons bay. The non-jettisonable system consisted of a 290-gallon buddy tank, two bomb bay fuel cells, a pump unit, and 78 feet of hose.
The A-5A achieved a reputation of being a difficult aircraft to land aboard a carrier. Pilot inexperience and a high approach speed resulted in several ramp strikes and losses of aircraft and crews.
In the early 1960s, the submarine-launched ballistic missile became the primary Navy strategic deterrent, and the A3J-1 no longer had a mission. In 1963, the Navy decided to halt any further procurement of the A-5A after only 59 had been built. With RA-5C deliveries beginning in January of 1964, the A-5As were removed from the heavy attack inventory and relegated to training roles. Most of them were returned to North American for conversion to RA-5C standard. Of the 59 A-5As built, 43 were eventually reconfigured to RA-5Cs.
Engines: Two General Electric J79-GE-8 turbojets, each rated at 16,500 lb.s.t with afterburning. Performance: Maximum speed 806 mph at sea level, Mach 2.0 (1320 mph) at 40,000 feet. Cruising speed 5660 mph, stalling speed 156 mph. Initial climb rate 8000 feet per minute. An altitude of 30,000 feet could be reached in 6.3 minutes. Service ceiling 52,100 feet. Combat radius 1290 miles. Combat ceiling 43,800 feet. Combat radius was 985 miles with a single with a Mk 27 weapin, or 1290 miles with a Mk 27 weapon and two 400-gallon drop tanks. Dimensions: Wingspan 53 feet, length 76 feet 6 inches, height 19 feet 4 3/4 inches, wing area 700 square feet. Weights: 32,700 pounds empty, 47,530 pounds combat, 56,290 pounds gross, 62,950 pounds maximum takeoff. Armament: One Mk 27, Mk 28, or Mk 43 nuclear weapon in the linear weapons bay, plus one Mk 43 nuclear or a pair of Mk 83 or Mk 84 conventional bombs on a weapons pylon underneath each wing.
145157/145158 North American XA3J-1 Vigilante (2) c/n NA247-1/2. Later redesignated YA-5A-1-NH 146694/146708 North American A3J-1 Vigilante (9) c/n NA247-3/11. Redesignated A-5A-5-NH in 1962 146703/146708 cancelled 147850/147863 North American A3J-1 Vigilante (14) c/n NA263-1/14. Redesignated A-5A in 1962. 148924/148933 North American A3J-1 Vigilante (10) c/n NA269-1/10. Redesignated A-5A in 1962. 149276/149299 North American A3J-1 Vigilante (24) c/n NA269-11/34. Redesignated A-5A in 1962.