page_title: North American A-5 Vigilante
section_title: Design and development
hierarchical_section_title: North American A-5 Vigilante / Design and development
caption_attribution_description: English: Internal bomb bay of the North American A3J-1/A-5A Vigilante.
context_page_description: The North American A-5 Vigilante was an American carrier-based supersonic bomber designed and built by North American Aviation for the United States Navy. It set several world records, including long-distance speed and altitude records. Prior to 1962 unification of Navy and Air Force designations, it was designated the A3J Vigilante.
  The aircraft briefly replaced the Douglas A-3 Skywarrior as the Navy's primary nuclear-strike aircraft, but its RA-5C tactical strike reconnaissance variant saw extensive service during the Vietnam War.
context_section_description: In 1953, North American Aviation began a private study for a carrier-based, long-range, all-weather strike bomber, capable of delivering nuclear weapons at supersonic speeds. This proposal, the North American General Purpose Attack Weapon (NAGPAW) concept, was accepted by the United States Navy, with some revisions, in 1955. A contract was awarded on 29 August 1956. Its first flight occurred two years later on 31 August 1958 in Columbus, Ohio.
  At the time of its introduction, the Vigilante was one of the largest and by far the most complex aircraft to operate from a Navy aircraft carrier. It had a high-mounted swept wing with a boundary-layer control system (blown flaps) to improve low-speed lift. It had no ailerons; roll control was provided by spoilers in conjunction with differential deflection of the all-moving tail surfaces. The use of aluminum-lithium alloy for wing skins and titanium for critical structures was also unusual. The A-5 had two widely spaced General Electric J79 turbojet engines, fed by inlets with variable intake ramps, and a single large all-moving vertical stabilizer. Preliminary design studies had employed twin vertical fin/rudders. The wings, vertical stabilizer and the nose radome folded for carrier stowage. The Vigilante had a crew of two seated in tandem, a pilot and a bombardier-navigator (BN) (reconnaissance/attack navigator (RAN) on later reconnaissance versions) seated on North American HS-1A ejection seats.
  Designated by the US Navy as a "heavy", the A-5 was surprisingly agile; without the drag of bombs or missiles, even escorting fighters found that the clean airframe and powerful engines made the Vigilante very fast at high and low altitudes. However, its high approach speed and high angle of attack contributed to a high workload during carrier landings.
  The Vigilante had advanced and complex electronics when it first entered service. It had one of the first "fly-by-wire" systems on an operational aircraft (with mechanical/hydraulic backup) and a computerized AN/ASB-12 nav/attack system incorporating a head-up display ("Pilot's Projected Display Indicator" (PPDI), one of the first), multi-mode radar, radar-equipped inertial navigation system (REINS, based on technologies developed for North American's Navaho missile), closed-circuit television camera under the nose, and an early digital computer known as "Versatile Digital Analyzer" (VERDAN) to run it all.
  Given its original design as a carrier-based, supersonic, nuclear heavy attack aircraft, the Vigilante's main armament was carried in an unusual "linear bomb bay" between the engines in the rear fuselage, which allowed the bomb to be dropped at supersonic speeds. The single nuclear weapon, commonly the Mk 28 bomb, was attached to two disposable fuel tanks in the cylindrical bay in an assembly known as the "stores train". A set of extendable fins was attached to the aft end of the most rearward fuel tank. These fuel tanks were to be emptied during the flight to the target and then jettisoned with the bomb by an explosive drogue gun. The stores train was propelled rearward at about 50 feet (15 m) per second (30 knots) relative to the aircraft. It then followed a ballistic path.
  In practice, the system was not reliable and no live weapons were ever carried in the linear bomb bay. In the RA-5C configuration, the bay was used solely for fuel. On three occasions, the shock of the catapult launch caused the fuel cans to eject onto the deck; this resulted in one aircraft loss.
  The Vigilante originally had two wing pylons, intended primarily for drop tanks. The second Vigilante variant, the A3J-2 (A-5B), incorporated internal tanks for an additional 460 gallons of fuel (which added a pronounced dorsal "hump") along with two additional wing hardpoints, for a total of four. In practice the hardpoints were rarely used. Other improvements included blown flaps on the leading edge of the wing and stronger landing gear.
  The reconnaissance version of the Vigilante, the RA-5C, had slightly greater wing area and added a long canoe-shaped fairing under t
caption: The A3J "stores train" within the bomb bay
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