domingo, 9 de junio de 2013

Familiarization in the A-5 Vigilante.-


The North American A-5 Vigilante was a carrier-based supersonic bomber designed and built by North American Aviation for the United States Navy. Its service in the nuclear strike role to replace the Douglas A-3 Skywarrior was very short; however, as the RA-5C, it saw extensive service during the Vietnam War in the tactical strike reconnaissance role.  Prior to the unification of the Navy designation sequence with the Air Force sequence in 1962, it was designated the A3J Vigilante.

United States Navy training film (1962) shows operating procedures of the North American A3J Vigilante on ground and in flight.




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 NAGPAW (North American General Purpose Attack Weapon) 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.

The 4th production North American A3J-1 Vigilante bomber (BuNo 146697) conducted the type's initial carrier suitability tests aboard the aircraft carrier USS Saratoga (CVA-60) during the week of 25 July 1960. Piloted by NATC's CDR Carl Cruse, LCDR Ed Decker and LT Dick Wright, the Vigilante made 14 successful launches and arrested landings. This aircraft is today preserved at NAS Patuxent River, Maryland (USA). Note the folded fin to fit in the hangars. Clearly visible two of Saratoga´s radars, SPS-8 on the island and SPN-6 in the mast. Photo By US Navy. July 1962.
At the time of its introduction, the Vigilante was one of the largest and by far the most complex aircraft to operate from a United States Navy aircraft carrier. It had a high-mounted swept wing with a boundary-layer control system (blown flaps) to improve low-speed lift. There were no ailerons. Roll control was provided by spoilers in conjunction with differential deflection of the all-moving tail surfaces. Use of aluminum-lithium alloy for wing skins and titanium for critical structures were also unusual. The A-5 had two widely spaced General Electric J79 turbojet engines (the same as used on the McDonnell Douglas F-4 Phantom II fighter), 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 recon versions— in individual ejection seats.

Photo By US Navy.
The Vigilante had advanced and complex electronics when it first entered service. It had one of the first fly-by-wire systems of 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 the Navaho missile), closed-circuit television camera under the nose, and an early digital computer known as VERDAN (Versatile Digital Analyzer) to run it all.

The reconnaissance version of the Vigilante, the RA-5C, had slightly greater wing area and added a long canoe-shaped fairing under the fuselage for a multi-sensor reconnaissance pack. This added an APD-7 side-looking airborne radar (SLAR), AAS-21 infrared linescanner, and camera packs, as well as improved ECM. An AN/ALQ-61 electronic intelligence system could also be carried. The RA-5C retained the AN/ASB-12 bombing system, and could, in theory, carry weapons, although it never did in service. Later-build RA-5Cs had more powerful J79-10 engines with afterburning thrust of 17,900 lbf (80 kN). The reconnaissance Vigilante weighed almost five tons more than the strike version with almost the same thrust and an only modestly enlarged wing. These changes cost it acceleration and climb rate, though it remained fast in level flight.

Photo By US Navy.

3 comentarios:

  1. Siempre me ha llamado la atención este bicho.
    Un avión avanzado para su época que ha pasado de puntillas por la historia de la aviación embarcada de EEUU.

    Saludos.

    Ro.

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  2. Ro:
    A mí el A-5/RA-5 también es un pájaro que me ha llamado vivamente la atención como a tí, ni más ni menos que un bombardero estratégico supersónico mach 2 en un portaaviones, vaya tela. Producto de una época fascinante, los años 50 y 60, en plena eclosión tecnológica en la que varios sistemas de armas novedosos surgen y compiten entre sí, para a veces anularse unos a otros; me explico:
    -. los submarinos Polaris anulan al A-5, pues la "deterrence" a cargo de la Us Navy pasa a los SLBM.
    -. a los submarinos picket- radar (algunos nucleares (!) como el Triton SSRN-586)se los cargan los E-2A Hawkeye.
    -. Al XB-70 se lo cargan los ICBM (Titan, y sobre todo Minuteman), que a su vez se cargan a los ALBM como el Skybolt.
    En fin, todo una época de esplendor y gasto.
    Y aprovechando que Tayun no nos ve, la pregunta provocadora:
    ¿Podrían progarmas rompedores, pero de gestación largísima, como el F-35, verse superados por tecnologías emergentes como los UAV/UCAV, misiles hipersónicos o armas de energía dirigida y quedar desfasados en poco tiempo como los que he citado arriba?

    Un saludo.
    Pablo.

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  3. He tomado buena nota y no quedará en el olvido la preguntita..., ¡que tiene bemoles la preguntita!.

    Me parece muy interesante el tema. Tanto, que merece algo especial. Ya veremos.

    Saludos a todos.

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