North American A3J-A-5
VigilanteOctober
9th, 2007
By:
rcolonfrias@yahoo.com
Raul Colon
PO Box 29754
Rio Piedras, Puerto Rico 00929
Just hours after the United States Army Air
Forces massive B-29 bombers had delivered the atom bomb to the Japanese
cities of Hiroshima and Nagasaki; the US Navy began to realize that its
position as the forefront of America’s defense and first strike capability
could be in jeopardy. The continued development of the long distance
bomber as a first strike platform and its perceived efficiency in bringing
both Germany and Japan to their knees, made the Navy’s top brass worried
about losing the service’s primary position within the US Armed Forces.
Things were more concerning when the newly formed US Department of Defense
separated the air force section from the Army; creating a brand new
service: the US Air Force. Within months after its creation, the Air Force
assumed the primary role of the use of the country’s nuclear arsenal. This
development, added with the perception that with the coming of the
aircraft’s jet age, the navy would be relegated to a more littoral duty;
forced the Navy’s leaders to find a weapon platform capable of providing
the service with a nuclear option of its own. The Navy’s first attempt to
field this concept was to equip its main strike force, the aircraft
carriers; with aircraft capable of delivering nuclear weapons. The
acquisition of North American’s AJ Savage and the Douglass Company A3
Skywarrior bombers in the late 1940s and early 50s, both subsonic
aircrafts; represented a first step toward nuclear strike independency.
But due to the increasing pace of aircraft developments, each type became
obsolete after a just a few years of front line service. The Navy needed a
new aircraft, and North American Corporation was once again ready to
provide the service with its requirement.
In mid November 1953, a group of North American engineers commenced
preliminary work on the development of a new type of aircraft. An aircraft
more similar to the Air Force’s medium bomber concept than with the Navy’s
types of carrier based bomber planes. North American designers proposed a
radical departure from the current carrier aircraft situation. An
all-weather, long range carrier based bomber capable of reaching speeds up
to Mach 2 was envisioned at North American and that vision was eagerly
expected to become a reality by the Navy. To meet the Navy’s and their own
company expectations, the designers, lead by a brilliant engineer named
Frank G. Compton; began work promptly on what was referred to as North
American General Purpose Attack Weapon System or designated project
NA-233. After months of close consultation with Navy engineers, North
American decided to base its new airplane on a twin engine concept. The
idea behind the dual propulsion system was the aircraft’s survivability in
case of one of the power plants failing. Another requirement for the
concept was the ability to reach Mach 2 speed. To achieve this parameter,
the aircraft was fitted with two of the most powerful engine systems
available at the time: the General Electric J79-2 afterburning jet engine,
capable of providing the aircraft with 15,150lb of thrust. To ensure the
airframe’s integrity at high fly speeds and the aerodynamic conditions
encountered by the frame at those speeds, some heat sensitive areas of the
fuselage were covered by titanium plates.
The wing surfaces were machined as one
complete piece from a combination of aluminum/lithium alloys. Nitrogen,
not conventional hydraulic fluids, was used by the 233 in some of the
hottest areas of the airframe. Even gold was utilized as heat reflectors
on the engine’s bays. In order to capture high aerodynamics angles, the
233 was fitted with a small high-loaded swept wing configuration with a
powerful flap system and a one piece powered vertical tail. The wingtips
folded up to allow the aircraft to be housed on an aircraft carrier
hangar. The single, vertical tail structure also bent for hangar deck
operations. The NA was one of the first aircraft to use a fully variable
engine inlet system installed to reduce supersonic air to subsonic levels
before it reached the engine main chamber, thus providing the engines with
ultimate performance at any speed level. Apart from the innovations on the
airframe, the latest technology was implemented on the 233 avionics
package. A state-of-the-art Versatile Digital Analyzer or VERDAN computer,
one of the first solid state computer systems ever utilized on an
aircraft; was fitted under the pilot’s seat. But the real technology
breakthrough was the North American Autonetics System. The AN-ASB 12
System, as the package was referred as, included a multiple mode radar
system housed on the aircraft’s nose cone. The radar was fitted with the
Pilot’s Projected Display Indicator or PPDI, an early generation
head-ups-display. A close captioned TV camera mechanism was installed
under the nose for daylight targeting operations. Its image transferred
directly to the pilot’s HUD and the rear seated navigator radar display. A
first of its kind, terrain avoidance radar system, similar to that on the
Navaho Cruise Missile, was used to guide the plane while on night
operations. The aircraft also had the distinction of being one of the
first designs to be fitted with a partial fly-by-wire system. The 233 was
manned by a crew of two. A pilot and a bombardier/navigator. The pilot was
seated in the front of the pressurized cabin and the navigator on the
rear, atop the advance electronic package assigned to the aircraft.
Originally, the navigator canopy did not posses any view windows or
reflective mirrors because company’s engineers estimated that the
navigator’s instruments would be easy to ready in darkness and to protect
them from the anticipated EM emissions expected from a detonated nuclear
bomb. The whole cabin was housed on a structure fitted with an HS-1 rocket
design to boost the ejection seats in case of an emergency. The final 233
aircraft’s specifications were as follow:
Size & Weight Characteristics
Wingspan Wing Area Length Height
53’-0” 754sq ft 75’-10” 19’-5”
Empty Fully Loaded
38,000lb 80,000lb
Overall Profile
Maximum Speed Operational Ceiling Range Climb Rate
1,385mph 67,000’ 3,200nm 8,000’/min
The first 233 prototype rolled out from North American’s Columbus, Ohio
factory on the afternoon of May 16th, 1958; when it was officially named
the Vigilante. The first flight took place on August 31st, 1958. The
aircraft performed as good as advertised by the North American design
team. It achieved supersonic speed for the first time on September 5th of
that year. Carrier trials began on the USS Saratoga on the morning of July
1960 with fourteen take-off and landing test flights performed by the
sixth Vigilante prototype built. On the afternoon of December 13th, 1960,
with Commander Leroy Heath at the controls and Lieutenant Larry Monroe on
the backseat, the Vigilante, flying at Mach 2.1, set a new world altitude
record for a bomber type aircraft when it climbed above 91,451ft while
carrying a payload of 2,403lb. The Vigilante’s payload was stored in an
unorthodox internal bomb bay without external doors located in the
airframe underbelly. This unique system was installed on the Vigilante
because the aircraft main purpose: the deliverance of nuclear ordinance.
The engineers at North American figured that the aircraft had an enhanced
percentage of escaping a blast from the new thermonuclear weapons if the
ordinance was ejected to the rear instead of a direct level drop. This was
achieved with the assistance of a complex long duct system that extended
back between the two engines. The duct would house the nuclear ordinance
until the order of release was given. The aircraft was built to carry one
of the MK27, MK28, or MK43; free fall nuclear bombs in its internal bomb
bay. Additionally, a pair of smaller, MK83 or MK84 nuclear bombs could be
fitted on pylons underneath each wing structure.
Deliveries of the A3J Vigilante commenced in
the spring of 1961 and lasted until the summer of 1963, when the US Navy
shifted its main nuclear deterrent platform from its carrier fleet to the
new Polaris augmented submarine force. When the production line was
terminated in 1963, fifty nine examples had been delivered to the navy.
The Vigilante first carrier deployment occurred when they were assigned to
the USS Enterprise on its maiden cruise in August 1962. In September of
that year, the US Defense Department changed the aircraft designation to
A-5A due to the decision of standardizing all US Armed Forces aircraft.
Once the Vigilante entered front line service, the aircraft was not well
received by carrier air commanders who, although impressed with the
aircraft payload capacity and airframe structure; felt that an aircraft
had such advanced technologies that they could become a problem. They were
right. Constant shutdowns by the VERDAN system meant that the aircraft’s
turn-around capabilities were severely curtailed. Problems also arose with
the use of its fly-by-wire system that required many man hours to prepare
to full operational mode. Also the aircraft’s size made it difficult for
airmen to operate during take off and landing situations. With the shift
of the US Navy’s nuclear deterrence platform, the days of the Vigilante as
an offensive aircraft were numbered. Rather than scrapping the examples
they already possessed, the Navy devised a new role for the Vigilante, a
role that would make the aircraft’s name “fit the bill”. The Navy’s deep
reconnaissance mission had been neglected partially by the lack of a long
range aircraft; this role was tailor-made for the A-5A. All of the Navy’s
Vigilantes were returned to North American for conversion to the standard
RA platforms. Eventually, fifty three examples were converted between
early 1963 and the spring of 1963. They were augmented by a batch of fifty
five newly produced aircraft and given the RA-5C designation. The RA-5C
retained the A-5A performance capabilities as well as its avionics
package. The main upgrade to the system was the installation of optical,
electronic, and electromagnetic sensors stored in the aircraft’s once
exposed bomb bay. They included an AN-ASS21 infrared sensor for the
continued filming of thermal targets images at angles of 140 degrees, a
Westinghouse Side Looking Airborne Radar or SLAR for all side-by-side
imagine mapping; a AN-ALQ61 Electronic Intelligence Unit System that would
pick-up radar emissions and triangulate their origination coordinates,
frequencies, and electronic signal patterns. A vast array of optical
camera systems such as panoramic, oblique or vertical; were fitted around
the airframe. The complete reconnaissance system was under the control of
the Recon Officer seated were the bombardier/navigator use to be. The new
RA version had a slightly different specification spectrum from the
original A-5A.
Size & Weight Characteristics
Wingspan Wing Area Length Height
53’-2” 760sq ft 75’-7” 19’-5”
Empty Fully Loaded
37,500lb 79,600lb
Overall Profile
Maximum Speed Operational Ceiling Range Climb Rate
1,320mph 52,100’ 2,050nm 7,860’/min
The first RA-5A example entered carrier service in1964. It went on to see
duty in the Vietnam War. The RA version proved to be more successful than
its predecessor. Usually, the Vigilante was the last aircraft launched
from the carrier during the operation envelop deployment since its speed
allowed it to catch up quickly with the mission package. Eventually, the
US Navy ordered the Vigilante production line to restart and the first of
a new batch of Vigilantes were delivered to the Navy. Forty four examples
were ordered, but only thirty six units were completed by the time the
line was closed again in August 1970. The last operational RA-5C Vigilante
squadron was disbanded in September 1979. A short lifespan for such a
revolutionary aircraft design. In the end, it was a magnificent aircraft,
but without a clear mission, it was an unsupported plane.
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