The Avenger was the proposed A-6 Intruder replacement from
the McDonnell Douglas/General Dynamics team.
It was to be an upgraded, stealthy, A-6 that could fly faster and
further than the Intruder though, apparently, not by a huge margin. Its main improvement was to have been
stealth. You can see in the picture
below that it was a flying triangle with smooth, blended surfaces, two engines,
and internal weapon bays. From Wiki, the
dimensions/specs were 38 ft long, 70 ft wingspan (36 ft folded), 39,000 lbs
empty weight, 5160 lbs internal weapon capacity (A-6 had 18,000 lbs weapons
capacity, all external), 800 nm range (this must be combat radius; by
comparison, the A-6 is credited with a combat range, presumably meaning radius,
of 878 nm).
However, the initial specs were much more ambitious.
… the initial
requirements for the A-12 called for an aircraft with a 1,700 nautical mile
combat radius and an internal payload of 6,000 lbs with a radar cross section
comparable to the Northrop B-2 Spirit strategic bomber. (4)
Technical problems conspired to reduce the A-12 capabilities
to 1000 nm unrefueled combat radius and, eventually, to perhaps as low as 785
nm. (4)
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| A-12 Avenger |
The A-12 had two main weapon bays, each designed to carry
one HARM and one strike weapon with the bay sized to fit any weapon in the Navy
inventory. In addition, there were two outer
self defense bays which would each hold one AMRAAM. Thus, the A-12 would have been a
self-escorting aircraft with capability against both land (SAM) and air threats
with two HARMS and two AMRAAMs. The main
strike weapons could have included guided or unguided bombs, Standoff Land Attack Missiles (SLAM – land
attack version of Harpoon), etc. that could strike defended targets from close
in or stand off distances.
Actual development and production efforts began in
1988. By 1990, the program was in
trouble due to excessive weight, radar problems, advanced avionics delays, and
runaway costs. The program was cancelled
in Jan 1991. Years of litigation between
the manufacturer and the Navy ensued.
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| A-12 Avenger |
Cancellation of the A-12 permanently removed long range
strike from the list of carrier capabilities and naval aviation has never
recovered. Termination of the A-12,
while certainly a proper and wholly justified decision, negatively and, thus
far, permanently impacted carrier strike capability, rendering carrier strike a
short to medium range capability instead of long range, stealthy, penetrating capability.
The two biggest problems were excessive weight, reportedly
30% overspec, and problems with the Inverse Synthetic Aperture Radar (ISAR).
Excessive weight was, apparently, due in large part to the
failure of new composite materials to achieve anticipated structural
performance and weight savings. (3) Some
composite structural elements had to be replaced by heavier metal versions
which lead to increased weight.
Now for the fun part.
Let’s speculate a bit. What if,
instead of insisting on leap ahead non-existent technology, we had settled for
state of the (then) art materials and electronics? In other words, the 80% solution instead of
the 110% one or good instead of perfect.
Here’s what we could have done to achieve a very good aircraft using
existing technology.
Radar. Instead of the ISAR, what if we had installed
the APG-70 radar that was installed on the F-15E Strike Eagle that was built
around the same time? It was a highly
effective radar. Here’s a brief
description of the APG-70.
Gate
array technology enables the APG-70 to incorporate modes not available in
earlier radars while providing greatly enhanced operational capabilities in
other modes.
The
APG-70 radar system allows aircrews to detect ground targets from long ranges.
One feature of this system is that after a sweep of a target area, the crew
freezes the air-to-ground map then goes back into air-to-air mode to clear for
air threats. During the air-to-surface weapon delivery, the pilot is capable of
detecting, targeting and engaging air-to-air targets while the WSO designates
the ground target.
…
during Operation Desert Storm … Pilots claimed the APG-70 attack radar in the
F-15E and the APG-68 in the F-16 offered "phenomenal" range and
resolution. In interviews, they proclaimed "if it had metal in it, we
could find it," and "with the APG-70, you could tell from 30 miles
away whether a MiG-sized target had weapons or fuel tanks on it." (1)
Composites. Instead of non-existent composite materials
to achieve stealth and weight savings, what if we had gone with existing
conventional materials and relied on shaping and internal weapons carry to
achieve stealth? Flying wing designs
have been demonstrated to be inherently quite stealthy, dating back to the
late-WWII German Horten HO 229. There is
no reason to believe that adequate stealth and acceptable weight could not have
been achieved.
Wing Fold. The wing fold mechanism was, apparently, a
major source of excess weight in that it had a complex, convoluted design. What if, instead of that design, we had gone
with a simple, straight forward design like any other folding wing Navy
plane? I don’t know the specifics of the
fold issue but folding wings are something that the Navy mastered long ago and
should not have been a problem had we simply stuck to the basics.
Avionics. Instead of non-existent advanced avionics
displays, what if we had used the same avionics as in the F-15E Strike Eagle?
Engines. Reports suggest that the A-12 was
significantly underpowered. (5)
The aircraft
was designed to have two General Electric F412-GE-D5F2 turbofans, each
producing about 13,000 lbf (58 kN) thrust … (2)
As an alternative, the F-15E Strike Eagle used 2× Pratt & Whitney F100-PW-220
afterburning turbofans
each producing 14,590 lbf (64.9 kN) thrust (Wiki). Substituting the F-15E engines into the A-12
would have provided a bit over 12% more thrust for the A-12. Even using older engines, such as the F-111
Aardvark’s 2× Pratt & Whitney TF30-P-100 turbofans
with 17,900 lbf (79.6 kN) each would have provided 38% more
thrust. What effect, good or bad,
alternate engines with differing fuel efficiencies would have had on the A-12’s
range is unknown but the point is that the power issue could have been easily
solved with existing engines.
There you have it.
Had we gone ahead with the A-12 using then current, state of the art
equipment we could have had a long range, penetrating, stealth attack plane
that, with suitable upgrades, would still surpass any other strike aircraft in
the world, including (you F-35 fanboys might want to turn your heads for a
moment) the F-35. Consider the following
characteristics for our notional A-12, built as we’ve described.
Stealth. We can only speculate about the A-12’s
stealth level, however, the flying wing form of the A-12 would far exceed the
F-35 stealth level and would do so from all aspects as opposed to the F-35
which is optimized for frontal stealth and is reportedly far less stealthy from
other aspects. Perhaps only the B-2
would equal the A-12 stealth levels.
Updates, including modern stealth coatings would further enhance the
stealth levels.
Range. This one is pure speculation but it’s
interesting to note that even the most downgraded range estimate is
significantly greater than the F-35 or F-18.
More likely, with appropriate engines and considering the lift imparted
by the flying wing, the combat radius would be in the 1000+ nm realm. Upgrades with more modern engines would
further enhance the range. Even the
F-15E Strike Eagle, listed at 700+ nm range is only at the very low end of the
A-12 range estimates. Recall that the A-12
was designed to have greater range than the A-6 which is credited with 800-900
nm combat radius. This suggests, again,
that a 1000+ nm range for the A-12 is not unreasonable.
Radar/Sensors. Using then state of the art radar and sensors
would have provided the A-12 with very capable sensing, equal to the F-15, for
example, and upgrades, as has been done for the Hornet and F-15E would have
kept the A-12 as good as any aircraft.
The sensor suite would have been state of the art but not some kind of
magical, unattainable capability – just darn good.
Weapons. The self-escorting design of the A-12 is
intriguing although, as regular readers know, I’m not a fan of multi-purpose
platforms. The drawback to the
self-escorting capability is that every weapon dedicated to self-escort (air to
air missiles and anti-radiation missiles) detracts from an already limited
weapons payload of 5,000-6,000 lbs.
Although the program never advanced far enough, presumably the A-12
would have been given external pylons for larger weapon loads in more
permissive environments, as was done for the F-35.
The internal weapons payload limitations are an inherent
problem for all smaller stealth aircraft like the A-12 and F-35. The 5,000 lb or so limits are dwarfed by the
15,000-20,000+ lb payloads of conventional aircraft.
Summary. We see, then, that it would have been
possible to build a very stealthy, very long range strike aircraft that, even
today, would be the best in the world for its size. The weapons payload would have been adequate,
though nothing special, given the requirement for internal carry. Radar and sensors would have been state of
the art, for the time, and upgrades would have maintained that status. In short, we could have had a very good
aircraft that would still be the standard for strike aircraft today.
More importantly, the A-12 would have kept long range,
penetrating, carrier strike aviation in the game instead of being woefully
short ranged and ineffective as is the case today.
The key to achieving this very good, but not magical,
aircraft would have been to resist the temptation to design around non-existent
technology and, instead, use existing, then state of the art equipment. The only saving grace from the A-12 debacle
is that at least we didn’t engage in concurrent production and
development. We were able to cancel the
program before we committed to vast numbers of unachievable aircraft as we’ve
done with the F-35.
The lesson from the A-12 is crystal clear: build with existing technology and leave
non-existent technology in the R&D world until it’s ready. Had we done so, we could have had a very good
attack aircraft, quite likely the best in the world – it just wouldn’t have
been magical but it would have existed and been better than anything else and
certainly better than the nothing that we got.
