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Author Topic: US NAVY ATA (Advanced Tactical Aircraft) program: A-12 Avenger II & its rivals  (Read 158599 times)

Offline Tailspin Turtle

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Re: US NAVY ATA (Advanced Tactical Aircraft) program: A-12 Avenger II & its rivals
« Reply #330 on: September 09, 2017, 07:12:45 am »
I periodically posted the status of the A-12 settlement process. If I remember correctly, this was the last one:

Offline LEG

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Well, John Lehman originally envisioned the ATA as a scaled-down B-2 using B-2 stealth technology, and contemporary accounts say Pete Aldridge did agree to terminate a competing fighter development and accept the ATA as the USAF replacement for its then-current generation of strike fighters. 

I guess we can disagree on how sincere Aldridge or the Air Force was, but there was a (perhaps coincidental) termination of a large unnamed program in that period that resulted in thousands of layoffs (this was reported in AW&ST at the time).   Certainly Stevenson and other authors have taken a shot at reconstructing the history here and are probably the authoritative sources on this episode.

In Stevenson's book, there is a Model 303 (or perhaps 323) which looks suspiciously like an F-111 had a one night stand with an F-14.  TFBDMU also details the performance criterion differences between a fighter/fighter attack/bomber configured airframe with the attack being a flying win with A/B as I recall.  Nothing makes sense with regard to expected radii, expected ordnance loads and expected fuel fractions.

Since the F-14 could haul 14 Mk.82 on the pallets but an F-111 could not haul 16 Mk.82 internally, something is clearly 'off'.

APQ-183 was a Ka band attack set.  Yet the A-12 was expected to both carry and provide guidance illumination for the AIM-152 AAAM, something that the F-14 itself could not do without an auxiliary radar pod.

The A-12 was a short chord wing with a 24,000lbf installed thrust on an airframe with a known 2,000lb weight overage, at program start.  The USN then went on a task master campaign with GD/MDD to 'get the weight out!' while promising a lot of VLO they didn't have the muscle to twist the AFSC fair haired children's arm far enough back to provide.

So bad were things like SEROC and Radius that the program was all but shut down until they literally changed the moldline (something that never should have happened during FSED) to a 'thick section' wing to buy back lift and gain more fuel.  You see this in the Anigrand vs. Planet Models replicas.

Despite what must have been a massive increase in both weight and lift at drag, SEROC supposedly ROSE, back to acceptable levels.  At the same time drawings of the jet began showing kickdown mass flow doors, like those of the X-32, which can only mean a pretty big change in powerplant inlet requirements, if not an entirely new engine.

If you read the end notes of TFBDMU, you'll note that one of the arguments used against the government (the contractors won the first judgment and two of the followon appeals) was that the entire industry came together to save the A-12, right at the last, and the USN auditor who condemned the aircraft, on weight grounds, did not know about a special modification to the jet which supposedly added a 'bra', like a sports car mud guard that totally changed the planform of the airframe to more of a double-delta shape, while finally solving a serious problem with the RCS of the inlets acting as cavity reflectors while removing the RCS vanes altogether, as these simply created multipath reflections across a couple of critical illumination angles.

Could this be part of what changed the available power levels?

If you look at any of the drawings of A/X, the flying wing version of that aircraft, essentially a simplified A-12, designed to harvest what was saveable from a politically non-capitalizable program, into a simpler airframe, has a double delta with protruding nose...

I am essentially 60:40 that the ATA was a monumental hoax as part of the Reagan Era 'spend them under the table' bluff.  An airframe configuration that nobody would have naturally chosen for a carrier attack jet (flying wings have huge lift margins until you get the AOA right up there and then they deep stall, unrecoverably, and sometimes even flip, due to the short couple moment between LEF/TEF across the CL). 

If it was real, it looked, in it's final configuration, nothing like a Flying Wing and much more like a Modified Delta, similar to the X-47B.  And it is this condition which makes the program all the more suspect because it again, does not match the configurational specs for any of the design points, strongly implies major design changes, post CDR, and has no flying testbed, to confirm aeros effects, separate from the structures and VLO systems work, which should have been separate engineering efforts in their own right.

No company in their right minds would accept so much risk, across all three primary design criterion, with 'promises' of support in areas which they themselves had no or limited experience.  Again, IF HONEST, this means that either GD had a lot more VLO experience (I would suspect a crash program after Have Blue/Tacit Blue) than is hinted or that the true source of VLO design revolutions was coming from someplace black/CSAR else.  Clearly not DARPA.

If it was false, then things like a Lawyer telling the USN to break federal DFAR laws by creating an automatic deficiency as fraud in the inducement and then doubling down when the contract defaulted as Northrop stepped out and forcing GD to 'bid against themselves' suddenly takes on a new fall-guy meaning.  As does Elberfeld's 'I never went to Defense Acquisition School but I'm game!' leadership of such a critical program for nearly a decade, AS A CAPTAIN.

Like any Admiral in charge of NavAir is going to let a snot nosed kid punk his retirement five years out.  Hmmmm, Garret?  I think it was him, was no such fool.

Both the USAF and USN have massive databases of past designs which they linked to FES structural models to calculate 'truthiness' in contractor promises, the USAF also having one of the largest independent modelling resources via all manner of labs from Ames to Armstrong.

The Blue Suiters said they ran tests which showed the A-12 would not take off from anything shorter than a 15,000ft runway, as far back as 1986-87, yet they didn't jump ship until just after the Marines did, right before cancellation of the program.  Again, NO.  This is beyond giving your competitor enough rope to hang themselves (See: _Illusions Of Choice_ and the F-111B) but instead looks more like a VR simulation of a program that was never supposed to lead to a working airframe.

They were not going to get 500 F-15Es, no matter what.  And the F-117 was a boutique program in it's own right, with every jet hand built and a monster to keep operational (as well as useless in the USAFE mission as all SALH platforms are) while the B-2 was SIOP oriented with all the Strategic Platform Risk that implies, if it shows up over Europe.  So if they were just not interested in the A-12 because it was a USN airframe, why didn't they at least exploit it as a testbed for their own new project start on a Gen-3/4 VLO with GAM level through-clouds IAM delivery as the F-35 clearly was designed around 'baked right in + MMTD' standoff stealth?
« Last Edit: February 09, 2019, 12:41:29 pm by PaulMM (Overscan) »

Offline LEG

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From the lawyers' point of view this contract is the "gift that keeps on giving". 

The US Supreme Court today ruled on this case.  It overturned the previous lower court ruling, which overturned  previous  rulings in even lower courts, which had said that Boeing and GD had to repay the Government money spent on this failed project.   In an unanimous ruling, the Supremes said that if the Government was going to continue with its strategy of using the State Secrets privilege, normally used for terrorism or national security issues to deny the companies the information they say is crucial to their case, then the Government can not prove it is entitled to the damages it claims are owed it. 

The Supreme Court then sent the case back to the lower courts for further litigation.  Like Tailspin said, from the lawyers' point of view this contract truly is the "gift that keeps on giving".

I have it on good authority that GDFW and MDD were both told that they would never work in industry again and should divest themselves of their aerospace divisions to other contractors.  In 1991.

It was _never_ a good day for the tax payers or the defense of this nation when the top two fighter houses of our country were replaced by...Boeing (last built the P-26) and Lockheed Martin (F-104).

That is just petty minded ignorance of the national priorities.

Offline LEG

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Yes but wouldn't the A-12 been adopted as a replacement as the F-111 by the USAF? A low altitude, high speed penetrator?

Think about the F-15E which, at low level, is a real gut buster, guaranteed to solve constipation problems faster than 2 liter overdose of Milk Of Magnesia. 

Now transition this from a 610sqft wing area to a 1,317sqft equivalent.

The A-12 would not have been a low altitude penetrator if it was going to get the 930nm radial it was eventually promised to achieve with the fat-wing mod.  Twenty one thousand pounds of fuel is simply not enough for a twin engine jet to touch 1,000nm at lolo.  The F-16s which did the Osirak mission were carrying ~14,000lbs, did the outboard 'in ground effect, at flight idle' (.6 and <200ft), cleaned the jet as the wing tanks emptied and went to burner only in the last 10nm of ingress before walking home at .76 and 19K because there were headwinds at 27. 

And when they rolled out on the ramp at Etzion, from a 550nm radius, none of the Netz' had more than 1,000lbs remaining on the totalizer.

Stealth buys you three things:

1.  Radius at altitude, where the air is thin and cold.
2.  Sensor Squint at altitude, where the air is thin and clear.
3.  Glide Range, for standoff glide munitions where are typically cheaper if they don't come with a long-life solid motor or micro turbine.

The A-12, as it was finally configured had a nose job that was described as a 'bra' which greatly modified the forward quarter RCS values of the inlets which were a known cavity reflector weakness in the design.  It was the presence of this mod, as well as the USN auditors lack of clearance in knowing about it's effects upon weight and signature, which carried the GD/MDD lawsuit for about 30 years.  The reason for the bra was to lengthen the inlet ducts and change their look angle to surface radars because the RCS control vanes were not working properly to mask the turbopath, at altitude.

The Avenger also had a mixing plenum as is hinted by the large venetian blind louvers;topic=1169.0;attach=9955;image;topic=1169.0;attach=101351

And internal vents called 'MULE'.

As well as a contrail suppression tank.

The F404/F5D2 exhausts are tilted down, hit an RCC strike plate and coanda flow upwards directly into the efflux of the large bypass duct which is arched up over the primary turbopath and under the spine louvres before shock mixing with the exhaust.  The hot exhaust acts as an endstage compressor, reaccelerating the bypass flow and giving a significant kick in thrust while at the same time cooling itself to near ambient so that, despite being ventrally located, the plume temps are not too outrageous to IR detection.

The A-12 may, as an initial impression, look like it's low level optimized but it isn't.

Nobody would be so stupid as to send a 143 million dollar jet (the original promise was 35) through the trashfire envelope where every Ivan, Muktar and Kim could toss rocks at it. Not even the Navy with their Petula Clark fetish.

Offline LEG

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The canopy the side by side version would have been a massive transparency.  Probably too big to actually be a single piece casting.

Why do you think that no stealth aircraft thus far, outside of the B-2 which is a cabin aircraft, has a two seat version?

Cost?  Bwuahahahahahah.

In 1979 or so, when they were looking into the A-10B as a precursor justification for the N/AW, they discovered that a tub would justify itself inside of two years on (otherwise section takeoff) check flights alone.  It's always a fantastic risk the first time a nugget takes off in a 100 million dollar jet, 'alone and underequipped'.  Yet they do it.  Why?  It's not netcentrics or Pilot's Associate.

They do something to RF seal the interior.  Something that likely has limits for aperture size or maybe charge density.

It is why the F-22 never adapted the JHMCS (though it's looking like getting Viper) and the JSF has an optical instead of RF head positioning sensors.

Offline Dragon029

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The F-35's HMDS (like JHMCS) uses electromagnetic tracking as its primary tracking method, though it has an optical system to help maintain boresight alignment. As for the transparency, I wouldn't expect there to be any major RF issue with making it larger - maybe you'd have charge density increases near the edges when dealing with lower wavelengths, but that should be manageable.

Offline lastdingo

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Wayback Machine entry of that A-12 documentation website that went missing.

Offline LowObservable

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Kurt, is that you? (Of course it is.)

Quick detail point: the GD AAAM needed an illuminator. Not sure the MDC version did.