Thread

1. ggm · 1790747290 · focus · HN ↗

   A couple of questions/observations:

   1) when people say "destroyed the jigs, tools and spares in 2007" What do they actually mean? Burying things isn't destroying. Putting them in a furnace is destroying. Is it possible that both parts, and tools actually are recoverable e.g. from the seabed? The dimensional stability might be off, but to help reconstruct tools, it's not nothing. Likewise digging up something buried in its packing crate is not rocket science.

   2) "that would be ludicrously expensive" doesn't mean much any more. It's not unlike "we can't make a saturn 1 any more because the tools were destroyed and it would be ludicrously expensive to make an F1 engine" -well yes, but thats not impossible, it's just unlikely and expensive. So maybe this is unlikely, expensive but ... has a unicorn sugar daddy?

   3) there are craft in all sorts of places. Not just on sticks outside NASA property. I am not a historian or a federal government employee, but I wouldn't think it impossible for people to ask other agencies to let you inside the shell and remove the bits you want, or even ask for it back. The one on a stick in Balboa Park San Diego might have associated boxes of bits-and-bobs..

   4) its a titanium alloy. It's temperature and corrosion resistant, noting some things (like chlorine according to the web) are bad for it. It's not made of pure chinesium or balsa wood. Interior surfaces would be in pretty good shape.

   1. Beretta_Vexee · 1790761238 · focus · HN ↗

      So titanium alloys are not completely resistant to all forms of corrosion. They are particularly prone to galvanic corrosion, which means that specific tools must be used, all forms of ferritic contamination must be avoided, special tools must be used, and they must be stored separately, etc.

      This is very labour-intensive, which is why it is generally carried out in dedicated workshops, with specialised equipment, and so on, by staff who have been specifically trained and do nothing else.

      If you add jigs, production-specific tools, and so on, all of that has been lost and needs to be recreated: staff need to be trained, QA defined and workshops need to be reorganised. This can take decades to return to the expected standard. You can throw as much money at this sort of problem as you like without actually being able to speed things up.

      Finding the drawings and dimensions is the easy part of reverse engineering a mechanical device. The real challenges lie in identifying the manufacturing processes and quality control procedures, and achieving the expected performance with an acceptable scrap rate.

      If I place a monocrystalline turbine blade on your desk, you’d be able to draw up the plans for it. But that would tell you absolutely nothing about the processes required to produce a monocrystalline ingot of a nickel superalloy.

      Source: former mechanical engineer in the nuclear industry, managing obsolescence was one of my day-to-day tasks.

      1. PostOnce · 1790772954 · focus · HN ↗

         "decades" is a stretch.

         The original A-12 took 4 years (or less) to design and build from scratch with slide rules and manual machine tools.

         Surely we can match that with our 70 years of advanced knowledge and equipment?

         Maybe our risk tolerance is low now, and we don't have Kelly Johnson.

         1. brookst · 1790773918 · focus · HN ↗

            Risk tolerance perhaps? But also our increased capabilities make it harder to keep things simple. Should it be radar-opaque? Of course! Capable of autonomous flight? Duh! Carrier landings? Well sure, that might be needed. Refuel midair? Obviously. Sigint to the gills? Seems useful…

            1. mitthrowaway2 · 1790781897 · focus · HN ↗

               The original definitely could refuel midair.

               1. brookst · 1790949374 · focus · HN ↗

                  Sure, my point was more that the original was carefully optimized, today it’s easier to just check all of the boxes.
         2. j4k0bfr · 1790774108 · focus · HN ↗

            Not a mechanical engineer here, but I reckon close to a decade would be pretty realistic for full operational restoration. Even a small amount of lost critical maintenance knowledge could cost the whole airframe.

            I'd compare it to a really old codebase. Sure, our modern tech is much better. But if you need to make an old, top-secret COBOL program work as-is, you're in a pickle. Sure, we could rewrite it in Rust and make it way better, but management sees it as more cost-effective to just "turn the old one back on, it worked great!". And unlike software, it's pretty hard to comprehensively test a plane in a non-destructive way. Bolt falls off turbine while in flight, etc etc. Losing even a single SR-71A airframe would be a massive headache, methinks.

            1. MisterMower · 1790776559 · focus · HN ↗

               “I’d compare it to a really old codebase.”

               Yes, you are not a mechanical engineer.

               1. j4k0bfr · 1790838933 · focus · HN ↗

                  What, it's a good analogy for this audience. I know enough to have an opinion though. You'll never see me using a thread to locate a part. And I know taste isn't the only difference between red and blue loctite!

                  If you think my reply was off-base, give me a bit more than this mate.

         3. Beretta_Vexee · 1790775100 · focus · HN ↗

            The A-12 was not developed from scratch, whether in terms of its design, production facilities or in-house expertise.

            Design is a very different matter when you have a workshop full of skilled workers and machinery right on your doorstep, who can critique your work and explain what they can and cannot produce. A lot of engineers discovered this the hard way when companies started outsourcing to the other side of the world and lost control of production process.

            Designing parts that look nice but are impossible to machine or assemble is simple.

            Designing the plane may only have taken four years, but training the staff, organising the workshops and mastering the production tools took much longer.

            Just look at the struggles faced by all the organisations that stopped producing anything for a long time and then wanted to restart production. Whether it’s ships, aeroplanes or nuclear power stations, each time it takes something close to ten years to restart.

            When they manage to do so.

            1. dingaling · 1790775735 · focus · HN ↗

               "Designing the plane may only have taken four years, but training the staff, organising the workshops and mastering the production tools took much longer."

               Lockheed had no experience with titanium prior to OXCART. 95% of the first 6,000 sheets of titanium had to be scrapped.

               It was the first production design to incorporate low-observable shaping.

               It was 50% faster than anything Lockheed had previously tried to build, and four times faster than the U-2.

               And they literally did all that between April 1958 and April 1962.

               So, yes, it was designed from scratch as nothing useful from prior projects read across to it.

         4. mmooss · 1790775214 · focus · HN ↗

            Complexity and knowledge grow over time. It's likely that the last SR-71 and the processes and materials behind it were much more complex than the first. You have to recreate not only the first unit, but decades of added knowledge, skill, and complexity.
         5. Merad · 1790778805 · focus · HN ↗

            The A-12 was built in an era when the aerospace industry was flush with knowledge and active R&D into mach 3+ flight - everyone was convinced that it was the future. Today's industry is heavily optimized for subsonic airliners and fighter jets that have top speeds of "only" mach 1.5-2. No one in the west has built a mach 3 aircraft since the 60s and not in Russia since the early 80s. The knowledge isn't _lost_ (well, we hope) but there is a lot that will need to be relearned, and we all know how even the best documentation is usually missing a lot of details.
         6. HumblyTossed · 1790791486 · focus · HN ↗

            > Surely we can match that with our 70 years of advanced knowledge and equipment? I don't think we can, because: > ... we don't have Kelly Johnson.

            or the engineers from that time who had an intuitive knowledge of how this should all be designed. You can't teach a computer intuition.

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