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The Air Force is having to reverse engineer parts of its own stealth bomber

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Re: The Air Force is having to reverse engineer parts of its own stealth bomber

#91

Post by workergnome »

My grandfather spent the last part of his career doing this sort of work—often on classified projects, I'm told. Usually there was an assumption made on the project about the useful working life of any part, and the expected duration of the program, and they made the "right" number of spares.

Things change, and the factory/tooling/people are long gone. Also, often the underlying tech isn't available. But the part needs to weigh the same amount, meet the same guidelines, and fit in the same hole.

It's cheaper to pay someone to spend the time to figure out how to make the replacement then to mothball the entire airplane—almost regardless of how expensive it might be.

Re: The Air Force is having to reverse engineer parts of its own stealth bomber

#92

Post by azernik »

LeonenTheDK wrote: post #11
projektfu wrote: post #5

I read once that if you tried to build WWII-era aircraft according to specs and mechanical drawings, they wouldn't fly. The real design was found in the dies and jigs that were adapted after many iterations and test flights.

That's an interesting though, like software documentation that hasn't been updated over years of patches. Do you remember where you read that? Sounds like an interesting bit of history.

A long write-up of an equivalent for the F-1 engine is here: https://arstechnica.com/science/2013/04/how-nasa-brought-the...

The analogy to out-of-date software documentation is very apt. As problems or inefficiencies popped up in the factory, they'd change things and just not write them down (because of deadline pressure, often). If you wanted to build new ones you'd have to either get the factory workers to show you how the thing was actually built, or tear down a working example to reverse engineer it. (Which has been done!)

Re: The Air Force is having to reverse engineer parts of its own stealth bomber

#93

Post by Jtsummers »

dylan604 wrote: post #77
jandrese wrote: post #14

Earlier quoted context omitted.

As someone who works with the government a fair bit, this kind of forward thinking is extremely unlikely to be the case. This is the kind of government competence that only exists in the most wild conspiracy theories. The idea that it was made by some long defunct subcontractor and nobody knows what happened to their blueprints and production notes is far more likely. Also, even if you had the blueprints you still ne…

>As someone who works with the government a fair bit, this kind of forward thinking is extremely unlikely to be the case. This is the kind of government competence that only exists in the most wild conspiracy theories. No, but we'll totally sponsor/fund research into things like mind control and astral projection. Funding something totally useful like reverse engineering skills is totally anathema. Just really sad co…

> No, but we'll totally sponsor/fund research into things like mind control and astral projection. Funding something totally useful like reverse engineering skills is totally anathema. Just really sad commentary

I don't get your point. The government does invest in reverse engineering, and much more than they invest into mind control and astral projection. It's nonsense to say that investing in useful skills is "totally anathema".

What GP was saying was not that they don't invest in reverse engineering, but they wouldn't try to backdoor it or secret the experience into the industry with some project like this. They wouldn't try to "trick" the industry into developing the experience by putting out smaller contracts like this. They do invest in it, but directly. That one program office has put out a contract for reverse engineering of one system does not mean that the general capability is ignored, within the government or the industry.

Re: The Air Force is having to reverse engineer parts of its own stealth bomber

#94

Post by azernik »

lambda2001 wrote: post #61
Jtsummers wrote: post #19

Earlier quoted context omitted.

Exactly. We're dealing with: - Limited production run. These aren't Ford Mustangs or Toyota Priuses with hundreds of thousands and millions being produced. There were 21 built over 13 years. This also leads to the consequence that each one should be considered a bespoke creation and not a "copy" of the others (even ignoring the 20+ years of individual maintenance work they've each had). - Time. It's been 21 years sin…

The last part is extremely true. I have known many engineers that worked on the B-2 and have since retired. There's very little chance many of them would come out of retirement and honestly I don't think the government would pay for that.

And even if they did, no one remembers that well the things they did decades ago.

Re: The Air Force is having to reverse engineer parts of its own stealth bomber

#95

Post by MattGaiser »

jaxx75 wrote: post #78
MattGaiser wrote: post #56

Earlier quoted context omitted.

I would be very interested in reading case studies where a company both does documentation well and does not get bogged down in vast amounts of paperwork. As yes, plenty of fixes for things are not written down anywhere.

If you haven't read it, you'd probably enjoy (and anyone interested in process) The Toyota Way by Liker.

Thanks!

Re: The Air Force is having to reverse engineer parts of its own stealth bomber

#96

Post by nullserver »

banana_giraffe wrote: post #54
nullserver wrote: post #23

Earlier quoted context omitted.

My dad was talking to an engineer at one of the major airlines manufactures apparently some critical part was foam injection or some such. Anyway the process as such did not work as documented. You had to add strings to the inside of the mold to get it to set correctly. This was not written down anywhere. Part of it may have been job protection. The union was bad about that. New hires would not be able to complete th…

It's also possible it was "Hey! The foam injection machine isn't working, I've tried everything", "There's this string trick I used once, try that", "Great, that fixed it, we should document that", "Sure, once we get all parts made that have backed up" Or, maybe I'm reading bad practices in my industry to everywhere else.

From the conversation, admittedly 20 years ago. Not documenting was highly intentional, and why I was being informed.

Re: The Air Force is having to reverse engineer parts of its own stealth bomber

#97

Post by nullserver »

MattGaiser wrote: post #56
banana_giraffe wrote: post #54

Earlier quoted context omitted.

It's also possible it was "Hey! The foam injection machine isn't working, I've tried everything", "There's this string trick I used once, try that", "Great, that fixed it, we should document that", "Sure, once we get all parts made that have backed up" Or, maybe I'm reading bad practices in my industry to everywhere else.

I would be very interested in reading case studies where a company both does documentation well and does not get bogged down in vast amounts of paperwork. As yes, plenty of fixes for things are not written down anywhere.

Reproducibility.

Have others come in and follow the directions.

Re: The Air Force is having to reverse engineer parts of its own stealth bomber

#99

Post by hondo77 »

benzene wrote: post #10
tablespoon wrote: post #6

Earlier quoted context omitted.

I don't think this kind of thing is all that uncommon for military airplanes that have been long out of production. I recall reading a decade or two ago that our local air guard wing had to fabricate some of its own replacement parts for its F-16s (IIRC, then some of oldest that were still in service). I also recall that Lockheed had to take special effort to preserve production know-how and tooling for the F-22 when…

>Long out of production. The difference in technology likely plays a large role - these parts were designed without CAD and modern fabrication protocols have changed. It reminded me of NASA's endeavor to reverse engineer the Saturn rockets https://arstechnica.com/science/2013/04/how-nasa-brought-the...

> The difference in technology likely plays a large role - these parts were designed without CAD and modern fabrication protocols have changed.

Actually, the B-2 was one of the first military aircraft designed with CAD.

https://www.northropgrumman.com/wp-content/uploads/B-2-Spiri...

(search for "NCAD")

Re: The Air Force is having to reverse engineer parts of its own stealth bomber

#100

Post by structural »

TheCondor wrote: post #39
dmurray wrote: post #3

Reverse engineering seems like a good skillset for the DoD to nurture, anyway. Yes, the US is going to be at the cutting edge of weapons design at least through the medium term, but the leadership isn't arrogant enough to think that all engineering innovations will come domestically. If the US acquired a next-generation Chinese fighter, wouldn't it be handy if someone had the expertise to tell you exactly how its par…

I've heard from various acquaintances that it's not unusual for the contractor to be required to destroy documentation and tooling for certain classified projects upon completion.

It is absolutely standard practice for this to happen. At contract completion, the contractor must destroy or return all classified materials: these sorts of designs would certainly be included.

It's pretty interesting, but a lot of this stuff is structured specifically so that the contractor organization doesn't retain knowledge that it's "not supposed to have", as wasteful as that ends up being. Even stuff like a list of personnel who worked on a project or production line might be included... so that a few years after the project is completed, the management of the contractor might not even be able to figure out who to ask, because they've destroyed even their knowledge of the list of people who worked on the component's design and manufacturing.

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