The (US) Air Force Is Having To Reverse Engineer Parts Of Its Own Stealth Bomber

[drawoh]

Here is an interesting article on an automotive website The Drive...

The Air Force Is Having To Reverse Engineer Parts Of Its Own Stealth Bomber

Evidently, people have not managed their engineering data, and/or their CAD files have become obsolete, and are no longer supported by anything. A long time ago, I worked on a design project for a European customer, where we had to make sepia copies of our drawings to be held in escrow for twenty five years, just in case of something like this.

With B[‑]52s in service since the 1950s, and the M2[ ]Browning in service since 1919, you would think the US military would have a long term document management strategy.

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JHG

 

[ewh]

I saw that and had to laugh...

"Know the rules well, so you can break them effectively."
-Dalai Lama XIV

 

[3DDave]

On one contract I worked the document manager went to deal with customer sign-offs and found that drawings were being bulldozed into pits for lack of storage space. I expect there was a Congressman who struck storage from the appropriations as a way to get more money to whoever was lobbying him to do so. Same thing that saw MIL-Specs handed out like candy to be re-sold to defense contractors for hundreds of dollars each, specs that had been free to distribute and now under copyright.

It seems most likely what happened to the heat exchangers is the problem that befell that same system our doc manager was dealing with - 15 years after initial production we got a long-term spares contract and a company bid on a weldment for it. Soon we got calls allowing as to how the drawings were impossible to build to and how there were many interferences with welds. They said their welder was an AF qualified welder certified for critical aircraft repair. (Red flag!) So we went out to see and found this guy could really pile on the metal. I had 100% confidence the welds were sound, but they were also huge. An additional problem was that it was taking him a long time.

We pointed out that originally nearly 100 units had been made to these drawings and soon put them in contact with the guy who welded them. After that we heard two things - "Wow, that guy is fast!" and "Can he train our guy?" He didn't work for us, so it was up to him; I think he probably did accept the job to train their welder. Within a week or two the production rate went from 0 and "impossible," to getting back on schedule for deliveries.

The fun part was that the original welding for the prototypes was done by our in-house welders before being moved to an outside firm; no changes had been made to customize it for the one guy. It's just a skills issue that is tough to put on a drawing.

I do take offense at the term "reverse engineering" when applied to "copy this with the material it might be made of." That has nothing to do with engineering. Analyzing the system, understanding the constraints and expected performance of the existing item, and building an item that fits in the same location is "reverse engineering." The part of the article dealing with the circuit board is an excellent example of that.

One area that is tricky about duplicating items is this: Under a refurb contract we were obligated to put a bunch of vehicles into like-new order. But there was also some verbiage about meeting the procurement specification. Seems simple - we had all the drawings, 3rd party parts were available, worn-out and broken parts would be repaired or replaced.

The catch? They failed to mention there were performance waivers on the original contract. Like-new, in compliance with the TDP, was not contractually compliant. Jerks.

 

[ctopher]

I saw the B2 in its hangar back in mid-80's. Lots of dwgs made in both hand drawings and CAD.

ctopher, CSWP
SolidWorks '17
ctophers home
SolidWorks Legion

 

[TheTick]

What were they designing with? CADKEY?

 

[ctopher]

I though it was UG or CATIA. I used GDS in 80's.

ctopher, CSWP
SolidWorks '17
ctophers home
SolidWorks Legion

 

[TheTick]

UG and CATIA are still live, viable platforms. No telling what the subcontractors were up to, though.

 

[drawoh]

TheTick,

One of the disadvantages of design on a drafting board is that some twit will look at the filing cabinets full of drawings, and they will toss everything. Who needs it anyway?

For that matter, who takes care of hold computer hard drives?

--
JHG

 

[looslib]

I worked for one company where we modified aircraft from multiple manufacturers. On one modification program we had the old board drawings and someone remarked that they had cost us a fortune to obtain the copies from the original company.

"Wildfires are dangerous, hard to control, and economically catastrophic."

Ben Loosli

 

[Jughandle]

Not unusual for the gov’t (or industry in general) to RE component parts such as the subject heat exchanger. It may have been purchased as ‘Sole Source’ or a ‘Commercial Off-the-Self’ part with no tech data or drawings. Contractors tend to hold back the tech data and make the gov’t pay extra, so this info is often not conveyed along with the deliverable hardware. Where does that leave the gov’t if the contractor is forced out of business, e.g., by a pandemic, or if the contractor wants an exorbitant amount? The gov will either do it in house, or get another contractor to do it. Laser scanners, point cloud software, CAD also make Chinese copying easier now.