enginehistory.org

[rwahlgren]

http://www.enginehistory.org/Piston/Junkers/Jumo222/Jumo222.shtml

At first sight, I thought this was going to be a full and thorough report about disassembling, reverse engineering this engine, such as what materials were used, the chemistry and heat treats, clearances etc.

Where to find that sort of information? I'm sure even in the day at Wright Pat they did that to the American engines as well.

[rwahlgren]

It looks like Calum's book covers some of it. Some very good info in the book.

[kmccutcheon]

In my experience you rarely find that sort of information. The Jumo 222 article was drawn from source documents that were better than most and were typical of the kinds of intelligence reports the U.S. Army Air Forces was producing. They would usually photograph and weigh a captured engine, take it apart, photograph the components and in the case where they were interested in some technology, perhaps do a lab analysis on a material. Doing such analyses was an expensive and time consuming endeavor in the 1940s, requiring considerable analytical skill, so such analyses were not commonplace. In some cases the captured engines would be reassembled and run on dynamometers to document their output.
Most American engine reports were type tests, with brief engine descriptions, a few photographs, test process description, test data, accounting of the stops, and photographs/descriptions of the busted parts. Sometimes you see some limited clearance data. In my experience, it is very rare that type tests reports go into any detail about material composition, manufacturing processes, etc. A couple of reasons for this come to mind. There was no need to supply this kind of information to achieve the type test objectives. Also, the manufacturers closely guarded their materials and processes; some even formulated their own alloys and gave them unique names or numbers. The only heat-treat information I recall seeing was when parts broke prematurely and were redesigned the testers would sometimes document the before and after processing steps, but that was only for the busted part.
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Kimble D. McCutcheon