There are in war, essentially two extremes to take with Technical Intelligence work. These tell you something about the overall approach of nations, I have to add these are purposely selected to illustrate THE most profoundly differing examples. But the overall message holds. The British approach, was this. An officer finds a crashed Messerschmitt Me 410 in Sicily, in view of the likely time needed to ferry the DB 603 engine back to britain for study, he decides that since the Daimler-Benz engines are all similar in form any changes in the breathing system will be important, the valves are opened and closed by the camshaft, so, seeing one of the cams exposed by impact damage, he stuffs a bit of cardboard on the side of the camshaft lobe, rubs an oily fingerprint on it, thus giving a very approximate indication of valve lift and duration, and sends it off in an envelope to A.I.2(g) (British Air Intelligence, equiptment branch). In Germany, probably the most famous (rightly so) engine scientist alive was Dr List (he founded the famous engine consultancy AVL, which still exists today), was given a Merlin engine. This was then stripped, inspected, and Dr Lists dept conducted a substantial study into what was wrong with the engine from a theoretical design perspective and what their recommendations were to improve it. There was some sense in this, in that this gave German technical intelligence some idea about the future power development of the Merlin. However, given the serious issues then at work in Germany in aero engines, it might have been more opportune for the engineers of List, to have been working at the Daimler-Benz, BMW and Jumo engine design offices to make THEIR own engines better. The German engineers noted in the report, with frustration that their conclusions were to be taken as only guidelines because all their detailed workings and calculations were destroyed by an Allied bombing raid ! Generally the American intelligence services were in between these two positions, in that they often conducted extremely thorough engineering investigations, but generally kept the reports very focused and practical. The British reports centered only on what items of interest they found inside a crash site. The advantage being, that especially in the initial phases, British firms like Rolls-Royce often got intelligence on German engine developmens within 3 days of a crash. The first German aircraft downed in Britain was shot down over the Lammermuir hills near Edinburgh, Scotland. Within hours Rolls-Royce had a couple of men on a hired crane driving across the heather to find the plane, they hacksawed it off the wing, and it was on the test-bed in Derby 2 days later. They were not very happy, because the German direct fuel injection system appeared to be really rather good. RR engine development technician, Geoffry Bone, later wrote: "I think it was an indication to Rolls-Royce engineers that they weren’t quite so much top of the pops as they claimed to be.” By the end of WW2, the Merlin 100 series engine was using fuel injection, albeit not nearly as sophisticated as the German system. Pictured are these two reports, the LIST report is in English as Allied Technical Intelligence had it translated. Also is the actual photo of the RR men removing the first ever captured direct fuel injected German aero engine on its way to the RR test cells in England, 350 miles away in Derby.