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The marking for No. 60 tube on the injector end ring, at approximately the 1:00 position on the injector

Picture 1 of 2.

The marking has an arrow pointing to the injector, a burnished area (as though some marking had been made there and then removed), and then the actual "60" marking. The "6" and "0" digits appear over different tubes. I assume that the actual No. 60 tube is the tube with the arrow (since that is the only tube which is unambiguously identified).

I'm a bit puzzled by this marking, as the arrow is pointing toward the injector, even though the No. 60 tube is a "down" tube. (Recall that fuel flows through the tubes comprising the thrust chamber to provide regenerative cooling; every other fuel is a "down" tube, carrying fuel from the forward end of the engine to the exit plane, where the fuel return manifold then redirects the fuel back up an adjacent "up" tube.)