The view into one of the fuel feed
passages showing two of the "steps" where the diameter of the passage
Note the hypergol feed
line. This line delivers pyrophoric fluid (fluid which spontaneously
combusts upon contact with oxygen) into the thrust chamber through igniter fuel
orifices in the injector.
This particular feed line leads to an igniter orifice between the outer
circular baffle and the outer edge of the injector.
After seeing how many shots I had to take before getting a good exposure on the
previous fuel feed passage shot, one of our
hosts noted that it would be possible to place my LED flashlight on the
injector face to have it illuminate the interior of the passage.
This makes it easy to note the holes in the
forward (top) side of the passage, where fuel is delivered to the 16 fuel ring