I want to get this group's thoughts, experience stories, and
possibly advice on regenerative cooling with liquid oxygen at the small
scale (<500lbf)? I have read the public NASA paper that concerns cracking
in the chamber and local hotspots and have looked into (what little has
been released to the public) Launcher's work with their small 3d printed
copper engines. On paper at least, it seems like one can get away with
cooling from the throat up (the entirety of the combustion chamber). This
is just curiosity-sparked research, nothing beyond that yet.