Here is a comparison of an unsteady heat transfer analysis vs.
the actual experimental results from a thermocouple on the outside
of the chamber for Run 1. The gas side heat transfer coefficient
was 0.000204 BTU/s-in^2-degR at 5400 degR. This assumes a thermal
resistance of the carbon deposit in the chamber of 1600
in^2-s-degR/BTU. See NASA SP-125 for details on how I came
up with these estimates. Since the start of the run had a hiccup
due to the late LOX valve timing, I wasn't sure where to "start"
the test data. Note how well the slope of the experimental
line matches the test data.