This was a very short duration design/build/test project that I did to show one of my co-op students at the time that you can complete a full engineering design through test project in a few days with minimal coast if you adequately simplify the requirements. This engine was a unique design but copied many details of heritage engines. The engine operated well on gaseous propane for a total of about 30 minutes of run time. The pulse frequency was higher than optimal making the engine hard to cold start, but a longer exhaust duct likely would have improved that problem.
Michael Fuchs Personal Projects 