Wimbi is a mechanical engineer with long career in heat engine research and development, starting with rockets and other whiz bang things of the cold war (first degree in 1950) and then migrating thru academic and business stuff to solar and non-carbon energy generation. He ran his own small R&D company for 50 years. He has done heat engine widgets of all forms from childhood, and in his career and as a hobby.  It is his form of fun.  Cheaper than golf, and way cheaper than globe trots.