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Since we are on the subject of gearless, 2:1 reduction mechanisms....Could a Geneva Wheel arrangement be used? For example: A 6-slot Geneva Wheel + a three lobe cam mounted to it for the 2:1 reduction. The driver pin that engages into the indexing slots would be on the crankshaft, and the indexing Geneva Wheel/cam combo would control the exhaust valve. You could even use a one lobe cam with wheel having 6 slots to make a 6-cycle engine, for better scavenging and air cooling the cylinder. Of course, intake would be atmospherically controlled.Would this set-up work?Frank