[onewhippedpuppy]

Originally Posted by legion

I would think that any gains that an opposed piston engine would be able to muster from more efficiently capturing combustion energy would be lost from more complicated mechanicals (two crankshafts, for example).

I was involved in some testing of a horizontally opposed 8 cylinder diesel aircraft engine that had a single crankshaft. The cylinders were staggered slightly and shared a crank journal if I remember correctly. Very cool product that is slowly making its way towards certification.