Like I've been saying, the future has to be hybrid:
1. Drive aircraft with electric power.
2. Power them with fossil fuel primary movers until the power storage has been solved.
Just as an example - A rough running diesel engine without a flywheel to make it stable is no problem for a generator - it can be as rough as it wants. The combo of a generator and an engine is also less than a engine+flywheel+transmission, so it's not even a weight issue anymore.
Better still - get a free piston generator diesel and you can eliminate most of the weight for crankshafts and bearnings and housings:
Free Piston Power Home