Hi All!

I'm new to this site, and am just starting on a CH750. In evaluating my engine options, I came up with a question that I haven't seen addressed anywhere. It's not about WHICH engine, but rather why one doesn't exist.

All of the current LSA offerings with speed reduction units use spur gears or belts to make the reduction, but why no planetary gears.

Automotive automatic transmissions all use planetary gears, and some of the old large radial engines also used them. (See attached diagram of Wright R3350).  Gear Reduction Unit

It seems that the layout would be more compact, stronger, and keep the prop centered on the crank.

The current engine units look like afterthoughts (which many are) while a planetary unit would appear as an integral component of the engine (slightly longer snout).

Any ideas, or does such a creature already exist?



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As Mark mentioned the biggest tax of the planetary drive application is its cost and weight. The problems rank right up there with 100 hp diesel engines for light-sport aircraft.


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