Hill-Diesel Engine Co in Lansing, Michigan made a very interesting engine model with horizontal cylinders and opposed pistons in each, but the most unique was the connecting-rod system with their joints before reaching the single crankshaft.

-It could be used for all types of vehicles, there is no known aerial application of this particular engine, although some subsequent trials of other brands with this intention are known.

-It's brought here for being interesting. Below we show the schematics of the mechanism.

"Deformed image in reproduction"

-We now have an illustration with a real view of the engine's shape and architecture.

"Drawing of the real engine"

-We see that even being an engine with horizontal cylinders, it is less wide than the classic engines with independent opposed cylinders.

"French version of the Hill formula"

"Drawing with Roots supercharger"