counter rotating props

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Some additional thoughts on the counter (contra?) rotating engine discussion.

One of the biggest hurdles in reversing the direction of rotation in an
engine is the oil pump. It only makes pressure if rotated in the correct
direction, and they are frequently integral to the infrastructure of the
crankcase. (like an Audi V6 and many other engines I am sure) Not the
easiest thing in the world to swap out.

Also, wrist-pins are not in the middle of the piston on many (most)
engines to aid in minimizing side loading of the piston-to-cylinder
during power stroke. They are really not designed to rotate in the
opposite direction. (Unless they are designed for both directions from
the start like industrial engines. Different animals from what are in our
grocery-getters). On a Fjord small-block V8, if you put the pistons in
backwards, it wears the bore out in about 30,000 mi. These have unusually
short rod-ratios, though.

Oh well!

Tom LH