Hi I'm designing a 2cyl single acting uniflow engine I'm using an IC style bearing I cylinder head approach (no cross slides) I have the idea that a 'square' bore/stroke ratio is good in terms of minimal surface area. Any advice? Does anyone have a rule of thumb regarding crank length (in proportion to bore/stroke)? Clearly a too long crank would mean the corned would pass through too widen angle to be mechanically efficient. OTOH, I'm thinking con rod should pass through 30 degrees, no more than 45 deg. Anyone got anything more specific? thanks!