I thought about it and for the system to work, the sun and planet gears must be a 1: 1 ratio. Anything else will bind. If there was a ring gear, then different gear ratios are possible. The ring gear would constrain the planet and then the connecting rod wouldn't need to be "fixed" relative to the planet. I wanted the sun-planet gearing to be on the side of the engine, prominently displayed. The gearing in the middle is where I'm not thrilled where it's going. I'm not done, it just needs for design work. ...Ved.