Hopefully this short video shows how the rotary engine works in terms of the conrods.
https://youtu.be/yLBuSv3S8ao
In rotary engines the crankcase rotates with the propeller. The conrods rotate about the crank pin. These two rotational axes are parallel and half the length of the stroke apart. In this way the early engines removed the need for a heavy flywheel by using the mass of the engine as rotational inertia.
Making the 5 cylinder rotary engine
