The Rotary Piston Engine offers greater torque with less energy, in other word instant torque at TDC with far less loss on the power stoke stage. With a basic understanding of piston traveling in a circle, this allows greater torque and higher efficiency.
Lets look a basic design:
A 12" wheel or say rotor with a radius of 6", and having a piston of 1"x"1 or 1 in/sq.
This piston is attach to the outer wheel to travel in a housing of 14" diameter.