The mechanisms and porting requirements of a new class of rotary piston machine are described. The machines can be regarded as a generalization to three dimensions of that class of planetary motion machine which includes the Wankel. Important features of the Wankel engine are retained, namely a compact arrangement, a sliding contact seal grid and multiple chambers on each rotor, but these new machines have twice as many chambers on each rotor, and they apply results of three-dimensional rigid body dynamics to select piston motions which involve very low inertial forces. An experimental engine is described with some results.
