Two oscillatory type engines detail paddles (vanes) that
are fixed. For one type by Vogel the vanes are fixed to
the outer stator and the motion is controlled by a cam
profile on the inner stator [73]. For the other type by
Sarich the vanes are constrained in the rotor to
reciprocate in the tangential direction and translate
through a stationary outer stator. The vanes are also
pinned and follow a cam profile in the end plates