Rotary-piston machine

A rotary-piston machine (10) comprising a housing (5) having a cavity (9). a rotor (2) received in the housing (5), which rotor (2) has a rotor axis (A) and a peripheral surface (21). inlet and outlet passages (3,4) in communication with said cavity (9), one or more vanes (1) that are radially slideable received in slots (11) in the rotor (2), each vane (1) extending radially from the internal surface (20) of the housing (5) to the rotor axis (A), at least one working chamber (9a) being part of the cavity (9) and defined by the internal surface (20) of the housing (5), the peripheral surface (21) of the rotor (2) and the side surface of at least one vane (1), each vane (1) being articulated connected about aa axis (C) to one end of a control arm (7) and in the other end thereof bein, pivotally supported in a fixed axle shaft (8) having a central axis (B) being coincident with the axis extending centrally through the cavity (9) of the housing (5), which axis (B) extend in parallel with and spaced apart (d) from the rotor axis (A), and the rotor (2) proper constitute the unit for power take off or power input, characterised in that each vane tip (1bt) describes a cylinder surface sector having centre of curvature in the axis (C) extending through the joint that connects the vane (1) to the control arm (7).