Abstract: The subject matter of this specification can be embodied in, among other things, a fluid pump that includes a housing with a cam block. The pump also includes a collection of vanes, each having a shank having a leading edge and a trailing edge, and a head having a curved outer side. The pump also includes a rotor having a collection of slots, each slot having substantially parallel leading and trailing edges spaced to accommodate the shank of one of the vanes, wherein each vane contacts the cam block at a contact point on the head controlled by the rotor slot position and the head outer curved surface, the contact point being located relative to the shank edge when the vane is radially aligned with the major and minor radii, and located rotationally to create a radial force between the head curved surface and the cam block.