Rotor systems and methods for improved performance with extended range to stall fabricated through the use of additive manufacturing. A rotor has blades that extend to tips and rotates about an axis. A casing fits over the rotor so that the tips are configured to pass proximate the casing when the rotor rotates. The casing channels a flow stream across the rotor. Grooves are defined in the casing and extend longitudinally at an acute angle relative to the axis. The grooves extend a distance upstream from a leading edge of the blades and over at least a portion of the blade tips so that the blade tips are configured to pass across the grooves when the rotor rotates.