A method of making an additively manufactured ejector pump, the method comprising: creating a computer file defining the ejector pump in layers, the ejector pump comprising: a duct extending along a centerline from an upstream end to a downstream end; a nozzle extending inward from the duct including a flowpath therein; an annulus connected to the duct including a cavity therein; a first gusset extending between the duct and the nozzle on a nozzle upstream side at an angle of fifty degrees or less with respect to centerline; wherein the flowpath comprises a cross-section with a flowpath shape of a semicircle on a nozzle upstream side and a peaked shape on the nozzle downstream side, wherein each leg of the peaked side extends at an angle of about fifty degrees or less with respect to centerline and has a fillet joining the two legs at the downstream end; wherein the cavity comprises a cross-section with a cavity shape of quadrant of a circle on an annulus upstream side and a slant on an annulus downstream side with two interior fillets where annulus meets duct, wherein the slanted side has an angle of about fifty degrees or less with respect to the centerline; and building the ejector pump, by applying said computer file, using an additive manufacturing process that builds the ejector pump on a layer-by-layer basis from the upstream end to the downstream end. creating a computer file defining the ejector pump in layers, the ejector pump comprising: a duct extending along a centerline from an upstream end to a downstream end; a nozzle extending inward from the duct including a flowpath therein; an annulus connected to the duct including a cavity therein; a first gusset extending between the duct and the nozzle on a nozzle upstream side at an angle of fifty degrees or less with respect to centerline; wherein the flowpath comprises a cross-section with a flowpath shape of a semicircle on a nozzle upstream side and a peaked shape on the nozzle downstream side, wherein each leg of the peaked side extends at an angle of about fifty degrees or less with respect to centerline and has a fillet joining the two legs at the downstream end; wherein the cavity comprises a cross-section with a cavity shape of quadrant of a circle on an annulus upstream side and a slant on an annulus downstream side with two interior fillets where annulus meets duct, wherein the slanted side has an angle of about fifty degrees or less with respect to the centerline; and a duct extending along a centerline from an upstream end to a downstream end; a nozzle extending inward from the duct including a flowpath therein; an annulus connected to the duct including a cavity therein; a first gusset extending between the duct and the nozzle on a nozzle upstream side at an angle of fifty degrees or less with respect to centerline; wherein the flowpath comprises a cross-section with a flowpath shape of a semicircle on a nozzle upstream side and a peaked shape on the nozzle downstream side, wherein each leg of the peaked side extends at an angle of about fifty degrees or less with respect to centerline and has a fillet joining the two legs at the downstream end; wherein the cavity comprises a cross-section with a cavity shape of quadrant of a circle on an annulus upstream side and a slant on an annulus downstream side with two interior fillets where annulus meets duct, wherein the slanted side has an angle of about fifty degrees or less with respect to the centerline; and a first gusset extending between the duct and the nozzle on a nozzle upstream side at an angle of fifty degrees or less with respect to centerline; wherein the flowpath comprises a cross-section with a flowpath shape of a semicircle on a nozzle upstream side and a peaked shape on the nozzle downstream side, wherein each leg of the peaked side extends at an angle of about fifty degrees or less with respect to centerline and has a fillet joining the two legs at the downstream end; wherein the cavity comprises a cross-section with a cavity shape of quadrant of a circle on an annulus upstream side and a slant on an annulus downstream side with two interior fillets where annulus meets duct, wherein the slanted side has an angle of about fifty degrees or less with respect to the centerline; and building the ejector pump, by applying said computer file, using an additive manufacturing process that builds the ejector pump on a layer-by-layer basis from the upstream end to the downstream end.