Abstract: A fan 10 has a hub 12, a plurality of fan blades 14 attached to the hub at one end and extending outwardly from the hub, and a ring 18 concentric with the hub and coupled to tips 16 of the blades. Wherein a dimensionless radius (r/R) is defined from a center of the hub (r/R=0) radially outwardly, wherein each tip of the blades is r/R=1. A stagger angle is defined as an angle between an axis of rotation of the fan and a set angle of each fan blade, and C/R is a dimensionless chord length where C is chord. The fan is defined by values of r/R, C/R and stagger angle.