Through the state-of-the-art CFD approach, the Eckardt radial bladed and backswept impellers were analyzed to investigate the effect of blade loadings from blade design shape on the slip factor variation for the change of the flow rate. In addition, a new design of the blade profile was arbitrarily attempted to generate a center-loading pattern in the Eckardt backswept impeller. Three dimensional compressible turbulent flow analysis was applied, with the Baldwin-Lomax turbulence model adopted, to get the numerical slip factor, using the mass-averaged concept, at the discharge plane of each impeller. The numerical slip factors are in good agreement with the experimental ones, and the Wiesner’s slip factors are found to deviate further from the numerical and experimental ones, especially in the two backswept impellers. The deviation angles and the blade loadings in the meridional channel are found in no direct relation with the trend of change of the slip factors. Blade-to-blade loadings in midspan location are, however, found in direct relation, especially at the sections where maximum loadings are to be expected. That information can be utilized in establishing an improved expression for slip factor in the future.