A novel analytical method is presented for the prediction of the normal force increment due to spin on a stalled wing. This model is based on the concept of fluid in the stalled semi-elliptical-shaped region behind the wing being pumped radially outward by centrifugal motion and ejected at the wingtip, where the ejection of flow at the tip is a new assumption. In the regime of Re ≈ 100,000, the maximum normal force coefficient increment predicted in this investigation was approximately 1.4 based on the wing planform and aircraft pitch angle, θ. The analytical model was validated against wind tunnel tests conducted specifically as part of this research, where the relationship of CN to ω2 was confirmed. Good agreement was demonstrated between the presented model and full airplane rotary balance data for various wing planforms over the pitch range of 30 < θ < 90 deg and nondimensional spin parameter, ω, range -0.9 < ω < 0.9. This method, which advances the current state of the field and leverages recent research from other fields, should provide useful results for wing modeling to provide a better design-for-spin, help improve the fidelity of transport category aircraft simulators for upset, loss of control situations or within the FAA "extended envelope," and aid in the simulations of flapping-wing aerodynamics for micro air vehicles or studies of insect flight.