Developed in this report are expressions for the lift, pitching moment, and location of the aero¬dynamic center due to free-stream angle of attack for an isolated cylindrical wing based on a solution of Weissinger's general boundary condition for ring wings. From the components of ring vorticity expanded in a Birnbaum series and satisfying the velocity boundary-flow condition, and from the Kutta-Joukowski relation for the force on a vortex surface, the lift, moment, and aerodynamic center can be expressed in terms of the Birnbaum coefficients. It was found that the lift and pitching moments for cylindrical ring wings are sub¬stantially different from the results for two-dimensional flat plate (thin) airfoils. Calculations show a significant shift in the aerodynamic center upstream of the 1/4-chord point for cylindrical ring wings.
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