The aerodynamic characteristics of a straight wing lying on a diameter in a circular open wind tunnel are studied. In my previous note,1) the exact expressions of the spanwise optimum lift distribution and the minimum induced drag have been obtained from the Trefftz plane flow field analysis, where an independent variable transformation and Sohngen's inversion integral formula were used. In the present study, an alternative analysis is done, where the conformal mapping and Sohngen's formula are used. The results obtained here are coincident with those of my previous note.