The theoretical lift of a cylindrical afterbody at zero angle of attack due to incidence of the wing is determined by means of slender body theory. It is assumed that the vortex sheet becomes fully rolled up ahead of the base of the afterbody, and the paths of the vortices in the presence of the body are determined. Since this requires the complete solution of the classical problem of the motion of a two-dimensional vortex pair past a circular cylinder, the analytical solution of that problem is presented herein.nThe total lift of a slender wing-body-tail combination due to incidence of the wing is also calculated by making use of the above solution, and lift curves are presented for a variety of tail lengths, span ratios, and body sizes. The lift due to the rolling-up of the vortex sheet is included and is discussed in relation to the calculated results.nIt is found that a short afterbody carries positive lift and that a long afterbody carries negative lift. Furthermore, there is a short after body length which carries a maximum positive lift and a long afterbody length which carries a maximum negative, lift.
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