A Body Modification to Reduce Drag Due to Wedge Angle of Wing with Unswept Trailing Edge

Ward's slender-body-theory formula for zero-lift drag contains three integrals plus a base-drag term. Two of these integral terms depend only upon the cross-sectional area distribution of the body. The third integral term depends only upon the body shape and axial slopes at the base of the body. This term is neglected in the transonic area rule because in many cases it is zero; however, there are also many cases in which it is not zero. This paper examines the term for the possibility of drag reduction for a particular case. The model considered consists of a body of revolution in combination with any wing that has an unswept trailing edge and a constant trailing-edge angle along its span. It is found that (neglecting any change in base drag) a drag reduction is obtainable which, for the case considered, is an additional 12 percent of that obtained with the area-rule modification. The probable effect of viscosity on this theoretical result is discussed