The greater the aspect ratio, the less twist is required. However, as aspect ratio increases, and the wing chord gets proportionally smaller, it becomes more difficult to build a strong stiff wing. The greater the sweep back angle, the less twist will be required. However, angles of sweep back in excess of 20 degrees adversely affect air flow over the wing and may lead to control problems. While some of this moment is derived from the downforce generated by the wing tips, it is also greatly influenced by the pitching moments of the airfoils used.
Sections used on contemporary swept wing tailless aircraft have near zero pitching moments.
The design coefficient of lift should be the coefficient of lift at cruise speed so that trim drag is minimized. Some amount of up trim is expected to be necessary for thermalling. The zero lift angles of the root and tip airfoils influence the geometric wing twist required. Calculation of required wing twist using the above formulae can be easily accomplished on a hand-held calculator. The main formula shows that a total of -8.6 degrees is required for this planform.