The C-Wing: A Novel Nonplanar Wing Configuration
From the survey of nonplanar wing geometries discussed previously, one is struck by the fact that one need not produce a closed system such as the box plane to achieve essentially all of the induced drag savings that this configuration offers. In particular, extending the upper part of the box only 10% of the span inward from the tip achieves a span efficiency within about 1% of the complete box. Thus, one could achieve the drag savings of the box plane without the Reynolds number and fuel volume penalties of the two-wing design. Furthermore, the small horizontal tip extensions have some interesting implications for airplane design. This section addresses the C-wing concept in a bit more detail and focusses on the application to a large commercial transport design.