Essentials of Supersonic Commercial Aircraft Conceptual Design

10Oblique Wing Aircraft

One of the unspoken assumptions in aircraft design is that of bilateral or mirror symmetry. For slow flying vehicles this assumption appears to be fully justified. However, once the flight speed exceeds the velocity of sound, the laws of aerodynamics change in such a way as to make it seem inadvisable to arrange the components of an airplane side by side.

R.T. Jones [4]

Since the optimum optimum angle of sweep increases with the flight Mach number, a fixed‐wing aircraft has a considerable disadvantage. Hence, the swing wing concept features a wing with two panels having a variable sweep‐back angle, which increases with increasing Mach number. Several military supersonic aircraft with swing wings been operational and one of Boeing's early SST projects of the 1960s featured a swing wing (cf. Section 1.2).

An oblique wing – also known as a skewed or slewed wing – was originally proposed by E. de Marcay and E. Moonen in 1912, following the idea to vary the sweep of a wing for landing in side‐slip. It was further studied by R. Vogt in Germany for increasing the wing sweep as the speed of aircraft increases. In 1935 A. Busemann pointed out that an infinite swept wing in a supersonic flow is affected only by the flow component normal to the leading edge. In 1958 R.T. Jones noted that wave drag and vortex‐induced drag can be minimized by a variable‐sweep oblique wing with an elliptic lift distribution, as explained in Section 7.4.1, and he concluded that a ...