Benefits of dual wings over single wings for high-performance business airplanes

An investigation was performed to compare closely coupled dual-wing aircraft and swept-forward sweptrearward (SFSR), dual-wing aircraft to corresponding single-wing aircraft to judge the advantages offered by aircraft designed with multiple-wing systems. The optimum dual-wing geometry used on the dual-wing designs were determined in an analytical study which investigated the twoand three-dimensional aerodynamic behavior of a wide range of dual-wing configurations in order to find the wing geometry that created the minimum cruise drag. This analysis used a multielement inviscid vortex panel program coupled to a momentum integral boundary-layer analysis program to calculate the two-dimensional aerodynamic data, which was then used as input for a three-dimensional vortex-lattice program, which calculated the three-dimensional aerodynamic data. The low drag of the dual-wing configurations is due to a combination of twoand three-dimensional drag reductions, and the structural advantages of the two wings, which permitted higher aspect ratios for the two wing systems, because of the wing tip structural connections.