• Box Wing
• lifting arc wing
• non-planar wing systems
• sistemi alari non-planari
• teoria dell'arco portante

The aim of this paper is to evaluate the theoretical limit of the induced drag
in non-planar wing congurations optimally shaped. The reduction in the induced
drag, with the same value of the maximum dimensions and performances
required, entails a reduction in the consumption and relative costs: the knowledge
of the theoretical limit of the induced drag of a wing system, hence, is
crucial for assess if the choise of a non planar wing can be economically justied
or not. The adoption of a curvilinear wing system, composed by one or more
wings, can be justied not only for a reduction in the induced drag, but also for
reasons thatconcern the structure, the maneuverability, the aerodynamic, etc.
This discussion shows a method with which it is possible to evaluate the
extent of the decrease of the induced drag of a curvilinear wing system with
respect to a planar wing having the same wingspan.