Preliminary aerodynamic investigation of box-wing
configurations using low fidelity codes

Abstract: This work outlines the different aerodynamic aspects of box-wing design
i.e. an unconventional aircraft design configuration exhibiting the
capability of reducing induced drag. Being a nonplanar concept, the basic
aerodynamic features differ from conventional designs.
To understand these features and their influence on box-wing aerodynamics,
parameter variations have been conducted while Munk’s theorem is validated
for stagger and sweep. In this process, several important aspects of box-
wing are highlighted. An optimization algorithm has been implemented by
considering all the design variables collectively to find the global
maximum for the box-wing design. All these investigations laid down the
important aerodynamic features of box-wing and also proved a method for
estimating the reduction in induced drag.
To conduct these investigations, vortex lattice methods (VLM) are used. Non
planar systems have certain limitations for best operations which provide
maximum induced drag reduction. These limitations are examined and applied
in the form of constant and specified lift distributions in the analysis.
Furthermore, it is concluded that vortex lattice methods do capture the
reduction in induced drag correctly if the limitations of span loading are
maintained during the analysis.
Based on previous results obtained, Euler inviscid analysis for a selected
box-wing and a reference wing are carried out. The results of Euler
inviscid analysis show good agreement with the results achieved by vortex
lattice method in drag reduction. Therefore, VLM methods are capable of
analyzing box-wing (and multi planar systems) to a good accuracy. At the
same time, transonic airfoil selection is identified as one of the key
factors in designing a commercial box-wing aircraft.
This study is closed up by discussing different potential advantages for
the aviation industry and discusses if a box-wing commercial aircraft
should be made reality.
On the whole, this work looks into a possible way of investigating
futuristic multi planar aircraft configurations by using low fidelity
aerodynamic codes.