Preliminary Analysis of the Stability and Controllability of a Box-Wing Aircraft Configuration

Abstract

This paper presents a study on the aeromechanical characteristics of a box-wing aircraft configuration with a focus on stability, controllability, and the impact of aeromechanical constraints on the lifting system conceptual design. In the last decade, the box-wing concept has been the subject of several investigations in the aeronautical scientific community, as it has the potential to improve classic aerodynamic performance, aiming at reducing fuel consumption per unit of payload transported, and thus contributing to a reduction in aviation greenhouse emissions. This study characterises the aeromechanical features of a box-wing aircraft, with a specific focus on the correlations between the aeromechanical constraints and the (main) aircraft design parameters. The proposed approach provides specific insights into the aeromechanical characteristics of the box-wing concept, both in the longitudinal and lateral plane, which are useful to define some overall design criteria generally applicable when dealing with the conceptual design of such an unconventional aircraft configuration.

A Review of Novel and Non-Conventional Propulsion Integrations for Next-Generation Aircraft

“…The reference represents a qualitative starting point useful to initialise more detailed studies. Indeed, the box-wing configuration with turbofan installation in the aft fuselage could remove three of the major problems that limit the application of this installation on traditional tube-and-wing aircraft: (i) box-wing architecture attributes both the lifting and stability functions to the horizontal wings, and therefore the typical issues of T-tails [106], required in aft-fuselage engine installations for traditional aircraft, do not occur; (ii) the backward shift of the center of gravity due to the rearward positioning of the engines does not introduce any critical issue towards longitudinal stability, nor does it imply the need to introduce major modifications to the optimal design of the lifting system (these specific aspects of the box-wing configuration are fully described in [107]); and (iii) the over-constrained design of the box-wing lifting system [108] allows for the structural optimization and for the design-driven internal stress redistribution, possibly overcoming the load alleviation effect that allows for lighter wing structures for conventional underwing installation in cantilevered wings.…”

Preliminary Performance Analysis of Medium-Range Liquid Hydrogen-Powered Box-Wing Aircraft

“…The issue of balance and control of the center of gravity for longitudinal and lateral stability and control is of crucial importance in the design of an aircraft; hydrogen-filled tanks are heavy and are intended to be installed in the tip areas of the fuselage, with a significant impact on the position of the center of gravity; in addition, large masses of hydrogen are burnt, with a significant impact on the evolution of the longitudinal position of the center of gravity during the mission. These aeromechanical aspects may affect the actual feasibility of the analyzed solutions and must therefore be taken into account from the earliest design stages, as, for example, proposed in [76] for a box-wing fueled by conventional kerosene.…”