Global Journal of Researches in Engineering, A: Mechanical & Mechanics, Volume 22 Issue 1

An Analysis of Aerodynamic Design Issues of Box Wing Aircraft Paul Olugbeji Jemitola α & Paulinus Peter Okonkwo σ Abstract- The potentials of the Joined/Box-Wing Aircraft as an environmentally friendly airliner that is capable of meeting current and future emission thresholds led to the investigation of this concept. This study reviews the evolution and current trends in the aerodynamics design of the Box-Wing aircraft with specific emphasis on Box-Wing theory, airfoil characteristics and aerodynamic issues of the Box-wing aircraft. The study was undertaken to highlight the distinct features of the Box-Wing configuration which makes it very attractive as a future airliner. The study reveals that the Box Wing Aircraft possesses a significant aerodynamic advantage over conventional aircraft. The Box-Wing Aircraft configuration is also a less radical departure from the conventional concept. It thus could be developed with existing tried and tested aircraft design technologies, methodologies and processes. Keywords: box-wing, biplane, lift distribution, best wing system, aerodynamic efficiency, downwash. I. I ntroduction he need to reduce the negative impact of airline operations on the environment led to renewed interests in unconventional designs such as the Blended Wing Body and Joined/Box-wing concepts. The Joined/Box-wing aircraft configuration attracted the attention of researchers due to its claimed merits of reduced structural weight and low induced drag (1). The potentials for improved fuel efficiency and reduced direct operating costs were other reasons that motivated researchers to investigate the aerodynamic concepts of the Box-Wing configuration. Though the Blended Wing concept claims to have some of the preceding advantages, the Joined/Box-Wing aircraft configuration offers lower design risk than the Blended Wing Body concept because it is not a completely radical departure from conventional aircraft configuration. These considerations influenced the National Aeronautics and Space Administration to award a contract to Lockheed Martin to investigate the Box-Wing aircraft configuration. The Contract required Lockheed Martin to examine the Box Wing claims of being able to reduce fuel burn by 40%, nitrous oxide emissions by 75% and minimize noise by 42Db (2). Wolkovitch (1) carried out extensive research on the Box-Wing aircraft configuration following Munk’s (2) and Prandtl’s (3) earlier work. Wolkovitch (1) viewed the Joined/Box-Wing aircraft configuration as a highly integrated concept that connects structural and aerodynamic properties in novel ways. This paper discusses the aerodynamic design issues of the Box- Wing aircraft with emphasis on the Box-Wing theory, aerofoil issues, aerodynamic considerations and optimization. It is essential to state that even though the terms Joined Wing and Box-Wing are used interchangeably in literature, the two concepts are not necessarily the same as could be seen from Figures 1 Author α σ : Air Force Institute of Technology, Nigerian Air Force, Kaduna-Nigeria. e-mails: pojemitola@yahoo.co.uk , paul.okonkwo@afit.edu.ng and 2. In Box-Wing aircraft, both wings form a closed non-planar design, produce equal amounts of lift, whereas for the classical Joined Wing aircraft, the fore wing produces approximately 80% of the total lift. This paper focuses on the novel aircraft concept that has fins T A Sketch of the Joined Wing Aircraft A Sketch of the Box Wing Aircraft Global Journal of Researches in Engineering (A ) Volume XxXII Issue I Version I 29 Year 2022 © 2022 Global Journals Figure 1: Figure 2: