From Tube and Wing to Flying Wing

Selecting the airplane's general arrangement is a complex issue. This chapter deals with finding the optimum allocation of a given useful load volume inside a generic combination of a fuselage and a wing. Although an all-wing airplane is often considered the ultimate ideal, it is not necessarily better than the traditional body and wing concept. For instance, a preferred integrated configuration may combine a body and a wing each containing about 50% of the total volume required for payload and fuel. For a very large airliner, such an integrated concept may be superior to the traditional tube and wing. Results of an analytical approach are illustrated with a parametric survey for a transport aircraft with 2,000 cubic meter useful volume. This leads to the conclusion that all-wing aircraft achieve a high lift to drag ratio only under flight conditions that may not be favorable to a practical design. The analysis is applied to several integrated concepts studied by airplane manufacturers and research institutions. Configurations compared are a discrete wing and body, an all-wing airplane, a blended wing and body, a hybrid flying wing and a very large span loader. The chapter concludes with a discussion of the feasibility of flying wing design.