THE DESIGN OF FAMILY OF TRANSPORT AIRPLANES WITH FUSELAGE COMMONALITIES

Abstract: Airplane manufacturers have opted to offer families of airplane designs to meet the ever-changing market demand. Product family concept has been a key aspect in manugacturer long-term strategy, which is to make agressive product differentiation using common product platforms and design commonalities. With this design concept, manufacturers can vary airplane configurations rapidly and adapt products to meet market demand in time with minimum development cost, by modifying designs currently on the market to obtain more operational flexibility, and performance capability in terms of flight range and seat capacity.This paper outlines a design study of a family of aircraft with similar fuselage. The commonality concept adopted in this study is similar to the approach in the Boeing 737 family. The designs maintain the same geometry of wing and tailplane, the same number and type of exist, and the same number and type of engines. Fuselage is extended by adding frames in front and aft of wing while maintaining the same cross section. The same number and type of exit doors are maintained for different number of seats across the variants.To obtain the right size of wing and tailplane geometry, the airplane designs are optimized for specific seating capacities under the same set of design constraints. The optimized designs are taken as baseline airplanes, from which a family of designs can be derived to meet different seat capacity requirements. Each baseline airplane would then have a certain wing and tail geometry. Derivative airplanea are modified from the baseline airplane in which fuselage frames are removed or inserted to obtain the final size of the fuselage. All derivative airplane modified from the same baseline will then have the same wing and tailplane geometry as the baseline airplane. Analysis would then be carried out on the flight performance, stability and control characteristics of the aircraft. Based on the analysis, design constraints and limitations can be applied to the geometry and design of the derivative airplane.