A Direct Synthesis Method for the Conceptual Design of Transport Aircraft

The problem of synthesizing a transport aircraft at the conceptual design level is considered. A direct sizing algorithm that does not require iteration is developed. Such direct synthesis methods can be used as important building blocks in an aircraft optimization process. New statistical equations based on current aircraft are derived for approximating the widths and lengths of the cabin and fuselage. A more accurate static thrust over gross weight, which is based on the equations of motion specified by the FAR part 25 climb requirements, is presented. A cruise at constant altitude with optional step-climb is taken into account. The operating empty weight is directly estimated using a statistical correlation for current twin turbofan transport aircraft. The analyses of the layout, performance, and weights are finally assembled in a direct sequential algorithm. This design method is tested on an existing transport aircraft and the results agreed well with the actual design