The development and application of a multi-criteria optimization method to the design of a 20-seat regional jet airliner

The aircraft design process traditionally starts with a given set of top-level requirements. These requirements can be aircraft performance related such as the fuel consumption, cruise speed, or takeoff field length, etc., or aircraft geometry related such as the cabin height or cabin volume, etc.; This thesis proposes a new aircraft design process in which some of the top-level requirements are not explicitly specified. Instead, these previously specified parameters are now determined through the use of the Price-Per-Value-Factor (PPVF) index. This design process is well suited for design projects where general consensus of the top-level requirements does not exist. One example is the design of small commuter airliners.; The above mentioned value factor is comprised of productivity, cabin volume, cabin height, cabin pressurization, mission fuel consumption, and field length, each weighted to a different exponent. The relative magnitude and positive/negative signs of these exponents are in agreement with general experience. The value factors of the commuter aircraft are shown to have improved over a period of four decades. In addition, the purchase price is shown to vary linearly with the value factor.; The initial aircraft sizing process can be manpower intensive if the calculations are done manually. By incorporating automation into the process, the design cycle can be shortened considerably. The Fortran program functions and subroutines in this dissertation, in addition to the design and optimization methodologies described above, contribute to the reduction of manpower required for the initial sizing process.; By combining the new design process mentioned above and the PPVF as the objective function, an optimization study is conducted on the design of a 20-seat regional jet. Handbook methods for aircraft design are written into a Fortran code. A genetic algorithm is used as the optimization scheme. The result of the optimization shows that aircraft designed to this PPVF index can be competitive compared to existing turboprop commuter aircraft.; The process developed can be applied to other classes of aircraft with the designer modifying the cost function based upon the design goals.