An integrated methodology for the design of an Unmanned Aerial Vehicle (UAV) derivative has been developed. The proposed methodology utilized the Multidisciplinary Design Optimization (MDO) for the derivative optimization and utilized flight simulation for virtual flight tests. Derivative design reduced the development time and the use of flight simulator allowed quick verification of the results. In this research, Found Aircraft Expedition E350 aircraft was selected
as the baseline for the UAV derivative. Empirical equations were used for the optimization process where the results were organized for easy transformation into a flight simulation model. An in house program was developed to convert raw simulation data for flight-data analysis. The optimization result yielded an improvement on the endurance of the aircraft. The flight simulation result for the original aircraft demonstrated agreement with the chosen aircraft. The application of the process demonstrated that using MDO and flight simulation was a viable method for developing a UAV derivative.