A Systems MDO Approach for an Unmanned Aerial Vehicle

[Abstract] Aircraft preliminary structural multidisciplinary design and optimization (MDO) is typically based on the application of a deterministic approach of minimizing airframe weight due to applied air and ground loads in an aero-elastic optimization process. This paper presents research on augmenting the typical preliminary aero-elastic MDO with a more system wide optimization approach that adds drag minimization (due to scheduled flap deflection), and gust and maneuver load minimization to further reduce weight and load. The results of these optimizations are then combined with the use of a probabilistic analysis to assess the probability of structural failure per flight hour. Finally we then relate the probability of failure to the deterministic design factor of safety providing an assessment of added risk due to the reduction in weight corresponding to a lower deterministic factor of safety. The UMAC SensorCraft configuration used as a basis for the MDO study is a blended wing-body flying wing with integrated multi-functional UHF and X-Band radar antennas that is designed for a long endurance intelligence, surveillance, and reconnaissance (ISR) mission. The result of this more complex MDO has shown a clear gain in weight reduction from the synergy of combining these optimizations over a simpler, more typical preliminary MDO.