Abstract

High Altitude Long Endurance Multidisciplinary Design Optimization of Empennage-Stabilized and Flying-Wing Aircraft

Recent progress in battery technology, solar cell efficiency, and material science have all dramatically improved the feasibility of solar-powered high altitude flight. However, the large number of competing design drivers and couplings makes for a difficult design exercise. For instance, low structural mass fraction allows for high battery mass but typically means lowered  structural mode frequencies and potentially unstable aeroelastic modes creeping in the operating envelope. A Multi-Disciplinary Optimization (MDO) framework was therefore developed to fully exploit potential couplings and avoid design pitfalls as early as possible. In order to rapidly and accurately explore the design space, physics-based first principles are emphasized and reliance on historical empirical data is minimized.  Low Reynolds number aerodynamics, composite structures, aeroelastic modes, are all captured and corresponding models are validated against higher-fidelity analysis tools. The resulting framework is applied on empennage-stabilized as well as flying wing configurations.