Gradient-Based Optimization of Solar-Regenerative High-Altitude Long-Endurance Aircraft

Abstract

This paper uses gradient-based optimization to minimize the mass of a solar-regenerative high-altitude long-endurance flying-wing aircraft while accounting for nonlinear aeroelastic effects. The aircraft is designed to fly year round at 35° latitude at 18 km above sea level and subjected to energy capture, energy storage, material failure, local buckling, stall, longitudinal stability, and coupled flight and aeroelastic stability constraints. The optimized aircraft has an aspect ratio of 54.52, a surface area of , a mass of 349.5 kg; exhibits little aeroelastic deflection at the design airspeed; and is primarily stability constrained. Several parameter sweeps are performed to determine sensitivity to altitude, latitude, battery specific energy, solar efficiency, avionics and payload power requirements, and minimum design velocity.