Testing of compact inflatable wings for small autonomous aircraft

A milestone in the development of deployable-wing technology was accomplished on July 3, 2007 with the first successful autonomous flight of the BIG BLUE inflatable-wing aircraft. Previous efforts included four high-altitude tests of inflatable wings and associated systems toward a future high altitude flight demonstration of inflatable-wing technology for Mars exploration. A parallel effort focused on CFD simulations for the inflatable-wing airfoil geometry in comparison to its ideal airfoil counterpart. A model of the aircraft with inflatable wings was developed for the autopilot including look-up tables for the engine and wings. The wing look-up table was developed based on the NACA 4318 profile, with 3d correction for sweep and aspect ratio. Weights and geometric measurements from the test aircraft were also required, along with flight control program adjustments to account for tail-only control (wing warping control was not available for this aircraft). Autopilot simulations, along with hardware-in-the-loop simulations, were conducted to adjust control gains for acceptable performance and stability. This paper is focused on aspects contributing to the success of the autonomous flight, including data from the flight itself.