Study of wing camber for optimal flight efficiency of a long-endurance solar-powered unmanned aircraft

The UIUC Solar Flyer is in development with the aim of performing computationally-intensive on-board data processing. The ultimate goal is to shift the paradigm of solar powered flight. The traditional approach for small size UAVs, is to capture data on the aircraft, stream it to the ground through a high power data-link, process it remotely, and then relay commands back to the aircraft. However, given the finite energy resources found onboard an aircraft, the traditional design greatly limits endurance since significant power is spent in transmission instead of being allocated for flight. The UIUC Solar Flyer is being developed to carry a high performance embedded computer system to minimize the need for data transmission. The process of reducing aircraft power consumption allows for decreasing aircraft size, prolonging flight time, and ultimately minimizing cost, therefore supporting widespread adoption of UAVs.The integration of a high-performance computation board however require a non-negligible amount of power and therefore power must be reduced elsewhere. A systemic search to reduce power consumption was undertaken. Initially, effort was directed towards reducing the power required by the propulsion system. However, one element has yet to be explored in optimizing the efficiency of the airframe using precise control of the wing camber, which will be the focus of this paper. The aircraft ailerons and flaps can be actuated precisely in order to effectively modify the airfoil shape of the majority of the wing. This paper provides a description of the UIUC Solar Flyer aircraft as well as an explanation of the control surface actuation that is the subject of this research. Then, preliminary work and methodology is presented. Finally, results from flight testing and simulation are provided.