Propulsion System Testing for a Long-Endurance Solar-Powered Unmanned Aircraft

Abstract

The increase in popularity of unmanned aerial vehicles (UAVs) has been driven by their use in civilian, education, government, and military applications. However, limited on-board energy storage significantly limits flight time and ultimately usability. The propulsion system plays a critical part in the overall energy consumption of the UAV; therefore, it is necessary to determine the most optimal combination of possible propulsion system components for a given mission profile, i.e. propellers, motors, and electronic speed controllers (ESC). Hundreds of options are available for the different components with little performance specifications available for most of them. In order to determine the performance specifications, a propulsion system testing apparatus has been developed and validated. This testing apparatus was designed to measure the performance and efficiency parameters of electric propulsion system components (propellers, motors, and ESC) while maintaining similar air flow characteristics in either a wind tunnel or on a moving automotive platform. Validation tests of four propellers are presented. All four propellers were tested under static conditions, and two were tested under advancing flow conditions where the testing apparatus was used on an automotive platform. The results show that this propulsion testing system provides for holistic testing of all possible compatible electric propulsion system components in a flight-like environment. Data from this system will be used in a mission-based propulsion system optimizer, currently in development, to select the best combination of components for a long-endurance solar-powered unmanned aircraft.

A Cyber-Physical Prototyping and Testing Framework to Enable the Rapid Development of UAVs

“…Once physical development occurs, the next step is to perform Measurement(s) of what has been constructed. If, say, only the propulsion system has been developed, one can test its performance [56]. Alternately, if an entire aircraft has been built/modified, one may wish to measure its Moment of Inertia [57].…”

“…Beyond the scope of the aforementioned review, commercial (closed-design) airframes such as the UAV Factory Penguin airframe have been used as a basis by over 20 research institutions since 2010 with similarly limited parameters available [82]. Therefore, to accurately create or update an aircraft model, several measurement methods were either developed or adapted to support the UAV Development Framework, including 3D aircraft scanning, moment of inertia measurement, and propeller testing [56]. The following two sub-sections describe these novel methodologies that allow a user to accurately measure aircraft geometry and moment of inertia.…”