Unmanned Systems Technology 008 | Alti Transition UAS | Ground control systems | Xponential 2016 report | Insitu Orbital N20 | UAVs | Solar power | Oceanology International 2016 report

78 W hen carefully designed, solar electrically powered fixed-wing UAVs have a far greater flight endurance than purely electrically or even gasoline-powered aerial vehicles, and that begins to open doors both for UAV projects and the solar technology itself. Given the right environmental conditions, a solar-powered UAV stores excess solar energy gathered during the day in its batteries, which can then power the aircraft through the night and, potentially, subsequent day-night cycles. Long-endurance capability, especially in the extreme cases of continuous multi- day flight or even perpetual endurance, is particularly interesting for applications such as large-scale mapping, observation or telecoms relay. It can also be applied to search and rescue (SAR) missions, industrial or agricultural inspection, meteorological surveys, border patrol and more. Recently, interest in using large-scale (wingspan greater than 20 m), solar- powered high-altitude long-endurance UAVs as atmospheric satellites, and stationary/loitering platforms for telecoms relay, has developed. Notable examples here are the Aquilla and Zephyr craft, the latter of which has already demonstrated a continuous flight of 14 days. By contrast, smaller scale solar-powered UAVs are designed mostly for low- altitude, long-endurance applications. Although faced with more challenging meteorological phenomena in the lower atmosphere – clouds, rain, wind gusts or thermals – low-altitude UAVs can deliver higher resolution imaging thanks to reduced cloud obstruction, are lower in complexity and cost and are simpler to handle. These traits are highly beneficial for first-aid SAR scenarios as well as other inspection tasks. Fly longer and carry more – that’s what every UAV customer wants. As the uses for small, electric, commercial UAVs expand, the demand for them to stay aloft longer and carry heavier, more powerful payloads increases constantly. Right now though there are few alternatives for extending electric UAV endurance other than adding batteries, improving the effciency of the electrical systems or redesigning the UAV to be more aerodynamic. The frst option tends to add signifcant weight and takes up a lot June/July 2016 | Unmanned Systems Technology A solar-powered version of the Puma AE (All Environment), a UAV designed for land-based and maritime operations (Courtesy of Alta Devices)