Inside Unmanned Systems

FEB-MAR 2018

Inside Unmanned Systems provides actionable business intelligence to decision-makers and influencers operating within the global UAS community. Features include analysis of key technologies, policy/regulatory developments and new product design.

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AIR RESEARCH 22   February/March 2018 unmanned systems inside upward at several tens of meters per second, to heights of one to two kilometers or more. As a consequence, air must replace that mass of gas moving up; the air comes from the edges of the crater, creating a sucking force that goes into the bottom of the crater." "Eddies also may form at the edges and within gas plumes, creating very powerful downdrafts that result in the drone losing lift," Castro added. "We've observed our drones d roppi ng due t o t h i s phenomenon." Drones that are not so powerful can get lost due to the suction from down- drafts. "But strong drones— for example, the DJI Matrice 600—will power out of this," Castro said. A nother challenge Castro and his col- leagues have faced is highly corrosive gases that can belch from volcanoes, such as sulfu- ric acid. "This has resulted in the malfunction of the drone's main control board, which in turn couldn't be fixed," Castro said. "Luckily, DJI supported us by replacing our drone with a new one as an effort to continue our collaboration." All in all, the high winds, volcanic explo- sions, corrosive gases and ash their drones may face can compromise the longevity of the unmanned vehicles. This leads Castro and his colleagues to "make sure that we don't over- f ly our batteries—that is, return to home with about 20 percent remaining, since voltage can be rapidly drawn down when high winds come and max throttle is needed to ensure stable f light." Still, Castro found himself quite surprised "by how well DJI drones operate in the harsh conditions of a volcanic crater," Castro said. "Mount Etna is 3,200 meters tall, meaning the air is very thin there and that means less lift." The drones they use "f ly as if they are at sea level, albeit with shorter f light times." A UAS Designed for Volcanoes To overcome the many challenges volcanoes can present, Black Swift Technologies in Boulder, Colorado, is now developing an un- manned aerial system (UAS) designed to ana- lyze their emissions. "The system is designed to f ly through a volcanic plume and give back near-real-time data," Co-Founder, President and CEO Jack Elston said. Elston got his doctorate in aerospace en- gineering from the University of Colorado at Boulder, where he and his colleagues helped develop the first UAS to officially intercept a supercell thunderstorm, the kind of storm that produces tornadoes. They later applied for and won a Small Business Innovative Research grant from NASA to develop a unique UAS- based soil moisture sensor that got them started as a full-time company. This work led NASA to suggest that Black Swift build an air- craft designed to sample volcanic plumes. The Black Swift S2 UAS is a single-rotor fixed-wing craft with a 10-foot wingspan and a five pound payload for a total weight of 16 lbs. The drone is designed to be launched by catapult and land on its belly. "The top speed measured so far is 35 meters per second," Elston said. The S2's wings cannot be too big, because volcanoes are typically in remote areas, mak- ing it difficult to lug a large aircraft over large distances over rugged terrain. Still, its wings are large enough to help support higher-alti- tude f lights. "We're hoping, depending on the altitude, to f ly for one hour at 10,000 feet and two to two- and-a-half hours at lower altitudes," Elston said. "Our goal is for the final design to be able to f ly at 20,000 feet." (This assumes f light us- ing lithium-polymer batteries; gas engines can f ly three to four times longer, Elston said.) The S2 will be equipped with downward- facing regular and thermal cameras to cap- ture images, and a front-facing video camera to help the pilots guide the UAS in real time if "DRONES WILL PAVE THE WAY TO MAKE VOLCANOLOGY MUCH SAFER BECAUSE THEY ALLOW US TO COLLECT SAMPLES AND SEE THINGS WITH VIDEO AND THERMAL INFRARED CAMERAS IN VERY OUT-OF-THE-WAY PLACES." Jonathan Castro, professor of volcanology, University of Mainz in Germany

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