Inside Unmanned Systems

OCT-NOV 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 POWER SOURCES 46  October/November 2018 unmanned systems inside "By combining solar photovoltaics with lighter-than-air lifting, we are creating a pathway for mankind and our robots to achieve aerial perma- nence," said Jonathan Nutzati, founder and CEO of Mothership. Mothership's proof-of-concept un- manned aircraft, the Scout, is a 7-me- ter-long airship filled with roughly 300 cubic feet of helium and powered by 400 watts of solar power cells. Developed within three months of the company's inception, the Scout has a top speed of 20 knots, a cruise speed of 12 knots, and is rated to carry 5 kilograms of payload. Each airship has enough energy to f ly for the sunlit portion of the day plus an extra 90 minutes using its reserve lithium-polymer batteries. They also can be configured to f ly at night by re- placing their solar power modules with battery modules, which currently can give them up to three hours of f light time in the dark, Nutzati said. The company uses monocrystal- line silicon-based photovoltaic cells for solar power. Although thin-film photovoltaic cells that companies such as Lockheed Martin and others use in their solar-powered high-altitude long-endurance aircraf t are eight times lighter than the ones Mothership is using, "their solar cells cost about $40,000 for 400 watts while our so- Photo courtesy of Impossible Aerospace. lution costs about $200, not includ- ing labor, and the amount of watts per square meter is exactly the same," Nutzati said. Unmanned airships not only have great endurance, but Nutzati noted they are extremely safe. "Not only are there no humans onboard to get in- jured in the event of a crash, but also the airship is unable to free-fall, act- ing as a parachute for itself," he said. "Impacts are soft and cushioned and the internal gas is inert. It is the safest aircraft you can possibly crash." Nutzati, an aerospace engineer, founded Mothership in 2016. He became interested in the applications of solar power while working at Tesla Motors, when he converted a motorhome to run on solar in the company parking lot. "The CEO of Impossible Aerospace actually sold me that RV after he had lived in the Tesla parking lot—it's a small world," Nutzati recalled. "I was having eggs Benedict with a friend at a diner af- ter a test flight of his electric motorized hang glider, and I was dreaming about what to do with the surplus of energy I had because of solar panels. I was strug- gling to find places to park my solar- powered RV, and so I dreamed about what would happen if the RV could float above the parking lot—then others could not get me to move it." Firefi ghters are buying US-1 drones to identify hot spots. TERRASOAR AND SENTINEL Originally, the company envisioned offering the Scout for precision survey applications such as pipeline inspec- tions. However, "sadly, we learned in the field that the dynamics of an air- ship did not lend well to precision pho- togrammetry," Nutzati said. Whenever the wind blew on the Scout, it would rotate to align itself with the wind. "If you are trying to take a photo of specific GPS coordi- nates, you do not want your camera to move," Nutzati said. "We had invested a lot of resources into using our airship for this application, only to find that the pictures it took were all over the place and terrible. It was an early mo- ment of heartbreak for the company." The company went back to the drawing board. "We decided we would need a new type of hybrid airship nev- er seen before to tackle this problem," Nutzati said. Mothership named the new airship it designed the TerraSoar, after the prehistoric f lying reptiles known as pterosaurs, the first vertebrates to take to the air. Whereas the Scout places its motors about halfway down its body, the TerraSoar uses a series of trusses to keep its motors suspended near its nose. This shifts the center of mass, the center of thrust and the aerodynamic center of the aircraft in such a way that even if the wind causes its helium-filled envelope to swing around, the motors can stay in the same position. "Imagine a horse pulling a chariot; TerraSoar is like a drone pulling a blimp," Nutzati said. "It is a hybrid air- craft that, like a drone, can position it- self very accurately, but also has a very long f light time supplemented by he- lium lift and solar power. It is like a car

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