As reported by RoboHub: The AtlantikSolar Unmanned Aerial Vehicle took off on June 30th, 2015 at 11:14 o’clock to attempt the “holy grail” of solar-powered flight: the crossing of a full day-night cycle on solar power alone. More than 28 hours later, on July 1st at 15:35, the aircraft landed safely and with fully recharged batteries, thus showing AtlantikSolar’s long-endurance flight capability. This is of significant interest for large-scale disaster support, industrial inspection or meteorological observation missions, especially in the compact form of a hand-launchable 7kg UAV such as AtlantikSolar.
The project’s next goal is to extend the flight duration to more than 80 hours (3 days), in order to beat the old endurance record for solar-powered UAVs below 20kg (48h flight by the 13kg SoLong UAV in 2005) by more than a day. If it is able to achieve an 80-hour flight endurance, the 7kg AtlantikSolar would be the third-longest flying aircraft in the world, only behind Airbus Space’s 53kg Zephyr and the 2300kg Solar Impulse 2.
The flight was performed at the Rafz RC-model club airfield in excellent sun conditions. After take-off at 11:14, with batteries charged to 57%, the aircraft was quickly setup to follow an efficient and fully-autonomous loitering path, which allowed a completed battery-charge by 14:08 o’clock.
The midday and afternoon were characterized by strong thermal up- and downdrafts, but enough power was generated by the solar panels to keep the batteries full. Their discharge started only when the sun slowly went down at around 19:30.
The night flight provided calm conditions, with the autopilot keeping the aircraft stable despite horizontal winds of up to 5m/s, and the safety pilots keeping a good eye on the aircraft using its position indicator lights. Flying at an average airspeed of 8.4m/s (the point of minimum sink rate) and an average power consumption of 43W during the night, the aircraft received first sun at around 5:50 o’clock, and maintained a minimum charge of around 35% until the solar modules regenerated enough power to stay airborne.
After 24 hours of continuous flight, the aircraft had recharged its batteries to 84%, a significantly higher state-of-charge than the day before. The batteries were in fact fully charged by 12:43 o’clock – one hour and twenty-five minutes earlier than the day before.
AtlantikSolar landed safely at 15:35, thereby setting a new Swiss endurance record for unmanned solar-powered flight, and improving upon the previous internal record (ASL’sSky Sailor) by a over an hour.
We’d like to thank everybody who made this flight possible — including all project partners and collaborators, the Rafz Model airfield club, and our safety pilots — for working so hard and making this big step in the project possible.
The AtlantikSolar project was developed at the Autonomous Systems Lab at ETH Zurich.
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