For Benjamin David, a perfect day combines his favorite forces of nature: wind, water, sun and sky, all working together with the best of human innovation to power a sleek racing sailboat over the ocean at top speed.
David, an avid water sport enthusiast, frequently windsurfed the waters off Guérande, in Loire-Atlantique on France’s scenic Atlantic coast, during his aerospace engineering studies at nearby Polytech Nantes. “Water sports provide absolutely incredible sensations, but I also love sailing because boats are concentrates of technology and use renewable energy,” he said.
Flight, too, drives David’s imagination, and his dreams of creating a flying machine powered by those same forces of nature are coming true in Guérande. After working on satellite technology for the European Space Agency and for Airbus in England and Germany, he has returned to Guérande to found a long-dreamed startup. Called XSun – X for technology, Sun for solar power – the company focuses on building, testing and proving the capabilities of solar powered, long-range drones for surveys, research and environmental-protection missions.
“The points of convergence between aeronautics and sailing are obvious,” David said. “The best-performing sailboats, including monohulls, now glide over the water using their daggerboard foils. They are gradually becoming flying machines, with control systems directly derived from aerospace know-how. These sailboats that fly on the water use a renewable energy: wind. At XSun, we use another renewable energy – the sun – to make our machines fly. I see a convergence here that really thrills me.”
ENVIRONMENTAL AND SAFETY MISSIONS
Besides being a beautiful place to live, Guérande provides the perfect environment in which to launch a high-tech startup focused on solar flight. In addition to its open coastline and plentiful watersports, it offers an uncluttered landscape perfect for testing long-distance drones and a rich heritage in aerospace and composite materials, with tech-oriented universities and innovation centers clustered around the region’s shipyards and its major Airbus facility.
The distance covered by an XSun drone in a 12-hour, autonomous endurance test conducted in mid-2020 with zero carbon emissions.
Unlike satellites or their near-Earth counterparts – helicopters and airplanes – drones are more economical to produce and operate. XSun’s solar-powered, remotely operated drones also offer operators longer ranges, increased autonomy and improved sustainability, with none of the CO2 outputs produced by other flying machines.
Returning here to launch XSun delivers on a concept that has been simmering in the back of David’s brain since he worked on the Galileo satellite array for the European Space Agency. The array is powered by solar energy and remotely controlled from the ground; those same two factors are true of XSun drones. “Just like a satellite constellation,” he said
Among the long-range tasks XSun drones might undertake: oil and gas pipeline surveillance in search of small leaks that need repair, or scans of railway lines to identify obstacles or damaged tracks.
“XSun flying machines are a kind of human eye that is always open, permanently in flight and monitoring the Earth to better protect it.”Benjamin David
“We are also thinking about the observation and monitoring of wildlife and plants in forest areas,” David said. “In the shipping world, the surveillance of vast stretches for military or environmental purposes, and the detection of oil slicks and illegal dumping, are other possible uses.”
Automation is important, he said, so that the drone can do most of its work without human supervision. “Our aim is to adapt the automation of space satellites into the drone sector, designing machines that can carry out programmed missions independently.” The only time human supervision might be required: during takeoffs and landings, to avoid tall buildings or other drones.
A WELL-REFINED DESIGN
The XSun team maximized the drone’s range using an ingenious, two-wing design that hearkens back to early airplane designs, allowing for twice as many solar panels as would be possible on a single wing. The two wings are arranged one behind the other, allowing all of the solar panels to soak up the sun at all times. “The design also has a number of advantages in terms of its aerodynamic performance, which the aeronautic industry has ignored, as the single wing has dominated until now,” David said.
To improve on its original SolarXOne design, the XSun team used digital 3D simulations to refine the drone’s surface quality and aerodynamics. Collaborating via a shared innovation platform on the cloud also allowed the team members to iterate their ideas repeatedly while maintaining a clear configuration of all subsystems.
“The cloud offers us remote access to powerful design and simulation tools,” David said. “We can work on the move, remotely or at a partner site, which ties in well with our central idea: Our machines can operate easily anywhere, so it’s only natural that the same applies to our working methods.”
The end result: In an endurance test conducted in mid-2020, the company’s newest XSun design achieved a 12-hour, autonomous flight – with a payload – that covered a distance of 600 kilometers (373 miles) with zero carbon emissions.
LOW WEIGHT FOR LONG RANGES
The drone weighs less than 25 kilograms (about 55 pounds), has a wingspan of more than 4.5 meters (nearly 15 feet), and a payload capacity of 7 kilograms (about 15 pounds) for flights lasting at least 12 hours. Composite materials are used throughout to minimize weight, and the team has hopes of achieving 20-hour flights.
The drone weighs less than 25 kilograms (about 55 pounds), has a wingspan of more than 4.5 meters (nearly 15 feet), and a payload capacity of 7 kilograms (about 15 pounds).
The low weight means that XSun’s drones qualify for use in all countries worldwide. Low weight also translates into the ability to fly longer distances; the greater the drone’s range, the bigger the challenges it can address. Which also drives David in his quest.
“It’s an incredibly exciting project that throws challenges at us every day, whether technical, regulatory or financial,” he said. “We are at the dawn of a new age, one in which autonomous machines are proliferating on the ground, in the air and in the water, with a clear interconnections between them. If XSun can get the message across that it is possible to use renewable energy right now, and that it is not something for the distant future but for the present, we can consider our mission accomplished.”
XSun is a member of the 3DEXPERIENCE Lab, an accelerator that facilitates and nurtures disruptive product innovation.
Watch a video to hear Benjamin David talk about his passion for finding innovative solutions to reduce carbon emissions.