Solar Impulse 2, a single-seat monoplane powered by photovoltaic cells made it around the world, 26,000 miles, in 2015 without fuel. The long-range, experimental solar-powered aircraft left Abu Dhabi in the United Arab Emirates in August 2015 and returned—with a months-long stop in Hawaii to repair thermal damage—in July 2016.
The plane made the first circumnavigation of Earth by a piloted, fixed-wing aircraft using only solar power.
Bertrand Piccard, Solar Impulse chief executive officer, and co-founder André Borscherg chose Dassault Systèmes 3DExperience platform to design their plane.
“Everything is new with this airplane,” Borschberg said of Solar Impulse 2. “Normally when building a new airplane you use existing engines. If you want to test new engines you use existing airplanes,” he added. “But here the propulsion is new. The energy is new. The structure is new. It’s all so incredibly complex. Our technical advisor told us we were crazy to rely only on 3D digital software instead of building a physical mock up. But we had confidence in these technologies.”
Engineers also used the 3DExperience platform’s design and simulation applications develop the plane without using physical prototypes, which are too expensive and take too long to build, Borschberg said.
“We began by designing the individual parts and then assembling them using the 3DExperience platform’s assembly features before proceeding with manufacture,” said Jonas Schär, head of the design team.
The engineers also used the platform’s composites and manufacturing capabilities, including defining and optimizing the plies of the plane’s carbon-fiber structure and machining the tools used to produce many of the carbon parts in-house, he added.
Pilot safety and comfort are primary concerns as the pilots will be flying five days and nights at a stretch in a plane capable of climbing to 8,000 meters, where hypoxia could prove fatal. The CAD tool helped design the cockpit with ergonomic considerations in mind, Schär said.
“The pilots trained long hours inside the cockpit sitting, moving, doing simple exercises, eating and sleeping. This enabled us to make the necessary adjustments so that André and Bertrand would be as safe and comfortable as possible,” he added.
Another challenge is to keep the plane airborne for five days and nights at a stretch.
“Its only source of energy is the sun, so to stay in the air, the plane must be able to run on very little energy and have a pretty long wingspan,” Borschberg said.
Though it’s as light as a car, weighing in at about 5,000 pounds, the Solar Impulse 2 has a 72-meter wingspan, longer than that of a Boeing 747.
Digital simulation helped engineers find the right span length to plane weight ratio for the long flight.
Working with a 3D model even helped engineers determine the space requirements for the cargo freighter used to transport the disassembled plane to its takeoff site.
Finally, the Solar Impulse team had to find the right components. These needed to be lighter and more resilient than those normally available on the market.
“When we started this project, we asked airplane manufacturers if they could build this plane and they simply said no, it’s not possible,” Borschberg said. “So we had to find new technologies and solutions, outside the world of aviation and then integrate them for the first time in an airplane. We had to design a completely revolutionary solar airplane from scratch.”
The CAD and simulation tools helped at every step of the way, Borschberg said, adding: “Without the 3DExperience platform, it simply would not have been possible.”