DIY creators often push boundaries with clever hacks and unusual builds, but every now and then someone attempts something that feels almost impossible. A drone that flies without a battery certainly fits that category — yet that’s exactly what a popular DIY engineer has just pulled off.
YouTuber and engineer Luke Maximo Bell has revealed his latest project: a drone powered entirely by solar energy, with no battery, no capacitor, and no backup storage of any kind. The feat comes just days after he and his father Mike Bell attempted to reclaim the Guinness World Record for the fastest drone with their 585 km/h Peregreen 3. This week, Luke shifted gears completely — from extreme speed to extreme efficiency.
To get a battery-free drone in the air, Luke kept the build as light as possible. He used a carbon-fiber frame and propellers, both for strength and to shave unnecessary grams. The star of the build is a long, rigid slat made up of 27 miniature solar panels, wired directly into the drone’s power system. With no storage buffer, every bit of energy needed for lift had to come straight from the sun.
After several adjustments and short test hops, Luke managed to fly the drone around a field. It wasn’t perfect — the drone wobbled whenever a light breeze hit it, and power delivery fluctuated with changes in sunlight — but it flew, powered only by the solar panel array. That alone marks the project as a success.
Looking ahead, Luke says this is just the beginning. He plans to build a more polished version outfitted with additional solar panels, GPS, and autonomous flight software. His ultimate goal: to attempt another Guinness World Record, this time for the longest-flying drone powered purely by the sun.
It may be early days, but the first flight proves the concept works — and hints at what dedicated hobby engineers can achieve with creativity, patience, and a lot of sunlight.
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A prototype for Radical’s Evenstar stratospheric solar-powered airplane flies over its Oregon test range. (Radical Photo)
Seattle-based Radical says it has put a full-size prototype for a solar-powered drone through its first flight, marking one low-altitude step in the startup’s campaign to send robo-planes into the stratosphere for long-duration military and commercial missions.
“It’s a 120-foot-wingspan aircraft that only weighs 240 pounds,” Radical CEO James Thomas told GeekWire. “We’re talking about something that has a wingspan just a bit bigger than a Boeing 737, but it only weighs a little bit more than a person. So, it’s a pretty extreme piece of engineering, and we’re really proud of what our team has achieved so far.”
Last month’s flight test was conducted at the Tillamook UAS Test Range in Oregon, which is one of the sites designated by the Federal Aviation Administration for testing uncrewed aerial systems. Thomas declined to delve into the details about the flight’s duration or maximum altitude, other than to say that it was a low-altitude flight.
“We take off from the top of a car, and takeoff speeds are very low, so it flies just over 15 miles an hour on the ground or at low altitudes,” he said. (Thomas later added that the car was a Subaru, a choice he called “a Pacific Northwest move, I guess.”)
The prototype ran on battery power alone, but future flights will make use of solar arrays mounted on the plane’s wings to keep it in the air at altitudes as high as 65,000 feet for months at a time. For last month’s test, engineers added ballast to the prototype to match the weight of the solar panels and batteries required for stratospheric flight. Thomas said he expects high-altitude tests to begin next year.
Radical CEO James Thomas and teammates monitor the first flight test of a full-size Evenstar prototype. (Radical Photo)
The prototype is mounted on top of a car for takeoff. (Radical Photo)
Radical’s prototype rises from the top of its launch car. (Radical Photo)
The Evenstar prototype takes to the air. (Radical Photo)
The prototype has a wingspan of 120 feet. (Radical Photo)
The company’s manufacturing operation is based in Seattle’s Ballard neighborhood. There are currently six people on the team, plus a new hire, Thomas said. “We’re still lean,” he said. “To make this airplane work, it has to be really efficient, right? Really efficient electronics and aerodynamics. And you also need a really efficient team.”
Thomas said Radical has attracted interest from potential customers, but he shied away from discussing details. “We’re working with groups in the government and also commercially,” he said. “Obviously there are applications at the end of this that span everything from imagery through telecommunications and weather forecasting. There are a lot of people really interested in the technology, and the thing that stops us from serving those customers is not having a product up in the sky. So, that’s what we’re working through.”
Radical’s solar-powered airplane, known as Evenstar, is just one example of a class of aircraft known as high-altitude platform stations, or HAPS. Thomas and his teammates use a different term to refer to Evenstar. They call it a StratoSat, because it’s designed to take on many of the tasks typically assigned to satellites — but without the costs and the hassles associated with launching a spacecraft.
Potential applications include doing surveillance from a vantage point that’s difficult to attack, providing telecommunication links in areas where connectivity is constrained, monitoring weather patterns and conducting atmospheric research.
“We have customers who are really excited about the way that this can improve how we understand Earth’s weather systems and climate,” Thomas said. “That’s an application that we’re really excited to get into.”
Evenstar will carry payloads weighing up to about 33 pounds (15 kilograms). “That was based on analysis about major use cases,” Thomas explained. “That payload is enough to carry high-bandwidth, direct-to-device radio communications, or to carry ultra-high-resolution imaging equipment.”
Thomas said the outlook for high-flying solar planes has brightened in the past decade.
“The key supporting technologies have matured enormously,” he said. “Commercial battery energy density has doubled in that 10-year time period. Solar cells are 10 times cheaper than they were just 10 years ago. And then you have advances in compute and AI, and all of these things feed into the situation we have now, where it’s actually possible to make the models close — whereas when we run the 10-year-old numbers, we can’t close the models.”
The way Thomas sees it, the concept behind Radical isn’t all that radical anymore.
“Not only do our models say this will work, but we have flight data that agrees with our models, and says this is a technology that can serve its purpose and unlock the potential of persistent infrastructure in the sky,” he said. “I can see why other people are pursuing it. It’s not a new idea. It’s one that people have wanted to crack for a long time, and we’re at this critical inflection point where it’s finally possible.”
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