At some point in your life, you’ve probably heard someone say something like “why don’t they just put a solar panel on top of an electric car to drive forever?” And, like us, you probably rolled your eyes, because that is a silly idea — you could never fit a car with solar panels large enough to provide enough juice. Except you can and people have. The Dawn by Prove Labs is one example. Solar Impulse was a similar concept in airplane form (though it had batteries). And Luke Maximo Bell just proved a drone can pull it off, too.
Conventional wisdom makes this feel farfetched, as drone motors require quite a lot of power to fly. To supply that power, you need to add on bigger solar panels. But the more solar panels you add, the more the drone weighs and the more power it consumes — necessitating the addition of even more solar panels. It is a vicious cycle.
But Bell didn’t let conventional wisdom stop him. His quadcopter drone flies entirely on the power coming directly from its solar panels. There isn’t any kind of battery or supercapacitor present, which would be a bit of a cheat.
Bell achieved that in the most sensible way: by reducing weight as much as possible. The drone itself is extremely light, with a frame that is essentially just a couple of carbon fiber rods held together with a 3D-printed bracket. The flight controller is a T-Motor H7 Mini that weighs just 6 grams, the ESCs (Electronic Speed Controllers) are on a 4-in-1 T-Motor F60A Mini weighing 14 grams, the video transmitter is a DJI O4 Air weighing about 9 grams with the camera and antenna, and the motors are T-Motor Antigravity MN4004 KV300 units that weigh about 52 grams each.
Those parts are all very lightweight, but the solar panels were the big problem. To get enough surface area to generate the required power, Bell could have easily ended up with solar panels weighing several pounds. That would have put him in the aforementioned vicious cycle. To get around that, he assembled super lightweight solar panels on a custom carbon fiber frame. That solar panel array is very fragile, but it is light enough for the job. The array contains 27 individual panels and produces 97 watts at 24 volts in bright sunlight.
Amazingly, that proved to be sufficient and the drone was able to fly with just the power from the sun gathered by the onboard solar panels in real-time. And, in theory, it could keep flying indefinitely when there is enough sunlight.
Next, Bell plans to add more solar panels and GPS-based autonomous navigation hardware in an effort to break the Guinness World Record for longest-flying drone.