No matter how cool, versatile, or sophisticated drones might be, they all suffer from the same problem: Limited flight time. They can only do so much on a single charge; you either have to wait until the battery is full to fly again or buy spares. I'm talking about commercial drones, not military drones that can stay in the air for hours or days. However, researchers are already studying technology that would allow drones to stay in the air forever.
These problems would impact the drone's flight time. Mingjing Qi and his team developed a drone that fixes both of them. First, a circuit scales the voltage from solar panels to between 6,000 and 9,000 volts. Then, an electrostatic propulsion system powers a rotor that measures about 10cm with minimal heat loss. The motor has components arranged in a ring. These components have alternating electric charges, which create the power that spins the rotor blade.