Chinese scientists have developed a drone called CoulombFly, which is able to run on its own solar panel. The drone's design includes solar panels, a voltage converter, an electrostatic motor, and a single propeller. The development was reported by Ars Technica.
However, hovering in the air is all this drone can do so far. It has no onboard control equipment, meaning that CoulombFly is not capable of controlled flight.
Given the developers' efforts to make the drone as light as possible, many of its components look rather fragile. The drone weighs only 4 grams.
One of the key differences in this development is the use of an electrostatic motor instead of the electromagnetic motor used in most drones. Electromagnetic motors have a large number of metal coils in their design, which significantly increase the weight.
The motor developed by the researchers is quite large compared to the size of the drone. It consists of an inner ring of fixed charged plates called a stator. These plates consist of a thin carbon plate covered with aluminum foil. During operation, adjacent plates have opposite charges. The stator is surrounded by a ring of 64 rotating plates.
The motor starts running when the plates in the outer ring are charged. Since one of the adjacent plates on the stator is guaranteed to have an opposite charge, the thrust will start rotating the rotating ring.
When the stator and rotor plates reach the closest point of convergence, the thin wires will come into contact, allowing charges to be transferred between them. The stator and rotor plates will receive the same charge and begin to repel.
Щоб протестувати свою систему, дослідники просто відчинили вікно в сонячний день у Пекіні. Дрон злетів та знаходився в повітрі понад годину, аж поки дослідники не забрали його назад. Для того, щоб залишатися в повітрі, вся система потребувала трохи більше піввата енергії.
Дослідники наводять довгий список речей, які вони могли б зробити для оптимізації конструкції, включаючи збільшення крутного моменту двигуна і підйомної сили пропелера, розміщення сонячних елементів на структурних компонентах і підвищення ефективності перетворювача напруги.
The researchers are now working on a miniature version of the device that is only 8 millimeters tall and weighs 9 milligrams. This version is capable of generating milliwatts of power that spins a propeller at more than 15,000 revolutions per minute.
Again, all of this is done without any onboard control circuitry or equipment needed to move the vehicle.