Watch: Student‑built 3D-printed drone flies, dives, and swims

A team of applied industrial electronics students at Aalborg University in Denmark has developed a 3D-printed hybrid drone capable of flying, diving underwater, maneuvering beneath the surface, and resurfacing rapidly in a seamless sequence. Central to this capability is a variable pitch propeller system that adjusts blade angles for optimal performance in air and water—higher pitch for flight to generate airflow, and lower pitch underwater to reduce drag and improve efficiency. These propellers also provide negative thrust for precise underwater control. The drone’s smooth transitions between air and water, captured in continuous video footage, highlight the effectiveness of this straightforward propeller-based approach. The prototype was designed, fabricated using 3D printing and CNC machining, and programmed by the students over two academic semesters under the guidance of associate professor Petar Durdevic. While hybrid drones are not entirely new, this project stands out for its polished demonstration of rapid, repeatable air-to-water transitions without complex mechanical reconfigurations. The students envision applications in military