This 3D‑printed drone defies gravity and buoyancy at the same time!
A team of applied industrial electronics students at Aalborg University in Denmark has built and tested a 3D-printed hybrid drone that can take off, plunge underwater, maneuver beneath the surface and then rocket back into the air, all in one seamless sequence documented in a recently shared two and a half minute video.
The prototype, created for a bachelor’s thesis, demonstrates rapid air-to-water transitions that even surprised its makers.
Variable-pitch propellers make the switch possible
Central to the drone’s performance is a variable pitch propeller system whose blades rotate to different angles for air and water. The pitch is higher in flight to generate airflow and lower in water to cut drag and boost efficiency. The propellers can also deliver negative thrust for tighter underwater maneuvering, the students explained.
“The development of an aerial underwater drone marks a major step forward in robotics, showing that a single vehicle can operate effectively in both air and water thanks to the use of variable pitch propellers,” the students told Live Science in a joint email.
In test footage, the craft lifts off beside a large pool, dives, swims briefly, then erupts vertically back into the air, repeating the routine multiple times from varied camera angles. The researchers credit the propeller system for enabling that quick, repeatable transition.
Built over two semesters with in-house fabrication
The team modeled the vehicle, engineered the propeller mechanism, and fabricated components with a 3D printer and a computer numerical control machine. They then programmed the drone with custom software before moving into the trial phase. According to associate professor Petar Durdevic’s LinkedIn post, the full design-build-test cycle unfolded across two academic semesters. Durdevic leads the Offshore Drones and Robots research group at Aalborg University.
The students said the hybrid platform is just a single prototype for now, but the process proved that relatively accessible tools, additive manufacturing, CNC machining, and bespoke code can produce a complex dual-environment vehicle.
Not the first of its kind, but a polished demonstration
Hybrid drones are not entirely new. The Live Science report notes that Rutgers University researchers unveiled a similar air-water prototype in 2015, and Chinese scientists showed off a comparable transition maneuver in 2023.
What sets the Aalborg effort apart is the apparent smoothness of the switch, captured in one continuous shot, achieved with a straightforward propeller-based solution rather than more elaborate mechanical reconfigurations.
As for where such machines might go next, the students see broad utility. “A few of the applications are military, vessel inspections, marine exploration, search and rescue,” the students said. While the current craft remains a proof of concept, those use cases hint at why a low-cost, easily fabricated platform that can scout both above and below the surface could attract serious attention.
For now, the drone stands as a student-built demonstration that a single, compact vehicle can handle two radically different fluid environments with minimal interruption, taking off, diving, and taking off again, all on command.
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