Engineers at MIT and the Swiss Federal Institute of Technology (EPFL) have developed a lightweight, flapping-wing aerial-aquatic vehicle (FAAV) capable of transitioning seamlessly between flight and underwater locomotion. Weighing less than 300 grams, the robot uses flexible carbon-fiber-reinforced membrane wings to navigate both air and water, according to lead researcher Raphael Zufferey. This design eliminates the need for heavy, multi-system drones, offering a scalable, open-source solution for marine monitoring and environmental research.
Engineering the Puffin-Inspired Flapping-Wing Robot
The primary challenge in amphibious robotics is the density difference between air and water, with water being roughly 1,000 times denser. Traditional drone designs often require two distinct propulsion systems—propellers for air and thrusters for water—which significantly increase weight and mechanical complexity. The MIT-led team bypassed this by modeling their robot after diving birds like the Atlantic puffin.
The FAAV relies on a single pair of wings to handle both environments. When the robot enters the water, the flexible membrane wings passively bend by up to 90 degrees. This deformation reduces the wing surface area, which mitigates the load on the motor and prevents mechanical failure under the high resistance of water. By avoiding rigid mechanical joints, the team kept the device’s total weight under 300 grams—roughly the mass of a large apple.
Did you know?
The researchers tested nearly 100 species of diving birds before finalizing the design. Their findings suggest that when birds tuck their wings underwater, they are primarily prioritizing speed over energy efficiency.
Overcoming the Surface Tension Barrier
Taking off from the water is notoriously difficult for small, winged machines due to surface tension. While many biological diving birds rely on powerful leg-paddling to generate the necessary speed for liftoff, the MIT prototype utilizes a mechanical shortcut. By programming the robot to pitch upward at a 70-degree angle, the wings generate sufficient thrust to breach the water’s surface.
To achieve this, the robot flaps its wings at a frequency of 10 times per second. This maneuver allows the craft to transition from a submerged state to flight in less than one second. This approach removes the need for landing gear or external propulsion, maintaining the weight-saving benefits of the design.
Simplifying Marine Exploration with Open-Source Design
The FAAV avoids the common drone pitfall of a heavy, air-tight shell. Instead, the engineers opted for an “open-body frame” that allows water to flood the interior. Each critical component—including the battery, motor, and sensors—is individually waterproofed using silicone. This design choice prevents the robot from suffering from buoyancy issues, allowing it to remain at a desired depth without wasting battery power to fight against rising or sinking forces.
The potential for this technology in oceanography is significant. A fleet of these robots could be deployed to remote reefs or whale pods to collect temperature readings or water samples. According to Zufferey, the current prototype can fly for approximately four miles or swim for over a mile on a single charge. To encourage widespread adoption, the researchers have made the designs open-source. Coastal communities and biologists can theoretically produce these units for roughly $300 in materials using a 3D printer.
Frequently Asked Questions
How does the robot stay waterproof without a sealed shell?
The robot uses an open-body frame where water flows freely through the structure. Each internal component, such as the battery and motor, is individually waterproofed with silicone rather than placing the entire system inside a single, heavy, air-tight box.
What is the maximum range of the current prototype?
On a single charge, the robot is capable of flying for about four miles or swimming for just over one mile.
Can this robot be built by non-engineers?
The research team has released the designs as open-source. With access to a 3D printer and approximately $300 worth of materials, the robots are designed to be accessible for marine biologists and local research groups.
Pro Tip:
If you are interested in building your own fleet, monitor the official EPFL and MIT research portals for the latest open-source hardware files and assembly documentation.
Have you seen advancements in bio-inspired robotics that could change how we monitor our oceans? Share your thoughts in the comments below or subscribe to our newsletter for more updates on emerging marine technology.