Birds like puffins and gulls pull off a rare trick: flying through air, plunging into water, and launching back into the sky. Engineers at MIT and EPFL in Lausanne, Switzerland, have now built a robot that does the same. The flapping-wing aerial-aquatic vehicle, or FAAV, weighs less than 300 grams and is driven by a waterproof electric motor that pumps two flexible wings through a crankshaft. A motorized tail helps the robot change pitch to fly up or dive down.
The team, led by MIT mechanical engineering assistant professor Raphael Zufferey, tested the robot in a water tank and in Lake Geneva. They found that medium-size wings worked best—flexible enough to reduce flapping amplitude underwater, yet firm enough to keep the robot aloft in air. A relatively steep pitch of 70 degrees allowed it to make the transition from water to air, and the robot did not need feet to take off, unlike many diving birds that paddle with them. Its speed and flapping frequency were similar to those of real birds.
Zufferey hopes the robot will become a low-cost tool for ocean science and coastal communities. The vision is to launch it from shore or a boat, fly it to sites like icebergs, port facilities, or whale pods, dive for measurements or samples, and return with data—repeatedly, even hourly. The researchers are now working on wings that can turn as well as flap, and they plan to test the robot in choppy water and strong wind before deploying it for ocean research.