AINEWS
A 300-gram flapping drone dives and takes off again, with a water-shedding wing
An MIT team, publishing in Science this week, built a sub 300 gram amphibious drone whose hydrophobic wing membranes let the same flapping wings swim and fly.
An MIT team, publishing in Science this week, built a sub 300 gram amphibious drone whose hydrophobic wing membranes let the same flapping wings swim and fly.
The MIT engineers behind the flapping robot that swims and flies describe it as a flapping-wing aerial-aquatic vehicle, or FAAV. The physics problem they were solving is that the same wing has to push water hard enough to swim and air thick enough to fly, and most designs sacrifice one medium for the other. Their answer, published this week in Science and described by MIT News, is a sub-300-gram amphibious robot whose thin, flexible wings are coated with hydrophobic nanoparticles. That coating is what lets the same flapping wing shed water adhesion quickly enough to return to the air after every dive.
The work was led by Raphael Zufferey, an assistant professor of mechanical engineering at MIT who heads the AURA Lab, with co-authors from EPFL and Northwest Indian College in Bellingham, Washington. The airframe pairs a central fuselage with two flapping wings and a steerable tail; the team built the wings and tail as swappable modules and tuned the airframe around the geometry that performed best in testing, which landed at a medium wingspan of around 80 centimeters. They ran field trials on Lake Geneva and controlled-tank tests, with swim speed of about 1 meter per second at a roughly 5 hertz wingbeat, flight speed near 6 meters per second, and a 70-degree launch pitch off the water surface.
The wings are thin membranes coated with hydrophobic nanoparticles, a treatment that keeps water from spreading across the surface the way it would on a bare foil. The gap between the two media shows up at every stroke. On the downstroke into the surface the wing still has to displace water; on the upstroke out of it, the coating is the difference between a wet wing dragging back into the air and clearing fast enough to push air again. The wings do the swimming, no feet or paddles involved; the coating sheds water fast enough to push air on the upstroke.
Loons, gulls, puffins, and petrels already solve the air-to-water transition biologically. The drone borrows their geometry and uses surface chemistry in place of the wing folding and sweeping that real birds use. MIT News describes the work as much about understanding how diving birds adapt flight mechanics between media as about the platform itself. The applied case the team names is monitoring: launch from a boat or from shore, fly to an area of interest, dive for measurements or samples, then fly back to deliver the data. Because the same drone takes off and recovers in both media, consistent launch geometry matters in both, which is why the team's reported 70-degree launch pitch is one of the headline performance numbers.
The public coverage of this work, including the NPR-syndicated pieces aired by WBAA and WAER, originates from a single MIT News release, and independent reporting on field performance has not yet appeared. The team's primary numbers, including swim speed, flight speed, optimal wing span, and launch pitch, come from that release and the Science paper it summarizes. The release does not address how the hydrophobic coating ages under repeated saltwater cycles, and a fleet of these platforms doing routine coastal monitoring remains a stated target rather than a deployed system. If a second lab rebuilt this drone from the published paper, the wing geometry and the hydrophobic surface chemistry it describes are both reproducible in principle, but no such replication has been published.
Whether the design crosses from a Science demonstration to routine coastal missions will come down to how the wings age under repeated saltwater dives and how consistently the 70-degree water-to-air launch holds past the first few flights. That is the next round of Lake Geneva trials, and where the vehicle either becomes a new monitoring platform or stays a one-off.