UC Professor Sameh Eisa is using the flight mechanics of albatrosses to develop more energy-efficient, wind-adaptive drones through a DARPA-funded biomimicry project.
Birds like this black-browed albatross harness dynamic soaring to cross oceans without expending much energy. UC aerospace engineers are applying these principles to create more efficient drones. Image Credit: Michael Miller
Albatrosses, with wingspans stretching up to 11 feet, are known for their ability to glide across oceans for days without flapping. But it’s not just their size that makes them expert flyers—it’s how they skillfully interact with wind and gravity. University of Cincinnati aerospace engineering professor Sameh Eisa is studying this phenomenon to design smarter, more efficient drones.
With support from a $700,000 grant from the Defense Advanced Research Projects Agency (DARPA), Eisa and his collaborators are working on a project rooted in biomimicry—engineering inspired by nature. Their focus is replicating the albatross’s extraordinary energy-saving flight technique, dynamic soaring.
This technique allows the birds to extract energy from wind currents as they alternate between climbing into faster winds and gliding downward to gain speed. Eisa’s team has developed a novel approach that mirrors this behavior, calling it a “natural extremum-seeking system.” It’s based on how albatrosses—and drones modeled after them—identify the minimum and maximum values of pitch, yaw, roll, and airspeed to maintain optimal efficiency.
The birds’ process resembles sailing: They tack into the wind to climb and find stronger currents, then dive, converting that energy into speed. At the bottom of their arc—often skimming just above the ocean—they turn back into the wind and repeat the process, all without a single wingbeat.
They use it skillfully. That’s the only way they can sustain such long flights. GPS trackers show these birds can fly hundreds of miles a week. By the time they die, they’ve flown 20 times the distance between the Earth and the moon.
Sameh Eisa, Assistant Professor, University of Cincinnati
But their wings aren’t the only factor. “Albatrosses literally have a nose for wind,” added Eisa.
Albatrosses can sense subtle shifts in wind speed and direction through their highly sensitive nostrils, allowing them to fine-tune their movements and maximize efficiency on both the ascent and descent of each soaring cycle.
Eisa’s analysis shows that the energy albatrosses extract from the wind effectively offsets what is typically lost in flight. As a result, the total energy throughout each dynamic soaring cycle remains nearly constant.
Their deep connection to the wind has long been reflected in literature and folklore. Sailors once saw albatrosses as omens of favorable winds. In Samuel Taylor Coleridge’s The Rime of the Ancient Mariner, the death of an albatross brings windless seas and disaster, leaving an entire crew to die of thirst—save for the mariner, who must wear the bird’s body around his neck as a symbol of guilt.
To take this gift from nature and make it available to humanity is engineering at its best.
Assistant Professor Sameh Eisa,UC College of Engineering and Applied Science
Eisa, an applied mathematician, tested the birds’ flight behavior through simulations and found that even advanced computer models struggled to match their real-time precision.
“They are solving an optimization problem that is unbelievably complicated,” Eisa said. “They make it look natural and easy.”
The underlying algorithm for dynamic soaring is anything but simple.
“A few seconds of data can take 100 seconds to generate. And albatrosses are doing it in real time with a high level of accuracy,” he said. “It seems implausible.”
To replicate this level of efficiency in autonomous drones, Eisa explained, they would need to constantly measure changing wind speeds and directions, then calculate the ideal angle of attack and rolling action—making flight control adjustments in real time.
“If we can get closer to how the albatross does it, we can be more efficient,” he said.
Overcoming Challenges
Eisa and his students are working alongside researchers from industry, meteorology, and the Massachusetts Institute of Technology on a DARPA-backed initiative called Project Albatross.
Traditionally, wind has been a challenge for drones. But this project aims to flip that idea, turning wind into an advantage.
Building on Eisa’s recent framing of dynamic soaring as a natural extremum-seeking system, the team is designing new real-time flight controls that mimic how albatrosses fly. These controls will be tested, validated, and implemented through experiments with UC’s DARPA industry partners to quantify how much energy can be saved compared to standard flight techniques.
Beyond engineering applications, Eisa believes the work could also deepen scientific understanding of bird flight by confirming the hypothesis that dynamic soaring is a natural example of extremum-seeking behavior.
“If we can fly more efficiently like birds, we’ll have a brighter future for unmanned aerial systems,” he said.
UC Associate Dean of Research Gautam Pillay called Eisa’s work a strong example of how biomimicry is shaping the future of aerospace.
“Eisa’s pioneering work exemplifies the transformative impact biomimicry is having on next-generation aerospace systems,” Pillay said.
By unlocking the secrets of dynamic soaring, we’re not just advancing unmanned aerial vehicle efficiency — we're addressing critical national defense priorities, such as endurance and adaptability in contested environments.
Gautam Pillay, Associate Dean of Research, University of Cincinnati
Pillay noted that the project also offers valuable opportunities for students, giving them hands-on experience with research that could significantly impact the aerospace industry.
“The project will give UC students a fantastic opportunity to work on a project with profound implications for the aerospace industry,” he said.
“Just as importantly, students will get unparalleled experiential learning opportunities, placing them at the heart of cutting-edge research where theory meets real-world application in collaboration with top-tier institutions and industry partners,” Pillay said.
For Eisa, the fascination with flight runs deep. Mastering its principles has long been central to his work. In the classic debate over choosing a superpower—flight or invisibility—he doesn’t hesitate.
“I think flying is fascinating. It’s something we always yearn to do because we can’t do it,” he said.
That passion is one reason biomimicry holds so much promise in aerospace engineering.
“Nature has been optimizing flight for millions of years of evolution,” Eisa said. “So to take this gift from nature and make it available to humanity is engineering at its best.”