Examining and emulating nature isn’t a new concept to engineers, or humans in general for that matter. Studying birds in flight, for instance—or just wondering how they do it—no doubt predates even Aristotle. Studies at the University of Florida show that emulating nature is a work in progress.

Studies of birds in flight led to the development of the first functional wing. According to this article, Sir Charles Cayley, in the late 1700s, ‘…realized that the lift function and the thrust function of bird wings were separate and distinct, and could be imitated by different systems on a fixed-wing craft.’ A hundred years later, in 1891, German engineer Otto Lilienthal ‘…began his work on heavier-than-air craft not by developing a complete airplane, but instead by focusing his efforts on a fixed-wing glider.’ Through his work with gliders, Lilienthal observed and recorded the lift provided by fixed wings. (In an ironic twist of fate, Lilienthal died in a gliding accident in 1896.)

Altering or morphing the shape of wings in order to produce much more varied capabilities than a typical fixed wing is relatively modern science, as presented, for instance, in this (Before you click, note that the following link is for a PDF.) Virginia Tech-DARPA paper called Wings: Out of the Box. The objectives of that paper included investigating the performance and maneuverability improvements of a morphing wing vehicle. Even non-engineers will appreciate Pg. 8 of that paper, “Multimission Vehicle Inspired by Nature.”

“A single wingtip feather, he found, moved a fraction of an inch, gives a smooth sweeping curve at tremendous speed. Before he learned this, however, he found that moving more than one feather at that speed will spin you like a rifle ball…and Jonathan had flown the first aerobatics of any seagull on earth.” –Jonathan Livingston Seagull, Richard Bach

Perhaps there are also a few Jonathan fans at the University of Florida. Working with assistant professor Rick Lind, who heads UF’s wing morphing project, is mechanical and aerospace engineering doctoral student Mujahid Abdulrahim. According to this article, Abdulrahim is impressed by the seagull’s ability to hover, dive and climb rapidly, and ‘photographed the gulls close-up during flight. The images showed the gulls’ wings flexing at both their shoulder and elbow joints as they altered flight patterns.’

The first wing-morphing prototype of the 3-year-old UF project used motors to twist threads which in-turn moved flexible wings. The next version used metal rods instead of threaded sections, enabling both up and down motion. Abdulrahim’s latest design mimics the seagull’s wing flexing ability. In the Down position, the prototype loses stability but becomes much more maneuverable. In the Elbow-Straight position, it glides well. In the Elbow-Up position, it’s highly controllable and easy to land. While I avoid linking to video files here in The Blog, you’ve got to see this. (Here’s a list of available both flight and on-board videos from UF’s Center for Morphing Control.)

That’s all well and good, but what practical applications exist for such aerodynamic capabilities? The UF project is funded by the Air Force, and the outcome is expected to be airborne, remote-controlled drones that will be small, silent, dive between buildings, zip under overpasses, and touch down on apartment balconies—’like tiny urban stunt planes.’ Lind explains that the ‘urban canyon’ will involve flying through alleys, around parking garages, and between buildings. He says ‘That could be useful, for example, if the planes, equipped with sensors for biological or chemical weapons, were investigating single buildings where the weapons were suspected of being made.’

From spider’s webs to seagull’s wings, biological inspiration will continue to fascinate and drive engineers to greater heights. I wonder, though. If humankind sees insects and birds, for example, as ‘nature,’ then what are we? Unnatural?