For millions of years, they made their astonishing flying skills the rulers of the sky – but in the search for bio-inspired flight technologies, pterosaurs and other fossil aerial acrobats have been largely overlooked. That should change now, researchers say. In a publication, they show the potential of modern paleontology as a source of inspiration for the development of new flight technologies.
The technical term is bionics: Researchers and developers have long been inspired by natural models to master various technical challenges. Because the biological concepts are highly optimized because they are based in part on millions of years of evolution. Especially in aeronautical engineering, the focus was on nature’s flight artists – birds, bats and insects. To date, they provide important impulses for concepts in the design of aircraft or drones. A look into the past of “animal aviation” has so far been unusual in bionics, according to researchers led by Liz Martin-Silverstone from the University of Bristol.
Paleontology as a source of inspiration for technology?
As they explain, one reason is that paleontological information traditionally appears to be inaccurate because it is often based on the study of fragmentary fossils. Martin-Silverstone and her colleague have now questioned to what extent this really applies. To do this, they evaluated studies on pterosaurs (pterosaurs) and other fossil flight specialists. Her focus was on the question of whether there is any potential for bio-inspired flight technology.
As the researchers report, there are some pterosaur fossils that provide amazingly detailed insights into the anatomy of their wings and thus their flight skills. What is particularly interesting about these animals is that their concepts have been extremely successful for a very long time and have made astonishing achievements possible: Their numerous representatives flew across the sky for around 160 million years – much longer than the birds have so far managed to do. They also produced the largest and heaviest beings that have ever risen into the air: these giants once hovered over the horizon with a span of over ten meters. The pterosaurs didn’t die out either because they were “outdated models”: the asteroid impact about 65 million years ago, together with the dinosaurs, violently swept them off the stage of evolutionary history.
It is worth looking at some fossils
From the point of view of bionics, the main question is how these large animals took to the air and how their flight membranes could withstand the aerodynamic loads. Because these are aspects that still represent a technical challenge. “There are two or three absolutely amazingly detailed pterosaur fossils that show the different layers within the wing membrane and can give us an insight into their fine structure,” reports Martin-Silverstone. Some fossils have also been preserved so well that the connections between the flying skins and the body can be seen, the scientists report. “Even if the shape of the wing is not clearly recognizable, knowledge of the membrane anchorage could be used to model the effectiveness of different wing shapes and determine which ones worked best under natural conditions,” says Martin-Silverstone.
It also seems to be emerging that the pterosaurs used technically interesting starting procedures. The implementation of the jump start, which allows some birds or bats to take off in one fell swoop, has so far proved to be tricky. With increasing size, it also becomes problematic for birds. But the pterosaur species, which weigh over 200 kg, apparently developed alternative methods of catapulting themselves into the air. According to a hypothesis by co-author Mike Habib of the Natural History Museum of Los Angeles County, special adjustments to the muscles and features of the elbows and wrists could have enabled the animals to take off without much effort. “A closer look at such capabilities could help solve technical problems such as the design of certain drones,” says Martin-Silverstone.
Ancient concepts with potential
As the researchers continue to report, the pterosaurs could also provide insights into how flight instabilities in the air can be prevented. In contrast to some technical concepts that become unstable in strong winds, pterosaurs have apparently developed strategies to prevent their wide wings from fluttering. “So far, there is still a need for optimization in the development of flight suits with membranes that can withstand the pressure during flight. If we understand how the pterosaurs’ wing membrane was constructed, we may be able to design better solutions, ”said Martin-Silverstone. As she and her colleagues report, some fossils have the potential to do so.
In addition to the pterosaurs, the scientists also focus on representatives of the winged dinosaurs. Some have therefore developed concepts that also produced technically interesting aerodynamic effects. One example is the so-called microraptor. He had feathered wings and legs and was probably flying with a kind of biplane strategy. Another small dinosaur, on the other hand, combined feathers with a bat-like membrane, which apparently also gave him special skills. “If we only consider modern animals as a source of inspiration, we may ignore many options that could be technically useful,” Martin-Silverstone is convinced.
That is why she and her colleagues now want to encourage scientists to work more closely with their publication: “We want developers to also turn to paleontologists when they are looking for solutions to flight problems, because there could be an extinct being that can serve as a model “Martin-Silverstone concludes.
Source: Cell Press, technical article: Trends in Ecology & Evolution, doi: 10.1016 / j.tree.2020.03.005