We would have to return to the 15th century to meet one of the most peculiar and versatile Renaissance inventors, Leonardo da Vinci. His extensive work covered painting, anatomy, architecture, botany, philosophy, engineering, urban planning and many other disciplines. In some cases he marked a revolution for centuries to come. In fact, we could classify him as one of the pioneers of aeronautics, which includes his work in the development of theoretical studies, designs of flying devices and even models, although there is no record that any of his inventions actually flew.
After more than 500 years since Leonardo proposed its design, the ornithopter can finally take flight and compete in performance with other unmanned aircraft.
Leonardo left several written documents in which he reflected his studies on the mechanics of bird flight. Among them, the “Codex on the flight of birds” stands out, an 18-page booklet dating from 1505 and containing his studies and illustrations.
Among the machines that he devised to cross the skies is one inspired by the physiognomy of a bird, in which the wings were mechanically activated by the pilot. He based this invention on a prolonged and exhaustive study on the mechanics of bird flight, his idea being to provide a human being with wings that would allow him to fly. Its name: ornithopter.
However, the concept was far from the expected results. The main problem lay in the enormous force required that he would have to apply to beat the wings, thus allowing the artifact to take off. The only confirmed construction of one of his flying machines took place throughout 1495, making a public demonstration test in Milan on January 3, 1496, which was unsuccessful.
In reality, all his work was ahead of its time and this design, like others, was forgotten with the passage of centuries, in the old pages of his notebooks.
Nowadays, we would still have the same design problem. What’s more, no flying object made by humans throughout history has achieved stable flight by flapping its wings. Nature is a good source of knowledge to be imitated, but it would be impossible for us to fly like a bird, since we lack its physiognomy. On the other hand, it was possible to fly with rigid wings, and machines with a mass of hundreds of kilograms were able to take off from the ground since the first flights at the beginning of the 20th century. But this milestone was achieved through the evolution of the engines and their development to generate greater thrust.
But let’s return to nature and Leonardo’s desire to fly like a bird. It may be impossible to do it directly for a man applying his force alone, although it could be done indirectly. Let’s think about replacing a man’s body with his inventiveness, by creating an object that was capable of maintaining controlled flight while flapping its wings. In short, like a bird.
The University of Seville (Spain) is one of the places where Leonardo’s dream of building and flying an ornithopter is coming true. There, they have been able to overcome the initial problem of the project: obtaining the necessary force to move the wings stably and counteract the gravitational pull. The path chosen was to reduce the mass of the device to the maximum possible thanks to robotics, since this invention consists of a skeleton and sensors that allow flight by flapping the wings. Likewise, they have copied another of the Renaissance ideas, and, like birds, this mechanical bird also glides.
Another significant aspect would be landing the device. The team have devised a mechanism similar to that of birds to be able to perch on trees or any similar surface, allowing them to fly outdoors. This part of the project is still in development and its greatest handicap is the ability to reduce forward movement in flight as much as possible, with the aim of landing on a surface, thus minimizing the violence of landing.
They even continue to add new qualities to improve its capabilities. For example, because of having the ability to remain in stable hover, they are looking for a way to add small solar panels to enable autonomous recharge. The difficulty lies however in the vast amount of energy required to maintain flapping and sustain the battery’s own load of the panels necessary for this purpose.
However, and without detracting from this inventiveness. Would this type of ornithopter aircraft be necessary? Let’s keep in mind the qualities of drones, which have experienced accelerated evolution in recent years. They even continue to evolve, offering increasingly more precise response and greater performance.
In reality, the ornithopter has little to do with drones and, in fact, its only similarity would be that of being an unmanned aircraft. Lacking a propeller, with the aerodynamic noise that this would entail, it has the quality of being silent and easily going unnoticed. This is an attribute that allows the device to act as an observer without actually making an impact on the environment under examination. On the other hand, it could also interact with humans, animals or plants without the risk of causing damage by the propellers.
The development and use of this type of aircraft would offer humans a different option than what the rest of the unmanned ships are offering today. Above all, in the field of observation and study of the environment; that is, it could be a great tool for science and, above all, for biologists and ecologists.
But it is not only the University of Seville that is developing the concept of the ornithopter. The German firm FESTO is also making progress with its own model. The main difference is that it lacks a landing system. On the other hand, as a peculiarity, it has the possibility of tuning in with other devices of the same species, with the aim of flying together in formations of up to a maximum of five aircraft.
It is premature to say that a new type of aircraft has been born, since there are still many details to be resolved, apart from the most important thing: for it to have a specific purpose and unique capabilities.
In any case, by flying any of these ornithopters, we will have been able to successfully overcome a design problem that Leonardo Da Vinci posed more than 500 years ago.