In modern warfare, drone is the key word. These unmanned aerial vehicles (UAV) have brought invaluable surveillance and attack capabilities to generals all over the globe. Militaries are trying hard to outclass each other and gain the edge in unmanned airspace.
Inspired by the owl, scientists across the world are busy developing drones capable of silent flight like the nocturnal bird. Counter-drone technology is a fast-growing competition.
A silent flight gives the owl the ability to capture prey by stealth. Scientists are using this idea for the design of low-noise drones inspired by the noise absorption structure of owl wings.
Jaworski and N. Peake of NASA’s Langley Research published their study in Aeroacoustic Annual Report 2020, “we know the owls’ silent flight ability is even more superior than we thought. You could say among all birds it is the ‘king of acoustic stealth’. It not only manages to suppress aerodynamic noise when gliding, but also mechanical noise caused by vibration during flying. Large species—long-eared owl, eagle owl and the barn owl—have superior ‘damping’ skills, meaning it can remain mind-blowingly stable and eliminate mechanical noise caused by the movement of its feathers – quite a feat of engineering.”
A pair of spotted owlets (Photo: Mrityunjoy Kumar Jha)
As night time predators, owls rely on their silent hunting tactics to successfully capture prey. To take off in flight requires a great amount of lift force to get off the ground, and more energy is needed to stay in the air. Generating this lift force, however, requires owls to flap their large wings. However, owls have evolved incredible mechanisms that reduce noise during flight, eliminating turbulence in the air caused by the flapping of a bird’s wings.
The secret lies within their feather structures. The "stealthy hunting hypothesis" holds that owls fly inaudibly so that prey can’t hear them and escape. Many countries have been experimenting with biomimetic drone designs in recent years because of their unique ability to hide in plain sight.
The American Intelligence Advanced Research Projects Activity (IARPA) has developed its own owl spy drones which glide silently above unsuspecting enemies collecting vital intelligence. The $4.8 million contract for the drone project—known as the Great Horned Owl Program to produce the vehicle is extremely quiet, which unlike other drones would make it hard for ground forces to locate.
The dusky eagle own at Bharatpur (Photo: Mrityunjoy Kumar Jha)
Russia is not far behind and in 2019, it had “unveiled” its own “snowy owl” drone and according to the Moscow Times, this “polar owl” can determine the coordinates of the target, and also uses laser illumination to guide artillery and aircraft.
Read More: This New Russian Spy Drone Looks a Lot Like an Owl
According to scientists this new technology or technique is known as biomimicry, where we learn from nature. Biomimicry is a practice that learns from and mimics the strategies found in nature to solve human design challenges — and find hope along the way. ·
Owl wings have feathers with sharp edges, called serrations, along their fronts, which are in contact with the air during flight. These serrations break up air turbulence that causes wind noise, reducing the noise generated during flight. Of course the secret of silence isn’t just limited to serrations. Airflow passing through the wing’s leading edge hits the velvety feathers which absorb the vibrations in air therefore even reducing the noise created by flight of owl further.
The dusky eagle owl (Photo: Mrityunjoy Kumar Jha)
One thing common in this species is the big yellow eyes. Owls can’t move their eyeballs because they don't have eyeballs at all. Instead, their eyes are shaped like tubes, held rigidly in place by bones called sclerotic rings. Since owls can’t roll their eyes around the way we do, they have to move their entire head to get a good look around. They frequently twist their head to expand their field of view. Owls can turn their necks about 270° in either direction, and 90° up-and-down, without moving their shoulders!
In Indian mythology, they are the vahanas (vehicles) of Lakshmi, the goddess of wealth. Some consider an owl sighting during the festival of Diwali extremely lucky, while some take drastic measures to accumulate the good luck.
But it is an “owl” drone, which brings bad luck for its “prey”.
