Humans don’t need to reinvent the wing to make a better flying machine. Instead, they can just copy a design from nature. Falcon evolution has had millenniums to perfect wing design, while humans have been flying for barely more than a century. So to find an efficient flying design for small drones, researchers at RMIT University in Australia borrowed from the wings of a kestrel.
Their study, published today in the journal Bioinspiration & Biomimetics, is about using air currents to save energy while in flight. Kestrels are small falcons, weighing on average less than half a pound. (If they were drones, they’d be so light the FAA wouldn’t register them.) Kestrels were chosen as the inspiration partly for their small size, and partly because, according to lead author Alex Fisher, “they’ve got a unique way of hunting – hovering over a location without flapping their wings. This allows them to keep their heads still with incredible precision, helping them spot prey on the ground.”
The researchers built a small, foam drone that uses a program that sends the drone into updrafts, to take advantage of kestrel-like flight. They flew it at a hill and near a building, collecting data on the aerodynamics of the flight as it happened. Flights near the hill were very successful, with the plane staying airborne a full 15 minutes until its batteries drained. Flights near the building were shorter, less than a minute even when remotely controlled by a skilled pilot. Gusty wind proved to be the biggest obstacle.
From the paper’s conclusion:
Flying near buildings remains the greatest challenge, but the researchers think they can overcome them that by modeling updrafts in cities and by flying near buildings outside of city centers, which are less of an obstacle.
This is hardly the first time researchers have turned to birds for inspiration with drones. Other attempts have tried to capture flapping and body shape. This study looks more at behavior and environment. Future work could lead to drones that learn to fly like birds, to occupy the same parts of the sky.
Read the full study.