Airplanes are designed to withstand many weather conditions. Though it isn’t pleasant to be a passenger onboard an airplane traveling through turbulent weather, it is a more than likely event. Of course, there are conditions in which it is necessary to delay flights. When it comes to smaller aircraft, particularly drones, which do not have an onboard pilot to account for unexpected weather, clear skies are even more important.

The majority of drones being used commercially and recreationally, like the DJI Mavic 3, weigh around 5 lbs. Medium and large-sized drones used for tasks like deliveries or within the agricultural industry can weigh anywhere between 25 and 100 lbs. Within the emerging drone taxi market, eVTOLs (electric Vertical Takeoff and Landing aircraft), like the EHang 216, which can support two passengers, have a maximum takeoff weight of 2,866 lbs. All of these drones need to be operated in low-wind conditions to avoid the risk of being blown off course and potentially causing an accident.

Drones are used in everything from law enforcement and search and rescue, to delivering life-saving medications and cups of coffee, inspecting critical infrastructure, providing news coverage, collecting data, and monitoring crop health. The world increasingly relies on drone technology to intersect and assist across many sectors. However, the drone industry is limited by its ability to handle even moderate wind conditions. That’s why a team of researchers from the Royal Melbourne Institute of Technology (RMIT) University’s Bundoora campus has been working to develop systems that strengthen drones’ tolerance to windy conditions.

Several studies have been conducted by lead lecturer Dr. Abdulghani Mohamed from RMIT’s Department of Aerospace Engineering and Aviation. Dr. Mohamed’s area of expertise lies in applying biomimetics to aerodynamics for unmanned flight systems. Biomimetics is the practice of studying how things work in nature and applying that knowledge to improve manmade systems. For example, how wetsuits are inspired by the skin of sharks, or how burdock burrs sticking to animal fur inspired the invention of Velcro. Similarly, bird-inspired biomimicry is often used in aircraft design.

Dr. Mohamed explains that previous studies have looked at how birds flap their wings to maintain control in wind gusts. These studies led to developments in how fixed-wing aircraft adjust their flaps for aerodynamic control. For his most recent project, Dr. Mohamed collaborated with Dr. Shane Windsor, Associate Professor of Bio-Inspired Aerodynamics at the University of Bristol in England, to examine how birds hover in windy conditions.

For the experiment, the team partnered with a local falconry that provided two Nankeen Kestrels, a small bird of prey native to Australia, named Kevy and Jedda. While the birds were fed by a handler, the team placed an array of motion capture sensors on them. These are the same type of sensors used to capture an actor’s movements for special effects, and the handler stated that the birds were entirely unbothered by the process. Kevy and Jedda were then released into a wind tunnel, where the slightest details in their movements were recorded for the team to study.

Dr. Mohamed said the study revealed that the birds had remarkable control over their heads, moving them less than 5mm, while making subtle adjustments to their wing shapes. These adjustments affect how the wind meets the surface of the birds’ bodies, enabling steady hovering in high winds. “Our findings surrounding the changes in wing surface area could be applied to the design of morphing wings in drones, enhancing their stability and making them safer in adverse weather,” he said.

Dr. Windsor noted that in many of the UK’s remote islands, mail delivery and access to basic necessities rely on air transport, a service increasingly supported by autonomous drones. However, these islands often face strong winds, making the system less reliable. He said this study could lead to drone designs that would allow people in these remote areas better access to the things they need. “The advantage of morphing wings,” Dr. Windsor said, “is that they could be continually optimized throughout a flight for a variety of conditions, making the aircraft much more maneuverable and efficient.” As drone technology continues to evolve, biomimetic projects led by researchers like Dr. Mohamed and Dr. Windsor may be the key to unlocking safer, more reliable flight in even the most challenging weather conditions.

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