Students at the National University of Singapore’s Unmanned System Research Group have developed a hybrid unmanned aerial vehicle (UAV) that can take off and land vertically like a helicopter, and transit to cruise flight like normal airplanes.
The drone, named U-Lion, features fully retracted wings, but is still efficient enough to lift in cruise flight. The drone can fly autonomously, including the vertical take off, landing and cruise flight.
Hybrid UAVs have attracted interest for their potential applications in military and civilian operations, especially where there are severe constraints in their operating environment, like sea surveillance or forest mapping. The ability to launch vertically minimizes the dependency of the take-off and landing facilities, expanding the capabilities to perform long-range and duration tasks, researchers say.
However, because of the difference in structure between fixed-wing UAVs and vertical take off and landing (VTOL) drones, it has been a challenge combining the two functionalities into a single UAV. Previous attempts have tended to focus on either one of the flying modes but not both, due to the high uncertainty of aerodynamic forces in the transition process.
In order to achieve both flying modes, the students from the National University of Singapore designed the tail-sitter configuration reconfigurable wings and vectoring thrust. The U-Lion drone could adopt different flying modes based on the mission requirements, and adjust the wings to achieve optimal performance. This ability allows the drone to fly much longer than typical VTOL UAVs, and possess greater maneuverability compared to normal fixed-wing UAVs.
"Being optimal in both flying modes, U-Lion may bring a new way people operate drones. The fast reaction and static hovering capabilities bring U-Lion great potential in many applications; the VTOL capability allows it to operate ... almost anywhere, including on vehicles on the sea,” says Ke Yijie, one of the Ph.D. students that led the project. “In five to 10 years' time, hybrid UAV will change the way people operate in areas like forest mapping, sea surveillance, power line inspection and disaster reaction.”