Fixed-Wing Drone can Fly and Swim

Researchers from North Carolina State University have developed what they say is the first unmanned, fixed-wing aircraft that is capable of traveling both through the air and under the water – transitioning repeatedly between sky and sea. The EagleRay XAV, which was developed with funding and assistance from Teledyne Scientific, holds promise for use in applications such as tracking and observing wildlife.

“Maintaining aerial surveillance can use a lot of energy,” says Warren Weisler, a Ph.D. student at NC State who worked on the EagleRay project. “The EagleRay can conserve energy by spending some of its time in the water. For example, the EagleRay could track a fast-moving pod of dolphins from the air, then spend time loitering in the water if the dolphins stop to take advantage of a good feeding spot. The EagleRay could then resume flight when the dolphins begin moving again.”

The EagleRay could also rapidly move underwater sensors from location to location or perform underwater monitoring, says William Stewart, another NC State Ph.D. student who worked on the project. “For example, sonar only works underwater. If you’re seeking a sonar target, the EagleRay could fly to a site, submerge to take sonar readings, and then resume flight to take readings elsewhere. Historically, an aircraft would have to drop sonobuoys to collect sonar data.”

A key point regarding the EagleRay design is that it is scalable, says Stewart. The current model of EagleRay has a wingspan of 59 inches and is 55 inches long, weighing in at 12.6 pounds. It has a dual-use propeller, powered by an electric motor, which propels it through both air and water.

The researchers are currently developing a custom controller for the drone and refining a dynamic model of the EagleRay, for use in simulations that can be used for training purposes, to predict performance under various conditions and to refine the vehicle design.