Researchers at the Johns Hopkins University Applied Physics Laboratory (APL) in Laurel, Md., have developed an unmanned aerial vehicle (UAV) that can operate in both the water and the air.
The corrosion resistant aerial covert unmanned nautical system – or CRACUNS – is a submersible UAV that can be launched from a fixed position underwater or from an unmanned underwater vehicle.
“Engineers at APL have long worked on both Navy submarine systems and autonomous UAVs,” says Jason Stipes, project manager for CRACUNS, from APL’s Sea Control Mission Area. “In response to evolving sponsor challenges, we were inspired to develop a vehicle that could operate both underwater and in the air.”
The resulting CRACUNS prototype system was developed and tested using internal research and development funding, says Johns Hopkins, adding that the UAV’s ability to operate in the harsh shore environment, as well as its payload flexibility, enables a wide array of potential missions.
According to the university, CRACUNS can remain submerged, as well as launch, from a significant depth without needing structural metal parts or machined surfaces.
First, the APL team fabricated a lightweight, submersible, composite airframe able to withstand the water pressure.
To ensure CRACUNS could not only survive but also operate effectively in a corrosive saltwater environment, the researchers sealed the most sensitive components in a dry pressure vessel. For the motors exposed to salt water, APL applied commercially available protective coatings.
The team then tested the performance of the motors by submerging them in salt water. Two months later, the motors showed no sign of corrosion and continued to operate while submerged.
APL’s Rich Hooks, an aerospace and mechanical engineer who was responsible for the additive manufacturing techniques used on CRACUNS, adds, “CRACUNS successfully demonstrated a new way of thinking about the fabrication and use of unmanned systems.”