Researchers from Johns Hopkins University in Maryland have developed an unmanned aerial vehicle (UAV) that can be launched from beneath the water into the air.
The Corrosion Resistant Aerial Covert Unmanned Nautical System (CRACUNS) is a submersible UAV designed to withstand harsh ocean environments, giving it capabilities not possible with current UAVs or UUVs (unmanned underwater vehicles).
The team at Johns Hopkins used advances in additive manufacturing and novel fabrication techniques available at its Applied Physics Laboratory to build a lightweight, submersible, composite airframe able to withstand the water pressure experienced while submerged. It has no structural metal parts or machined surfaces.
Project manager Jason Stipes said engineers at the laboratory had worked on both Navy submarine systems and autonomous UAVs.
“In response to evolving sponsor challenges, we were inspired to develop a vehicle that could operate both underwater and in the air,” he said.
The resulting CRACUNS prototype system was developed and tested using internal research and development funding.
A challenge was to ensure CRACUNS could not just survive, but operate effectively in a corrosive saltwater environment. To do that, the team sealed the most sensitive components in a dry pressure vessel. For the motors that are exposed to salt water, they applied commercially available protective coatings.
The team tested the performance of the motors by submerging them in salt water. Two months later, they showed no sign of corrosion and continued to operate while submerged.
Rich Hooks, an aerospace and mechanical engineer at the Laboratory, was responsible for the novel additive manufacturing techniques used on the vehicles.
“CRACUNS successfully demonstrated a new way of thinking about the fabrication and use of unmanned systems,” he said.
Photo: Johns Hopkins Applied Physics Laboratory