Unmanned Systems Technology 007 | UMEX 2016 report | Navya ARMA | Launch & recovery systems | AIE 225CS | AUVs | Electric motors | Lethal autonomous weapons

Vehicles that can operate in both water and air are rare, but a team at the Johns Hopkins University’s Applied Physics Laboratory is developing and has flown a quadcopter UAV that can launch from and return to a fixed position under water or a submerged UUV. Known as the Corrosion Resistant Aerial Covert Unmanned Nautical System (CRACUNS), a name reminiscent of the legendary Kraken sea monster, it is intended to be flexible enough to support various payloads yet tough enough to operate in harsh littoral environments. It can be lifted by one person and is low enough in cost to be considered expendable. The CRACUNS features a pressure- resistant polymer composite airframe that is strong enough for it to remain at and launch from a depth of several hundred feet, says the team, while needing no structural metal parts or machined surfaces. Built using additive manufacturing techniques including 3D printing, the pressure vessel that keeps the most sensitive components dry also provides some buoyancy, as a video on the Johns Hopkins website shows. The rotors are shown turning underwater, helping to drive it to the surface and confirming motor functionality before take-off. Most electrical components are sealed inside the pressure vessel, but the Avroto electric motors that drive the rotors are exposed to the water, so they are protected by commercially available coatings. In tests, said the team, the motors ran normally after being submerged in salt water for two months. A domed lid seals the pressure vessel at the top, screwing down onto a metal ring moulded into the top of the cylindrical main body. The video shows the lid in a 3D printer. Wiring to the motors emerges from the pressure vessel in extended pressure- tight grommets and wraps around the outrigger arms on which the motors and propellers are mounted. The four arms bolt into sockets on the outer wall of the pressure vessel and support the motors and their two-bladed, fixed-pitch composite rotors. A dark conductive mesh skin provides shielding from electromagnetic interference, with cut-outs for antennae revealing areas of the whitish pressure vessel material underneath. Water or air, it doesn’t care Multi-environment craft