Uncrewed Systems Technology 048 | Kodiak Driver | 5G focus | Tiburon USV | Skypersonic Skycopter and Skyrover | CES 2023 | Limbach L 2400 DX and L 550 EFG | NXInnovation NX 100 Enviro | Solar power focus | Protegimus Protection

52 tip speeds and noise, although different props can be used with different speeds to trade off between speed and torque. “We got our patent after 11 months,” Enriquez notes. “It was very straightforward and no changes were needed from our original version, partly because it seems that no-one else is doing this, despite all the benefits of the airboat design for hydrographic surveys. “The 400 Wmotor provides a maximum speed of about 6 knots, and its efficiency is particularly good at around 4 knots, which is good for getting accurate and data-dense readings from the sonars, DVLs and so on.” The batteries The Tiburon’s exact endurance varies according to the degree to which all the onboard systems are used simultaneously throughout each mission. However, Enriquez notes that a 2 hour minimum runtime has been achieved when running the electric motor, HD cameras, video streaming and all other systems at their peak power, and says a maximum endurance of more than 4 hours is achievable with the present batteries. Those are built around LFP (lithium iron phosphate) cells, with the inherent behavioural properties of this cathode system having been a major factor of their selection. “With a lot of lithium- ion materials, you find that the voltage decreases as the battery discharges energy, so you actually start to lose power over the mission’s runtime,” Enriquez explains. “These LFP batteries stay at the same voltage though – about 25 V DC in our use case – and the drop won’t come unless you get right to the end of battery capacity, before you have chance to recharge.” As the drop in voltage comes nearly instantly, at a known and predictable point in the battery cycle, the Tiburon’s autopilot can be programmed to send a warning message to the GCS operator to end the mission shortly and return the vessel to its recovery point (if a timely return has not already been input into the waypoint schedule) as a function of runtime and SoCmeasured by the BMS. “And of course, specific energy was critical – the batteries weigh 5 kg. We want to achieve as much runtime and distance as possible between maintenance stops, and the more payload weight our customers want, inevitably the slower the vessel will move, so energy versus weight is everything to us,” Enriquez says. Powertrain roadmap The next iteration of the Tiburon will feature a significantly upgraded powertrain, albeit with the same general configuration as the present third version. At the upper rear, the 400 W airboat drive will be replaced with a customised 24 V DC, 2.4 kW electric motor and a 34.3 cm propeller (from an undisclosed supplier) that is optimised for producing torque in the air. February/March 2023 | Uncrewed Systems Technology A camera mast in the middle on top of the hull houses four HD cameras, enabling 1080p panoramic videos to be taken of the Tiburon’s surroundings An onboard industrial computer from Neousys-Technology records the videos coming from the onboard cameras