Unmanned Systems Technology Dec/Jan 2020 | Phoenix UAS | Sonar focus | Construction insight | InterGeo 2019 | Supacat ATMP | Adelan fuel cell | Oregon tour | DSEI 2019 | Copperstone Helix | Power management focus

74 December/January 2020 | Unmanned Systems Technology mapping and anti-poaching surveillance, as well as in floods and other large area applications where UAVs have the potential to make a big difference.” By using AI software modules, Overwatch is able to reconfigure its imaging systems to alter, sharpen or re- focus the data they produce, according to a customer’s needs and operating environment. The TK-5 integrates colour, NIR and temperature-calibrated LWIR sensors, which operate simultaneously and are actively stabilised in a dual-axis gimbal. Using Nvidia Jetson processors has also been key to providing the computational power needed to run Overwatch’s algorithms. “We’re continuing to incorporate additional onboard software analytics modules, which allow us to find new things of interest and map them out, to reduce workflows for operators,” Davis said. “The aim is to enable them to focus on the response to seeing something of interest, rather than the dull task of searching, with actionable information on maps put out for them automatically. “We’re also beginning work on a new variant of our PT-8 Oceanwatch automated maritime airborne search sensor, which will be able to function at night time. We’ll have further details on that later this year.” Northwest UAV After Hood River we travelled to McMinnville, to the laboratories and workshops of Northwest UAV and where Chris Harris and Jeff Ratcliffe discussed the latest updates to the company’s NW-44 and NW-88 multi-fuel engines. “We’ve operated the NW-44 now for over 20,000 hours in-theatre, and have amassed experience and data on how the engine really performs and is being maintained in real-world flight operations,” Ratcliffe said. “Having such tangible data led to some very specific upgrades for the NW-44, to make maintenance of the system a lot easier and less time-consuming, as well as to make the engine a little more robust.” Harris added, “After that much operating time, you notice that some problems tend to arise during scheduled maintenance work. For example, when engines were returned for overhaul we noticed there were pieces of safety wire in the generator rotors, which were being introduced when the muffler was removed to have its packing replaced. “To stop that from happening, we developed a muffler that doesn’t need the packing replaced. By not having to take the muffler off, we are not removing the safety wire that could find its way into the generator during maintenance, which could cause a generator failure.” The company is planning to extend the NW-44’s TBO rating to 500 hours (from 400 hours previously), with only the spark plugs needing changing in the interval between overhauls of the engine. “The original design spec was 500 hours, but we reduced that to 400 as a conservative safety measure,” Ratcliffe said. “Based on what we’ve seen after 20,000 hours of maintenance, repairs and overhauls, we’re now confident enough to advise our operators that they can run the NW-44 for 500 hours before sending it back in.” The company has also been tracking flight data logs and running trend analyses on areas such as rpm, fuel pump health, servo signal variances, throttle performance, ignition or crank errors, and other ECU data. That has gradually informed it on which components can be improved, such as updating the generator windings with a urethane flow coat to protect against nicks, and swapping out the ball links for more aerospace-grade linkages. The company has also developed a new active cylinder head cooling shroud, roughly 100 g lighter than the older version it replaces. It is made from PA- 640, a glass-Nylon-carbon composite. “We’re also looking towards a lighter version of the NW-44,” Harris added. “With a lighter muffler, a smaller generator and some new materials and coatings, we’ll go from 4.2 kg to around 3.4 kg. Those updates could potentially mean another three hours of endurance for a UAV.” These updates also extend to the NW- An NW-88 multi-fuel engine in one of Northwest UAV’s many testing rooms (Courtesy of Northwest UAV)