Issue 39 Unmanned Systems Technology August/September 2021 Maritime Robotics Mariner l Simulation tools focus l MRS MR-10 and MR-20 l UAVs insight l HFE International GenPod l Exotec Skypod l Autopilots focus l Aquaai Mazu

53 missions such as aerial photography, innovations in AI technologies and propulsion are unlocking some comparatively novel new capabilities far beyond those of manned aircraft. Medical aid delivery We last spoke with Aergility at AUVSI Xponential 2019 regarding the Florida- based company’s Atlis UAV, which flies using a technique the company calls ‘managed autorotation’ and is aimed at applications including logistics for medical and humanitarian aid delivery. It launches using a distributed lift architecture before switching to forward flight using a gasoline-powered pusher propeller. During this latter phase the electric motor drives are turned off in order to provide lift via autorotation – and as the rotors are driven by airflow, they can also act as generators to replenish the UAV’s batteries. That enables the Atlis to achieve flight times far exceeding those of octocopters of comparable size while also carrying fewer batteries. Such is the promise of the energy efficiency and carrying capacity of this patented technology that the company has unveiled its next-generation Atlis design. As with its previous design, Aergility has produced what is approximately a quarter- scale model as both a demonstrator and an r&d platform before investing time and tooling in the full-sized version. As CEO Jim Vander Mey explains, “The ‘full-size’ 682 kg MTOW version is still in the development phase, but we’ve updated it extensively after what we learned from the previous design.” The new design has six rotors rather than the original’s eight, as well as two slender wing-like arms that mount the middle rotors while also serving to provide some lift at higher airspeeds, and a tractor propeller for improved aerodynamic efficiency over the pusher propeller. “Overall, the aircraft still produces most of its lift through autorotation, and without needing any control surfaces either,” Vander Mey says. “It’s much more efficient in flight than our old architecture too, with our highest lift-to-drag ratio yet. With this configuration, we’ve revised upwards our expected useful load-carrying capacity on the full-size aircraft, from 180 kg to 272 kg of payload and fuel.” While endurance and range will vary depending on payload weight, flight tests thus far indicate that the full-sized craft will be able to carry about 260 kg of payload over 250 km, or 200 kg over 750 km, before needing to be refuelled. The MTOW of the craft will also allow Aergility to install redundant batteries, flight controllers, sensors and comms buses to further enhance safety. The Atlis’ carrying capacity, range and extensive failure tolerances have drawn considerable interest from several key markets, particularly delivery of life-saving supplies across rural regions where road conditions are poor, as a replacement for comparatively expensive and dangerous helicopter transportation. “Island nations and parts of Africa in particular could benefit from the Atlis,” Vander Mey adds. “It can supply cargo on a very regular timetable without any real threat from ground or weather conditions. “To ensure that, one of our partners is an expert in developing flight controllers. They are helping us come up with the control laws, logic and system architectures for the full-scale Atlis using our latest demonstrator. Being able to plan ahead and find good help on such an unusual flight controller design is really important.” UAVs | Insight Unmanned Systems Technology | August/September 2021 Overall, the aircraft still produces most of its lift through autorotation. It can supply cargo on a regular timetable without any real threat from weather Flint Hills Solution is integrating UAV Navigation’s Vector autopilot for safe BVLOS package deliveries and other missions (Photo: Flint Hills Solutions, courtesy of UAV Navigation)