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19 The company bought two vehicles and a pneumatic catapult launcher “at enormous cost”, Hannaford said, only to be stymied by the US International Traffic in Arms Regulations (ITAR) as they applied to the autopilot and the gimbal. Approval for their export to South Africa took 18 months, by which time the urgency of the requirement had forced Hannaford and his team to come up with their own solution – “Boer maak ‘n plan”, as Afrikaners like to say (meaning to devise a new way of looking at something). The plan took him back to RC model aircraft technology, and UDS bought several cheap, 2.5 m-span model aircraft, integrated a PixHawk open source autopilot and some off-the-shelf video equipment. “Suddenly we realised we could end up with a capability that was crazily good for next to no money,” he said. Fuselage and wings Over time, the foam fuselages proved to be the system’s Achilles heel, so UDS developed its own modular composite fuselage in a pod-and-boom configuration, making its own moulds and fabricating the parts in carbon cloth using conventional wet lay-up techniques. However, the team stuck with cheap foam wings and horizontal and vertical stabilisers, all off the same model aircraft. The company also developed its own two-axis gimbal for the camera payload, choosing off-the-shelf AlexMos controllers and 3D-printing many parts. It even developed its own camera interface controllers to allow internal settings to be manipulated through the PixHawk using pulse width modulation values. That was the genesis of the Bat Hawk. “The Bat Hawk, essentially, has ended up as our platform of choice in Africa because it is very, very cheap for us to build. “We can also repair it in the field within minutes, by swapping out parts or repairing those parts very quickly,” Hannaford said. “And we control the entire production process from start to finish. It was an African problem and an African solution that took us down this road.” High-end RC He stressed that the high end of the RC model industry is a natural source of parts for UAVs for developers who want to keep costs down. “You can buy componentry that is super-reliable, highly efficient and has the longevity and MTBF to make it more than safe for operation. Yes, you spend money on the top-spec parts, but it’s worth every cent,” he said. “If you compare them to military-grade actuators, servo motors and so on, there’s not really much difference other than that the Mil-Spec version might have an IP rating, so we can’t fly in heavy rain, while they can – not that we want to because for our operation it’s pointless. “Building a shopping list of all best-in- class RC components was a top priority, then testing them all and finding which were the most reliable.” The Bat Hawk fleet has around 14,000 flight hours on it. Almost 120 of them Robert Hannaford | In conversation Unmanned Systems Technology | August/September 2018 Detail of the FLIR camera and stabilised, vibration-isolated mount on the Bat Hawk. The propeller and motor are on the front end of the same structural tube