Unmanned Systems Technology 027 l Hummingbird XRP l Gimbals l UAVs insight l AUVSI report part 2 l O’Neill Power Systems NorEaster l Kratos Defense ATMA l Performance Monitoring l Kongsberg Maritime Sounder

53 UAVs | Insight “As the helicopter OPV approaches its destination, the pilots can hand over control to ground personnel for placing the cargo, before retaking the controls to return to base; there are lots of use cases for OPVs like that.” As well as improving safety and functionality, converting helicopters into OPVs could enhance their endurances or carrying capacities by removing the 100- 200 kg weight of onboard personnel. In another innovation towards greater endurance in defence aircraft, Boeing has awarded Harris a contract to supply the mission management processor for the former’s MQ-25 refuelling tanker UAV. The MQ-25 is being developed for the US Navy to extend the range of carrier air wings, in an $805 million contract to Boeing for four refuelling UAVs by August 2024. That programme might be extended to encompass 72 aircraft and $13 billion in funding. The processor will handle sensor and comms functions on the UAV, while also providing onboard processing capacity for further advanced computational requirements. That and any further hardware or firmware provided by Harris will follow Boeing’s open systems architecture solution, which is aimed at developing common standards across avionics systems. BAE Systems has also been granted a contract by Boeing to supply critical avionics components for the MQ-25 project. The UK company will provide the UAV’s vehicle management control system for operating all the flight control surfaces, as well as its IFF (identification friend or foe) system for discerning enemy vehicles from friendly ones. Aerospace engineering Meanwhile, BAE Systems is continuing with its r&d for flight control systems, using its own flying wing platform. The Magma demonstrator UAV (featured in UST 26, June/July 2019), developed in collaboration with the University of Manchester, in England, has been used to trial ‘wing circulation control’ and ‘fluidic thrust vectoring’, techniques that use blown air from a compressor on the Magma’s gas turbine engine to control pitch and roll, and which were tested in May this year. The theory behind both techniques has existed for several decades, but testing was stopped long ago owing to the belief that they were fundamentally unachievable. As Bill Crowther, leader of the Magma project at the University of Manchester, explains, “Previous attempts at wing circulation control have used large slots and large trailing edges, but our research has focused more on miniaturisation, high speeds and high pressures. “Advances in CFD have helped, and additively manufacturing the required parts from titanium to very precise resolutions was critical to creating the 4-5 mm slots needed at the trailing edges of the Magma’s 4 m wingspan.” The fluidic thrust vectoring assembly was also additively manufactured in titanium, with the overall system weighing about 3.3% of the weight of the aircraft (the team was targeting a maximum weight budget of 10% of the Magma’s total weight). “For example, the engine nozzle weighed 700 g. That delivered 200 N of thrust, with the whole system held in place by four M3 bolts,” Crowther notes. While conventional aircraft use numerous servos to actuate the flaps, ailerons, elevators and so on for flight control, these fluidic control techniques use only one or two servos each to actuate the required control valves. They are also much smaller, lighter and less power-hungry. “If you compare the weight of the actuators used on the Magma with those on a similar but conventionally controlled aircraft, you use about 15% of the mass of the conventional control system, and they would probably consume less than 5% of the electrical power,” adds Clyde Warsop, engineering fellow at BAE Systems. “There is some cost in terms of the air bled from the engine, and the extra fuel burnt to do that, but our initial studies indicate a less than 0.5% increase in fuel consumption over a 1 hour flight.” Conclusion Common among many of the new technologies being trialled on UAVs is transferability, and systems being developed for niche commercial, defence or research organisations will inevitably be reinvented and refined to provide even better performance and new use- cases as time goes on. Unmanned Systems Technology | August/September 2019 A fluidic control system on this Magma UAV saves considerable weight and power over a conventional system’s many servos and so on (Courtesy of BAE Systems)