Uncrewed Systems Technology 043 l Auve Tech Iseauto taxi l Charging focus l Advanced Navigation Hydrus l UGVs insight l MVVS 116 l Windracers ULTRA l CES 2022 show report l ECUs focus I Distant Imagery

79 operate from unprepared runways in hot, dusty, turbulent conditions without a sophisticated support and maintenance infrastructure. Finally, the overall system needed to have extremely high levels of reliability to provide a dependable service. The initial concept design work was led by Andrew Lock in the Computational Engineering Design Group at the university. The group undertakes work for many large aerospace companies including Rolls-Royce, Airbus, BAE Systems and Thales. In particular, it develops logical, systematic, efficient and analytical aircraft systems design tools and processes. The early design work included an exhaustive analysis of a wide range of alternative concepts. This ensured that the final ULTRA design was based on solid foundations of a deep and wide-ranging evaluation of alternative configurations. VTOL solutions were eliminated as being unnecessary, overly complex, expensive and with unacceptable payload/range constraints. The ULTRA’s design A design goal of carrying 100 kg of aid over 1000 km was adopted early on in the design phase. This allows a single aircraft flying a humanitarian aid mission to feed 30 people for a week, while allowing operation from the safety of remote airfields. It was also crucial that the system be low-cost to enable it to be built in sufficient numbers to tackle the scale of the aid distribution problem. The urgency of the humanitarian crisis in South Sudan was also a catalyst for the design, with conventional fixed-wing configurations favoured to reduce development time. The ULTRA is a twin-engine aluminium alloy twin-boom aircraft. There are currently no specific certification standards for this class of uncrewed craft, so the team chose to adhere to the nearest relevant design code: the EASA’s CS-VLA Airworthiness Requirements. The university team had already gained considerable experience in the design of this class of aircraft, having built a TLAC Scout 490 kg aircraft. Satisfying these requirements required extensive physical load testing of the primary structure to validate the computational structural analysis carried out. The ULTRA is designed for highly scalable production, to accelerate the transition from prototypes to actual craft, a consideration that influenced the choice of material for the primary structure. The unparalleled structural efficiency offered by composites made them attractive, but their vulnerability to impact damage, and difficulties associated with inspection and repair, add to the challenges of operation in unforgiving environments. Tooling costs make prototyping slow and expensive, while alternative mouldless techniques can be highly labour-intensive. Conversely, a primarily aluminium airframe could be built with minimal tooling, offering low-cost prototyping and potential for rapid scalability. Moreover, it is robust, repairable and recyclable at the end of its life. The fuselage is novel in its extensive use of aluminium honeycomb panels, yielding a stiff, light and space-efficient structure. Bonded foam ribs and an Windracers ULTRA UAV | Digest It was crucial that the system be low- cost to enable it to be built in sufficient numbers to tackle the scale of the aid distribution problem Unmanned Systems Technology | April/May 2022 Early design work included analysing a range of alternative concepts