Issue 45 | Uncrewed Systems Technology Aug/Sept 2022 Tidewie USV Tupan | Performance monitoring | Bayonet 350 | UAVs insight | Xponential 2022 | ULPower UL350i and UL350iHPS | Elroy Air Chaparral | Gimbals | Clogworks Dark Matter

110 Digest | Clogworks Dark Matter Structure and materials A weight saving of more than 30% over the Gen1 has been accomplished with a range of measures, primarily through the way the CFRP fuselage is produced, Opdam says. However, other contributions have come from optimising parts machined from aircraft-grade aluminium, re-engineering 3D-printed fittings and improved integration of the UAV’s electronics. All Dark Matter UAVs are of monocoque construction, meaning that the outer skin forms the load-bearing structure that handles all the static and dynamic loads on the aircraft. Opdam points out that producing all the CFRP parts in-house gives the company’s engineers full control over where and how to reinforce the structure. The composite material that Clogworks uses is a certified 3K prepreg carbon that offers the flexibility in layup needed to form the airframe’s complex shapes, and offers an excellent surface finish when cured, he explains. “The raw material has a very low VOC [volatile organic compounds] content with no added solvents during manufacture, and cures at a relatively low temperature. The finished parts offer great mechanical properties,” he says. Where precision metal fittings are required, such as where the arms that support the motors and propellers attach to the core of the fuselage, they are CNC-machined from aircraft-grade aluminium alloy. The arms themselves are an example of the UAV’s modularity, as they can be detached quickly in case they need to be replaced, and they are interchangeable between the six-motor and four-motor models. “It is important that they are standalone, as you can replace an arm like-for-like in the field if needed, or quickly replace arms when motor maintenance is due and downtime is not an option,” Opdam says. Options for retractable or fixed landing gear also fits Clogworks’ modularity philosophy. Retractable gear, he explains, allows for an unobstructed 360 º horizontal view from a payload camera. “For the Gen2 we have a better and more robust retractable solution,” he says. “The new design features moulded T-shaped CFRP legs under the main shell that pivot upwards on take-off, with retraction and extension controlled by servo motors. When fully retracted, the gear legs lie roughly parallel to the UAV’s arms. “Other applications, such as package delivery, might not need retractable gear, but do require more ground clearance and greater strength to cope with landing at higher weights.” Opdam explains that the hexacopter configuration was chosen for the Dark Matter hX because it provides six points of thrust and an overall footprint that is optimal in terms of size, efficiency and power-to-weight ratio, while also offering arm and motor redundancy. “The size of the core is important for best placement of antennas, GPS masts and any extra systems that may be required,” he says. While Clogworks keeps an eye on the market for high-quality propulsion system components on offer from other manufacturers, it uses motors and electronic speed controllers from KDE Direct. He notes that KDE quotes an MTBF of many hundreds of hours for the motors, and says they need minimal servicing. August/September 2022 | Uncrewed Systems Technology Clogworks chose the hexacopter configuration for its six points of thrust, arm and motor redundancy and optimal footprint in terms of size, efficiency and power-to-weight ratio Even when lifting its maximum payload, the system is still within an acceptable window for current draw, so it can be operated all day, every day