Unmanned Systems Technology 024 | Wingcopter 178 l 5G focus l UUVs insight l CES report l Stromkind KAT l Intelligent Energy fuel cell l Earthsense TerraSentia l Connectors focus l Advanced Engineering report

94 Show report | Advanced Engineering 4 and 8 g/cm 3 .” As well as exhaust ducts and exhaust shields, the material can be used in heat shields and thermal protection systems. It has a thermal expansion coefficient of 3 μm/mK at 650 C, and a thermal conductivity of 0.9 W/mK, compared with 18.7 μm/mK and 21.5 W/μm for typical Inconel alloys. Rockwood Composites showcased its capabilities in bladder moulding and compression moulding prepreg composites for propellers and wings. “We use matched metal tooling, in which we have top and bottom cavities that are close together, giving us control over all the surfaces around a part we’re curing,” said Mark Crouchen. “That gives precision when we’re trying to get the weight down and improve the functionality of parts we’re producing – including embedding electrical circuits within moulded parts.” Matched metal tooling also ensures precise volumes of space inside wings and wingtips, so that avionics such as antennas and RF receivers can be housed while still minimising the amount of material used in the manufacture of the aerofoil. “We combine bladder moulding and compression moulding, with bladder moulding being ideal for hollow sections of aerofoils and compression moulding being more suited to the leading edge, trailing edge and any other load-bearing sections along the wing,” Crouchen added. Materion Corporation displayed its engine components, which are produced from its SupremEX aluminium-silicon carbide composites. These ceramic- reinforced alloys are produced by a novel powder metallurgy process in Farnborough, UK. “The fundamental concept is similar to putting carbon fibres in plastic, but we put micron-scale and nano-scale silicon carbide [SiC] ceramic particles into aluminium,” said Stuart Godfrey. “That makes our SupremEX composites ideal for space, aerospace, defence, motorsport and other applications that need greater strength and stiffness from aluminium. “The key to the materials’ performance is the fine and even distribution of SiC ceramic, and our components have relatively high-volume fractions of it compared with what the industry typically sees – between 20% and 40%.” As a result, Materion says it can produce engine pistons that weight 18-20% less than conventional pistons while offering better high-temperature fatigue strength and wear performance, along with lower thermal expansion and increased stiffness. With correct piston design, this can lead to increased engine performance, longer life and lower emissions. Similarly, valve spring retainers made from SupremEX composites weigh up to two-thirds less than those made from steel, and up to one-third less than titanium retainers. This reduces valvetrain mass, which can lead to improved power and acceleration. The SupremEX 225XE and 225XF materials, for example, have a density of 2.88 g/cm 3 , compared with 4.43 g/cm 3 for Ti-6AI-4V alloy titanium and 7.85 g/cm 3 for 4140 alloy steel. The strength and stiffness of the materials could also have applications in the noses, wingtips and other high load- bearing sections of tactical fixed-wing UAVs that manoeuvre at high velocities and pull higher g -forces than those which manned aircraft pilots can safely endure. LDD Technology exhibited its design and development capabilities in producing complex embedded processing boards, including a range of sonar boards for UUVs carrying out seabed imaging operations. “Underwater boards such as these have a few key differences to boards for aerospace vehicles,” commented Malcolm Locke. “For example, the need for vibration tolerance isn’t as high for UUVs as it is for UAVs, and subsea circuit boards also tend to be coated for protection in damp conditions. The technology and design tools are generally the same between the two, however.” The company uses Altium Designer as its PCB schematic design tool. Many of its boards are FPGA-based to enable them to perform the processing required in the available volume. FR-4 glass fibre- reinforced epoxy is used as the substrate material in almost all its board designs. LDD also showcased the LDD-ES8, an eight-port embedded Gigabit Ethernet switch, which consumes 5 W while providing 1 Gbit/s comms through all ports. February/March 2019 | Unmanned Systems Technology Cutaway of a Rockwood composite propeller The eight-port embedded Gigabit Ethernet LDD-ES8 switch from LDD Technology