106 The value of UAVs for mapping and inspection is directly linked to the efficiency with which they carry their sensor payloads. While this has been known for years, it is only recently that advances in modern design capabilities have enabled aerospace engineers to pursue alternatives to conventional aeroplane designs in pursuit of a fully maximised payload-to-weight ratio. Latvia-headquartered FIXAR-AERO LLC is best known for its 007 UAV product, which resembles a conventional, twin-boom, quadrotor, fixed-wing UAV, but this was only ever intended to trial and introduce the company’s technology into real-world commercial applications. However, the company’s newest UAV, the FIXAR 025, is the ultimate optimisation of its namesake FIXed Angle Rotor technology. It can simultaneously generate aerodynamic surface-lift forces (as in fixed-wing planes) and vertical-lift force (as in multirotors), and is engineered to maximise payloadcarrying efficiency. Through that technology, the 025 features a VTOL-transitioning capability, but with a rare configuration featuring a closed, triangular wing, wrapped around a blended-wing body. This configuration maximises aerodynamic and weight efficiency relative to the UAV’s physical footprint (its wingspan is 2800 mm), principally by forgoing landing gear, struts, tiltrotors or servos, which do nothing to specifically generate lift and indeed serve no purpose for 99% of mission time. It instead lands ‘backwards’ on the corners of its triangular wing, so every part of the craft contributes to producing lift. With the wing closed, this arguably reduces losses at the tips, compared with conventional reduction design techniques, such as adding winglets. Overall, this gives the 25 kg, fixedwing UAV a 10 kg payload capacity, as well as an endurance of 3.5 hours and a flight range of 300 km on its standard battery configuration. Additionally, the 025’s compact size means it can be disassembled into two small Pelican cases and transported by a single, small road vehicle. While both the FIXAR 007 and 025 can VTOL-transition, neither does so quite like other VTOLs (be they tailsitters, tiltrotors or hybrid-quads), which must be exhaustively programmed to safely deal with the hazardous manoeuvring required to go from hovering into forward flight, and vice versa. Nor do the company’s UAVs use tilting rotors. Instead, their rotors are integrated, such that they bear a nonvertical angle of attack (AoA) when landed or hovering: around 42° relative to the ground, rather than 90°. By angling the fixed rotors between the fully vertical and fully horizontal angles, the work needed by the autopilot and its programmers is minimised to a program that merges traditional quadcopter and aeroplane control system logic. “It takes a few unique control loops, and some smart use of one’s navigation system, because it’s not a simple matter of switching between a ‘copter mode’ and an ‘aeroplane mode’ – it’s both of those modes combined in different permutations, depending on whether you’re looking at the lower- or higher-level logic,” says Vasilii Fainveits, CEO of FIXAR. FIXAR started as a UAV engineering services company, carrying out design, development and validation of various systems and subsystems for different manufacturers. Development of the Rory Jackson investigates this established UAV manufacturer’s new flagship product, engineered with a unique form in pursuit of a fully maximised payload-to-weight ratio Triangulate this February/March 2025 | Uncrewed Systems Technology The FIXAR 025 has a rare triangular wing around the fuselage of its blended wing body, maximising its lift-generating area relative to its footprint (Images courtesy of FIXAR)
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