USE Network launch I UAV Works VALAQ l Cable harnesses l USVs insight l Xponential 2020 update l MARIN AUV l Suter Industries TOA 288 l Vitirover l AI systems l Vtrus ABI

30 tongue-and-groove system and are fixed in place with adhesives from 3M’s Scotch Weld range. Small bolts hold the winglets on, and these screw into nuts bonded into the CFRP structure. Other small nuts and bolts secure internal components, with nuts bonded into sandwich structures and press-nuts installed in solid sheets. The large winglets incorporate two fixed landing gear struts, while a third deployable strut is mounted on the fuselage and extended by an actuator during the approach to landing, cued by a ground detection algorithm. “Landing in high winds, with low motor rpm and close to a 45 º pitch forward requires an algorithm to detect the shock of ground contact,” Ortiz explains. The landing gear and the entire structure are designed to be robust enough to shrug off the landing loads, which can be as high as 8 g , he adds. These days, a few components – including the pylons on which the motors are mounted, some internal support structure and enclosures, and the removable panels that provide access to components – are additively manufactured using the synthetic laser sintering method of 3D printing. However, UAV Works is keen to investigate replacing this conventional structure with a completely 3D-printed alternative, which it believes will allow an even higher strength-to-weight ratio and improve the production process. Propulsion and power The company turned to Chinese UAV motor design and manufacturing giant BrotherHobby for custom-built brushless DC motors for the VALAQ family, and to Xoar in the USA for the two-bladed, fixed-pitch propellers. UAV Works’ development process addressed the motors and propellers together, using a test bench and a wind tunnel to refine their configurations, with Xoar’s expertise helping it to optimise the diameter, twist and pitch for this demanding application. “After many tests we found the most efficient tandem using the chosen brands, but this changes every six months so we always have to be testing new products to get the best configuration at all times,” Ortiz explains. While the VALAQ uses the same motors and propellers for VTOL and horizontal flight, it uses different batteries for them: a lithium-polymer battery powers the motors during vertical flight, and a lithium-ion unit takes over in aircraft mode. Lithium-polymer batteries are better suited to the kind of short-duration, high-power operation needed for VTOL operations, because they can deliver higher currents in relation to their size and weight than lithium-ion ones, even though the latter have higher energy densities overall. Lithium-ion’s higher energy density is exploited in horizontal flight to maximise the range and endurance, as this flight mode does not require as much power from the motors. UAV Works designed its own power regulation and safety electronics board, June/July 2020 | Unmanned Systems Technology VALAQ 120 Maximum take-off weight: 4 kg Payload: 800 g Wingspan: 1212 mm Length: 705 mm including gimbal Maximum speed: 120 kph Maximum altitude: 4500 m for take-off and landing (theoretical) Range: 70 km Video & telemetry link range: 15 km Endurance: more than 40 minutes with maximum payload Power plant: lithium-ion and lithium-polymer batteries driving four electric motors Some key suppliers Batteries: Sanyo Motors: BrotherHobby Motor controllers: DALRC Propellers: Xoar Servos: Shantou Jianxian Electronic Technology GNSS/inertial navigation sensors: Drotek Ground control station: in-house Stabilised cameras: NextVision CAD/CAM software: Solidworks, KiCad Video & telemetry link: Suntor Specifications The motor pylons are 3D printed, with brushless DC motors and two-bladed fixed-pitch propellers. Flow from the props over the wing eliminates stalling