Uncrewed Systems Technology 047 l Aergility ATLIS l AI focus l Clevon 1 UGV l Geospatial insight l Intergeo 2022 report l AUSA 2022 report I Infinity fuel cell l BeeX A.IKANBILIS l Propellers focus I Phoenix Wings Orca

102 Focus | Propellers case and how strenuously the payload must be protected. However, 0.25- 0.3 mm is probably the minimum thickness physically possible; any thinner and the material can suffer microfractures while being removed from its mandrel. It follows that this type of erosion protection can be mounted around the whole blade or simply over the tip, covering the front third or half of a blade, where most of the erosion will take place. That saves on material costs and weight – many adhesive tapes are sufficient to safeguard the middle and rear regions of prop blades in most cases. While these nickel-cobalt protection systems are not cheap to produce, they can significantly lower overall operating costs. Aside from helping propellers to last longer, their required mean time between inspections runs into the thousands of flight hours. As well as keeping prop blades safe against physical strikes, protecting them from icing-up becomes increasingly important as more missions in colder climates are requested. To that end, installing resistance wires inside a propeller’s materials looks to be one of the most promising preventative approaches for uncrewed systems working in such conditions. For this, an electrical interface is needed between the propeller and the onboard power system, to enable current to run through the wires in the prop blades. The wires act as resistors, converting effectively all the current into heat as commanded by their control system. Testing methods Naturally, as more stages of propeller manufacturing become automated, quality control becomes easier, with mistakes in resin distribution or heat regression during curing becoming rarer as computer control largely eliminates human error. Meanwhile, testing methods for prototyped or finished propellers are also being improved in order to satisfy regulators and investors for uncrewed systems that such vehicles’ propellers are robust, professional-grade components. For instance, 3D scanning of propeller profiles can reveal a lot of information about how precise the manufacturing processes are, where mistakes are being made, and how closely or consistently manufacturing tolerances are being met. It can also provide a vital insight into the properties of newly simulated and prototyped propeller designs, and examine how robust new designs are in real-life compared with, say, FEA. In addition to well-established laser scanner systems, blue-light sensors are used to inspect some propellers. The sensors work by projecting a pattern of narrowband blue light across the surface of a part to filter out any potential interferences from ambient light, then use stereo cameras to capture that pattern and recreate the 3D shape of the part by recognising any distortions in the projected pattern created by the part’s profile. December/January 2023 | Uncrewed Systems Technology Metallic leading-edge protection is increasingly popular for safeguarding props against impacts and erosion (Courtesy of Xoar) Nickel-cobalt alloy protection systems can be electroformed to precise tolerances for aerodynamics and mounting (Courtesy of Fichtner & Schicht)