DroneX 2023 | Show report (each designed for 30 A of continuous current, 50 A peak), an LED driver for four WS2812B-type strips, and DC outputs of 3.3, 5 and 18 V. The standard power distribution board is offered as a default, although as the interface is open source, it can be customised into a form or architecture better suited to the needs of a specific UAV. Electric motor manufacturer Alva Industries announced the second generation of its Altus X60 electric motor series, the company’s flagship product family that uses its patented FiberPrinting technology for constructing e-motors with ironless stators. “We’ve done a lot of harsh and abusive testing on the motor, including 24/7 test rig cycling and simulations of uneven loading during high-speed and oscillation flights, the biggest cause of motor failures in UAV flights,” said Anton Frantzen. “Based on the test results, we’ve pinpointed and implemented several areas of improvement. “Those include structural changes to enhance the lifespan against fatigue, along with some design changes to make manufacturing easier. For instance, the stator housing used to be assembled from two components – the cooling and bearing housings – joined with an adhesive. But now they’re manufactured as a single piece, which simplifies things a lot.” Both the Uno and Duo versions of the X60 were previously tested to a maximum of 1000 hours, and Alva Industries anticipates this figure being revised upwards, the exact new figure to be determined via testing. “We’ve also done some redesigns at the system level to make the motor housings weatherproof under any normal rain or thunderstorm conditions, including an extension to the housing that allows the motor to seal around the rotor arm or boom, to prevent water ingress into the motor or UAV,” Frantzen added. The X60s can also now incorporate accessories. A port has been designed into the motor housing to power and interface over CAN with navigation and warning LEDs, among other devices. The company also now designs motor housings for integration with 40 mmdiameter rotor arms, or rotor arms with octagonal cross-sections measuring 25 x 38 mm. Previously they could only mount directly onto 30 mm-diameter arms (now covering all industry-standard multi-rotor arms). Hydrogen Craft Corporation exhibited for the first time at DroneX to showcase its two hydrogen PEM fuel cell products: a 1.7 kW unit weighing just under 2 kg, and a 550 W unit weighing about 800 g, which are also used in a range of UAVs the company manufactures. “Historically, air-cooled fuel cells have suffered from critical engineering challenges which affect their operating performance,” Haili Liu told us. “For instance, as well as being sensitive and fragile, they have very long re-activation times if they’ve been left standing for a long time, due to the exposure of the proton exchange membrane to the air. “That causes the PEM to dry out, so restarting it takes at least several minutes. When you compare that to batteries, which work almost instantly, you realise that’s a serious hurdle to the practical use of air-cooled PEMFCs and a big reason why they’re not used in a widespread way, despite being at least three to four times more gravimetrically energy dense than batteries.” Since its founding in 2017, Hydrogen Craft Corporation has therefore focused its r&d on the catalyst-coated membrane level of its fuel cell technologies, resulting in the creation of material layers within the stack that manage its internal water channels differently to other fuel cells. The layers preserve the ambient humidity about the MEA for long periods between operations of the PEMFC. “Last year, we achieved a 1.8 second start-up time with our fuel cell products, which was verified and certified by the Shanghai Auto Testing Centre,” Liu added. “That’s a key reason why our UAVs powered by our fuel cells are now regularly flying in power grid and oil pipeline inspections. “Our next goals are working towards lighter fuel cells as well as HT-PEMFC [high temperature PEM fuel cell] technology. We believe the latter is going to be the future for eVTOL taxi powertrains, and we’ve started collaborating with COMAC [Commercial Aircraft Corporation of China], supplying hydrogen powerplants to their eVTOL programme.” 87 Uncrewed Systems Technology | December/January 2024 Alva Industries’ Altus X60, coaxial version
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