Uncrewed Systems Technology 049 - April/May 2023

Come join the autonomous revolution www.uncrewedengineeringjobs.com Come join the autonomous revolution Rotron Power RT600-HC | Dossier configured the electric part of the powertrain in a few different ways over the years, starting with an InnovateUK project a few years back, where we worked with Cranfield University [in England] to produce a series-hybrid powertrain,” Head recounts. “That used an Emrax motor/generator but we’ve used other suppliers, and we’ve even put generators together ourselves. What we’d particularly like to do is couple the engine to, say, a YASA axial flux motor in order to create a hybridised generator pack that fits all our customers’ aircraft. We’re aiming to do that by raising r&d funding through InnovateUK.” For now, when it comes to customer requests for electric power within specified voltage, volume and weight constraints, Rotron opts to integrate COTS systems that suit the desired specifications. Sullivan-Acutronic is among its preferred suppliers for permanent magnet generators and regulator units, and 3 kW systems are typically the largest Rotron has integrated, 1-3 kW versions having become quite commonly supplied to its customers. “In general we’ll tend towards picking a high-power system but rating it a bit lower than what’s on its data sheet,” Head notes. “Because it’s typically working in the loud, hot and very harsh environment of a helicopter engine bay, even the most mature generators we use are being pushed to the limits of what they can tolerate environmentally.” Green future Rotron anticipates an increasing share of its r&d going towards hybridisation for cleaner and more efficient power, with higher energy densities than present battery technology, and the use of alternative fuels such as hydrogen. “Aviation needs high power density, and burning hydrogen in our engines might be the most reliable and cost- efficient way to achieve that with zero emissions,” Head says. “Mazda for instance are bringing out their rotary range extender which can run on hydrogen or gasoline, so there’s clearly technical as well as commercial viability in developing our engines in that direction.” At the time of writing, Rotron had completed some preliminary tests of running its rotary power plants on hydrogen, and is keeping an eye out for the right type of grant funding or partner to take it towards its aim of a hydrogen- powered Wankel engine. Rotron has integrated a range of different generators for customers’ varying electrical or hybridisation needs, with 3 kW systems being the largest so far