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20 In conversation | Ray Leto and r&d facilities in central Ohio, near Leto’s home, just as he was looking for a new challenge. “We talked and decided to start a US- based arm of the company, with Naethan Eagles leaving Williams F1 after founding a successful CFD department there to join as CTO and co-found TotalSim US,” Leto recalls. The basis of TotalSim’s technology solution was a vehicle engineering workflow built around the open source OpenFOAM CFD software, which has since been rolled out under support contracts to numerous places (including Honda in the US). “Again, racecar modelling is all about rapid turnaround, rapid analysis and a consistent methodology to produce results that you can recreate come race day. And that world in the mid-2000s saw CFD go from a very laborious, handcrafted black art into something detailed and laid out – it essentially went from ‘science’ to ‘engineering’, in that it became a sequence you could examine, divide up and iterate,” Leto explains. “We wanted TotalSim to apply that mentality to different industries, to help aerospace, automotive, marine and other users to make vehicle simulation and testing more repeatable, more trustworthy, and faster. That way we could dial modelling fidelity up or down depending on what people needed and on the physics of the problems they were dealing with.” From racing to unmanned systems Although the collective contacts of Leto, Eagles and Lewis were almost all originally in motorsport, the CEO has noticed more and more race engineers over the past decade leaving racing behind for greener pastures, unmanned systems being the most popular destination for them. “General aviation has had a huge rebirth through UAVs, and that’s continuing in the eVTOL world too,” he says. “We run into so many people in these new aircraft spaces that we’d last met in motorsport or related industries. “Advances in modelling and simulation have flowed outward into so many other industries, and greater accessibility to CFD through CAD packages has democratised what was once a fairly inscrutable science. “It’s still challenging to execute high- quality CFD, and it still takes a lot of resources and knowhow. As well as bringing together a really great team of engineers here, we have a couple of thousand computer cores and a 10 Gbit/s connection to the Ohio Supercomputer Center, which has 40,000-50,000 more cores if we need them. Through those, we can output giant models with incredible fidelity to understand what changes need to be made to get that last 1-5% of efficiency. “For companies moving towards designs for manufacturing, our tech captures minute details in things like stall separation, rotor design and other things that need really heavy-duty computational hardware and software. “Marine CFD is also really challenging: USVs have to cut through two sets of fluids, so they’re not straightforward to simulate at all. There are huge opportunities for improving designs and performance among USVs through the latest wind tunnel and CFD practices.” TotalSim US’ first foray into unmanned systems came in 2012, mainly through Andy Luo (the head of its California office) who had previously worked with Swift Engineering, the manufacturer of the Swift020 UAV featured in UST 16 (October/ November 2017). Leto and his team identified how to increase performance and mitigate issues on an existing (and so far undisclosed) vehicle design, as well as how to adapt it for different powerplants and thermal management approaches, while noting the knock-on effects on aerodynamics. April/May 2022 | Unmanned Systems Technology Extensive modelling capabilities are especially important to aerodynamic and safety analyses of the latest generations of heavy-lift UAVs and eVTOL aircraft