Train track to novel plane propulsion

Deep Dive

Revolutions are about bringing radically different ideas to the table and/or combining them in ways previously unseen. 

Compared with today’s passenger aircraft, those in development to operate tomorrow are just that. Once in a while a company strays a little further outside the box than most. This year, father and son-founded early-stage startup, MagLev Aero revealed plans for its proprietary ‘HyperDrive’ system.

Inspired in part by the maglev train, which has examples operating in China, Korea and, soon, Japan, Boston-based MagLev Aero’s system could be the first certified aviation application of magnetic levitation. A real second-mover, MagLev recognises the achievement of the first-generation of eVTOLs. Its founders want to represent the next generation of ultra-quiet, high-performance, vertical lift and cruise propulsion.

The HyperDrive’s magnetic levitation is thanks to an array of magnets found in the circular duct that houses two counter spinning rotors. The magnets basically act as a guide rail for the rim to which the rotor blades are attached, allowing them to spin without friction. Similar to how a maglev train ‘levitates’ on a rail. This allows the MagLev HyperDrive propulsor to operate with lower blade loading at slower speeds whilst maintaining hover lift efficiency.

One of the key benefits of such an approach is significantly reduced noise levels compared with traditional helicopters and multi-rotor eVTOLs. Ian Randall, MagLev Aero’s founder and CEO tells us: “What we’re doing is basically developing a novel propulsion platform that uses the most efficient proportion of your blade spin, so that we can load them more lightly and spin them more slowly, so they can produce less noise.” A large cutout ration means a lot of the hub is not used, making use of only outer portion allows for much slower spinning – it also makes for a striking design.

MagLev’s founders see ‘ultra-quiet’ operations as a necessity for deep market penetration. Rod Randall, MagLev Aero’s co-founder and chairman tells us: “There has been a tremendous amount of financing in this space but it is largely found among the top 10-15 companies. We have seen preorders grow from virtually nothing to over $30bn. But one of things that has not yet been completely solved is what it takes to get all the way to deep mass market adoption.” Randall built his career off building companies capable of such in the cellular network industry and he says it takes a lot more than just market entry to capture subscribers in their millions.

“Whilst redundancy level table stakes are there and one or two players appear to have an architecture suited to initial market entry, noise remains a problem,” says Randall. “Many eVTOLs are quieter than traditional helicopters in flyover. What is necessary to penetrate deep into neighbourhoods is it needs to be much quieter in flyover and takeoff and approach – which is the most difficult and loudest part of the mission sequence.”

Take a 5,000lbs helicopter operating in an airspace with a 65 decibel (db) day/night average noise limit. That gives that operator 40 flights per day in that particular region. An aircraft that is 12db quieter can achieve 500 flights per day per region, 15db quieter and that increases to 1,200 flights per day. Getting 20db quieter gets the figure to 4,000 flights per day. “It is not that you would do 4,000 flights in that area in one day, but it means if the average restriction is lower in certain regions then you can still fly. Which you cannot do today or with a first-generation eVTOL.” According to MagLev’s analysis, being 20-25db quieter ups mission opportunities 300x.

“Consumer appeal has to go from functional to beautifully inviting,” adds Randall.

As MagLev Aero defines them, first-generation multi-rotor eVTOLs are susceptible to unsteady loading. Understood as noise is the rate of change of pressure per unit and time. This means when blade surfaces go from high pressure to low pressure, they can produce significantly more noise than a steadily-loaded surface. “So, what we have is a configuration where recognising where the most effective portion of your blades are, maximises the utilisation of the blade span so we dramatically lower the loading per unit blade area. Taking the peaks out of the equation. We then shape our blades using the shorter span to then basically smooth out the loading across the entire span of the blade,”  Randall explains.

Operating in stealth since 2022, MagLev Aero’s initial fund-raising efforts have garnered support from investors including Breakthrough Energy Ventures, Stage 1 Ventures and Grit Capital. The firm holds more than 21 issued patents with more applications filed. It also recently announced a partnership with GE Additive’s Addworks unit to develop additive manufacturing and materials for the HyperDrive platform.

The firm has a crawl-walk-run-fly approach to market entry and is targeting small applications first in the unmanned cargo sector. MagLev has used its seed funding to complete some successful iron bird ground tests this summer and plans to fly a prototype in the next two to three years.

Josh Elvander, senior vice president, Engineering tells us the team is also quietly very proud of its AI modelling system. “We are following a very established engineering process which involves decoupling the challenges to individual technology demonstrations and then you evolve it into increasingly complex sub scale integration tests. The key element of it is the multi-physics model we have developed.”

This AI software model is the core of MagLev’s development. “We are continuously refining it through a combination of high and medium fidelity models. In many cases, because our system is so brutally unique, we’ve had to create a lot of the high fidelity approaches ourselves as exiting toolsets don’t really exist.” The takeaway for MagLev Aero from the models they have built is they show the company is able to scale.

Maglev Aero is soon to begin development of a flying prototype. To date its investors have made various bets on future mobility sectors, for example Breakthrough Energy Ventures has investments in ZeroAvia, LanzaJet and Heart Aerospace. Whilst Stage 1 Ventures has put money into automotive software firms, PureCars and Openbay.

Until now it would be easy to think maglev technology and aviation are poles apart. But whether or not that’s true, it seems like a good bet. There is no doubt this field is beginning to attract investment.

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