The tremendous power density, low weight and efficiency of MTS machines (motor/generators) and inverters (controls and electronics) make them ideal for electric flight.
The MTS Electric Power Systems Team - US
First Row (L to R): Nick Gruber, Chris Hutson, Saurabh Tewari
Second Row (L to R): Ramon Guitart, Christoph Leser
Third Row (L to R): Sam Denny, Victor Aronovich, John Wattleworth, Colin Sturdevant
Fourth Row (L to R): Rohit Baranwal, Bob Buffin, Isaac Bandy, Alex Cosgrove
The MTS Electric Power Systems Team – U.K.
(L to R): Sam Guest, Kenny Lowe, Martin Akhurst, Stephen Blay, Wayne Webb, David Jerom
Poised for FlightMTS is renowned for its mechanical test systems; please explain the company’s new venture into electric/hybrid aircraft.
Guitart: MTS’ entry into the electric/hybrid aircraft industry actually stems from our achievements on the ground, supplying energy recovery systems for Formula 1 vehicles and traction motors and systems for Formula E vehicles. Our success in these highly competitive motorsports environments is directly attributable to the extreme high power density and efficiency of our electric power systems - characteristics that are equally, and arguably, even more important for airborne vehicles. While our primary focus is providing compact, lightweight electric solutions for aircraft propulsion, our motor/generator units and state-of-the-art controls are also well suited for a number of niche applications. These include power generation, driving high-speed pumps and compressors, and certain energy recovery applications.
Summarize the status of the electric/hybrid aircraft technology. What are the critical challenges that must be overcome to make it viable?
Leser: The emergence of electric aircraft is part of the same global megatrend that we see in automobiles - away from internal combustion engines - and in this case gas turbines - and towards electric propulsion.
However, the development path for electric aircraft will be a much longer than that of electric cars, due in no small part to the fact that electric batteries currently have very low per density in contrast to regular fuel – it is a factor of one to ten. This is particularly unfavorable for flight, so electric power needs to bring other advantages to the equation to justify this weight penalty.
One key reason to pursue electric power is that it enables more distributed, and thus more redundant, propulsion schemes. Whereas typical conventional aircraft employ a single internal combustion engine or a couple gas turbines, an electric aircraft could integrate upwards of ten highly compact motors, for example, across a single wing surface, greatly enhancing aircraft reliability and safety in the event of motor failure. Distributed electric motors are also more aerodynamically efficient, and a simpler system architecture presents far lower maintenance requirements than conventional propulsion. Another advantage is noise: for example, an electric helicopter would have a lower noise footprint and therefore allow more urban deployment than is currently possible.
Realizing fully electric flight, as with the development of electric automobiles, will likely require an extended period of hybridization - combining electric motor/generators and internal combustion engines or gas turbines. Not to say that there are not people looking at fully electric aircraft, but aerospace manufacturers will not be turning away from internal combustion engines anytime soon.
What attributes of MTS electric power systems make them suitable for electric/hybrid aerospace applications? What advantages do they offer vis-à-vis competitive offerings?
Guitart: As mentioned, MTS motor/generator units exhibit extremely high power density and are thus very compact and lightweight. This is critical for deployment in aircraft.
However, what really sets our offering apart is our systems approach. We engineer the machines (motor/generator units) and inverters (controls and electronics) in conjunction, so we can integrate and synchronize the two to a degree unmatched by anyone else. This approach stems from more than five decades as a leading provider of state-of-the-art mechanical test and simulation systems. These systems are built to orchestrate the precise application dynamic forces and moments throughout six-degrees of freedom to test the performance and durability of ground vehicles, aerospace structures and civil structures like buildings and bridges. As a result, our electric power system controls, application software and integration processes are unparalleled, yielding complete solutions capable of delivering optimal power density at the highest possible efficiency point.
In addition, and this is not trivial, MTS electric power systems have already proven very reliable under extremely harsh motorsports racing conditions, successfully withstanding tremendous acceleration cycles, high temperatures and punishing vibration.
Tell us more about the motorsports origins of MTS’ machine/inverter units.
Leser: As Ramon said, MTS is a world-class innovator of mechanical test solutions. One of our technology milestones was the development of an electric, lab-based system that could replicate the torque and acceleration of a high-performance Formula 1 engine in order to test F1 transmissions. At the outset, a global search revealed that no vendor could provide an electric motor dynamic enough for this application, so we had to develop it in-house. After exploring the physics, MTS’ Victor Aronovich devised a highly optimized permanent magnet design capable of delivering the tremendous dynamic response required for this type of test.
From there, the MTS team further optimized and adapted Aronovich’s motors for deployment as onboard kinetic energy recovery systems for Formula 1 racecars. Meeting the demanding performance and compact physical requirements for that application, truly, is what launched us on our current trajectory as a manufacturer of extremely power dense, low weight and efficient electric power systems. Also, as mentioned, the harsh motorsports environment - extreme accelerations/decelerations, high temperatures, jarring shocks and vibrations - served to temper our technology, driving us to meet very high standards of robustness and reliability.
The rigors of Formula E racing, as well, have served to propel MTS technology to new levels. Meeting Formula E requirements compelled us to explore new ways to reduce costs and further optimize efficiency. The product of this was a new silicon carbide inverter, which enabled us to reduce size and weight by a factor of three relative to previous units.
Talk about what your offering brings to your primary application focus: Propulsion
Guitart: Again, the tremendous power density of our machines and the low weight and efficiency of our integrated systems make them the ideal solution for electric flight propulsion. In addition, our engineers have devised a new, highly compact mechanical design that tightly integrates propeller, pitch control mechanism and motor, essentially eliminating the need for a gearbox. We call it an inside-out motor, and its streamlined profile and lower weight make it ideal for deployment throughout aerodynamically efficient, distributed power architectures.
What attributes of your offering make it suitable for the niche applications you mentioned initially?
Guitart: Obviously, our low weight, high efficiency systems would serve well as onboard power generators. As aircraft transition from hybrid to fully electric - i.e. battery powered - there will applications for compact IC motor/generator sets to power specific systems or localized zones. We have been in touch with numerous customers already to explore these types of applications.
We are also building machines and inverters to drive next-generation pumps and compressors for both hybrid and IC/turbine aircraft. Unlike the relatively massive, centralized pump and compressor schemes deployed today, the next generation will be smaller, lighter and distributed throughout the aircraft, affording far higher levels of control and operational efficiency. To achieve the weight and size reductions to make this distributed approach feasible, our engineers leveraged ultra-high-speed machine technology developed originally for electric turbo compounding, or eTurbo, applications in Formula 1 racing. eTurbo machines recover heat energy from high-performance IC engine exhaust and so must be capable of reaching tremendous speeds, well in excess of 100 thousand RPM. Indeed, eTurbo is applicable to conventional piston-driven and hybrid aircraft. It could recover IC motor heat energy to drive auxiliary electric motors and/or charge batteries, boosting overall efficiency and extending range of flight.
It is important to point out that this diversity of motor uses, all spinning off (pardon the pun) from Aronovich’s original innovation, really highlights a core MTS competency: our ability to take a breakthrough technology and aggressively pursue it through the full trajectory of application possibilities.
The EPS team seems quite small relative to MTS’ greater test organization. What special infrastructure or tools does it have at its disposal to optimize and adapt electric power systems across applications for Formula1, Formula E and now hybrid and electric aircraft?
Leser: As stated earlier, MTS has spent the last fifty years providing state-of-the-art testing equipment and infrastructure for research and development across automotive, aerospace and civil engineering. Nobody does it better. So of course, we have managed to put in place an array of EPS test benches aimed at different tasks. We manufacture hundreds of specialized motors yearly for the motorsports industry, so we have numerous QA/QC benches. And obviously, we have several high-performance R&D benches for any kind of custom project that we undertake; these capable of up to 150 thousand RPM – anywhere between 1 kilowatt to 1 megawatt of power. While engineered for our own product development, we also manufacture them for customers to help them reach optimal performance from their machine/inverter designs – whether for traction/propulsion, energy recovery (heat or kinetic), or other motor applications.
Do MTS test systems used for conventional aerospace structures have applications in the development of electric/hybrid aircraft?
Guitart: Absolutely. Aircraft design will certainly have to evolve to contend with the physics of electric flight. The wings themselves will have different structural characteristics – think distributed power - and airframes will have to integrate new, lighter weight materials to a far greater degree than conventional IC or turbine powered aircraft. Again, it is the same phenomenon we are seeing with electric/hybrid ground vehicles. New structures comprising new materials and components will have to undergo rigorous mechanical testing for determining fatigue life, strength and, of course, safety.
With regards to conventional testing, I think it is interesting to point out that one of the first non-motorsports applications for our electric power systems was replicating the aerodynamic effects of powered jet engines during wind tunnel testing of scale aircraft models. Our compact, power dense motors can provide the thrust required for these simulations far more accurately and efficiently than conventional, energy and infrastructure intensive air turbine powered simulators.
Aside from the technology itself, what makes MTS as a company well suited to serve the electric/hybrid aircraft industry?
Leser: Primarily, the strength of our EPS team. We have world-class talent in place, spanning software, hardware, electrical, power electronics and mechanical engineering. This allows us we take the systems approach we spoke of earlier in terms of controls, electronics and electro-mechanics.
Next, our experience. Of course, there is our 50 years of mechanical testing leadership. But taking electric motor technology originally developed for laboratory-based mechanical testing and successfully adapting it for onboard motorsports applications - Formula 1 and Formula E - is not trivial. Because the same challenges - maximizing power density and efficiency while reducing weight - are also critical for electric flight, we are uniquely qualified to make the technological leap from the ground to the air.
Lastly, I would like to mention our supply chain. We have been a reliable global supplier of high-performance electric power solutions, often highly customized, for more than ten years now. Our partners are trusted and reputable, and can be relied upon to adhere to the evolving standards regimes that will surely accompany the emergence of this brand new industry.
Speak more about the emergence of this new industry. Profile MTS’ presence in this new environment.
Guitart: The electric/hybrid aerospace industry is at the beginning of a long development cycle. Even so, we are seeing an incredible diversity of players worldwide, actively working the challenges. These range from small start-ups to the established air framers to conventional propulsion system suppliers; and of course, government agencies around the world are putting their best foot forward. Currently, we are covering the whole spectrum: working with numerous companies (some as small as a few people, even individuals) all the way up to prominent universities and agencies, like NASA. Our work, too, is diverse, ranging from innovating (what we do best) to analyzing and validating the designs of others to providing general technology guidance. Ultimately, while MTS is among the new players in this industry, we have the potential to make a significant contribution, given the relevance of our experience, the unmatched attributes of our offering and the world-class talent and capabilities of our EPS team.
>> CONTACT MTS
>> SIGN UP TO RECEIVE OTHER VERSIONS OF FORCE & MOTION