Harbour Air is nearing the 100th flight of its electric eBeaver, which is powered by a MagniX propulsion system that includes the motor, control electronics, and cooling system. At the McKinsey Regional Air Mobility Summit on March 28, MagniX chief technology officer Riona Armesmith provided an update on the development of MagniX’s electric propulsion system and Harbour Air’s eBeaver, in which the original float-equipped de Havilland DHC-2’s Pratt & Whitney R-985 piston radial engine are replaced with a smooth-running, quieter, and easier-to-maintain electric powerplant.

“We’ve been flying the eBeaver for five years now,” at Harbour Air’s Canada headquarters in Richmond, British Columbia, Armesmith said. “We still learn stuff all the time with the aircraft, especially with operations and maintenance. We just did our second teardown, strip, and inspection on the engine, then put it all back together and back in the aircraft. We do that about every two [to] two and a half years to see what’s going on.”

Dispatch reliability of the MagniX powerplant is 100%, according to Armesmith, “which is pretty phenomenal for a first engine, and that’s across all of our platforms. It behaves very well.” One of those other platforms is a Robinson R44 helicopter modified by Unither Bioelectronics, with a MagniX electric motor powered by a hydrogen fuel cell. The hydrogen-powered helicopter achieved its first flight on March 27.

Better Batteries Boost Endurance

At the time of the McKinsey Summit, the eBeaver had flown 97 times since being converted to electric propulsion, but each flight didn’t last long, so the number of hours logged isn’t high. The first batteries are an earlier generation that requires time to cool after each flight before being recharged overnight. New batteries developed by MagniX are cooled while they charge, which will speed up the turnaround process. “The rate of flights that they were able to do with the older battery system was quite limited,” she explained. “Now we’re hoping to get through the cadence of this faster charging, with cooling while they’re charging.”

Harbour Air next plans to demonstrate the eBeaver with an international flight between Canada and the U.S., which should help stimulate Transport Canada’s electric aircraft regulatory muscles, she explained. Another effort will be to put the eBeaver on wheels, she added, “because they’ve had a lot of interest in the aircraft on wheels instead of floats. They’re going to be doing performance flights to see how much more they can get out of the aircraft when it’s on wheels.”

Meanwhile, MagniX has introduced a new HeliStorm propulsion package for helicopters. The plan is to match the MagniX system with the helicopter’s existing gearbox to make conversion simpler, and the motor runs at higher RPM to match the input speed of the gearbox.

“Everything [the motor] is direct drive,” Armesmith explained. “It’s more customer demand-driven than we have done before. When we first started out, no one was doing this. So, we … drew a box around part of the industry that we were wanting to go after and developed an engine for that. We see a lot of opportunity.”

MagniX motors have powered the first electric R44 and the recent hydrogen fuel cell-powered R44. “You can do a lot with where batteries have gotten to just now; it’s opened up the space for electric helicopters without redesigning the whole vehicle,” she said.

MagniX began developing its own batteries 18 months ago for better integration with its propulsion system. “We felt like we needed to control our own destiny in that,” she said. Battery development still is a pacing item for certification of electric propulsion, but she believes that Harbour Air should have a smoother path to certification of the eBeaver as it qualifies as a Level 2 Part 23 airplane with seating for two to six passengers, as opposed to more complex rules for higher numbers of passengers or Part 25 aircraft.

However, the eBeaver can’t be certified until its electric powerplant receives approval. “We have special conditions against Part 33 for the electric engine, and we’re making good progress,” Armesmith said. “It’s been a big focus of the last year.” Some of that work includes high-altitude testing at the NASA Electric Aircraft Test Bed at the agency’s Armstrong Flight Test Center in Sandusky, Ohio, as part of the NASA Electrified Powertrain Flight Demonstration project.

“There’s nothing like it that exists elsewhere in the world,” she said. “For the past year, we’ve been testing our engine in that facility up to 31,500 feet, proving that it’s partial discharge-free, which is not an easy thing to do.” This means preventing any leakage of electricity at altitude, where the air is thinner and provides less insulation. “It’s an electrical phenomenon, so the insulation reduces with altitude. It’s whether you’ve got a sort of reduction or a breakage in your insulation system, like a partial arc, right where you’re having leakage, and it’s especially difficult to avoid that at altitude. You have to have an almost perfect insulation system to be able to test for it. That’s what we’ve worked through with some great partners and with NASA to prove it out.”

Electric Engines Pose Novel Certification Challenges

“This past year [we have] been working on the more novel aspects of certification of an electric engine,” Armesmith added. “One of them is partial discharge and the other is every single electrical fault, showing that we can detect it, accommodate it, and not just shut the engine down every time there’s a fault, so that we can ride through them, accommodate them, do something about them, and [it’s] not leading to a fire. It’s something that we’re proud of, the work that we’ve been doing in that area and in the controls and protection space. [We’re] just working through the harder aspects of proving this absolutely is as safe, if not more, and as reliable, if not more reliable than existing engines.”

The 650-kilowatt Magni650 electric propulsion unit that powers the eBeaver has four inverters, she pointed out, “so we have four opportunities for failure. We can lose one inverter and still provide 85% of power on the engine. And there’s more ability to respond to faults as well. With electrical faults, you are able to detect them. There are fewer parts. You don’t have wear mechanisms that you do in gas turbines. It’s really about managing the much higher part count in your electronics relative to a simple mechanical system. That’s the kind of work you have to go through on the reliability side, especially to prove that you can hit the same probability of failure rates.

“On the electrical side, you have to deal with not only all the electrical things that can happen, but keeping things cool. We’ve got a cooling system built into the propulsion unit, but that’s all got to meet those same reliability [standards].

“There are basically two camps in the industry now: air-cooled motors and liquid-cooled motors. We have a liquid-cooled motor, and so we have a similar system to a small gas turbine or piston engine with a mechanically driven oil pump and an oil system that lubricates bearings and cools the motor.” 

The same oil also drives the propeller governor and lubricates the gearbox, and this simplifies maintenance because there is only one fluid to check and change. “We try not to add new or novel fluids that aren’t available at the airfields where you operate these things,” she said. “That’s the power of our relationship with Harbour Air, it’s taught us a lot. They’re a real airline. We’re able to learn a lot from them about real-world operations and maintenance. We try and slot in as easily as possible into the existing aerospace system; we’re trying not to be novel. It just adds layers of friction we don’t believe are necessary.”

Another milestone MagniX expects to reach this year is endurance testing. “We’re about to start running that [engine] on our propeller test facility and put it through its paces,” Armesmith said. “We’re building candidate-conforming hardware to run through an endurance test campaign.” The plan is to run internal testing first before the formal FAA campaign. “It’s working through that journey with the FAA … saying, ‘this is how we propose to do an electric engine endurance test, how it’s different from a piston or a gas turbine test, and show that you stress the engine in ways that it will be stressed in service.’”

“That’s like the next year of work,” she added. “We’re working through our software and developing our battery so that we can have hardware to deliver to customers. There is nothing more powerful than getting in-service feedback on how it integrates into an aircraft. Is it easy? Is it difficult? How does it interact with everything? How does it talk to everything? And then we’re working on developing our new HeliStorm engine with everything that we’ve learned and building all of those learnings into a new product.”

For its new battery, MagniX has been researching the available energy storage technology, including working with NASA on cell testing. “Picking the right cells has been a lot of our focus and developing a battery module around that,” she said. “We’re working toward bringing a module together and testing that. We’ve been developing the battery management system and all of these parts as well. Now it’s bringing it all together to test it as a unit. We aim quite high. It’s already 300 watt-hours per kilogram energy density, which would be the highest in the whole industry. [These are] some high targets to go after, and getting the right balance between cost of the cell and the cycle life of our battery solution.”