Propulsion pioneer MagniX is developing a new family of electric engines specifically designed for helicopters. This week, the U.S. company is going public with its response to demand for faster rotor speed motors with between 6,000 and 7,000 rpm, compared to 1,900- to 2,500-rpm powertrains it is already developing for other applications.

MagniX is working the helicopter motors, which it announced on Monday at Verticon 2025, with a view to be ready to start tests next year. It is aiming to have hardware, which will be integrated with the company's Samson batteries with an energy density of up to 300 Watt hours per kilogram, delivered to early customers in 2026.

According to MagniX chief technology officer Riona Armesmith, several rotorcraft manufacturers have approached the company seeking a fresh approach to electric and/or hybrid-electric propulsion. MagniX’s engineering team is working on configurations for direct drive applications with no gearbox, and also for the motor to be combined with a turbogenerator, which in some instances might be used to produce power for non-propulsive purposes on aircraft.

While MagniX has yet to announce an initial rotorcraft application for the Helistorm engines, Robinson Helicopters has already shown interest. “MagniX has a proven track record when it comes to powering our R44 with their electric motors,” said the manufacturer’s CEO, David Smith. “Robinson is supportive of MagniX’s HeliStorm electric engine range and we look forward to continuing our collaborative efforts to deliver market leading sustainable helicopters.”

The power rating for the new engines would be no higher than the 350- to 650-kilowatt Magni350 and Magni650 electric propulsion units (EPUs) now in development for other applications. Armesmith said her team would leverage the company’s experience of integrating motors with five different aircraft that have flown to deliver increased rotor speed. 

Smaller, Lighter and Faster

Fundamentally, the architecture of the new engine will be fairly similar to what MagniX has already produced, but they will be smaller and lighter. The first powertrain in the range is expected to deliver peak power of 330 kilowatts and weigh just 165 pounds.

“Getting higher speeds is mainly a mechanical challenge,” Armesmith told AIN. “For what we have today [for converting aircraft such as the Cessna Caravan] there is a large cone at the front of the engine to take the load of the propeller. We can take this off and won’t have a propeller governor so we can skinny it down. The challenge is to make it smaller.”

Asked whether the higher speed motors would have increased wear and heat issues, MagniX CEO Reed Macdonald said the company will deliver new motors that can match the maintenance intervals of established helicopter engines. The Seattle-based company has been developing electric propulsion for the past 19 years and has produced motors for converted Caravan and Beaver utility airplanes, as well as for new airframes such as the Alice fixed-wing model being developed by Clermont Group sister company Eviation.

According to Macdonald, the path to market for an electric helicopter will be more straightforward than it is proving to be for eVTOLs. Acknowledging that European rivals such as Safran and Pipistrel have already achieved certification for electric propulsion with EASA, he indicated that MagniX feels it is in a good position to be the first to get to this point in the U.S. with the FAA, which agreed to Part 33 special conditions with the company in 2021.

“The helicopter market represents a tremendous opportunity for MagniX, as the strengths of our technology align well with the market need,” Macdonald commented. “MagniX’s Helistorm engines expand upon our existing world leading capabilities and deliver a step change in performance, reliability, and value for our customers.”

Plans For Electric Robinsons

In June 2022, an electric Robinson R44 helicopter developed by Tier 1 Engineering for prospective customer United Therapeutics flew for the first time at the Los Alamitos Army Airfield in California. MagniX provided the electric motor for the planned conversion program, for which Tier 1 was seeking a supplemental type certificate.

In August 2024, Unither Bioelectronics announced a partnership with Robinson Helicopter to developer hydrogen-electric powered versions of the R44 and R66 rotorcraft. MagniX is partnered with Unither to develop the fuel cell-based propulsion system for this program.

MagniX is also working with NASA to test the Magni650 EPUs with the agency’s Electric Aircraft Testbed laboratory. This simulated flight conditions at 30,000 feet with a maximum continuous power output of 700 kilowatts. The next phase of the work will see the EPU being installed in place of one of the four turboprop engines on a DeHavilland Dash 7 that should start flight testing in 2026.