The aviation industry has never seen a propeller quite like this before.
Hartzell—which has designed and built propellers for more than a century—on Monday revealed that the FAA awarded Part 35 type certification for a new prop tailored specifically to electric, hybrid-electric, and other advanced air mobility (AAM) aircraft.
The five-bladed, carbon-fiber, ground-adjustable, fixed-pitch design is the first Part 35 propeller of its kind. It is designed for high-performance, low-noise operations, making it a natural fit for electric vertical takeoff and landing (eVTOL) air taxis and other models that are expected to fly in cities.
Hartzell, which has certified hundreds of propeller designs, began exploring AAM in 2019. Since 2021, it has worked with electric aircraft manufacturer Beta Technologies to test and refine its next-generation prop. Now, the FAA has opened the door for operational flights on models such as Beta’s four-passenger CX300, which could debut as soon as next year.
“From OEMs to propulsion companies, we’re working with them all to develop the future of electric and hybrid powered aviation,” Mitch Heaton, director of sales and marketing strategy for Hartzell, told FLYING.
Hartzell has also installed custom propellers on Eviation’s all-electric Alice, and its lightweight, four-bladed, carbon fiber composite prop powers Harbour Air’s eBeaver seaplane.
Propelling the Future
According to Beta, certification testing for the electric engine propeller was conducted exclusively on the company’s H500A motors, a pair of which feature on the CX300. Its test aircraft have flown with Hartzell propellers for more than four years. The manufacturer plans to install them on both the CX300, a conventional takeoff and landing (CTOL) model, and Alia eVTOL. Like the propellers, it plans to certify the H500A separately.
“We are developing several types of propellers for many different requirements, including constant speed, ground-adjustable fixed-pitch, lifters, and tiltrotors,” Heaton said. “Each requirement is a little different.”
Beta conducted the evaluations at its “motor-propeller farm”—a set of test stands that operate 24 hours per day. It ran the props on- and off-aircraft, testing different load cases, endurance, and even ice ingestion (it plans to certify the CX300 as IFR).
The firm said its proprietary electric engines are built to operate under diverse conditions, for which the Hartzell prop is “uniquely designed” as well. Earlier this year, for example, it took the CX300 on a six-week, 25-state, 8,000 nm barnstorm across the U.S., during which it flew in day, night, IFR, and VFR conditions, as well as snowstorms and scorching heat. A second aircraft is making its way across Europe and featured prominently in June’s Paris Air Show.
Among Beta’s customers are UPS, Bristow Group, and Republic Airways, which in Paris accepted a CX300 delivery scheduled for later this year. Republic operates regional service on behalf of United Airlines, American Airlines, and Delta Air Lines, which could be some of the first to deploy the new Hartzell prop.
Beta at the air show said it is building its first type inspection authority (TIA) conforming aircraft, with critical full-aircraft testing set for later this year. The Alia eVTOL is expected to begin that process about one year later.
A Beta spokesperson told FLYING that the testing with Hartzell will have no impact on TIA requirements from the FAA. But the company did participate in the certification definition phase, giving it a front-row seat to the agency’s process that could help it accelerate its efforts.
So far, only a handful of electric aircraft have been deemed safe for commercial operation. Pipistrel’s two-seat Velis Electro was the first, earning European Union Aviation Safety Agency (EASA) type certification in 2020. Flight schools in the U.S. are just starting to adopt the Velis.
But new entrants could be on the horizon. Earlier this year, for example, EASA certified Safran’s ENGINeUS as the first airworthy electric motor for civil aircraft. The approval allows Safran to install the engine on customer Diamond Aircraft’s eDA40, after which it will move to larger models. Other ENGINeUS customers include electric aircraft developers Electra and VoltAero as well as flight simulation provider CAE.
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