Hybrid-electric ‘Hawaii Bird’ makes first flight

PUBLISHED: 11:00 15 October 2020

The use of electric or hybrid aeroplanes is being explored in Hawaii to connect its numerous islands

The use of electric or hybrid aeroplanes is being explored in Hawaii to connect its numerous islands

Ampaire 2020

When the Hawaii Bird flies on Maui, it will be the first time a hybrid-electric powered aircraft has flown under an FAA ‘market survey’ Experimental aircraft certificate in order to gain real-world flight experience

Electric aviation company Ampaire flew its second technology demonstrator on 10 September. The aircraft is a refined version of its Cessna 337 ‘Electric EEL’ hybrid-electric power conversion.

The company refers to the new flight test aircraft as the ‘Hawaii Bird’, as it will be flown by Ampaire and Mokulele Airlines pilots on air routes in Hawaii later this year in a series of demonstration flights. When the aircraft flies on Maui, the second largest Hawaiian island, it will be the first time a hybrid-electric powered aircraft has flown under an FAA ‘market survey’ Experimental aircraft certificate in order to gain real-world flight experience.

“Since flying our first Electric EEL last year, we have made substantial improvements to the power train for efficiency, increased performance, reliability, and safety,” says Ampaire CEO Kevin Noertker. “This technology is scaleable with wide applications for scheduled passenger and cargo services, as well as charter services. Our flights with Mokulele Airlines will be an opportunity to test both the aircraft and the infrastructure required to advance electric aviation and transport access in Hawaii.”

Noertker added that he expected the company to leverage knowledge from the 337 conversion program into retrofits of larger regional aircraft that could enter service in just a few years.

The Hawaii Bird is powered by a 310hp IO-550 in the tail, and a 268hp (200kW) rated electric motor in the nose, limited in this application to 160hp (120 kW). Compared to its first technology demonstrator, in this second conversion the aircraft’s battery pack has been relocated from inside the cabin to the underside of the fuselage and enclosed in a composite aerodynamic shell. The new configuration frees cabin space for flight test engineers, test equipment, and observers. Ampaire claims aircraft such as Electric EEL can cut direct operating costs and emissions by fifty per cent versus conventional aircraft, playing an essential part in helping Hawaii reach its goal of one hundred percent renewable energy for electricity by 2045.

In this latest conversion, the Electric Power Unit (EPU) has been designed with improved energy efficiency, less weight, and better thermal margins thanks to a liquid cooling system (versus the previous air-cooling system). The aircraft also has improved cockpit instrumentation and power controls for monitoring outputs from the combustion engine and electric motor. Designed to cruise at 120kt for one hour and fifteen minutes, plus a thirty minute reserve, the ‘Hawaii Bird’ can fly most Mokulele Airlines routes round trip before a required recharge.

During its first thirty-five minutes flight, test pilot Justin Gillen climbed to 3,000ft and made a series of handling and power checks, assessing engine and motor performance, temperatures and other readings, with both powerplants performing as expected. The aircraft will perform a further series of test flights before being shipped to Hawaii.

Ampaire is working in partnership with Elemental Excelerator, one of the world’s leading ‘climate tech accelerators’, to fund the Mokulele Airlines flight trials.

“Ampaire’s hybrid electrically-powered aircraft becoming an integral part of Hawaii’s transportation ecosystem will pave the way towards affordable and sustainable air transit throughout the US,” says Danielle J. Harris, Director of Mobility Innovation of Elemental Excelerator. “The success of this second flight test aircraft is a strong signal that innovative solutions like Ampaire’s electric-powered aircraft play a key role in helping a heavily visited state like Hawaii reach its ambitious renewable energy goals and meet its unique transit needs.”

Last year test flights for commercial flights using electric aeroplanes were also started in British Columbia, another promising area for electric aircraft as numerous islands are connected by a dense network of short-haul air routes.

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