15 September 2020
+VIDEO Electric aviation company Ampaire has flown an updated version of its Cessna 337 ‘Electric EEL’ hybrid-electric aircraft 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.
“Since flying our first Electric EEL last year, we have made substantial improvements to the power train for efficiency, increased performance, reliability, and safety,” said Ampaire CEO Kevin Noertker.
“This technology is scalable with wide applications for scheduled passenger and cargo services, as well as charter services. Our flights with Mokulele will be an opportunity to test both the aircraft and the infrastructure required to advance electric aviation and transport access in Hawaii.”
Noertker said he expected the company to take knowledge from the 337 conversion into retrofits of larger regional aircraft that could enter service in just a few years.
The Hawaii Bird is powered by a conventional 310-horsepower Continental IO-550 combustion engine in the tail, and a 200kW-capable electric motor in the nose, limited in this application to 120 kW.
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 aerodynamically-optimised shell. The new configuration frees cabin space for flight test engineers, test equipment and observers.
On September 10th, 2020, we successfully flew, for the first time, our 2nd hybrid Electric EEL. The flight lasted 35 minutes and all systems performed nominally. #LeadingtheChargehttps://t.co/QD48SxV58j
— Ampaire (@AmpaireInc) September 14, 2020
Ampaire says that an aircraft such as its Electric EEL can cut direct operating costs and emissions by 40-50 percent versus conventional aircraft.
In this latest conversion, the Electric Power Unit (EPU) used by the aircraft is designed for improved energy efficiency with less weight. The EPU has 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 1 hour and 15 minutes, plus a 30-minute reserve, The Hawaii Bird can fly most Mokulele routes round trip before requiring a recharge.
During its 35-minute first 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 fly for a series of checkouts before being shipped to Hawaii in October.
