Though you've likely ridden inat some point, hybrid airplanes are much more difficult to come by. The technology exists only in the experimental stage, but several companies are working to bring it to passenger planes and make air travel a little greener.
One of those firms is Hawthorne, California-based Ampaire. On Nov. 22, it operated a round-trip demonstration flight of its Electric EEL hybrid plane over the Hawaiian island of Maui between Kahului and Hana. Planned in partnership with Hawaii-based Mokulele Airlines, the EEL covered the 31-mile route in 20 minutes each way on a single charge.
"Air travel is the final frontier of sustainable transportation," said Ampaire CEO Kevin Noertker. "And we're working really hard to get compelling electrified sustainable aircraft into service as soon as possible."
The EEL isn't a completely new aircraft that Ampaire designed and built. It's a converted Cessna 337 Skymaster, a six-seat utility aircraft with a push-pull propellor configuration, where one prop is mounted on the nose and the other is on the rear of the fuselage.
A 160-kilowatt electric motor powers the front propellor, with the battery housed in a separate compartment beneath the fuselage. A conventional 300-horsepower piston engine drives the rear propellor. Together they give the EEL, which first flew in 2019, a range of more than 200 miles.
Ampaire says the hybrid arrangement will reduce fuel consumption and carbon dioxide emissions from 40% to 50%. "We've taken electric vehicle technology and incorporated it into the plane," Noertker said. "It's almost like a [Toyota] Prius flying in the sky."
Mokulele, a commuter airline that operates several routes within Hawaii, including the one between Kahului and Hana, has signed a letter of interest with Ampaire to eventually operate hybrid aircraft.
"The future for regional airlines is electric," said Stan Little, the CEO of Mokulele's parent company, Southern Airways. "We expect to put hybrid- and all-electric designs into service as soon as possible, and we know other regionals are watching us with great interest."
Before that can happen though, the US Federal Aviation Administration must certify the EEL to carry passengers. Noertker expects that to happen in about three years.
"Our planes will meet the same FAA standard as all conventional planes do," he said. "All the while being cheaper to operate and better for the environment."
The EEL flight comes 6 months afteron a 30-minute demonstration tour over Washington state. That aircraft, which Magnix also is developing for commercial service, is the largest electric plane to fly so far.