9-Seat Hybrid Aircraft Completes Maiden Flight

­While battery power might be impractical for commercial air travel, it could definitely play a role in the (near) future of private aircraft. Take, for example, the Hawthorne, California-based Ampaire, which just completed the maiden flight of a nine-seat regional airplane with a hybrid-electric drive system.

The “Eco Caravan”, based on a Cessna Grand Caravan, is also a stark reminder of electrification’s aerial limitations.

Let’s start with the definition of “regional airliner” (or a feederliner), a small aircraft designed to carry up to 100 passengers on short-haul flights.

But electrifying an aircraft, regional or not (and hybrid or fully electric), dramatically limits its size.

That’s because "Electric batteries pack much less energy per unit of weight than jet fuel," says Bjorn Fehrm, an independent industry aviation expert at Leeham News. To be specific, about 40x less energy.

To compensate for that innate disadvantage, hybrid and fully-electric aircraft need to tote large batteries, and that strictly limits the craft’s design and capabilities (if it can fly at all).

Even Kevin Noertker, Ampaire’s CEO, admits that “Aviation is the hardest industry to decarbonize. Fully-electric aircraft are range limited because of the weight and energy capacity of current-generation batteries.”

The somewhat workable compromise is a hybrid system, which “can preserve the range and utility of today’s aircraft,” claims Noertker.

We previously covered Ampaire’s retrofitted Cessna 337 Skymaster, a six-seat hybrid design with an electric-powered propeller in the front and a combustion-engine-powered propeller in the back for redundancy (and to share power to optimize speed, power, fuel consumption or noise) during test flights.

This latest nine-seater took an initial 33-minute flight, climbing to 3,500 feet at full power and with the internal combustion engine and electric motor working in concert. All told, the Eco Caravan has a range of over 1,000 miles, though its maiden flight was strictly limited.

That said, all went according to plan.

“The Eco Caravan propulsion system performed just as expected,” said test pilot Elliot Seguin. “It was smooth and quiet. All temperature and power output readings were normal.”

That’s not nearly enough to get me – with my crippling motion sickness – into an airplane that tiny, but it’s very exciting news for the incremental decarbonization of air travel.