Sometimes a hybrid is more than a hybrid.
The Terrafugia uses a hybrid powertain as it drives down the road. It's also a hybrid car and airplane. Even in the sky, it can make use of hybrid power.
Terrafugia started in 2005 and designed what observers have called a "flying car," and it plans to put its vehicle into production by the end of next year, says Josh Elvander, the company's vice president of engineering. He prefers to call the Terrafugia a "roadable aircraft."
It can't land or take off on streets, and has to use an airport. The advantage of the Terrafugia's roadability is its ability to make a door-to-door trip without the need to find a rental car or taxi at a local general-aviation airport.
To drive on the road, the Terrafugia uses a strictly series hybrid system, with a generator driven off the engine to power two motors at the rear wheels. A small lithium-iron phosphate battery—safer for flying than other types of lithium batteries—about the size of a battery in conventional Toyota Prius hybrid, helps buffer power.
The company is targeting a 65 mph cruising speed on the highway, though Elvander says the latest prototype has yet to be tested, so he couldn't verify that number.
In the air, the Terrafugia can use the extra battery power for a momentary boost to the 100-horsepower, 1.4-liter Rotax flat-4 when climbing. In steady cruising in the air, it will recharge the battery.
Top speed in the air is 100 mph, and the Terrafugia carries four hours worth of fuel for a range of about 400 miles.
After landing, the pilot has to install rearview mirrors on each side and fold the wings electronically. The pusher propeller locks into position for street driving, and the all-digital instrument cluster automatically switches from flying instruments to road gauges.
As a half-car, the Terrafugia doesn't require avgas, as most piston airplanes do. It can run on ordinary premium unleaded pump gas, which today will save pilots about $2 a gallon.
As a light-sport aircraft the Terrafugia seats only two and is rated for good weather, but it takes only half the number of solo flying hours to get a license as it would to get a general aviation license.
For safety in the air and on the road, it has both an airframe parachute and front air bags.
In Terrafugia's latest announcement, the company says it will begin production in 2019. That once sounded like a long shot for a flying car. Elvander says the company's latest backers, Chinese auto giant Geely, which also owns Volvo, is committed to bringing the Terrafugia to market in 2019 but he didn't specify when.