Autobahn To Airborne: Germany’s Carplane Unveils Flying-Car Prototype

Apr 27, 2015

Graham Warwick | Aviation Week & Space Technology

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Germany’s Carplane project unveiled the near-complete prototype of its twin-hull flying car at the Aero Friedrichshafen general aviation show on April 15-18. The vehicle is planned to fly later this year. Credit: Aero Friedrichshafen

Carplane, A Roadable Aircraft Designed For Drivability

In the land of the autobahn, drivability is a passion-even if the car is designed to fly. And the need for good road performance has driven the design of Germany's Carplane flying car, the near-complete prototype of which was unveiled at the Aero Friedrichshafen general-aviation show on April 15-18.

Braunschweig-based Carplane is developing the prototype with funding from the EU and the German state of Lower Saxony. The prototype is expected to be complete by the time funding support ends in July, after which Carplane plans to fly the vehicle and continue working toward certification on private investment, says program manager John Brown.

The Carplane has an unusual twin-hull configuration driven by the need for good road handling. Stowing the removable wings between the hulls prevents them from producing lift at higher road speeds, or the forces that could be produced by sidewinds if the wings were folded along the sides of the fuselage, he says.

Dual hulls also enable use of full-size car wheels to improve road-holding. While other flying-car designs use smaller aircraft-size wheels to reduce drag in flight, Brown says the twin hulls allow the vehicle to accommodate 13-in. road wheels (from the Smart car) while minimizing parasitic drag in flight.

The Carplane is powered by a 151-hp piston engine burning unleaded gasoline. This drives a gearbox with seven positions: four forward and one reverse driving the road wheels in car mode; one that drives the pusher propeller in flight; and one that drives both wheels and prop for a shorter takeoff.

Driving both wheels and prop increases acceleration. "We can get off the ground in 80 meters [260 ft.], at 45-50 kt," says Brown. "And we can land and stop within 80 meters."

Licensed by LSA Engines from Weber Motor and originally designed as a snowmobile powerplant, the 850-cc two-cylinder, four-stroke engine is turbocharged for use in flight and is already certified by the European Aviation Safety Agency (EASA), he says, and meets the Euro 6 emissions standard in Europe.

In the prototype, the sailplane-style wings are removed, stowed and reattached manually, but Carplane has designed a mechanism that enables the wings to stow and unstow, and empennage to extend and retract, automatically. This has been demonstrated with a quarter-scale model, and the prototype's structure is designed to accommodate the mechanism.

Carplane plans to certify its flying car as a very light aircraft (VLA) under EASA airworthiness regulations. This limits maximum gross weight to 750 kg (1,650 lb.). With the automatic deployment mechanism, the vehicle weighs 795 kg. "We either go manual or apply for an exemption," says Brown, adding that EASA has indicated it would consider approving a heavier weight.

The company is pursuing EASA approval, rather than self-certification under industry standards for light sport aircraft (LSA), because the VLA category is recognized worldwide, he says. VLA certification does require a private pilot's license, whereas an LSA can be flown with a sport pilot's certificate requiring as little as 20 hr. flight time.

The Carplane is too heavy for the LSA category, but if the FAA approves flying-car developer Terrafugia's request for an exemption to raise the gross-weight limit to 1,800 lb. for its Transition, then the vehicle could be ready more quickly. As a VLA, "we will not be on the market before 2018," Brown says. "But if Terrafugia gets a weight exemption, that sets a precedent. We could self-certify as an LSA and go to market sooner."

For now, Carplane has focused efforts on getting the prototype flying later this year. "The measure of progress for our funding is based on whether it can fly, not drive. As we are getting close to the end of that funding, we have stopped engineering involved with ground certification to concentrate on flying," says Brown.

For road certification, the vehicle will have to pass a 5-mph/8-kph crash test. The next level of testing is a 27-mph/40-kph crash "in which 98% of the vehicles are destroyed," says Brown. But the higher level of safety testing is not required until vehicle sales exceed 1,000 per year in Europe or 1,500 per year in the U.S., he says, so Carplane will start with the 5-mph safety test.