OSHKOSH: Terrafugia unveils TF-X wind tunnel model

Terrafugia unveiled a newly-moulded wind tunnel model for a hybrid-electric, stop-fold tiltprop concept at the Experimental Aircraft Association’s annual fly-in in Oshkosh, Wisconsin.

The model, presented under glass at the Terrafugia exhibit, is the first tangible product of the TF-X concept programme, which was launched two years ago as an at least decade-long development project.

Terrafugia also released a new promotional animation showing how the T-FX would operate. To take-off, the electric-powered propellers tilt 90 degrees for a vertical take-off. As the vehicle transitions to forward flight, the propellers rotate until they are parallel with the fuselage. As a rear-mounted ducted fan activates, the propellers stop spinning and fold back along the nacelles.

“This is why it’s going to be all computer-controlled,” says Richard Gersh, Terrafugia’s vice-president of risk management. “There’s no way that somebody is going to [control] that.”

The T-FX concept envisions a highly autonomous control system with a manual override available in case there is trouble. Terrafugia’s vision, subject to regulatory approval, would require no pilot license to fly the aircraft, but an operator certificate to use the manual override system, Gersh says.

The electric propulsion for the aircraft would be supplied by batteries, but the needed power level exceeds anything available today. “Batteries are a problem for everyone,” he says. “Mabye Tesla will solve it.”

The power source for the ducted fan has not yet been selected, but it could be a gas-driven piston engine or a turbine engine, Gersh says.

Meanwhile, the company is still working to certificate the Transition roadable aircraft. Although originally expected to be certificated by this year, Terrafugia now plans to begin deliveries of the initially $299,000 aircraft in 2017, Gersh says. The unit price could rise into the “low 300s” after the first 10 aircraftt deliveries, he adds.

Parts for the third-generation version of the Transition vehicle are now being produced. The changes from the second-generation variant are relatively minor, involving mainly an upgraded Rotax 912IS engine and improved comfort features in the cockpit, Gersh says.

Terrafugia is waiting for the US Federal Aviation Administration to decide on a petition for a weight exemption. The FAA has already approved a special weight category under the light sport aircraft rule, allowing readable aircraft up to 762kg (1,680lb). But the Transition’s maximum take-off weight has grown to 816kg, prompting Terrafugia’s request for an exemption.