The technical challenge now before the team is to build a power train that uses one engine both in the air and on the ground and is capable of running on a tank of super unleaded gasoline--the kind that can be bought at any gas station. To make the transition between engine uses smooth, the team is devising a mechanism to transfer power from the propeller to the wheels and back as needed. The difficulty here, Dietrich says, is that the system has to be as simple, reliable, and lightweight as possible. (For the team, the weight of the vehicle is a constant concern, not only because the vehicle has to be relatively light in order to fly, but also because FAA regulations require it to be less than 1,320 pounds.)
"They're doing some interesting things," says Mitch LaBiche, an engineer at LaBiche Aerospace, a company based in Alvin, TX, that has assisted the military in the construction of a wide variety of flying vehicles, from the F-117 to the Apache AH-64 helicopter. LaBiche's company is now working to build a flying sports car called the FSC-1. "[The Transition] is a light sports aircraft, so they're going to have to work hard to meet the weight requirements," LaBiche says.
The greatest nontechnical challenge Terrafugia must face is meeting the regulatory requirements of both the FAA and the National Highway and Traffic Safety Administration (NHTSA). To satisfy FAA regulations for the category of light sports aircraft, the Transition must have a maximum level speed of 138 miles per hour, a one- or two-person occupancy, and fixed landing gear, among other things. For the NHTSA, the Transition must be able to pass the same requirements that a regular car would.
"There are systems in place with both organizations to make working with them as painless as possible," Dietrich says. "It is still a lot to go through, but we've made inroads with both, especially the FAA."
The company plans to build and sell between 50 and 200 Transitions a year, most likely starting in 2009, and it's marketing the vehicle to the roughly 600,000 licensed pilots in the United States. The Transition will be comparable in size to a Cadillac Escalade but won't be nearly as heavy. Terrafugia plans to charge $148,000 per vehicle.
"Very interesting! I would love to have one," says Kenny Huffine, a pilot for a major commercial airline who flies recreationally. "My one concern, though, is about having a plane parked around other cars. If it were pushed or damaged, would that make it unflyable and dangerous?"