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The Terrafugia Transition: Is this the Start of a New “Aeromotive” Engineering Category?

by Bill Martin-Otto on 29 Mar, 2012 in CATIA

Look! Up in the sky! It’s a plane. It’s a car? It’s both. The Transition®, from Woburn, Massachusetts-based Terrafugia, is a “roadable aircraft” that can go 107 mph in the air and 65 mph on the highway.

A team of MIT engineering students conceived of the vehicle while studying in the Department of Aeronautics and Astronautics. According to Anna Dietrich, Terrafugia’s COO, the team “used the resources that were available at MIT and with our local Experimental Aircraft Association chapter to start building…a business while doing early conceptual design on the Transition itself.”

The market opportunity for the Transition arrived in 2004, when the Federal Aviation Administration (FAA)  created the Light-Sport Aircraft classification to open the skies to more people. Terrafugia CEO Carl Dietrich surmised that the new breed of pilots would appreciate a little extra convenience and cost savings.

The Transition has a sticker price of $279,000, but owners will actually save money by using unleaded gasoline, not having to rent hangar space, and not having to pay for parking at the airport. Roughly 100 planes have been reserved to date.

As of early 2012, Anna Dietrich says that Terrafugia is conducting an extensive set of tests on its two production prototype aircraft. “Covering both flight and road use, we’re using a combination of powered testing, static load testing and sophisticated analysis and simulation,” she said to an audience at a TED conference in Scotland.

The Transition has a range of 100 to 500 miles and can take off and land at any public use general aviation airport with at least 2,500 feet of runway. On the ground, the Transition can be driven on any road and parked in a standard parking space or household garage.

In flight, the engine power is directed to the propeller through a carbon fiber drive shaft. After landing, the pilot activates the electro-mechanical wing folding mechanism from inside the cockpit. The wings fold, once at the root and once at the mid-span, and rest vertically on the sides of the vehicle in less than 30 seconds. Simultaneously, the engine power is directed to the wheels with a continuously variable transmission.

Having ground and air mobility in the same vehicle provides new options for travel that aren’t available with separate vehicles. If bad weather is encountered en route, for example, you can land and drive to your destination. At destination airports, you can fold the wings and drive off the airfield without having to move bags or arrange for additional transportation. You have a lot more flexibility to change your travel plans.

“As with many disruptive products, it is difficult to predict where this technology will take us in the future,” says Anna Dietrich. “But I believe that the Transition® is the next major step in improving how we navigate our world.”

Design considerations and challenges

Terrafugia is self-certifying the Transition to meet FAA requirements for Light-Sport Aircraft, as well as the automobile safety standards of the National Highway Transportation Safety Administration. It’s the first light airplane to incorporate dash-mounted airbags, a passenger safety cage and energy-absorbing crumple zones. For added safety in flight, there’s a full vehicle parachute for use in case of emergency.

One of the biggest design challenges was building a suspension system that could absorb landing impacts and ensure a sporty driving experience on the road.

While the vehicle’s body and interior were designed in SolidWorks, the Terrafugia team relied heavily on CATIA Composites Design,  with integrated fiber modeling solutions from Simulayt, to solve the most significant design challenge: reducing weight.

According to an article by Greg Rice in Dassault Systèmes’ Contact magazine, the CATIA Composites Design solution eliminates guesswork by enabling engineers to visualize the loads being carried by the structure’s carbon fibers. Parts can be designed to minimize stresses and weight while maximizing strength.

CATIA also aided draping analysis, fiber orientation and flat-pattern generation. According to vehicle design engineer Ben Zelnick, “The accurate flat patterns … save time and material during manufacture.” Structural analyst Danny Bouldin adds that, unlike with other composites packages, analyses can be run without simplifying the model. “That simplification always left us guessing whether the part was actually as strong as the analysis showed,” Bouldin says, resulting in over-designed parts that add time, cost and weight.

Want to see it up close? You can catch the Transition and its creators at the 2012 New York International Auto Show (NYIAS), from April 6 to 15 at the Jacob Javits Convention Center in New York City.

In the meantime, let us know what you think about the Transition. Do you think it’s a creative design? Do you think it will revolutionize transportation? Will you keep one at your house?

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