AVweb caught up with Carl Dietrich, CEO and Chief Technical Officer of Terrafugia Inc., Sunday, at EAA AirVenture Oshkosh to discuss the aerodynamic challenges revealed through testing and 28 flights of its roadable aircraft prototype, and where the company is headed now. In short, the prototype proved that the lift generated by the canard was compromised by its proximity to the vehicle’s large front wheelpants. That, along with an unforeseen body-effect that complicated things by producing more than the expected lift farther aft on the fuselage than expected. Viewers of AVweb‘s video saw the result of these effects showcased as a large amount of up elevator and canard trim deflections necessary to keep the vehicle aloft. Now, after several rounds of funding (and with more ahead), the company is using practical experience earned from 28 flights of the prototype along with empirical data collected from ground runs and recently computational fluid dynamics modeling not previously available to the company to design its second vehicle. “Everything is changing a little,” Dietrich told AVweb, “but the design heritage will follow through.” Half of the ten-person team that is Terrafugia has remained home to work on the new design, which Dietrich hopes to show (in computer graphics form) in early 2010, with a physical prototype to follow later in the year, but almost certainly post-OSH 2010.
The new prototype will likely include molded interior surfaces and, according to Dietrich, will likely pass NHTSA crash test requirements. It will also incorporate a stand-alone rear bumper that is independent of the elevator and the space between the canard and front tires will be increased.
