Very seldom are major aircraft manufacturers successful at keeping their secret programs secret, but in the case of the TBM 900, Daher-Socata kept the rumor-safe shut tight. The program, called the “Century Project” internally, has been in the works for a few years now and takes advantage of technologies not available to the company when the airplane was born a quarter of a century ago. Chief among these is computational fluid dynamics (CFD), which existed but was beyond the reach of a company like Socata at the time. In reworking the 900, Daher-Socata engineers made extensive use of CFD in order to minimize drag. While that sounds simple enough, nothing could be further from the truth. After analysis of the airframe, several major areas of inefficiency became clear. The cowling, now in carbon fiber, was extensively redesigned to cut drag and improve cooling, with a big inlet below the prop. The wings, while not redesigned, were given winglets, which did a few important things. First, they kept the spanwise flow along the wing from spilling over, adding efficiency mostly by decreasing drag. They also increased the effective wingspan of the airplane, again increasing lift. Finally, they improved the handling of the ailerons, with some reporting smoother roll response and others greater control feel. To me, it felt as if both were true. That’s a lot of bang for a pair of winglets.