To celebrate the 100th anniversary of Socata a new paint scheme was developed for the TBM 850. The stripes mimic—at least in an artist’s impression—the way the computational fluid dynamics models show air flowing over the wing of the airplane.
he creation of a great-performing successful
airplane design is not necessarily based on use
of exotic technology. Usually the most success-
ful airplanes are the product of combining
proven technologies in a new and different
way. The Cessna Caravan comes to mind. And
that’s what Socata did to create the TBM—
employ the techniques it understood to make
an airplane with unprecedented capability.
The fundamental decision was to use a single turboprop to
power the TBM. Using only one engine increases range dramatically—more than 1,400 nautical miles with IFR reserves—because
the need to lug along the weight of the fuel to feed the “spare”
engine is gone. A single also reduces pilot workload and makes
the airplane available to a wide range of pilots that may not
qualify, or even want, a twin.
But would pilots accept a single-engine airplane of such performance and price? Nobody knew for sure because it hadn’t been
done before; however, Socata had a big ace up its sleeve—the Pratt
& Whitney Canada PT6 engine. The PT6
is the most popular general aviation turboprop and has earned a reputation for
unparalleled reliability. Pilots who may
hesitate to fly at night, or in solid IFR, with
only one engine don’t have the same worries if that single engine is a PT6.
Choosing to use only one engine drove
other design decisions, particularly for the
wing. Certification rules require singles—
even turbine singles—to stall no faster than
61 knots at maximum weight with the flaps
down. That means the wing flap on a heavy,
high-performance single must be very effective, and the airfoil must be carefully
designed for good low-speed lift without
being draggy at high speed and high altitude.
The Socata solution is a wing of nearly
constant chord using a proprietary airfoil