Socata Trinidad GT A beautiful little French
retractable with a certain je ne sais
quoi
By Bill Cox Photography By James
Lawrence
By any measure, the sky around us is an aviation
mecca. For one week each spring, the weeklong Sun ‘n Fun
Fly-In brings thousands of flying machines and several hundred
thousand people to warm, comfortable central Florida.
It’s early morning on the third day of Sun ‘n Fun, and
in the far distance, we can see the line of airplanes already
starting inbound toward Lakeland Airport. I’m headed the
opposite direction in a new Socata Trinidad GT. It’s Socata’s
20th anniversary version of its retractable single. The
Trinidad GT is a highly-modified, retractable variation on the
earlier Aerospatiale Rallye singles, the 150, 180 and 235.
Certainly one of the TB-20’s primary attractions is its big
cabin. From the beginning, Aerospatiale concentrated on
designing an airplane around an unusually roomy and
comfortable cockpit.
The company started with a wide interior, 50
inches across at the elbows. The Trinidad’s large cockpit
allows the use of a center console that houses most of the
engine, fuel, flap, trim as well as electrical controls.
Next, Socata applied automotive interior-design
techniques, fitting seats that look more appropriate to a BMW
or Audi, plush, smoothly contoured, multi-adjustable bucket
seats that support in all the right places.
The panel
is conventionally split into three segments: flight
instruments on the left, radios on the center and power
instruments on the right. The Trinidad incorporates
maintenance features that should make mechanics and avionics
technicians cheer. Left and right instrument panels hinge at
bottom front and swing down to allow ready access to the
gauges. Similarly, there is a trio of panels atop the cowling
and just aft of the firewall that provide access to
avionics.
One of the Trinidad’s signature design
characteristics is its gull-wing doors. They’re hinged at the
roof and swing up and out for entrance and egress to front or
rear seats. Socata’s gull-wing entryways are built tough, they
look great, and they open up a huge entryway to either row of
seats.
If there is any significant wind-blowing, the
doors can blow down unexpectedly, or the hinges may be warped
by a gust of wind. On the plus side, the fiberglass frame
doors are almost pure-clear Plexiglas from the pilot’s and
copilot’s elbows almost to the tops of their heads. This makes
visibility to the sides and up quite exceptional.
A
cursory examination of the Trinidad’s wing might suggest the
airfoil is a standard Hershey-bar design. Hardly. Although
there is nothing terribly unusual about the wing, it was
computer-designed specifically for the Trinidad. Goals were
predictability and safety, and Aerospatiale achieved those
goals in spades.
For the aerodynamicists among you,
the small, rectangular, 128-square-foot wing is a
constant-chord, RA16-3C3 airfoil with 6.5 degrees of dihedral,
conventional in shape and Cherokee-like in configuration, but
it provides the Trinidad with a comparatively high 24.1 pounds
per square feet of wing loading. High wing-loading lends
itself to a smoother ride in turbulence. It’s hard to imagine
a more docile high-performance retractable airfoil. In
combination with 250 hp out front, the wing generates
sea-level climb in excess of 1,000 fpm.
The TB-20’s
empennage also is a little different, featuring totally
separate horizontal and vertical tail surfaces with the lower,
all-flying stabilator mounted well aft of the vertical. The
rudder is reasonably effective, but hardly necessary for
coordination of most normal maneuvers.
In addition to
their obvious visual appeal, the TB-series airplanes benefit
from high-tech applications of aerospace construction
techniques and equipment that make the airplane simpler rather
than more complex. The Caribbean singles are built at Socata’s
ultramodern Tarbes, France, facility. Parts are manufactured
on the same numerical control machines used to subcontract
components for Airbus airliners, Falcon business jets and
Eurocopters. With the help of its advanced design and
automated manufacturing equipment, Socata realizes economies
not possible for other builders. The company puts together the
fixed-gear Tobago’s 800 parts in only about 600 labor hours.
The more complex, retractable Trinidad is slightly more
labor-intensive, but still far less time-consuming than other,
comparable airplanes.
Power for the Socata Trinidad GT
is provided by a 540-cubic-inch Lycoming engine, specifically,
the IO-540-C4D5D, derated to 250 hp. This is essentially the
same engine that was used so successfully in pairs on the old
Piper Aztec, so it’s a well-proven powerplant, under-worked
and rated for 2,000 hours between overhauls. It’s interesting
that Lycoming uses the same block to produce up to 350 hp for
applications such as the Piper Navajo Chieftain.
Max
takeoff weight is listed at 3,080 pounds (1,400 kg in
European-speak), and a typical empty weight runs about 1,900
pounds. The test airplane had the optional air conditioning,
which probably boosted empty weight by at least 50 pounds and
price by an additional $18,000. In other words, there is a
payload-per-price penalty for the privilege of a cool cabin on
the ground.
The result is an empty weight just under 2,000
pounds, so full-fuel payload winds up right at 540 pounds,
about what we’ve come to expect from most single retractables.
Technically, the Trinidad is a five-seater, but it’s hard to
imagine a loading situation that would allow carrying five
folks, unless the aft three were children.
Its engine
start is pure Lycoming, and taxiing is conventional with
nosewheel-steering through 18.5 degrees of turn. Once off the
runway with wheels in the wells, rate of climb is an easy
1,000 to 1,100 fpm at gross, 1,200 fpm with two up front and
full tanks—the way most pilots operate four-seat retractables
most of the time. Initial climb bleeds off to about 700 fpm at
8,000 feet, where upward mobility often is more critical.
Service ceiling is listed at 20,000 feet for the
normally-aspirated Trinidad. If you need more altitude
capability, you can opt for the Trinidad TC, which is approved
for flight at 25,000 feet.
The new Trinidad offers no
great surprises in straight-line performance, not a big shock,
since the basic airplane remains, aerodynamically, pretty much
the box it came in back in 1984. Externally, the TB-20 hasn’t
changed much in the last two decades, although it incorporates
a retractable step (that hides with gear retraction) and
wingtips from the turboprop TBM-700.
Cruise with the
left lever to the stop at a 7,500-foot density altitude works
out to 155 to 160 knots, depending on load, rig, CG,
temperature and the phase of the moon. Pulled back to 55% up
at 11,500 feet, the number is more like 140 knots. Best
economy fuel burns at the above settings are 14 and 11 gph,
respectively. With the price of avgas well over $3 per gallon
in the U.S. and at least half again that figure overseas,
hardly anyone uses best power settings anymore, but if you
feel a need for a few extra knots of cruise, you could plan on
spending about two gph more at each setting. The TB-20’s
handling falls somewhere between a Piper Arrow and a Skylane
RG. Roll control is reasonable, and pitch authority is quick;
the airplane lays into turns with the authority of a heavier
machine, and hands-off stability is good.
Perhaps
because of Aerospatiale’s military and aerospace experience,
the Trinidad’s manual is unusually thorough, even including a
chart called “Antennas’ Effect On Performance” for cruise loss
to various antenna and light installations. Everyone knows
that hanging antennas and lights from an airplane subtracts
speed, but I had never seen engineering data that quantified
the loss until I checked the TB-20 handbook. (I own a Turbo
Mooney with 13 antennas hanging out, sometimes referred to as
the “Pincushion” by my avionics expert, Robin Howard, and I’ve
always wondered what those antennas cost me in
speed.)
The chart suggests an ADF antenna (for those
strange folks—like me—who still use ADF) costs about .75
knots, a VOR antenna subtracts .59 knots, a glideslope antenna
deducts .32 knots and even the tiny ELT antenna reduces cruise
by .16 knots. Additionally, Socata suggests wingtip strobes
decrease speed another .43 knots and a rotating beacon
subtracts .16 knots. Put them all together, and a full package
of IFR antennas and lights on a standard Trinidad will
diminish cruise by 4.3 knots. The accuracy of the figures
suggests the numbers probably were obtained theoretically (in
a wind tunnel) rather than empirically. Granted, there are
different types and styles of antennas, and these values
wouldn’t necessarily hold true in other airplanes and
different speed regimes, but they may be somewhat
representative for retractables in the 140- to 180-knot class.
(The late Roy Lopresti, speed guru, former NASA rocket
scientist, president of Mooney and all-around good guy, told
me he had once stripped a 201 of antennas and recorded 3.5
knots better speed on the totally clean airframe, so Socata’s
numbers look about right.)
Gear and flap extension
result in minimum pitch disturbance, but they do generate a
notable difference in power-off stall speed. With the
underwing totally clean, the GT stops flying at a quick 65
knots. In full dirty configuration, gear down and full flaps,
stall drops all the way to 54 knots, and the stall itself is a
non-event.
Approaches in the Socata Trinidad GT work
well at any speed from 80 to 120 knots. The airplane makes a
stable instrument platform, happy to drive down the ILS in
soft- or hard-IFR conditions with minimum fuss. Excursions are
generally easy to correct, and the Trinidad seems to settle
easily into that indefinable “groove” that instrument pilots
recognize.
Compared to the Aerospatiale Rallye STOL
models that featured leading-edge slats and more aggressive
flaps, the Socata Trinidad GT doesn’t post spectacular
short-field numbers, but the TB-20 does just fine on
unobstructed strips that are longer than 2,000 feet. The
model’s tough, trailing link gear system absorbs most
reasonable impacts and even some unreasonable ones to smooth
the most ham-handed touchdowns.
Price is always in the
eye of the debtor, but at $419,000 base, the 2004 Trinidad GT
is more expensive than either the Cirrus SR-22 or Lancair
Columbia 300, and it’s about $30,000 more pricey than a Mooney
Ovation 2DX. Remember, however, that the base price buys a
well-equipped airplane—a Garmin 430 and 530, 330 transponder
with traffic uplink and 340 switching panel, Shadin fuel
computer, backup artificial horizon, a Stormscope, a KFC225
flight director and autopilot, a pair of Bose X headsets and
virtually everything else you would need for normal IFR
conditions. The two biggest options are air conditioning and a
TKS anti-ice system.
With the exception of Diamond’s
fixed-gear Star and C1, the Socata singles are the only
foreign airplanes to succeed in America’s piston
general-aviation travel market. France’s premier
high-performance retractable Trinidad GT offers an uncommon
combination of ingredients that makes the airplane more than
competitive with its American counterparts, especially when it
comes to comfort.
