Plane Talk: Top Flite AT-6 Texan Gold Edition ARF - 2010/02

THE NORTH American AT-6 Texan was
dubbed a trainer—more correctly, a fighter
trainer. The distinction separates those aircraft
that are easy to fly from those that are easy to
replace, in case a student playing fighter
games totally loses respect for the aircraft.
The AT-6 was inexpensive to build and
maintain. Therefore, it was offered in
quantities as a way for military organizations
to save money for the expensive fighter while
brewing its talent for the challenge that laid
before it.
As bluntly as that all might read, through
years of use and abuse, the Texan earned the
respect of its students and later owners. Its
charm is now world renowned.
In World War II, this airplane
was really the instructor—not the
trainer. I know it as a colorful air
show performer, personified heroic movie
character, and rare treat on the tarmac at the
local FBO (fixed base of operation).
After visiting Scale competitions
and the AMA Nats, I’ve learned that
the AT-6 has a colorful history among the
veteran competitors. Models of this aircraft
have earned a reputation all their own.
Many who have had experience with
Texan replicas have been humbled. Some
have graduated from the experience and
claimed that, among the gamut of warbird
offerings, the rite of passage achieved by
piloting a model AT-6 is similar to that of the
full-scale pilots. Flying this airplane takes
skill.
The stories a person uncovers when
researching an aircraft are interesting. The
tails of wonder and whoa, as I like to call
them, both encourage me to continue the
project and make me want to take up fishing
instead.
All in all, it’s good entertainment, and for
me it lasted close to 15 years; a decade and a
half passed between when I decided to get a
Texan and when the opportunity arose.
I’m happy that the chance came to review
the Top Flite (TF) Gold
Edition AT-6 ARF, because which Texan
model I would get was more or less decided
for me. From micro-size to giant scale and kit
to RTF, there are tons of choices.
Because the TF aircraft is 60 size, all
necessary accessories are practical choices.
Not only are the engine and radio pieces
readily available (such as in my parts drawer)
and reliable beyond a doubt, but the model
will easily fit in my SUV with the rest of the
family and their comfort gear (chairs, cooler,
laptop, and pop-up tent).
In addition, a person who chooses the
TF AT-6 gets a heck of a deal. I didn’t
include a “parts” shot of the kit, because a
great one is posted on the TF Web site.
It’s the most well-appointed scale version
of this warbird I’ve seen in this size. And
it’s exceedingly accurate, for the most
part.
After viewing the TF Web page, you
might notice that many of the finished
detail shots look similar to those in this
article. When the model is finished, it
looks practically the same as
the version that the
company uses to advertise
the product.
Yeah, I found a few goofs, but overall
I’m extraordinarily pleased with my TF
24 MODEL AVIATION
Static photos by the author Flight photos by Jay Smith
The elevator servo requires a precise amount of movement. A
standard Futaba wheel is just the thing. A Futaba FASST R617
receiver is tucked in under the tank.
The fuel tank is easy to service when mounted to the
removable equipment tray. Twin Futaba receiver batteries
were used to add redundancy and ballast.
An easy way to center the cowl around the
crankshaft is to make a fixture from foam
or cardboard. If done properly, the
included dummy engine will fit perfectly.
The elevator linkage is concealed in the
fuselage. A welded steel control horn
securely deflects independent elevator
halves. Clamps keep parts centered while
epoxy sets.
A few coats of silver make the fuel-proofed
wooden rib structure look more authentic.
A metal pin links the outer flaps with the
center-section.
Four coreless Futaba S9001 servos drive
ailerons and flaps. The author custom-dyed
the included hardware and substituted dyed
nylon mounting screws. Nice look!
The included spinner and adapter fits 5/16
threaded engine shafts. Run fuel lines
above the fuel tank to prevent siphoning.
The O.S. .81α runs sweetly.
The included hatch, insignia, and markings for the TF Texan are opaque. A wet
application method assures a bubble-free finish.
Massive mechanical retracts mount easily
into the prealigned hard points. Gear
struts are premounted and authentically
formed. Silver paint by the author seals
bare wood.
02sig1.QXD_00MSTRPG.QXD 12/21/09 9:29 AM Page 24
February 2010 25
Test-Model Details
Engine used: O.S. Engine 81FS-α
four-stroke
Propeller: APC 13 x 7 break-in,
Master Airscrew 14 x 6 S-2
normal
Fuel: 14.2-ounce tank, Magnum
#1 fuel
Radio system: Futaba 10C
transmitter; R617 FASST
receiver; six Futaba S9101
servos; one Futaba S136G
retract servo; one Futaba
S3001 throttle servo; two 1000
mAh, 4.8-volt batteries in
parallel; two 24-inch Y-harness
extensions; three 12-inch
extensions
Ready-to-fly weight: 9 pounds,
3 ounces
Flight duration: 12-18 minutes
Pluses and Minuses
+•
Built-up and sheeted wood
construction with fiberglass details
and aluminum spinner.
• Cockpit details provided include
pilot and radio operator.
• Fuelproof and opaque decals.
• Sturdy, high-quality mechanical
retractable landing gear.
• Accurate details with high-visibility
WW II Navy trim scheme.
• Scale documentation is available for
AMA Scale competition.
• Flies like a dream.
-•
Minor assembly-recommendation
errors.
• Exaggerated wing root strap detail.
• Warped flying surfaces needed
straightening. (Simple to fix.)
Specifications
Model type: AMA-legal RC Fun
Scale ARF
Skill level: Intermediate builder
and pilot
Wingspan: 69 inches
Wing area: 730 square inches
Length: 51 inches
Weight: 8.5-9.5 pounds
Wing loading: 27-30 ounces/
square foot
Engine: .61-.91 (two-stroke), .70-
.91 (four-stroke)
Radio: Six channels with eight
servos
Construction: Balsa and plywood,
fiberglass details
Covering/finish: MonoKote,
painted plastic and fiberglass
Price: $279.99
The O.S. .81α runs cleanly. It was easy to start and set directly out of the box. The
engine will turn a 14 x 6 propeller at 8,300 rpm on 20% nitro fuel.
Flaps are unnecessary for takeoff—as is full
power, for that matter. Rudder is necessary;
stand on the right pedal during takeoff, and
coordinate rudder in the turns.
The half-flap position is shown in this dirty pass. Most
of the .81α
fits inside the cowling. The engine is well
ventilated with the TF’s recommended openings.
02sig1.QXD_00MSTRPG.QXD 12/21/09 9:31 AM Page 25
Texan. As I write this, it’s been dubbed my
favorite model.
This warbird is almost as shiny as the fullscale
aircraft. When you have looked at the
Gold Edition online, type the AT-6’s tail
numbers into an Internet search engine (such
as Google) and look for “Images.” Hundreds
of pictures will come up, all of which are
eligible to qualify the TF Texan to compete in
AMA Fun Scale competition. That’s an
outstanding bonus.
This ARF is a great representation of the
full-scale trainer. I’m happy with the fit and
alignment of all the parts—especially in the
tail section, where the relationship of those
parts with the wing are critical. There are a
few things I’d do differently, but they are
cosmetic and in no way a slight against TF’s
effort.
For instance, the wing-joiner covers are
heavy, solid plastic parts that are molded to fit
around the outer wing root. Around the LE, a
gap visible only on the outboard end needed
an extra puddle of epoxy to clean up.
That small complaint invited further
examination of the full-scale airplane, which
brought attention to a subjective comment I
made that the cover is grossly exaggerated.
However, it does match the silver covering
almost perfectly. A custom-made alternative
from wood and matching MonoKote might
suit this detail more accurately.
26 MODEL AVIATION
On the subject of paint matching, I have
no complaints. The Aluminum, Black, Cub
Yellow, and Missile Red film used on the
parts was well finished and neatly trimmed.
The effort even inspired me to go further.
I applied matching trim to the aileron and
elevators, to seal hinge gaps and to the
horizontal stabilizer joint, where a 1/8-inch
strip was used to conceal the obvious gap.
A can of fuelproof silver paint is handy to
have for this model. I had a spray can of
LustreKote, and I put approximately 1/2 ounce
into a paper cup. The flap and gear wells can
use a few healthy coats of this silver, to fuelproof
the mechanical retract hard points and
dress up the already fuel-proofed rib interior
of the split flaps.
I wish I had used that silver paint on the
included dummy engine, or had at least taken
a “dry” brush to the cylinder fins, to make
them look aluminum and not polished
charcoal.
One other area to brush is the cockpit. The
included components for this region are
generous and high in quality. The rear area
under the turtledeck needs the balsa covered
in black paint. I’m being picky, aren’t I?
Instead of using glue, I fastened the
canopy in place with dainty #1 screws. This
way, I have the option of adding more detail
or doing maintenance later. I adhered all of
the components inside the cockpit with Zap-
A-Goo.
In accordance with my picky nature, I
couldn’t resist personalizing the hardware by
dying the nylon parts to match; gray for the
silver hinges and yellow and red for the wing
and tail hardware. As before, TF’s effort
inspired me to go further.
This AT-6’s major components are
wood, including the wingtips and fillet
areas. Those parts in other ARFs are
sometimes made from molded fiberglass.
The wheel-well area is molded from
fiberglass, painted, and then built into the
wing center-section; the look is fairly
convincing.
Port and belly air intakes and the
starboard side exhaust are also made from
fiberglass. They are finished with glossy
paint on the outside and dressed with a
flat-black interior. I chose to attach these,
and the dummy radial engine, with clear
silicone adhesive, because it is fuelproof
and excellent at absorbing vibration.
The wing, tail surfaces, and fuselage
are fully framed and sheeted with balsa.
Control surfaces are ribbed and have the
look of fabric-covered parts, as on the
full-scale warbird.
For stiffness, 3mm plywood is used in
the laser-cut processed form or laminated
in areas such as the firewall and landing
gear. Maple hardwood blocks are used
sparingly to save weight but are included
where they do the job best: in the servo
wing mounts, cowling mounts, and fuel
tank support. Wherever a screw is needed
to hold reliably, TF makes sure that the
right material is installed to do the job—
for a long time.
The recommended components fit into
the TF Texan exactly as prescribed. I’ve
been a happy Futaba user for years and had
no complaints with this project. I did feel
the need to fiddle with the linkage setup,
but only on the elevator.
As the manual shows, recommended
control rates will happen automatically
except on the elevator. This is where I
substituted a standard servo wheel to
connect the elevator pushrod.
Doing so gave me exactly the control
movement necessary without having to
reduce the Adjustable Travel Volume
(ATV) settings on my Futaba 10C radio to
50%. Using the wheel, I increased the
elevator ATV setting to 125%, thus
improving the elevator’s fidelity for supersmooth
control.
O.S. 81-FSα: This company’s new line of
four-stroke engines is the Alpha series. I’m
an old Surpass fan, and I see many
welcome improvements in this engine’s
design that appear to be a new approach to
this type of power system.
Foremost, this is a much more robustlooking
engine with vastly more heat-sink
area and support webbing. The .81α is a
new displacement for O.S., but it’s a
welcome one. As have the previous engine
series, this design includes three main
pieces—a lower crankcase, upper cylinder
enclosure, and cylinder head—all bolted
together with 3mm hardware.
The carburetor is familiar-looking, and
I appreciate the fact that it includes both
flow needles on one side and the mounting
option of having them on the left or right
side of the engine. For the TF AT-6, these
needles need to point out the port side
(flipped from the factory location). An
extension should be mounted to the main
needle from leftover pushrod material.
The Alpha head design is vastly improved
compared with the old Surpass’s; nearly twice
the amount of flange material surrounds the
exhaust port. The exhaust system is also new,
to enable quieter operation and more position
options.
O.S.’s Alpha series is likely the cleanestrunning
line of four-stroke model airplane
power plants today. Provisions no longer need
to be made for a crankcase vent; these engines
recycle the lubricating oil in a new way.
The Alpha .81 is a dream to operate, even
inverted in the Texan. To function at a
blubbery rich setting for the initial run, the
engine doesn’t need glow heat to stay running.
When primed, it starts easily on the first flip.
I used an APC 13 x 7 propeller for benchrunning
and flight-testing, which turned with
the needles peaked at 10,200 rpm. The lowspeed
needle was turned inward roughly 11/4
times from the factor start point, so that the
transition would be smooth and the idle would
be reliable at 1,800 rpm. That’s what I call
dreamy.
Magnum #1 fuel was employed for
running in and flying. The 13 x 7 propeller
made the model accelerate and fly well
beyond scale speeds. On the bench, the .81α
could turn an APC 14 x 6 at 9,300 rpm; that’s
almost as healthy as the old .91 Surpass.
After a gallon of fuel is run through the
engine, I’ll test a Master Airscrew S-2-series
14 x 6 or APC 15 x 4 to bring the AT-6’s
airspeed down to a more believable level.
Flying: I was nervous flying the Texan for the
first time; 15 years of imaginary performance
anxiety had taken its toll. TF’s well-written
manual calmed my nerves, because it left
nothing to chance. The flight-performance
section spoke my language and didn’t make
me feel intimidated. My 10C radio and
equipment was working flawlessly, as was the
O.S. engine that I was happy to have taken the
time to set up and tune at home. The only
thing not going for me was the direct
crosswind; however, this, too, would be
overcome.
Flying from pavement, my first surprise
was the taxi performance; this airplane had a
healthy footprint for a 60-size model that
weighed only a bit more than 9 pounds. It
helped that the wheels were snugged against
the collars for a friction fit.
The AT-6 worked its way onto the active
runway as the full-scale version would. And
the 81α purred and sounded identical to a Pratt
& Whitney at less than 3,000 rpm.
As did the full-scale Texan, the model
needed rudder work to stay straight down the
runway on takeoff. The rudder had a great
deal of authority and could have used a bit of
exponential on the high rate to prevent
overcorrecting for torque.
Before half throttle, and the 10 mph
breeze, the aircraft came up on the mains and
the rudder work became less demanding.
Before 60% throttle, the AT-6 was extremely
light and could be pulled off of the runway
if the pilot so chose. Mind you, no flaps
were needed for takeoff.
At 70% throttle and a 30-foot run into
the wind, the model would lift off of a
smooth runway and climb out with
authority. The mechanical retracts were an
authentic replication of the full-scale
version, but smoother.
Replace the nylon security clip on the
included screw-lock connectors used on the
retract pushrods. A metal compression
fitting is much less likely to fail.
The recommended aileron throw gave
the Texan a sporty feel. The roll rate was
very quick. I now have roughly 40%
exponential programmed into the ailerons,
so corrections don’t look so obvious. My
low rate is currently 50% or so—much
lower than recommended. This helps input
for rolls and turns look more scale (softer).
Through turns, the AT-6 likes slight
rudder in the same direction, to counter
adverse yaw. For the dreaded mandatory
Figure Eight maneuver in RC Scale, you’ll
want the turns to look coordinated; get used
to mixing the rudder in the turns.
It’s helpful in Point Rolls to fight loss of
altitude where the Texan flies knife edge.
And this Texan is excellent at knife-edge
flight.
By far the best maneuver to watch this
airplane do is the Victory Roll. Only close
to 50% power is needed for the entry, and it
probably looks a bit more authentic if
started from a slight dive.
Exit the dive and start a 15° climb while
simultaneously inputting roll control. The
full roll is done at the same time a shallow
arc is drawn over the field. The
recommended CG is nearly perfect on this
model, so not much altitude will be lost
while inverted. The roll should finish at the
same time as the arc.
There is enough power in the .81α to
pull loops as large as you want. This
aircraft will fly them outside as well as
inside.
Use rudder to counter torque when you
give elevator input: right for positive
maneuvers and left for negative. The torque
effects aren’t obvious until a good amount
of speed is lost. This tells me that engine
thrust built into the TF AT-6 is a good
compromise.
Flap control, as instructed, is spot-on. I
have the flap function linked to one of the
sliders on the Futaba 10C. (All of its eightchannel
and more radios come with sliders
on the sides of the transmitter case.) This
allows me to choose as much deflection as I
want, without being limited to a switch’s
positions.
As recommended, approximately 2° of
down-elevator is mixed into the flap
function to counter the pitch up that occurs
with the change in apparent incidence. I
have the elevator compensation begin at
roughly 40% of deflection. This setup is
working well for me.
With half flaps, the Texan can cruise at
a scale rate. This doesn’t look good to the
judges, so I’m going to have to learn how to
fly the model more slowly for cruise
without the flaps.
With flaps fully deployed, the airplane
floats like a Cub. To me, this warbird
normally flies like a tank. (They fly, just
not for too long.) And there I was, feeling
cozy with this AT-6 that was starting to fly
similar to a glider. It’s teaching me.
With full flap and the gear down, the
airplane needs close to one-quarter throttle
to keep flying. This is a great setup,
because propeller thrust keeps the pitch
control feeling the way it does in a normal
cruise.
The aircraft creeps in for landing; it
looks so cool down and dirty. Managing the
power helps it to reach the runway
threshold, and it’s best to keep the attitude
as constant as possible. (Try not to pitch or
roll around.)
To counter crosswinds, the Texan can be
crabbed, or slipped, with the upwind wing
down, to counteract drift. Again, the high
power setting on the throttle helps keep all
controls effective. This model has a gentle
stall that, predictably, went gently to the
left, so right rudder input was at the ready
to counter an early stall.
The best way to land the AT-6 is on the
mains; it looks right. To do so doesn’t mean
coming in hot; as mentioned, the flaps do a
wonderful job of slowing the airplane.
When the wheels touch, the power can be
reduced, which will keep them on the
ground and start to settle the tail. Bring
up the flaps at the conclusion of the
rollout.
Except for nose weight, I wouldn’t
want a .91 four-stroke in this model;
the smaller 81α is perfect. A .70 would
do the job well too, as would a twostroke
.61. The smaller engine neatly
fits the well-ventilated cowling. My
solution for the required ballast was to
add a duplicate 4.8-volt battery and
wire the packs in parallel under the
fuel tank.
There have been reports that this
Texan feels touchy on the elevator,
and some owners have added nose
weight to compensate. I believe that
the recommended pushrod geometry
forces the user to reduce the elevator
throw electronically, which
simultaneously reduces that surface’s
precision (giving it a touchy feel).
With the right mechanical pushrod
setup, this model’s pitch feels friendly.
So much so that landings are as
predictable as if flying a primary
trainer.
This airplane’s rigid flight envelope
is starting to harden this soon-to-be RC
fighter pilot. The growl of its engine
and the load of its control surfaces
have me feeling more confident with
every flight, and I’m already starting
to think about my next warbird
challenge. MA
Michael Ramsey
[email protected]
Manufacturer/Distributor:
Top Flite/Great Planes Model
Distributors
Box 9021
Champaign IL 61826
(217) 398-8970
www.top-flite.com
Sources:
O.S. Engines
(217) 398-8970
www.osengines.com
Futaba
(217) 398-8970
www.futaba-rc.com
Other Published Reviews:
Model Airplane News: February 2009
Fly RC: June 2009

THE NORTH American AT-6 Texan was
dubbed a trainer—more correctly, a fighter
trainer. The distinction separates those aircraft
that are easy to fly from those that are easy to
replace, in case a student playing fighter
games totally loses respect for the aircraft.
The AT-6 was inexpensive to build and
maintain. Therefore, it was offered in
quantities as a way for military organizations
to save money for the expensive fighter while
brewing its talent for the challenge that laid
before it.
As bluntly as that all might read, through
years of use and abuse, the Texan earned the
respect of its students and later owners. Its
charm is now world renowned.
In World War II, this airplane
was really the instructor—not the
trainer. I know it as a colorful air
show performer, personified heroic movie
character, and rare treat on the tarmac at the
local FBO (fixed base of operation).
After visiting Scale competitions
and the AMA Nats, I’ve learned that
the AT-6 has a colorful history among the
veteran competitors. Models of this aircraft
have earned a reputation all their own.
Many who have had experience with
Texan replicas have been humbled. Some
have graduated from the experience and
claimed that, among the gamut of warbird
offerings, the rite of passage achieved by
piloting a model AT-6 is similar to that of the
full-scale pilots. Flying this airplane takes
skill.
The stories a person uncovers when
researching an aircraft are interesting. The
tails of wonder and whoa, as I like to call
them, both encourage me to continue the
project and make me want to take up fishing
instead.
All in all, it’s good entertainment, and for
me it lasted close to 15 years; a decade and a
half passed between when I decided to get a
Texan and when the opportunity arose.
I’m happy that the chance came to review
the Top Flite (TF) Gold
Edition AT-6 ARF, because which Texan
model I would get was more or less decided
for me. From micro-size to giant scale and kit
to RTF, there are tons of choices.
Because the TF aircraft is 60 size, all
necessary accessories are practical choices.
Not only are the engine and radio pieces
readily available (such as in my parts drawer)
and reliable beyond a doubt, but the model
will easily fit in my SUV with the rest of the
family and their comfort gear (chairs, cooler,
laptop, and pop-up tent).
In addition, a person who chooses the
TF AT-6 gets a heck of a deal. I didn’t
include a “parts” shot of the kit, because a
great one is posted on the TF Web site.
It’s the most well-appointed scale version
of this warbird I’ve seen in this size. And
it’s exceedingly accurate, for the most
part.
After viewing the TF Web page, you
might notice that many of the finished
detail shots look similar to those in this
article. When the model is finished, it
looks practically the same as
the version that the
company uses to advertise
the product.
Yeah, I found a few goofs, but overall
I’m extraordinarily pleased with my TF
24 MODEL AVIATION
Static photos by the author Flight photos by Jay Smith
The elevator servo requires a precise amount of movement. A
standard Futaba wheel is just the thing. A Futaba FASST R617
receiver is tucked in under the tank.
The fuel tank is easy to service when mounted to the
removable equipment tray. Twin Futaba receiver batteries
were used to add redundancy and ballast.
An easy way to center the cowl around the
crankshaft is to make a fixture from foam
or cardboard. If done properly, the
included dummy engine will fit perfectly.
The elevator linkage is concealed in the
fuselage. A welded steel control horn
securely deflects independent elevator
halves. Clamps keep parts centered while
epoxy sets.
A few coats of silver make the fuel-proofed
wooden rib structure look more authentic.
A metal pin links the outer flaps with the
center-section.
Four coreless Futaba S9001 servos drive
ailerons and flaps. The author custom-dyed
the included hardware and substituted dyed
nylon mounting screws. Nice look!
The included spinner and adapter fits 5/16
threaded engine shafts. Run fuel lines
above the fuel tank to prevent siphoning.
The O.S. .81α runs sweetly.
The included hatch, insignia, and markings for the TF Texan are opaque. A wet
application method assures a bubble-free finish.
Massive mechanical retracts mount easily
into the prealigned hard points. Gear
struts are premounted and authentically
formed. Silver paint by the author seals
bare wood.
02sig1.QXD_00MSTRPG.QXD 12/21/09 9:29 AM Page 24
February 2010 25
Test-Model Details
Engine used: O.S. Engine 81FS-α
four-stroke
Propeller: APC 13 x 7 break-in,
Master Airscrew 14 x 6 S-2
normal
Fuel: 14.2-ounce tank, Magnum
#1 fuel
Radio system: Futaba 10C
transmitter; R617 FASST
receiver; six Futaba S9101
servos; one Futaba S136G
retract servo; one Futaba
S3001 throttle servo; two 1000
mAh, 4.8-volt batteries in
parallel; two 24-inch Y-harness
extensions; three 12-inch
extensions
Ready-to-fly weight: 9 pounds,
3 ounces
Flight duration: 12-18 minutes
Pluses and Minuses
+•
Built-up and sheeted wood
construction with fiberglass details
and aluminum spinner.
• Cockpit details provided include
pilot and radio operator.
• Fuelproof and opaque decals.
• Sturdy, high-quality mechanical
retractable landing gear.
• Accurate details with high-visibility
WW II Navy trim scheme.
• Scale documentation is available for
AMA Scale competition.
• Flies like a dream.
-•
Minor assembly-recommendation
errors.
• Exaggerated wing root strap detail.
• Warped flying surfaces needed
straightening. (Simple to fix.)
Specifications
Model type: AMA-legal RC Fun
Scale ARF
Skill level: Intermediate builder
and pilot
Wingspan: 69 inches
Wing area: 730 square inches
Length: 51 inches
Weight: 8.5-9.5 pounds
Wing loading: 27-30 ounces/
square foot
Engine: .61-.91 (two-stroke), .70-
.91 (four-stroke)
Radio: Six channels with eight
servos
Construction: Balsa and plywood,
fiberglass details
Covering/finish: MonoKote,
painted plastic and fiberglass
Price: $279.99
The O.S. .81α runs cleanly. It was easy to start and set directly out of the box. The
engine will turn a 14 x 6 propeller at 8,300 rpm on 20% nitro fuel.
Flaps are unnecessary for takeoff—as is full
power, for that matter. Rudder is necessary;
stand on the right pedal during takeoff, and
coordinate rudder in the turns.
The half-flap position is shown in this dirty pass. Most
of the .81α
fits inside the cowling. The engine is well
ventilated with the TF’s recommended openings.
02sig1.QXD_00MSTRPG.QXD 12/21/09 9:31 AM Page 25
Texan. As I write this, it’s been dubbed my
favorite model.
This warbird is almost as shiny as the fullscale
aircraft. When you have looked at the
Gold Edition online, type the AT-6’s tail
numbers into an Internet search engine (such
as Google) and look for “Images.” Hundreds
of pictures will come up, all of which are
eligible to qualify the TF Texan to compete in
AMA Fun Scale competition. That’s an
outstanding bonus.
This ARF is a great representation of the
full-scale trainer. I’m happy with the fit and
alignment of all the parts—especially in the
tail section, where the relationship of those
parts with the wing are critical. There are a
few things I’d do differently, but they are
cosmetic and in no way a slight against TF’s
effort.
For instance, the wing-joiner covers are
heavy, solid plastic parts that are molded to fit
around the outer wing root. Around the LE, a
gap visible only on the outboard end needed
an extra puddle of epoxy to clean up.
That small complaint invited further
examination of the full-scale airplane, which
brought attention to a subjective comment I
made that the cover is grossly exaggerated.
However, it does match the silver covering
almost perfectly. A custom-made alternative
from wood and matching MonoKote might
suit this detail more accurately.
26 MODEL AVIATION
On the subject of paint matching, I have
no complaints. The Aluminum, Black, Cub
Yellow, and Missile Red film used on the
parts was well finished and neatly trimmed.
The effort even inspired me to go further.
I applied matching trim to the aileron and
elevators, to seal hinge gaps and to the
horizontal stabilizer joint, where a 1/8-inch
strip was used to conceal the obvious gap.
A can of fuelproof silver paint is handy to
have for this model. I had a spray can of
LustreKote, and I put approximately 1/2 ounce
into a paper cup. The flap and gear wells can
use a few healthy coats of this silver, to fuelproof
the mechanical retract hard points and
dress up the already fuel-proofed rib interior
of the split flaps.
I wish I had used that silver paint on the
included dummy engine, or had at least taken
a “dry” brush to the cylinder fins, to make
them look aluminum and not polished
charcoal.
One other area to brush is the cockpit. The
included components for this region are
generous and high in quality. The rear area
under the turtledeck needs the balsa covered
in black paint. I’m being picky, aren’t I?
Instead of using glue, I fastened the
canopy in place with dainty #1 screws. This
way, I have the option of adding more detail
or doing maintenance later. I adhered all of
the components inside the cockpit with Zap-
A-Goo.
In accordance with my picky nature, I
couldn’t resist personalizing the hardware by
dying the nylon parts to match; gray for the
silver hinges and yellow and red for the wing
and tail hardware. As before, TF’s effort
inspired me to go further.
This AT-6’s major components are
wood, including the wingtips and fillet
areas. Those parts in other ARFs are
sometimes made from molded fiberglass.
The wheel-well area is molded from
fiberglass, painted, and then built into the
wing center-section; the look is fairly
convincing.
Port and belly air intakes and the
starboard side exhaust are also made from
fiberglass. They are finished with glossy
paint on the outside and dressed with a
flat-black interior. I chose to attach these,
and the dummy radial engine, with clear
silicone adhesive, because it is fuelproof
and excellent at absorbing vibration.
The wing, tail surfaces, and fuselage
are fully framed and sheeted with balsa.
Control surfaces are ribbed and have the
look of fabric-covered parts, as on the
full-scale warbird.
For stiffness, 3mm plywood is used in
the laser-cut processed form or laminated
in areas such as the firewall and landing
gear. Maple hardwood blocks are used
sparingly to save weight but are included
where they do the job best: in the servo
wing mounts, cowling mounts, and fuel
tank support. Wherever a screw is needed
to hold reliably, TF makes sure that the
right material is installed to do the job—
for a long time.
The recommended components fit into
the TF Texan exactly as prescribed. I’ve
been a happy Futaba user for years and had
no complaints with this project. I did feel
the need to fiddle with the linkage setup,
but only on the elevator.
As the manual shows, recommended
control rates will happen automatically
except on the elevator. This is where I
substituted a standard servo wheel to
connect the elevator pushrod.
Doing so gave me exactly the control
movement necessary without having to
reduce the Adjustable Travel Volume
(ATV) settings on my Futaba 10C radio to
50%. Using the wheel, I increased the
elevator ATV setting to 125%, thus
improving the elevator’s fidelity for supersmooth
control.
O.S. 81-FSα: This company’s new line of
four-stroke engines is the Alpha series. I’m
an old Surpass fan, and I see many
welcome improvements in this engine’s
design that appear to be a new approach to
this type of power system.
Foremost, this is a much more robustlooking
engine with vastly more heat-sink
area and support webbing. The .81α is a
new displacement for O.S., but it’s a
welcome one. As have the previous engine
series, this design includes three main
pieces—a lower crankcase, upper cylinder
enclosure, and cylinder head—all bolted
together with 3mm hardware.
The carburetor is familiar-looking, and
I appreciate the fact that it includes both
flow needles on one side and the mounting
option of having them on the left or right
side of the engine. For the TF AT-6, these
needles need to point out the port side
(flipped from the factory location). An
extension should be mounted to the main
needle from leftover pushrod material.
The Alpha head design is vastly improved
compared with the old Surpass’s; nearly twice
the amount of flange material surrounds the
exhaust port. The exhaust system is also new,
to enable quieter operation and more position
options.
O.S.’s Alpha series is likely the cleanestrunning
line of four-stroke model airplane
power plants today. Provisions no longer need
to be made for a crankcase vent; these engines
recycle the lubricating oil in a new way.
The Alpha .81 is a dream to operate, even
inverted in the Texan. To function at a
blubbery rich setting for the initial run, the
engine doesn’t need glow heat to stay running.
When primed, it starts easily on the first flip.
I used an APC 13 x 7 propeller for benchrunning
and flight-testing, which turned with
the needles peaked at 10,200 rpm. The lowspeed
needle was turned inward roughly 11/4
times from the factor start point, so that the
transition would be smooth and the idle would
be reliable at 1,800 rpm. That’s what I call
dreamy.
Magnum #1 fuel was employed for
running in and flying. The 13 x 7 propeller
made the model accelerate and fly well
beyond scale speeds. On the bench, the .81α
could turn an APC 14 x 6 at 9,300 rpm; that’s
almost as healthy as the old .91 Surpass.
After a gallon of fuel is run through the
engine, I’ll test a Master Airscrew S-2-series
14 x 6 or APC 15 x 4 to bring the AT-6’s
airspeed down to a more believable level.
Flying: I was nervous flying the Texan for the
first time; 15 years of imaginary performance
anxiety had taken its toll. TF’s well-written
manual calmed my nerves, because it left
nothing to chance. The flight-performance
section spoke my language and didn’t make
me feel intimidated. My 10C radio and
equipment was working flawlessly, as was the
O.S. engine that I was happy to have taken the
time to set up and tune at home. The only
thing not going for me was the direct
crosswind; however, this, too, would be
overcome.
Flying from pavement, my first surprise
was the taxi performance; this airplane had a
healthy footprint for a 60-size model that
weighed only a bit more than 9 pounds. It
helped that the wheels were snugged against
the collars for a friction fit.
The AT-6 worked its way onto the active
runway as the full-scale version would. And
the 81α purred and sounded identical to a Pratt
& Whitney at less than 3,000 rpm.
As did the full-scale Texan, the model
needed rudder work to stay straight down the
runway on takeoff. The rudder had a great
deal of authority and could have used a bit of
exponential on the high rate to prevent
overcorrecting for torque.
Before half throttle, and the 10 mph
breeze, the aircraft came up on the mains and
the rudder work became less demanding.
Before 60% throttle, the AT-6 was extremely
light and could be pulled off of the runway
if the pilot so chose. Mind you, no flaps
were needed for takeoff.
At 70% throttle and a 30-foot run into
the wind, the model would lift off of a
smooth runway and climb out with
authority. The mechanical retracts were an
authentic replication of the full-scale
version, but smoother.
Replace the nylon security clip on the
included screw-lock connectors used on the
retract pushrods. A metal compression
fitting is much less likely to fail.
The recommended aileron throw gave
the Texan a sporty feel. The roll rate was
very quick. I now have roughly 40%
exponential programmed into the ailerons,
so corrections don’t look so obvious. My
low rate is currently 50% or so—much
lower than recommended. This helps input
for rolls and turns look more scale (softer).
Through turns, the AT-6 likes slight
rudder in the same direction, to counter
adverse yaw. For the dreaded mandatory
Figure Eight maneuver in RC Scale, you’ll
want the turns to look coordinated; get used
to mixing the rudder in the turns.
It’s helpful in Point Rolls to fight loss of
altitude where the Texan flies knife edge.
And this Texan is excellent at knife-edge
flight.
By far the best maneuver to watch this
airplane do is the Victory Roll. Only close
to 50% power is needed for the entry, and it
probably looks a bit more authentic if
started from a slight dive.
Exit the dive and start a 15° climb while
simultaneously inputting roll control. The
full roll is done at the same time a shallow
arc is drawn over the field. The
recommended CG is nearly perfect on this
model, so not much altitude will be lost
while inverted. The roll should finish at the
same time as the arc.
There is enough power in the .81α to
pull loops as large as you want. This
aircraft will fly them outside as well as
inside.
Use rudder to counter torque when you
give elevator input: right for positive
maneuvers and left for negative. The torque
effects aren’t obvious until a good amount
of speed is lost. This tells me that engine
thrust built into the TF AT-6 is a good
compromise.
Flap control, as instructed, is spot-on. I
have the flap function linked to one of the
sliders on the Futaba 10C. (All of its eightchannel
and more radios come with sliders
on the sides of the transmitter case.) This
allows me to choose as much deflection as I
want, without being limited to a switch’s
positions.
As recommended, approximately 2° of
down-elevator is mixed into the flap
function to counter the pitch up that occurs
with the change in apparent incidence. I
have the elevator compensation begin at
roughly 40% of deflection. This setup is
working well for me.
With half flaps, the Texan can cruise at
a scale rate. This doesn’t look good to the
judges, so I’m going to have to learn how to
fly the model more slowly for cruise
without the flaps.
With flaps fully deployed, the airplane
floats like a Cub. To me, this warbird
normally flies like a tank. (They fly, just
not for too long.) And there I was, feeling
cozy with this AT-6 that was starting to fly
similar to a glider. It’s teaching me.
With full flap and the gear down, the
airplane needs close to one-quarter throttle
to keep flying. This is a great setup,
because propeller thrust keeps the pitch
control feeling the way it does in a normal
cruise.
The aircraft creeps in for landing; it
looks so cool down and dirty. Managing the
power helps it to reach the runway
threshold, and it’s best to keep the attitude
as constant as possible. (Try not to pitch or
roll around.)
To counter crosswinds, the Texan can be
crabbed, or slipped, with the upwind wing
down, to counteract drift. Again, the high
power setting on the throttle helps keep all
controls effective. This model has a gentle
stall that, predictably, went gently to the
left, so right rudder input was at the ready
to counter an early stall.
The best way to land the AT-6 is on the
mains; it looks right. To do so doesn’t mean
coming in hot; as mentioned, the flaps do a
wonderful job of slowing the airplane.
When the wheels touch, the power can be
reduced, which will keep them on the
ground and start to settle the tail. Bring
up the flaps at the conclusion of the
rollout.
Except for nose weight, I wouldn’t
want a .91 four-stroke in this model;
the smaller 81α is perfect. A .70 would
do the job well too, as would a twostroke
.61. The smaller engine neatly
fits the well-ventilated cowling. My
solution for the required ballast was to
add a duplicate 4.8-volt battery and
wire the packs in parallel under the
fuel tank.
There have been reports that this
Texan feels touchy on the elevator,
and some owners have added nose
weight to compensate. I believe that
the recommended pushrod geometry
forces the user to reduce the elevator
throw electronically, which
simultaneously reduces that surface’s
precision (giving it a touchy feel).
With the right mechanical pushrod
setup, this model’s pitch feels friendly.
So much so that landings are as
predictable as if flying a primary
trainer.
This airplane’s rigid flight envelope
is starting to harden this soon-to-be RC
fighter pilot. The growl of its engine
and the load of its control surfaces
have me feeling more confident with
every flight, and I’m already starting
to think about my next warbird
challenge. MA
Michael Ramsey
[email protected]
Manufacturer/Distributor:
Top Flite/Great Planes Model
Distributors
Box 9021
Champaign IL 61826
(217) 398-8970
www.top-flite.com
Sources:
O.S. Engines
(217) 398-8970
www.osengines.com
Futaba
(217) 398-8970
www.futaba-rc.com
Other Published Reviews:
Model Airplane News: February 2009
Fly RC: June 2009

THE NORTH American AT-6 Texan was
dubbed a trainer—more correctly, a fighter
trainer. The distinction separates those aircraft
that are easy to fly from those that are easy to
replace, in case a student playing fighter
games totally loses respect for the aircraft.
The AT-6 was inexpensive to build and
maintain. Therefore, it was offered in
quantities as a way for military organizations
to save money for the expensive fighter while
brewing its talent for the challenge that laid
before it.
As bluntly as that all might read, through
years of use and abuse, the Texan earned the
respect of its students and later owners. Its
charm is now world renowned.
In World War II, this airplane
was really the instructor—not the
trainer. I know it as a colorful air
show performer, personified heroic movie
character, and rare treat on the tarmac at the
local FBO (fixed base of operation).
After visiting Scale competitions
and the AMA Nats, I’ve learned that
the AT-6 has a colorful history among the
veteran competitors. Models of this aircraft
have earned a reputation all their own.
Many who have had experience with
Texan replicas have been humbled. Some
have graduated from the experience and
claimed that, among the gamut of warbird
offerings, the rite of passage achieved by
piloting a model AT-6 is similar to that of the
full-scale pilots. Flying this airplane takes
skill.
The stories a person uncovers when
researching an aircraft are interesting. The
tails of wonder and whoa, as I like to call
them, both encourage me to continue the
project and make me want to take up fishing
instead.
All in all, it’s good entertainment, and for
me it lasted close to 15 years; a decade and a
half passed between when I decided to get a
Texan and when the opportunity arose.
I’m happy that the chance came to review
the Top Flite (TF) Gold
Edition AT-6 ARF, because which Texan
model I would get was more or less decided
for me. From micro-size to giant scale and kit
to RTF, there are tons of choices.
Because the TF aircraft is 60 size, all
necessary accessories are practical choices.
Not only are the engine and radio pieces
readily available (such as in my parts drawer)
and reliable beyond a doubt, but the model
will easily fit in my SUV with the rest of the
family and their comfort gear (chairs, cooler,
laptop, and pop-up tent).
In addition, a person who chooses the
TF AT-6 gets a heck of a deal. I didn’t
include a “parts” shot of the kit, because a
great one is posted on the TF Web site.
It’s the most well-appointed scale version
of this warbird I’ve seen in this size. And
it’s exceedingly accurate, for the most
part.
After viewing the TF Web page, you
might notice that many of the finished
detail shots look similar to those in this
article. When the model is finished, it
looks practically the same as
the version that the
company uses to advertise
the product.
Yeah, I found a few goofs, but overall
I’m extraordinarily pleased with my TF
24 MODEL AVIATION
Static photos by the author Flight photos by Jay Smith
The elevator servo requires a precise amount of movement. A
standard Futaba wheel is just the thing. A Futaba FASST R617
receiver is tucked in under the tank.
The fuel tank is easy to service when mounted to the
removable equipment tray. Twin Futaba receiver batteries
were used to add redundancy and ballast.
An easy way to center the cowl around the
crankshaft is to make a fixture from foam
or cardboard. If done properly, the
included dummy engine will fit perfectly.
The elevator linkage is concealed in the
fuselage. A welded steel control horn
securely deflects independent elevator
halves. Clamps keep parts centered while
epoxy sets.
A few coats of silver make the fuel-proofed
wooden rib structure look more authentic.
A metal pin links the outer flaps with the
center-section.
Four coreless Futaba S9001 servos drive
ailerons and flaps. The author custom-dyed
the included hardware and substituted dyed
nylon mounting screws. Nice look!
The included spinner and adapter fits 5/16
threaded engine shafts. Run fuel lines
above the fuel tank to prevent siphoning.
The O.S. .81α runs sweetly.
The included hatch, insignia, and markings for the TF Texan are opaque. A wet
application method assures a bubble-free finish.
Massive mechanical retracts mount easily
into the prealigned hard points. Gear
struts are premounted and authentically
formed. Silver paint by the author seals
bare wood.
02sig1.QXD_00MSTRPG.QXD 12/21/09 9:29 AM Page 24
February 2010 25
Test-Model Details
Engine used: O.S. Engine 81FS-α
four-stroke
Propeller: APC 13 x 7 break-in,
Master Airscrew 14 x 6 S-2
normal
Fuel: 14.2-ounce tank, Magnum
#1 fuel
Radio system: Futaba 10C
transmitter; R617 FASST
receiver; six Futaba S9101
servos; one Futaba S136G
retract servo; one Futaba
S3001 throttle servo; two 1000
mAh, 4.8-volt batteries in
parallel; two 24-inch Y-harness
extensions; three 12-inch
extensions
Ready-to-fly weight: 9 pounds,
3 ounces
Flight duration: 12-18 minutes
Pluses and Minuses
+•
Built-up and sheeted wood
construction with fiberglass details
and aluminum spinner.
• Cockpit details provided include
pilot and radio operator.
• Fuelproof and opaque decals.
• Sturdy, high-quality mechanical
retractable landing gear.
• Accurate details with high-visibility
WW II Navy trim scheme.
• Scale documentation is available for
AMA Scale competition.
• Flies like a dream.
-•
Minor assembly-recommendation
errors.
• Exaggerated wing root strap detail.
• Warped flying surfaces needed
straightening. (Simple to fix.)
Specifications
Model type: AMA-legal RC Fun
Scale ARF
Skill level: Intermediate builder
and pilot
Wingspan: 69 inches
Wing area: 730 square inches
Length: 51 inches
Weight: 8.5-9.5 pounds
Wing loading: 27-30 ounces/
square foot
Engine: .61-.91 (two-stroke), .70-
.91 (four-stroke)
Radio: Six channels with eight
servos
Construction: Balsa and plywood,
fiberglass details
Covering/finish: MonoKote,
painted plastic and fiberglass
Price: $279.99
The O.S. .81α runs cleanly. It was easy to start and set directly out of the box. The
engine will turn a 14 x 6 propeller at 8,300 rpm on 20% nitro fuel.
Flaps are unnecessary for takeoff—as is full
power, for that matter. Rudder is necessary;
stand on the right pedal during takeoff, and
coordinate rudder in the turns.
The half-flap position is shown in this dirty pass. Most
of the .81α
fits inside the cowling. The engine is well
ventilated with the TF’s recommended openings.
02sig1.QXD_00MSTRPG.QXD 12/21/09 9:31 AM Page 25
Texan. As I write this, it’s been dubbed my
favorite model.
This warbird is almost as shiny as the fullscale
aircraft. When you have looked at the
Gold Edition online, type the AT-6’s tail
numbers into an Internet search engine (such
as Google) and look for “Images.” Hundreds
of pictures will come up, all of which are
eligible to qualify the TF Texan to compete in
AMA Fun Scale competition. That’s an
outstanding bonus.
This ARF is a great representation of the
full-scale trainer. I’m happy with the fit and
alignment of all the parts—especially in the
tail section, where the relationship of those
parts with the wing are critical. There are a
few things I’d do differently, but they are
cosmetic and in no way a slight against TF’s
effort.
For instance, the wing-joiner covers are
heavy, solid plastic parts that are molded to fit
around the outer wing root. Around the LE, a
gap visible only on the outboard end needed
an extra puddle of epoxy to clean up.
That small complaint invited further
examination of the full-scale airplane, which
brought attention to a subjective comment I
made that the cover is grossly exaggerated.
However, it does match the silver covering
almost perfectly. A custom-made alternative
from wood and matching MonoKote might
suit this detail more accurately.
26 MODEL AVIATION
On the subject of paint matching, I have
no complaints. The Aluminum, Black, Cub
Yellow, and Missile Red film used on the
parts was well finished and neatly trimmed.
The effort even inspired me to go further.
I applied matching trim to the aileron and
elevators, to seal hinge gaps and to the
horizontal stabilizer joint, where a 1/8-inch
strip was used to conceal the obvious gap.
A can of fuelproof silver paint is handy to
have for this model. I had a spray can of
LustreKote, and I put approximately 1/2 ounce
into a paper cup. The flap and gear wells can
use a few healthy coats of this silver, to fuelproof
the mechanical retract hard points and
dress up the already fuel-proofed rib interior
of the split flaps.
I wish I had used that silver paint on the
included dummy engine, or had at least taken
a “dry” brush to the cylinder fins, to make
them look aluminum and not polished
charcoal.
One other area to brush is the cockpit. The
included components for this region are
generous and high in quality. The rear area
under the turtledeck needs the balsa covered
in black paint. I’m being picky, aren’t I?
Instead of using glue, I fastened the
canopy in place with dainty #1 screws. This
way, I have the option of adding more detail
or doing maintenance later. I adhered all of
the components inside the cockpit with Zap-
A-Goo.
In accordance with my picky nature, I
couldn’t resist personalizing the hardware by
dying the nylon parts to match; gray for the
silver hinges and yellow and red for the wing
and tail hardware. As before, TF’s effort
inspired me to go further.
This AT-6’s major components are
wood, including the wingtips and fillet
areas. Those parts in other ARFs are
sometimes made from molded fiberglass.
The wheel-well area is molded from
fiberglass, painted, and then built into the
wing center-section; the look is fairly
convincing.
Port and belly air intakes and the
starboard side exhaust are also made from
fiberglass. They are finished with glossy
paint on the outside and dressed with a
flat-black interior. I chose to attach these,
and the dummy radial engine, with clear
silicone adhesive, because it is fuelproof
and excellent at absorbing vibration.
The wing, tail surfaces, and fuselage
are fully framed and sheeted with balsa.
Control surfaces are ribbed and have the
look of fabric-covered parts, as on the
full-scale warbird.
For stiffness, 3mm plywood is used in
the laser-cut processed form or laminated
in areas such as the firewall and landing
gear. Maple hardwood blocks are used
sparingly to save weight but are included
where they do the job best: in the servo
wing mounts, cowling mounts, and fuel
tank support. Wherever a screw is needed
to hold reliably, TF makes sure that the
right material is installed to do the job—
for a long time.
The recommended components fit into
the TF Texan exactly as prescribed. I’ve
been a happy Futaba user for years and had
no complaints with this project. I did feel
the need to fiddle with the linkage setup,
but only on the elevator.
As the manual shows, recommended
control rates will happen automatically
except on the elevator. This is where I
substituted a standard servo wheel to
connect the elevator pushrod.
Doing so gave me exactly the control
movement necessary without having to
reduce the Adjustable Travel Volume
(ATV) settings on my Futaba 10C radio to
50%. Using the wheel, I increased the
elevator ATV setting to 125%, thus
improving the elevator’s fidelity for supersmooth
control.
O.S. 81-FSα: This company’s new line of
four-stroke engines is the Alpha series. I’m
an old Surpass fan, and I see many
welcome improvements in this engine’s
design that appear to be a new approach to
this type of power system.
Foremost, this is a much more robustlooking
engine with vastly more heat-sink
area and support webbing. The .81α is a
new displacement for O.S., but it’s a
welcome one. As have the previous engine
series, this design includes three main
pieces—a lower crankcase, upper cylinder
enclosure, and cylinder head—all bolted
together with 3mm hardware.
The carburetor is familiar-looking, and
I appreciate the fact that it includes both
flow needles on one side and the mounting
option of having them on the left or right
side of the engine. For the TF AT-6, these
needles need to point out the port side
(flipped from the factory location). An
extension should be mounted to the main
needle from leftover pushrod material.
The Alpha head design is vastly improved
compared with the old Surpass’s; nearly twice
the amount of flange material surrounds the
exhaust port. The exhaust system is also new,
to enable quieter operation and more position
options.
O.S.’s Alpha series is likely the cleanestrunning
line of four-stroke model airplane
power plants today. Provisions no longer need
to be made for a crankcase vent; these engines
recycle the lubricating oil in a new way.
The Alpha .81 is a dream to operate, even
inverted in the Texan. To function at a
blubbery rich setting for the initial run, the
engine doesn’t need glow heat to stay running.
When primed, it starts easily on the first flip.
I used an APC 13 x 7 propeller for benchrunning
and flight-testing, which turned with
the needles peaked at 10,200 rpm. The lowspeed
needle was turned inward roughly 11/4
times from the factor start point, so that the
transition would be smooth and the idle would
be reliable at 1,800 rpm. That’s what I call
dreamy.
Magnum #1 fuel was employed for
running in and flying. The 13 x 7 propeller
made the model accelerate and fly well
beyond scale speeds. On the bench, the .81α
could turn an APC 14 x 6 at 9,300 rpm; that’s
almost as healthy as the old .91 Surpass.
After a gallon of fuel is run through the
engine, I’ll test a Master Airscrew S-2-series
14 x 6 or APC 15 x 4 to bring the AT-6’s
airspeed down to a more believable level.
Flying: I was nervous flying the Texan for the
first time; 15 years of imaginary performance
anxiety had taken its toll. TF’s well-written
manual calmed my nerves, because it left
nothing to chance. The flight-performance
section spoke my language and didn’t make
me feel intimidated. My 10C radio and
equipment was working flawlessly, as was the
O.S. engine that I was happy to have taken the
time to set up and tune at home. The only
thing not going for me was the direct
crosswind; however, this, too, would be
overcome.
Flying from pavement, my first surprise
was the taxi performance; this airplane had a
healthy footprint for a 60-size model that
weighed only a bit more than 9 pounds. It
helped that the wheels were snugged against
the collars for a friction fit.
The AT-6 worked its way onto the active
runway as the full-scale version would. And
the 81α purred and sounded identical to a Pratt
& Whitney at less than 3,000 rpm.
As did the full-scale Texan, the model
needed rudder work to stay straight down the
runway on takeoff. The rudder had a great
deal of authority and could have used a bit of
exponential on the high rate to prevent
overcorrecting for torque.
Before half throttle, and the 10 mph
breeze, the aircraft came up on the mains and
the rudder work became less demanding.
Before 60% throttle, the AT-6 was extremely
light and could be pulled off of the runway
if the pilot so chose. Mind you, no flaps
were needed for takeoff.
At 70% throttle and a 30-foot run into
the wind, the model would lift off of a
smooth runway and climb out with
authority. The mechanical retracts were an
authentic replication of the full-scale
version, but smoother.
Replace the nylon security clip on the
included screw-lock connectors used on the
retract pushrods. A metal compression
fitting is much less likely to fail.
The recommended aileron throw gave
the Texan a sporty feel. The roll rate was
very quick. I now have roughly 40%
exponential programmed into the ailerons,
so corrections don’t look so obvious. My
low rate is currently 50% or so—much
lower than recommended. This helps input
for rolls and turns look more scale (softer).
Through turns, the AT-6 likes slight
rudder in the same direction, to counter
adverse yaw. For the dreaded mandatory
Figure Eight maneuver in RC Scale, you’ll
want the turns to look coordinated; get used
to mixing the rudder in the turns.
It’s helpful in Point Rolls to fight loss of
altitude where the Texan flies knife edge.
And this Texan is excellent at knife-edge
flight.
By far the best maneuver to watch this
airplane do is the Victory Roll. Only close
to 50% power is needed for the entry, and it
probably looks a bit more authentic if
started from a slight dive.
Exit the dive and start a 15° climb while
simultaneously inputting roll control. The
full roll is done at the same time a shallow
arc is drawn over the field. The
recommended CG is nearly perfect on this
model, so not much altitude will be lost
while inverted. The roll should finish at the
same time as the arc.
There is enough power in the .81α to
pull loops as large as you want. This
aircraft will fly them outside as well as
inside.
Use rudder to counter torque when you
give elevator input: right for positive
maneuvers and left for negative. The torque
effects aren’t obvious until a good amount
of speed is lost. This tells me that engine
thrust built into the TF AT-6 is a good
compromise.
Flap control, as instructed, is spot-on. I
have the flap function linked to one of the
sliders on the Futaba 10C. (All of its eightchannel
and more radios come with sliders
on the sides of the transmitter case.) This
allows me to choose as much deflection as I
want, without being limited to a switch’s
positions.
As recommended, approximately 2° of
down-elevator is mixed into the flap
function to counter the pitch up that occurs
with the change in apparent incidence. I
have the elevator compensation begin at
roughly 40% of deflection. This setup is
working well for me.
With half flaps, the Texan can cruise at
a scale rate. This doesn’t look good to the
judges, so I’m going to have to learn how to
fly the model more slowly for cruise
without the flaps.
With flaps fully deployed, the airplane
floats like a Cub. To me, this warbird
normally flies like a tank. (They fly, just
not for too long.) And there I was, feeling
cozy with this AT-6 that was starting to fly
similar to a glider. It’s teaching me.
With full flap and the gear down, the
airplane needs close to one-quarter throttle
to keep flying. This is a great setup,
because propeller thrust keeps the pitch
control feeling the way it does in a normal
cruise.
The aircraft creeps in for landing; it
looks so cool down and dirty. Managing the
power helps it to reach the runway
threshold, and it’s best to keep the attitude
as constant as possible. (Try not to pitch or
roll around.)
To counter crosswinds, the Texan can be
crabbed, or slipped, with the upwind wing
down, to counteract drift. Again, the high
power setting on the throttle helps keep all
controls effective. This model has a gentle
stall that, predictably, went gently to the
left, so right rudder input was at the ready
to counter an early stall.
The best way to land the AT-6 is on the
mains; it looks right. To do so doesn’t mean
coming in hot; as mentioned, the flaps do a
wonderful job of slowing the airplane.
When the wheels touch, the power can be
reduced, which will keep them on the
ground and start to settle the tail. Bring
up the flaps at the conclusion of the
rollout.
Except for nose weight, I wouldn’t
want a .91 four-stroke in this model;
the smaller 81α is perfect. A .70 would
do the job well too, as would a twostroke
.61. The smaller engine neatly
fits the well-ventilated cowling. My
solution for the required ballast was to
add a duplicate 4.8-volt battery and
wire the packs in parallel under the
fuel tank.
There have been reports that this
Texan feels touchy on the elevator,
and some owners have added nose
weight to compensate. I believe that
the recommended pushrod geometry
forces the user to reduce the elevator
throw electronically, which
simultaneously reduces that surface’s
precision (giving it a touchy feel).
With the right mechanical pushrod
setup, this model’s pitch feels friendly.
So much so that landings are as
predictable as if flying a primary
trainer.
This airplane’s rigid flight envelope
is starting to harden this soon-to-be RC
fighter pilot. The growl of its engine
and the load of its control surfaces
have me feeling more confident with
every flight, and I’m already starting
to think about my next warbird
challenge. MA
Michael Ramsey
[email protected]
Manufacturer/Distributor:
Top Flite/Great Planes Model
Distributors
Box 9021
Champaign IL 61826
(217) 398-8970
www.top-flite.com
Sources:
O.S. Engines
(217) 398-8970
www.osengines.com
Futaba
(217) 398-8970
www.futaba-rc.com
Other Published Reviews:
Model Airplane News: February 2009
Fly RC: June 2009