Plane Talk: Top Flite AT-6 Texan Gold Edition ARF
Michael Ramsey
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 breeding its talent for the challenge that lay 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 tales 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.
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
Test-Model Details
- Engine used: O.S. .81 FS Alpha 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 WWII 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.)
The Texan has become my favorite model. This warbird is almost as shiny as the full-scale 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-jointer covers are heavy, solid plastic parts that are molded to fit around the outer wing root. Around the leading edge, 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.
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 fuelproofed 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 located where they do the job best: in the servo mount rails, 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 Alpha (four-stroke)
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 robust-looking engine with vastly more heat-sink area and support webbing. The .81 Alpha 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 cleanest-running 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 bench-running and flight-testing, which turned with the needles peaked at 10,200 rpm. The low-speed needle was turned inward roughly 1 1/4 times from the factory 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 .81 Alpha 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 were 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 .81 Alpha 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 with 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 .81 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 eight-channel 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 .81 is perfect. A .70 would do the job well too, as would a two-stroke .61. The smaller engine neatly fits the well-ventilated cowling. My solution to 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.
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
Transcribed from original scans by AI. Minor OCR errors may remain.
