Looks Like A Warbird And Flies Like A Trainer

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Written by Terry Dunn
Review
As seen in the March 2021 issue of Model Aviation.

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CLEARLY, THE DESIGNERS of the full-scale Nanchang CJ-6 were not constrained by any aesthetic requirements. It is a stunning example of rugged simplicity. For example, the wheel brakes, retracts, flaps, and engine starter are all powered by pressurized air. A compressor, driven by the engine, keeps the dual onboard air tanks charged and makes the CJ-6 largely self-reliant.

More than 60 years after its introduction, examples of this radial-engine trainer are still serving in numerous Far East militaries. The CJ-6 has also found increased popularity among warbird collectors in the West. Private owners have discovered that the airplane’s minimalistic design and youth (it’s still in production) make it extremely reliable and relatively affordable to own (as warbirds go).

Few modifications are necessary to make the CJ-6 a practical civilian airplane; however, one common upgrade among private owners is to install larger fuel tanks in the wing. Rumor has it that the limited range afforded by its stock 40-gallon fuel capacity was intended to discourage military pilots from defecting.

The FMS downsized rendition of the CJ-6 captures every aspect of the full-scale airplane’s unique appearance. It has large wing with dihedral on the outer panels and a long, skinny fuselage behind a blunt engine cowling. These parts sit on top of a stork-like tricycle landing gear. As with its namesake, the RC model’s true charm is found within.

The CJ-6 is a molded-foam model that includes most of the necessary onboard electronics. Six 9-gram, factory-installed digital servos actuate the ailerons, elevator, rudder, nose wheel steering, and a single flap. Electric retracts are provided as well. You will have to source a 4S 2,200 mAh LiPo battery and a six-plus-channel radio system.

All of the control surface servos are connected to a preinstalled FMS Reflex V2 gyro. This device can be switched off or set to either of two modes during flight. Stabilized mode provides auto-leveling, as well as pitch and bank limits. Optimized mode helps keep the CJ-6 on a smooth flight path when flying in turbulent air.

The included power system consists of an outrunner brushless motor. It spins a scalelike 11-inch diameter propeller. The system is connected to a 40-amp ESC.

Unlike many warbirds, visibility is not a concern with this model. It comes out of the box in a red, white, and blue trim scheme from the Chinese Air Force (People’s Liberation Army Air Force). The colors and markings are a combination of paint and decals. The quality of the finish on my example is outstanding.

Assembling the CJ-6

This model is mostly prebuilt, so there are not many assembly steps to be completed. One of the first tasks involves installing the elevator pushrod. In stock form, the elevator clevis engages with the control horn at an odd angle. I was concerned that this might cause binding and premature wear of the plastic clevis. I was able to bring the parts into alignment by applying a slight S-bend to the pushrod.

All of the foam airframe components fit together precisely. The seams are tight, with no large or uneven gaps. Plastic accent pieces, such as engine louvers, a pilot bust, and landing gear doors, further improve the CJ-6’s scalelike appearance. This kit creates a fine-looking model.

It is always a good idea to check the propeller balance before installing it on any model airplane. I found that the included propeller was significantly unbalanced. I corrected it by applying tape to the backside of the lighter blade.

The entire canopy is actually a removable, magnetically secured hatch. It provides great access to the radio gear and battery compartment. The gyro is hard mounted to the fuselage at the rear of the radio bay. With all of the servo wires going into and out of the gyro (in addition to wires for the navigation lights), careful wire management is necessary to prevent a messy bird’s nest.

I used a Futaba R7008SB receiver with S.Bus. This allowed me to connect the receiver to the gyro with a single servo extension (instead of an extension for each channel). I still found it necessary to bundle and use a zip tie on the wires to keep things organized. I installed a shelf made of scrap foam just in front of the gyro. This provided a handy location to mount the receiver with hook-and-loop tape.Equally important, it created a space for tucking excess wire.

There is a plywood tray with hook-and-loop straps for securing the battery. Unfortunately, this tray is positioned too far rearward. When I moved my 4S 2,200 mAh battery to balance the model at the recommended center of gravity (CG) location, it was almost completely forward of the tray.

Rather than extend the tray toward the nose, I added .75 ounces of lead just behind the louvers in the cowling. This allowed me to place the battery solidly on the tray while maintaining the CG. Even with the additional nose ballast, my model still weighed slightly less than the advertised weight.

Flying the CJ-6

The CJ-6 has roughly 1.25 inches of ground clearance for the propeller. Despite the tight margin, this airplane has no trouble operating from my club’s rough grass runway. Ground handling is excellent, and the model can easily muscle its way into the sky. It might clip a few blades of grass as it goes, but it goes!

With the landing gear tucked away, the CJ-6 cleans up nicely. The power system provides a good balance of speed and climb performance. It is actually surprisingly fast. The model covers ground in a hurry! Full-power vertical climbs are tall, although not unlimited. Loops can be as big as you want them. I quickly realized that I could ease the throttle back to 50% to 75% and still have lots of fun.

fms cj 6 has few components
The FMS CJ-6 has few components to assemble. The fit and finish of the parts is superb.
scalelike propeller
A scalelike propeller, hub, and engine louvers are included. Be sure to check your propeller’s balance.
stock form the elevator clevis engaged
In stock form, the elevator clevis engaged the control horn at an odd angle. Adding an S-bend to the pushrod improved its geometry.
stock form the elevator clevis engaged

Aileron authority is good. The suggested high-rate aileron setting (12 mm) might not look like much deflection, but it’s plenty. Rolls are quick and axial. Elevator authority is sufficient for most aerobatic moves. I found that high-rate elevator (and harsh input) was required to make the CJ-6 stall, but that capability is there. I have to admit that I still have not managed to perform a respectable snap roll. I might experiment by nudging the CG rearward.

The rudder authority is definitely softer than I like. There is no doubt that the rudder falls short on yaw-heavy maneuvers such as knife-edge flight and stall turns. Those maneuvers are possible, but they require good planning and execution because there is no surplus of rudder control.

Although I tend to focus on aerobatic ability, I should point out that the CJ-6 is fun to fly in simple circuits around the field. It is stable and predictable across a wide speed range. I particularly enjoy shooting touch-and-gos with this model.

Engaging Stabilized Mode on the gyro made the CJ-6 extremely docile. Even fullstick deflections did not yield a strong response from the model. Pilots who are transitioning from a trainer will likely find this behavior reassuring. More-experienced pilots might find it disconcerting. That’s why the gyro can be switched off.

To be honest, I could not determine much difference between flying with Optimized Mode and when the gyro was off. Ground testing assured me that Optimized Mode does has some effect. I’m simply not calibrated precisely enough to detect those nuances when flying but that’s okay. The CJ-6 is a well-behaved airplane with the gyro off or in Optimized Mode.

I like to fly the CJ-6 with a mix of aerobatics and lazy cruising. My flight times with 4S 2,200 mAh batteries average approximately 6 minutes with a little power to spare.

shelf made from sheet foam provided
A shelf made from sheet foam provided a convenient mounting area for the receiver and a way to hide some of the servo wires. Note the plywood battery tray on the left and the gyro (orange) on the right.
the kit includes electric
The kit includes electric retracts with doors on the main gear.

If you’re a pilot who likes to keep the throttle firewalled, your flight time will suffer accordingly. I have also flown with a 4S 3,300 mAh battery. The slightly heavier battery did not seem to affect performance, and I comfortably added 2 to 3 minutes to my flights.

The CJ-6’s vibrant color scheme provides excellent in-flight orientation. I was truly surprised by how significantly the navigation lights improved visibility as well. This has been especially true when flying the CJ-6 at dusk and on overcast days. Those lights really pop!

As with the full-scale CJ-6, the FMS model has a single split flap in the wing’s center section. The manual does not provide suggested throws for the flap. I programmed a three-position switch on my Futaba 14SG transmitter to get 0, 15 mm, or 28 mm of flap deflection. Following my initial flight testing, I also mixed 15% of down-elevator with the flap. This prevents any pitch change when I drop the flap.

included brushless
The included brushless motor provides a good mix of speed and climb performance.

Landing the CJ-6 is easy. Although it isn’t necessary to lower the flap, it is quite effective at slowing things down—way down! With full flap, landing speeds are surprisingly sedate. Just be ready for the airplane to float in ground effect for a second or two before settling in. All of the control surfaces stay effective throughout the landing.

Conclusion

The Nanchang CJ-6 might not be the prettiest airplane ever made, but no one can argue its successful track record. It does what it was designed to do and that functionality carries over into the FMS rendition of the famous Chinese trainer. This model is a well-rounded aircraft that does many things competently. It is nicely made, easy to assemble, and exciting to fly. Even its looks are starting to grow on me!

grass runways are no problem
Grass runways are no problem for this model. With the full flap, the airplane slows down nicely for landings.

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