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Written by Mike Hurley
A capable precision and 3-D aerobat
Product review
As seen in the May 2017 issue of
Model Aviation.



Bonus video


Specifications

Model type: Giant Scale ARF
Skill level: Intermediate sport flier to expert competitor
Wingspan: 111 inches
Wing area: 2,139 square inches
Length: 99.5 inches
Wing loading: 21.8 ounces per square inch
Ready-to-fly weight: 29 pounds, 3 ounces
Power system: 100cc to 120cc gas engine
Radio system: Minimum four-channel 2.4 GHz; six to 11 servos
Construction: Built-up balsa, plywood, carbon fiber, fiberglass, and iron-on covering
Street price: $1,069.95


Test-Model Details

Power system: Desert Aircraft DA-120 twin-cylinder two-stroke engine with electronic ignition; JR NXB8921 brushless programmable high-torque servos; JR Aluminum HD 2-inch servo arms for rudder and elevator and 1.5-inch servo arms on aileron; JR XBus XB1-CHB Heavy Duty Center Hub distribution system; two 2S 3,800 mAh LiPo batteries for the servos and one 2S 2,500 mAh LiFe battery for ignition
Exhaust: DA standard mufflers
Radio system: JR 28X DMSS transmitter; JR RG613BX six-channel XBus DMSS 2.4 GHz receiver
Spinner: Tru-Turn 4.5-inch Ultimate aluminum with lightened backplate (5.5 ounces)
Propeller: Falcon 29 x 9W
Fuel tank: Fiji 750 ml water bottle with PSB manufacturing hardware


Pluses

• Great scale looks and details.
• Quality hardware and construction.
• Excels in both precision and 3-D flying.


Minuses

• Inconsistent incidence settings.
• Overlapping cowl design.
• Landing gear location slightly forward.


Included Equipment

• Carbon-fiber landing gear; tail gear; wing tube; stabilizer tube
• Carbon-fiber 4.5-inch spinner with carbon-fiber backplate (5.5 ounces)
• Tiller-style tail wheel with machined aluminum hardware
• Clear water-bottle-style fuel tank
• Heavy-duty ball-end control linkages with turnbuckle rods
• Fiberglass control horns
• Drill guide templates for various commonly used engines
• Preglued pin-style hinges
• 3mm Allen-head cap screws with nylon locknuts
• Aluminum hub wheels; fiberglass wheel pants (no cuffs)
• Removable rudder via hinge wire pin
• Provisions for remote pull-pull or rear-mounted rudder servos
• Removable wingtips and side-force generators
• Mounting plates and silicon cushion tube for various popular canister and tuned exhausts
• Miscellaneous hardware and servo mounting boxes for alternative installations
• Laser-cut AeroPlus RC mini practice stick airplane


Product Review

The full-scale EXTRA 330LT was certified in 2010, making it the latest certified offering from EXTRA Aircraft. It was designed as a high-performance, fully aerobatic aircraft with long distance and touring capabilities. According to EXTRA Aircraft, it is the fastest certified, naturally aspirated piston airplane in
the world.

The 330LT has some design features not found on other EXTRA models, including rounded tips on the vertical and horizontal stabilizers, along with scimitar-shaped wingtips that do not carry the ailerons, making the shape and look unique among all of the EXTRA models we’ve seen so far. The cowl is configured more like a full-scale Unlimited SC EXTRA rather than the older 300L, from which the 330LT seems to be born. Of course, details about the full-scale airplane go much further into making it a better touring machine, but those creature comforts won’t matter much to a modeler.

AeroPlus RC has done an exceptional job at capturing the essence of the 330LT with a scalelike outline, even down to the newer cowl style. The size of my review model is 111 inches tip-to-tip, making the model almost exactly 35% of the 26.3-foot full-scale airplane. One of the reasons I was so drawn to this new aerobatic airplane was its scale outline. The designers even rounded the fuselage and contoured the wing roots to fit. This is the first model I’ve seen designed like this, and it works beautifully. AeroPlus RC even got the unique wingtips right. The airplane looks fantastic in flight.




With a scalelike outline, the AeroPlus RC EXTRA 330LT features rounded wingtips and has only a 3% stretch. The designer clearly had powerful control in mind with huge barn-door ailerons and more than 70% of the horizontal stabilizer dedicated to elevator.


Although I like my airplanes to look as scalelike as possible, I don’t want to sacrifice state-of-the-art 3-D and precision performance. AeroPlus RC got this right, with a large wetted area, plenty of height in the fuselage sides for great knife-edge performance, and thin, relatively sharp wings with a Pattern-style airfoil that moves the aerodynamic center aft of common National Advisory Committee for Aeronautics (NACA) airfoils.

In my experience, Scale Aerobatic airplanes with these design elements perform well in both 3-D and precision flight. What will stand out to most people who see the airplane are the gigantic control surfaces clearly intended to excel at 3-D. The ailerons have a 93/4-inch chord at the root, and the elevators take up more than 70% of the stabilizer area!

The airplane arrived with prehinged ailerons and elevators and with a removable wire pin-style hinge for the rudder. The landing gear and wing tubes are carbon fiber, and the root sections of the stabilizers are made of a composite (I assumed so that the mounting tabs were of sufficient strength). The removable wingtips have a provision for a set of unusual-looking side-force generators that mount between the wing and the wingtips.

There is a set of cables prerouted inside of the fuselage for a rudder pull-pull system. I wanted to mount the servos for the rudder in the tail, so I removed these and patched the holes left in the covering.




The EXTRA is designed with provisions for a cable pull-pull-type rudder control and has mounting provisions in the rear of the fuselage as well. The author chose to mount the rudder servos in the tail.


The cowl is one piece, but big enough that installing and removing it from around the engine and mufflers isn’t hard. One of the few design elements that I don’t like about this model is that the cowl overlaps the fuselage sides and the top hatch instead of cleanly butting up to the fuselage as on most modern models. It works fine this way, but it’s not as neat looking as it could be.

The hatch and canopy are one piece, and painted instead of covered. Doing the hatch this way is not only better looking and more reliable, but there’s also no covering to wrinkle in the sun. The model comes complete with high-quality hardware and a clear, water-bottle-style fuel tank. I used all of the control linkage hardware, but I had a Fiji water tank with PSB hardware on hand that I wanted to use.

There are instructions, but they are obviously a generic write-up used for several offerings, with a few added details specific to this airplane. I looked at the directions to get the center of gravity (CG), and that was it.

The airplane is straightforward: glue in the control horns, mount the servos and electronics, install the control linkages, use the drill guide for the engine, set the CG, and program the model into your radio. If you’ve done one before, you can do this one. I changed the mounting method for the wheel pants to my usual system and used a pair of Du-Bro axles and wheel collars instead of the supplied bolts and wooden spacers. I also made some simple air ducts for engine cooling out of 1/8-inch balsa and glued them into the cowl.

During the build, I checked the incidence of the wings and stabilizers. The left wing was +0.4° and the right wing was set almost perfectly at +0.1°. I modified the left wing to match the right at +0.1°. The stabilizers were slightly farther off. The right stabilizer was at +0.4° and the left at +1.6°, but I didn’t reset them.
In flight, the stabilizers will always find level, with positive incidence as the tail rises. Raise the tail too much and the airplane dives. This is easily adjusted with elevator trim, but the offset is visible on the ground with the radio on.




Checking the incidence is a step often overlooked by modelers putting together ARF aircraft. This one required an adjustment that would have affected flight performance had it not been corrected.


During the first flight, I found that I needed approximately 20 points of up-elevator to counter the incorrect incidence and fly level. It is not a big deal, but it would have been nice for these incidence settings to be a little better from the factory.

I have a JR 28X transmitter and decided to go full XBus and route all of the wires via JR’s XBus XB1-CHB Heavy Duty Center Hub. I installed a set of programmable JR NXB8921 brushless digital XBus servos. This made the setup inside of the airplane simple and straightforward, with no need for additional electronics or regulators. I used a single JR RG613BX six-channel receiver connected to the Center Hub and no additional satellite antennas. I set up the servo configuration so that each servo has its own channel, then set the endpoints and center data and stored it in each servo’s memory. From there, I did all of my programming, matching, and mixing using the radio.

The receiver acts as a receiver and telemetry transmitter only. All of the channels are handled with a single wire via XBus and the Center Hub. I used two servos for each wing panel, although the model has provisions for three. I put one servo in each stabilizer half and used two servos mounted in the rear of the airplane for the rudder, which are controlled via push-pull titanium turnbuckles. I had to supply the rudder turnbuckles, but the rest of the hardware was included.

My engine of choice is a Desert Aircraft DA-120 with standard mufflers. There are provisions for tuned pipes or canister mufflers built into the airplane. I used two 3,800 mAh 2S LiPo batteries for the radio, and a 2,500 mAh 2S LiFe battery for the ignition. With the electronics on the wing tube and the batteries mounted in the motor box, the balance was perfect. The airplane weighed 29 pounds, 3 ounces on my uncertified mechanical scale—lightweight for a 111-inch airplane, but slightly heavier than advertised.




A DA-120cc twin engine was used to power this model. Standard mufflers help keep the weight up front for balancing purposes, but the model is designed to accommodate a variety of canisters or tuned pipes.



Flying

The AeroPlus RC 330LT surprised me in flight. With huge control surfaces, I expected its 3-D performance to be good, but I wasn’t sure how it would affect the airplane’s precision. I didn’t install the side-force generators for testing.

The rolls are competition-worthy axial, and the lines are true and clean. Knife-edge flight is easily controllable right off the table with no mixes—just a slight rudder-to-elevator and aileron mix, making knife-edge flight hands off.

The rudder is extremely effective without the side-force generators and I found myself practicing knife-edge loops on the first flight. This effectiveness means the angle of attack while the airplane is on its side is low to maintain altitude. Point rolls require minimal input to look clean and stable and carry a straight line.

Speed is smooth and controllable in any attitude, and downline speed is slow enough to maintain uniformity. A small throttle-to-elevator mix that is typical of any International Miniature Aerobatic Club (IMAC) airplane made downlines perfect. Rolling circles require less work to maintain altitude, and the airplane seems to hold the line better than other 35% airplanes that I’ve flown in the past. Snaps with those big ailerons are magic. The airplane instantly starts and stops the snap, making nailing that exit point accurate and consistent.

Overall, the airplane feels tight and precise in the air. It stays with you and gives you time to react. It doesn’t do anything unexpected and does exactly what your fingers tell it to do. That might sound normal, but not all airplanes do that. When I compete, I fly 40% and 42%-scale aircraft. This is the first 35%-scale airplane that I would consider flying in a contest. It’s that good!




This picture shows how the AeroPlus RC EXTRA 330LT would look right out of the box. The author removed the original graphics on the airplane in this review and replaced them with his own design.


In 3-D flight, the 330LT is a beast. Its control surfaces are extremely effective, yet with a little exponential, the airplane is easy to fly, with smooth, sure reactions to your input, even with full 3-D deflection rates.

Rocking in Harrier flight is always a big question. With this model, controlling the rocking with those huge ailerons is positive and connected. Controlling the airplane while in a Harrier is a matter of cross-controlling and roll attitude, and even then, some airplanes don’t want to respond to input.

The 330LT is responsive while low and slow and extremely positive even at high angles of attack. High-alpha rolls are as easy and as controlled as point rolls, and steering the airplane around while Harrier rolling is merely a matter of timing the elevator inputs. To get the airplane into an extremely high angle of attack while rolling, the forward momentum needs to be slower than with some other airplanes because of the big fuselage side area.

Knife-edge spins look great, but require much less aileron input. Too much will pop you flat. Flat spins are tight and descend slowly, and blenders are surprisingly smooth and clean without that explosiveness that can damage your airplane.

Pop-tops are super flat and I can usually get a couple of rotations before the momentum stops. Waterfalls are tight, nearly spinning the airplane around the wing axis without losing any altitude. Rolls are not as fast as you might think. They are fast, but not “turning the airplane into a blur” fast. I think the static wingtips might have something to do with that.

This airplane isn’t as fast in the modern hyper-3-D stuff as are some of the smaller, thinner airplanes, but it feels more stable and responsive. You would think the rolls and transitions would be aggressive with the big control surfaces, but the airplane is big and relatively lightweight for its size, so it feels slightly less explosive than other 100cc airplanes. Of course, that might be my “old-school” 3-D style and my inclination to not be too hard on my airplanes.

Landing the airplane the first couple of times was interesting. I found that it wanted to bounce on landing unless I stuck it like a warbird and wheel landed it. I later checked the position of the gear, and the axles are approximately 1.5 inches forward of the ideal location for a balanced touchdown. That’s okay—wheel landings look cool.


Conclusion

We usually have to sacrifice something to get an airplane that excels at one type of flight or another, and sometimes we find airplanes that can do everything well, but nothing great. This airplane is fantastic at everything I want it to do, and despite a few minor misses, this is the best-flying 35%-scale aerobatic airplane I’ve ever flown.

For me, the best part about the AeroPlus RC EXTRA 330LT is that it does it all and it looks the way a full-scale EXTRA 330LT is supposed to look.

—Mike Hurley
mhurley222@twc.com


Manufacturer/Distributor:

AeroPlus RC
stephen@aeroplusrc.com
www.aeroplusrc.com

Mile High RC
www.milehighrc.com


Sources:

EXTRA Aircraft
extraaircraft@extraaircraft.com
www.extraaircraft.com

JR Americas
(217) 352-7959
www.jramericas.com

Desert Aircraft
(520) 722-0607
www.desertaircraft.com

Tru-Turn
(281) 479-9600
www.truturn.com

Falcon Propellers
(407) 277-1248
www.falconpropellers.com

Bad Brad Graphics
(262) 377-3944
http://badbradgraphics.com






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