Great planes: Extra 300S ARF

Model Airplane News, Jun 2003 by Bell, Rick

State-of-the-art, high-performance aerobatic ARF

How would you like to own an aircraft that spans 78 1/2 inches, is built of high-quality materials and has plug-in wing and stabilizer panels for easy transportation and storage? Are you interested? Here's more to whet your appetite. Let's add a fiberglass cowl with an elaborately painted checkerboard on its nose. Need still more? What if the model was an almost-ready-to-fly (ARF) version of one of the most aerobatic and recognizable planes of all time? Well, that's what you get with the new Great Planes Extra 300S ARF.

Great Planes Model Manufacturing Co. has been a major player in the ARF market for a few years now, and the company really raises the bar with this, its best offering yet. Great Planes has accurately captures the sleek and purposeful lines of this aviation icon using traditional materials and construction techniques. Let's take a look at this much-anticipated model.

A CLOSER LOOK

The Extra 300S requires very little time to assemble. All you'll need to finish the model are an engine (glow or gas), radio system, adhesives and the appropriate fuel lines for either glow or gas engines. The plane is constructed of balsa and ply and comes covered with MonoKote. The wing panels are the plug-in type and are secured by four 1/4-20 nylon bolts from inside the fuselage. The three-piece stabilizer is somewhat unusual; two aluminum tubes run through the center section, and the outer panels are bolted to them. The kit includes CA hinges, painted aluminum landing gear, an adjustable engine mount, a fuel tank, painted fiberglass cowl and wheel pants, wheels, a painted canopy deck, a beautiful, polished-aluminum spinner, aluminum wing tubes, decals and a very generous hardware package.

The major parts come individually wrapped in cellophane bags, and I was very pleased to see that there were hardly any wrinkles in the covering. The instructions are what we've come to expect from Great Planes-a concise manual that's full of information and photos. To power the model, I chose a Fuji Engines BT-50SA gas engine.

ASSEMBLY

Wing. Before I begin any assembly, I like to make all of the necessary openings in the covering. I feel that it saves time, and it allows me to thoroughly examine all of the major parts. Assembly starts with the wing panels, but there isn't much to do here. Using the supplied CA hinge material, I test-fit the ailerons, and when I was satisfied with their fit, I secured them with liberal amounts of thin CA. Installing the aileron servos is next, and the hardwood servo mounts are recessed in the wing so that when the servos are installed, color-matched hatches cover them. Only the servo arms are exposed. A plane of this caliber and potential deserves high-quality servos, so I installed Futaba S9250 digital servos along with the control horns, and I made up the pushrods. The last detail was to epoxy the anti-rotation pins into each root rib, and the wing panels were finished.

One minor problem I encountered was the fit of the aluminum wing tubes; it was a little too tight in the wing panels. To improve the fit, I used a half-round Permagrit sanding stick. A few minutes spent sanding the insides of the wing tubes loosened things up nicely. When I talked to Great Planes about the problem, I learned that the cardboard tubes in the fuselage and wing panels are being changed to fiberglass to eliminate the fit problem.

Fuselage. Again, there's very little to do. Have your engine of choice handy to keep assembly moving along. The first step in the manual is to install the servo tray (mine was installed at the factory, and I suspect that all of the kits out there are the same). The firewall and engine box are built into the front of the fuselage, but they need to be pegged using the included dowel material. It's nice to see this important step included for a plane of this size.

Installing the engine is straightforward, and many engines are suitable for this model. If you like, you can use a 1.60 to 2.10ci 2-stroke or a 2.00 to 3.00ci 4-stroke engine. As mentioned earlier, I went with the Fuji Engines BT-50SA gas engine. With its 3.2ci displacement, the Fuji was near the middle of the recommended gas-engine range of 2.5 to 3.8ci, and I felt it would be a good match for the model. I also used a Great Planes large-engine isolation mount and engine kill switch.

The manual shows in great detail how to install both glow and gas engines. I skipped right to the gas section, which shows the BT-50SA installation. Even though I used the isolator engine mount, installing the engine was a no-brainer. Next, I installed the throttle and kill-switch servos on the servo tray and fabricated the pushrods for each. I also plumbed the fuel tank with gas-compatible fuel tubing and installed the tank in the fuselage.

Mounting the cowl is about as easy as a task can get, and it took me only a few minutes. It lined up perfectly with the engine, and I only had to make a cutout for the spark-plug cap. If I hadn't used the isolation mount (which pushes the engine forward 1/2 inch), the cutout wouldn't have been needed. Don't forget to make an exit hole for hot air to escape through on the bottom of the cowl (the manual doesn't mention this). I decided to skip ahead and install the landing gear and wheel pants instead of waiting till later. I also installed a Sullivan tailwheel assembly.