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This item is discontinued. GREAT PLANES PIPER J-3 CUB ARF 
SPECIFICATIONS HITS
MISSES
The Piper J-3 Cub is probably the most widely recognized airplane ever built. It first appeared in 1935, and more than 5,000of them were produced by the beginning of WW II! This enormously popular, two man trainer is said to have introduced nearly 75 percent of WW II aviators to flying. The Cub proved to the general public that airplanes could be both safe and economical. Models of this classic airplane are offered by dozens of manufacturers and can probably be found at most RC flying fields on any given Sunday. Great Planes offers Cubs in several sizes, including this 81 inch span, fabric covered ARF that is made of high quality materials. This latest entry into the work of Cubs is easy to build and fly. Because I do a great deal of float flying, I decided to outfit the Cub with a pair of Great Planes Sport Floats. I knew if would be a natural on water. THE KIT The fine quality of this kit was obvious as soon as I opened the box. It is built using balsa and ply and comes fully covered with 21st Century fabric. The various parts are individually wrapped in cellophane bags. Everything is included except the radio, engine, propeller, spinner nut, fuel tubing and a pilot. The kit also comes with a generous hardware package that includes hinges, an adjustable engine mount, preformed landing gear, self adhesive decals, gel coated fiberglass cowl, dummy engine, a vacuum formed windshield and formed cockpit windows that pop into place from inside the fuselage for an attractive flush fit. An excellent 24 page instruction manual loaded with photos and drawings guides you through the assembly procedure. There is no need for a plan. Although the instructions say this is 1/4 scale, its 81 inch wingspan translates to approximately 1/5.3scale, but it's still IMAA-legal. ASSEMBLY First, I used a heat gun to remove the wrinkles from the covering; they came out with very little effort. Next, I removed the covering over the windows, painted the exposed wood surfaces with Cub Yellow paint and fuel proofed the firewall and tank compartment. The firewall had already been fuel proofed, but I gave it a coating of thinned epoxy anyway. After I removed the covering over the aileron servo openings, I glued the wing halves together with 30-minute epoxy. The wing joiner is made of three, 1-1/8 x 5-1/4 inch plywood pieces that have a combined thickness of 11/32 inch. A piece of string passes through the wing from the aileron servo to the root; this is used to pull the aileron servo lead through the wing later on. I cut out the exit holes near the root and threaded the string through these holes before joining the wing halves. The wing is supposed to be built flat with no dihedral, but when I joined the halves, I taped them together tightly so there was no gap at the root ribs, and this resulted in a slight amount of dihedral. Great Planes recommended an O.S. FS-70 4 stroke engine for the best scale appearance and sound, but 2 stroke engines ranging in size from .45 to .60 are acceptable alternatives. I chose the O.S. FS-70 4 stroke. Your choice of engines determines the location of the throttle servo and throttle pushrod exit on the firewall. An adjustable engine mount and drill template are included in the kit. I attached the engine mount to the firewall with 8-32 socket-head cap screws and blind nuts. I used the Great Planes Dead Center Hole Locator to mark the location of the engine-mounting bolts then drilled and tapped the mount for 8-32 mounting bolts. To allow the exhaust to exit out the bottom of the cowl, I mounted the engine sideways. I also turned the carburetor around so the needle valve would be on top. The Piper Cub kit includes a gel coated fiberglass cowl that doesn't need to be painted. I trimmed the cowl to accommodate the engine and then attached the engine with 4x1/2 inch sheet metal screws. The cowl in my kit was quite thin and turned up slightly at the edges, but it looked OK after I installed it. I painted the dummy engine black and silver and glued it to the left side of the cowl. I attached the wing using two 1/4 inch dowels in the leading edge and two 1/4 20 bolts at the trailing edge. The bolts thread into blind nuts that have been inserted into a factory installed, 1/4 inch mounting plate. A pre covered wing bolt plate is also provided to reinforce the TE. After I removed the covering from the slots in the fuselage, I epoxied the stab and fin into place. Everything lined up nicely without any cutting or shimming. I then added the tail wheel assembly. The torsion landing gear comes in two pre-bent pieces and is attached to the fuselage with nylon straps and 2 x 1/2 inch sheet metal screws. There are no cross braces. Covered landing gear fairings come with hinged, 3/16 inch thick wooden mounts already attached. I attached the fairing mounts to the fuselage with sheet metal screws and connected the fairing to the landing gear with small rubber bands; this is an effective way to prevent the fairings from being knocked off when the landing gear flexes, but it is not very scale like. Also, I thought the fairing mounts were a bit bulky, so after seeing how the landing gear was assembled, I removed them so I could attach the floats. I cut the hinges from the strip of hinge material included with the kit and installed all of the control surfaces using thin CA. The Cub's roomy fuselage made it easy to install the radio gear, and the step by step instructions for installing the servos and pushrods were very easy to understand. Even first-time RC'ers should have no problem installing everything correctly. The vacuum-formed windshield and cockpit windows are well made and fit perfectly. The cockpit windows simply pop into place from the inside. Apply RC 56 glue to the flanges on the inside of the cockpit for an easy attachment. This gives the model a neat, attractive, flush fit appearance. The last step in the assembly is the addition of the wing struts, which have 3/16 inch thick mounting blocks hinged to the struts at both ends with CA type hinges. The struts have an airfoil shape and really keep the wings rigid; however, the 3/16 inch mounting blocks were much too bulky. As it turned out, the hinges tore after only a few flights. I subsequently replaced all of the strut hinges with a heavier material that I cut from a plastic lid. Incidentally, the struts are functional, and the Cub should not be flown without them! After completing all of the assembly, I set out to apply the decals, but I ran into a bit of a problem. I usually spray a mixture of detergent and water on the area to which the decal is being applied, so that I can reposition the decal if necessary; when I did this, however, the decals started to curl and would not lay flat. I had to use vinyl for the registration numbers and the lightning design on the fuselage sides. I didn't have any problem with the small decals because I applied them to a dry surface. I attached Great Planes size 40 balsa and ply Sport Floats to my Piper Cub. The floats come as a kit that includes all the necessary mounting hardware, a water rudder and a ventral fin, but I chose not to use the fin. I covered the floats with fiberglass and spray painted them with aluminum LustreKote. CONCLUSION The Great Planes Piper J-3 Cub is a high quality ARF that is easy to build and looks great on the ground, on the water and in the air. The fabric covering is perfect for this type of airplane. The model's light wing loading and inherent stability make it an excellent first scale kit. I thoroughly enjoyed building and flying the Piper Cub, and I highly recommend it for both beginners and experienced sport fliers. Reprinted with permission.July, 2001 Model Airplane News Editor: Gerry Yarrish
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