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This item is discontinued. GREAT PLANES PIPER J-3 CUB ARF  Aircraft Type Sport Scale Basic Materials Used In Construction RCM PROTOTYPE SUMMARY
Every modeler needs a model of the venerable Piper J-3 Cub - especially every radio control modeler. It's probably the most universally recognized airplane ever produced. The ubiquitous Cub can be found at almost every airfield in the United States, and at many foreign airports as well. Anyone who has ever flown a taildragger has at one time or another flown a Cub, and many of today's senior pilots learn to fly in the J-3. Once an R/C flier gets the hang of steering the Cub down a paved runway (grass runways are not a problem), and remembers that he will usually need a little rudder when he initiates a turn, the Cub will become one of his favorite lazy Sunday afternoon airplanes. Great Planes has made it pretty easy to own a high quality, nicely finished, reasonably sturdy, good flying, moderate sized J-3 Cub. At 81" wingspan, it is just large enough to be IMAA legal and still small enough to fit in the family wagon, van, SUV, or pickup. There's a lot of suitable engines to power the plane, reasonably priced, and fuel thrifty. It's close enough to scale to satisfy most folks. And remember, all this is ARF! Every float fly I have attended has had several float-equipped J-3's on the beach, and they all seemed to fly well. Since Great Planes also markets floats, I asked RCM if it would be all right to equip the subject of this review with floats in addition to the conventional landing gear. They gave their permission, and I also obtained a Great Planes 40-size Sport Float Kit for the plane. The float kit is not ARF.  40 size Great Planes floats were installed to increase our fun! The 45" x 12-1/2" x 9-1/2" box is covered with full-color photographs of the model, construction details and helpful information. Don't throw the box away, as the photographs show the locations of the "decals." When you open the box, you will find the major portions of the airplane separately bagged in clear plastic protective sacks. Other items are also bagged for your convenience, like the hardware, wheels, pushrods, and struts. The preformed side and front windows and the fiberglass cowl are bagged as well. The photographs and illustrations in the manual ensure that you will have no trouble identifying the parts in this kit. Since this is an "Almost Ready To Fly" model, there are no plans included. The instruction manual is really all you will need. It is well written and comprehensive, and leads you through the construction process (actually, the assembly process) carefully and logically. If you should run into any problems, you are given an e-mail address to get the help you need - and a phone number (not toll-free) if e-mail doesn't work for you. Take the few minutes necessary to read through the whole manual a couple of times to familiarize yourself with the construction methods and sequence. Construction of this ARF is of conventional balsa sticks and sheet, with lite ply where needed for strength or stiffness. Workmanship is very good throughout. Ease of assembly has been given thoughtful consideration. All exposed parts are precovered, including the pre-shaped wing struts. Parts fit together as they should - with reasonable care in assembly, a very straight and true model will result. Before you actually begin the assembly, you should decide what engine you will choose for your Cub. The kit manufacturer recommends an O.S. FS-70 4-stroke for the best scale appearance and sound. Other suitable engines include a 2-stroke O.S. 46FX, Super Tigre G-45, O.S. 65LA and O.S. 60FP. Other than the minor modifications necessary to install the floats, I made no significant changes to the con-struction and assembly as presented in the instruction manual. Covering: The covering material is Coverite's 21st Century Fabric. The covering application is very well done, and the very few minor wrinkles can be quickly eliminated by shrinking them away with a low temperature setting on your heat gun, followed by ironing the contact areas with a covering iron and a hot sock. This will securely bond the covering to the wood, so that the wrinkles will be less likely to reappear in the future. The lightweight fiberglass cowl has a glossy paint job that matches the Cub Yellow Coverite perfectly.   Assembly: Assembly starts with joining the wing halves, using the die-cut wing joiner. Just two things to remember here - pay careful attention to alignment, and don't lose track of the string that is provided in each wing half to enable you to pull the servo lead extensions through the interior of the wing panels. The manual shows you how to prepare the right wing panel. The left wing panel must be prepared in the same manner. Pull the ends of the strings through the holes in the bottom of the wing and tape them down before you glue the wings together.  Small screws may be used in lieu of glue to fasten the front windshield in place. Next, using the template provided, drill the holes for mounting the adjustable engine mount furnished with the kit. The manual gives instructions for pulling the blind nuts into place in the firewall. To locate them from the back side of the firewall, I ran a bamboo shishkabob skewer through the holes from the front side of the firewall and threaded the blind nut onto the end of the skewer. Then pulling the skewer forward until the blind nut contacted the firewall, I was able to hold the nut in place with a fingertip while I unscrewed the skewer and threaded in the 8-32 cap screws as directed by the manual. The manual gives detailed instructions on fitting the adjustable mount to your engine, and locating and drilling the hole in the firewall for the throttle pushrod. Once the engine position is determined and the engine is mounted to the firewall, the fiberglass cowl is prepared and fitted to the fuselage. The manual illustrates how to install the hardwood wing dowels and the 1/4" blind nuts for the wing bolts. The wing is put in place, aligned, and drilled for the wing bolts. When everything is properly aligned, the wing bolt plate is epoxied in place on the trailing edge of the wing.  Rear sheeting being applied to float frame. Simple, straightforward construction. When mounting the stab and fin, the covering must be carefully removed from the solid balsa stab and fin where they will contact the fuselage. The manual shows how to align the stabilizer to ensure that it is centered and at 90 degrees to the fuselage centerline, and the fin so that it will be vertical. The stab and fin are secured in place with 30-minute epoxy. The tail wheel is installed using the supplied plastic tail wheel bracket. The 3/16" piano wire main landing gear is inserted into the vertical grooved blocks inside the fuselage. The gear wires cross the fuselage in a pre-cut groove, and are held in place with plastic straps and sheet metal screws. The lightweight foam type wheels, with Cub logos on the hubcaps, are secured to the landing gear with wheel collars. Prior to installing the sheet balsa elevator halves, they are joined together with a piano wire joiner. The manual shows how to ensure that the wire is properly installed and epoxied in place. The control surfaces are then installed using the provided CA-type hinges. All control surfaces, the wing, horizontal stabilizer, and the fin have the hinge slots pre-cut for you. The instructions for using these hinges are quite specific and should be carefully followed. You will be pleased with the results. Radio: For control, a JR-XP642 radio with standard servos was used. The aileron servos are installed in prebuilt trays in each wing. The manual has illustrations, photographs, and instructions that will ensure that you get them properly installed and made ready to plug into the receiver. In the fuselage, the supplied lite ply servo tray has punch-outs for standard servos. The pushrods are solid wire, running in plastic sleeves. Do not omit the plywood pushrod brace shown in Section 10 of this Division - it is essential to stabilize the ends of the plastic guide tubes for the rudder and elevator. A brace is also required for the throttle pushrod guide. The preformed windshield is probably the easiest-to-install Cub windshield you will ever find. When properly trimmed it fits perfectly, I installed mine with tiny screws rather than glue, which avoided cutting strips out of the covering so the glue would have bare wood for better bonding. The side windows are also premolded, and provide a very neat installation. The prefabricated wing struts are functional - the manual instructs you not to fly the plane without the struts in place. Installation is easy, but must be precise in order to keep everything in proper alignment.  Water rudder installation is simple and sturdy. A table showing suggested control surface deflections for both High Rates and Low Rates is provided. If your radio does not have dual rate options, you should set the throws halfway between the suggested high and low rates. Easy to understand instructions for precise balancing of your model, both laterally and fore-and-aft, are provided. The Great Planes "C.G. Machine" Airplane Balancer is a big help in getting this just right. As the manual states, "A model that is not properly balanced will be unstable and possibly unflyable." Flying: To cancel out the effect of "builder of the model" jitters, I usually arrange for someone else to test-fly my new planes for me. Friend Ray Care is a steady, unflappable, careful test pilot, and he consented to be the first to fly the ARF Cub. Ray did the pre-flight test on the Cub, checking out the radio installation, clevises, throws, balance, and engine installation and throttle settings. When he pronounced the plane ready to fly, we filled the tank, flipped the prop a few times, and he taxied it to the center of the strip. Advancing the throttle slowly, the plane moved forward twenty or thirty feet, the tail came up, and in another twenty feet it lifted off before we expected it. Ray kept the wings level, and it climbed steadily to flying altitude. He tried turns with and without rudder input - not a whole lot of difference. The plane was very responsive - we were using the "high rate" throws - but was not at all skittish. A couple of clicks of down elevator and it was flying "hands off" straight and level at half throttle. Ray flew a few passes to get acquainted with the flight characteristics of the Cub, then tried some mild aerobatics. It did all the maneuvers full-scale Cubs are able to do, and a few that would have made a full-scale pilot pretty queasy. Then a few two-mistakes high landing patterns to check for snaps, and Ray brought it down and dropped it lightly on the pavement. Very satisfactory test flight. Since I was going to fit it with floats, we didn't attempt to wring it out - we just wanted to check it out to ensure that it didn't have any bad habits. Conclusions: Construction of this plane is almost entirely just "assembly" rather than building. Almost anyone with the ability to read and with normal hand-eye coordination should be able to produce a satisfactory result. As for flying, the J-3 would make a good second plane. Floats: Kit: Great Planes produces "Sport Float" kits in three sizes, and after careful consideration, the .40 size kit seemed to be the best fit for the ARF Cub. We had some doubts when we hefted the box that contained the kit - it was a whole lot heavier than I expected it to be. (When completed, the floats weighed only one pound each!) Opening the 37" x 7" x 4" box, we found it full of sheets of die-cut lite ply and balsa sheet. There was a package of hardware, a couple of pieces of heavy duty music wire and a well-written and illustrated 20-page instruction manual. Construction begins with a full-length plywood spine, which is keyed into and glued to the sheet balsa top. Plywood doublers are glued to the top and the spine at the gear attachment points. Plywood formers are keyed into the spine and glued in place. Forward and aft plywood keels are keyed into the formers and glued in place. With just reasonable care, it is pretty hard not to get the whole assembly properly aligned. Forward and aft balsa stringers are glued to the notched corners of the formers. Some special attention is needed at the nose of the floats to get the stringers properly curved into the nose former. After sanding the stringers to match the slope of the formers, the sheet balsa sides are glued into place, and finally the plywood bottom sheets are fitted and glued. The manual suggests that you glue some ballast in the nose before you apply the bottom sheeting. I chose not to do this. Big mistake - you'll need the ballast. The balsa nose block is glued in place and sanded to the proper contour - and you are ready for final sanding and application of your choice of finishes. Finish options are to apply a shrinkable film (e.g., MonoKote), or glass cloth and paint. The glass cloth is adhered to the floats with epoxy resin (e.g., Great Planes Pro Epoxy Finishing Resin). Instructions for both methods are included in the manual. About the glassing method, the manual states, "This can be an involved, messy project, but yields a highly durable finish." I chose the glassing method - the manual is right. Installation: On the ARF Cub, you use the landing gear struts furnished with the plane for the front float struts, and bend up the one-piece rear strut from music wire. The piece of wire furnished with the kit is not long enough to provide the proper angle for the floats, so just buy another hunk and bend it to the proper shape. All the necessary mounting hardware is furnished with the kit. The angle of the top of the floats in relation to the wing is critical, so take the time to get it right. A little soldering is required to fit and mount the water rudder on the right-hand float. The flexible pushrod attaches to the float and the rear strut, then loops up to a control horn on the rudder. A ventral fin is included with the float kit, and the manual "strongly recommends" that you install the fin to your airplane when flying with the Great Planes Sport Floats. About half the Cubs you see on floats have the fin installed, and they seem to fly well either way. You can temporarily attach the fin with screws or double-sided tape if you want to try it both ways. Mine flies well without the fin, but I wouldn't want to steer you away from starting with the "strongly recommends" above. Conclusions: Flying R/C models off the water adds another dimension to the hobby, and more "Float Fly's" are being scheduled every year. You will enjoy flying your J-3 Cub with floats fitted, and will soon be shooting "touch and go's" with the best of them. Photos by Darrel Stebbins. Reprinted with permission.October, 2001 R/C Modeler Magazine Editor: Dick Kidd
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