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GREAT PLANES PITTS SPECIAL ARF 
SPECIFICATIONS HITS
MISSES
A giant-scale S-1S in classic colors!Yes, this model is an eye-opener! Every time I take the new 1/3-scale Great Planes Pitts Special ARF to the flying field, people are amazed that I spent so little time building it. When they learn it took less than 12 hours to build, they simply shake their heads in disbelief! Once they see it fly, their amazement and their smiles grow. If these kinds of reactions are what you want, look no further! There's nothing like a giant-scale Pitts, and Great Planes got it right! When you open the box, you have to take a few moments to admire all the big and beautiful parts. Expertly covered in MonoKote, everything is ready for assembly and very little gluing is required. The straight lower wing comes in two halves while the swept upper wing has three panels. Before you join the panels, install the ailerons and the aileron servos. The panels come with strings taped inside to help guide the servo leads to the wing root. It takes almost no time at all to assemble the wings with 30-minute epoxy. There's also a wooden belly pan that you must glue to the lower wing. This is easily done by first placing the wing in the wing saddle. The Pitts' manual is illustrated with photos, and if you read the instructions, you shouldn't have any problems putting it together. The Pitts comes with all the alignment holes for the mounting brackets; cabane struts and interplane wing struts are already drilled, and the factory-bent attachment brackets speed assembly. It took less than an hour for me to assemble the wings and attach them to the fuselage. Wing alignment with the fuselage was perfect the first time I assembled the model. I can't say that for any of my scratch-built biplanes. Once the wings and struts are in place, install the tail surfaces. I installed the landing gear before I attached the tail surfaces so that I wouldn't need a stand to support the model. Also, to make it easier to slide the horizontal stabilizer into its slot, I removed a small section of the fuselage just aft of the slot; then I slid the stab in from the back instead of from the tightly fitting side. With the stab in place, I glued the wedge-shaped section back into position. To speed construction, install the elevator and rudder control horns before you attach the surfaces to the stabilizer and fin. Servo Installation The fuselage has four servo cutouts in its tail (two on each side), and you must cut the covering open and seal it around the openings before you install the servos. The instructions call for three servos for the tail surfaces (two for the elevator halves and one to operate the rudder and tailwheel steering). Since there are four openings, I decided to install an additional servo for the tailwheel steering. This simplified the control-linkage setup and added just a little tail weight to offset the extra weight of the Fuji-Imvac 50 engine. The Pitts also has four aileron-servo openings (one in front of each aileron), and the instructions show a four-aileron-servo installation (two in the top wing and two in the bottom). This works extremely well and gives tremendous roll authority. I don't like the look of servo leads attached to the cabane struts and going from the top wing into the fuselage, so I decided to use only two servos in the bottom wing. I connected the upper and lower ailerons with scale slave pushrods. Using two or four servos works very well, and it is entirely a personal choice. I used a Futaba Super 8 and Futaba 3003 servos throughout. The landing gear is made of aluminum, and two, thin plywood fairing pieces give the gear its proper appearance. I used Hobby Lobby PFM adhesive and two 4-40 cap-head screws to attach the fairings to the gear legs. Certain full-size Pitts Special variants used the thinner, Cessna-like gear, so again you have a choice. A little work is required to securely install the wheel pants, but reading the instructions will keep you out of trouble. Two 4-40 cap-head screws secure each wheel pant to the gear leg, and the bolt holes have already been drilled for you. My only gripe is that the foam wheels that come with the kit flatten too easily when the model is stored resting on its gear. If you plan to store the model for an extended time, block up the wheels so they don't support the model. Engine Installation As soon as the Pitts Special kit was introduced, I thought it would be ideal for the new Fuji-Imvac 50 cc gasoline engine (also available from Great Planes). The distance from the firewall face to the spinner backplate is 6 1/2 inches, and the Fuji-Imvac 50 fits perfectly with the optional prop-hub extension. I installed the engine inverted and attached it to the firewall with 8-32 bolts and blind nuts. You have to drill a clearance hole in the center of the firewall to clear the aft end of the crankshaft, but that's all there is to installing the big gas burner. The muffler that comes with the engine fits easily in the cowl, but I did add a 1-inch extension piece to the exhaust pipe so it would clear the bottom of the cowl. I also replaced the stock Fuji-Imvac choke plate with a Zenoah velocity stack. This makes it very easy to choke the engine for starting; I simply stick my finger in the stack while flipping the prop. I also attached an ignition kill switch to the firewall with a small plywood bracket. The switch passes through a thin slot cut in the cowl. A big, beautifully polished aluminum spinner comes with the kit, and it fits the Fuji-Imvac engine nicely with one of the included prop-shaft adapters. I used a Menz 20x8 wooden prop from Frank Tiano Enterprises, and it fit the spinner cutout nicely without alterations. Final Assembly To give the model a finished look, I installed a Hangar 9 1/3-scale civilian pilot, and I painted the cockpit interior before I installed the instrument panel decal and the bubble canopy. I used Model Graphics decals to enhance the model's scale appearance, and I have to say that they make a huge difference. The decals come on transfer sheets and are made of thin printed vinyl; simply stick them on and rub them smooth. The kit does come with steel cable and clevises to make non-functional flying wires, but I used thin, plastic craft lace to replicate flat, chromed flying wires (see Nick Ziroli's "How To" article in the April 2002 issue for more details). With everything installed, my model came out at exactly 17 pounds, 1 ounce, ready to fly, and it balanced exactly on the forward CG (5 inches back from the top wing's leading edge) without any additional ballast. I used the recommended control throw settings and the model flew very nicely. Throw values:
The 1/3-scale Pitts Special ARF is one of the nicest models I have ever built and flown, and when powered with the Fuji-Imvac 50 cc gasoline engine, it has awesome flight performance. If you are looking for a new IMAA-legal biplane or a great sport-scale competition ship, or if you just want a new eye-opener for the local flying field, this biplane is it! Upright or inverted, climbing vertically or coming in for a smooth landing, this Pitts Special makes it all look easy! Takeoff and landing I kept the departure angle low until the model had gained a little more airspeed, and then I applied more up-elevator. The Pitts climbs with authority and can easily climb with only 3/4 throttle. I trimmed in some down and added a bit of right aileron, and the Pitts flew hands-off at 1/2 throttle. Honest! It really did! My first landing was anything but perfect, and I broke the prop! I chopped the throttle prematurely and landed about 5 feet short of the runway. The proper way to land this model is to reduce power on the downwind leg to about 1/2 throttle and then lower the nose to begin losing altitude. Fly the base and final legs with about 1/3 throttle, and keep the nose down. Once over the end of the runway, chop the power and level the nose. The model will slow quickly and you can begin to flare just as the wheels are about to touch down. In windy conditions, I hold just a touch of down elevator after touchdown for a 2-wheel landing; on calm, undemanding days, I hold the model off the ground as long as I can in a 3-point attitude. Done just right, the model gently kisses the ground and doesn't even wobble–a beautiful sight! General flight characteristics (I used the instructions' suggested control throws.) With fully symmetrical airfoils, the wings work equally well upright and inverted; either way, the model requires very little elevator trim to fly straight and level. At full throttle, vertical performance is brisk. Stall behavior is good; the model slows quickly and breaks straight ahead every time if the wings are level. The Pitts is a delight to fly, and though not intended for beginners, it is well behaved. Aerobatics Great Planes Model Distributors Co. (800) 682-8948; http://www.greatplanes.com/. February, 2003 Model Airplane News Editor: Gerry Yarrish
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