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GREAT PLANES EXTRA 300S 40  SPECIFICATIONS Basic Materials Used In Construction RCM PROTOTYPE SUMMARY WE LIKED THE: WE DIDN'T LIKE THE: Great Planes Extra 300S is an aerobatic, sport-scale design that is intended to be powered by a .40-.51 (2-stroke) or .48-.70 (4-stroke) engine. Any 4-channel radio system may be utilized, using standard-size airborne components. Except for the ABS molded plastic cowl, wheel pants, and clear butyrate canopy, it is of all wood construction. Great Plane's Extra 300S is neatly packaged in a sturdy 5" x 10-1/4" x 48" corrugated carton that is adorned with attractive, highly visible, full-color labeling that shows numerous views of the aircraft, both as a finished model and "framed up" ready for covering. The carton labeling also shows suggested finishing color schemes, recommended engine/propeller combinations, and lists all of the items that are required in order to complete the kit. There is a wealth of kit information provided before one even opens the carton. All small parts are packaged in vinyl bags. The computer drafted plans consist of two rolled sheets, measuring 36" x 46" and 36" x 50", which are of top-notch quality. Rather than listing all of the various accessories and items that are included in the hardware package, it is much easier to list the additional items that are required in order to complete the aircraft. Other than a radio system, engine, muffler, propeller, adhesives, and the normal finishing/covering materials, all that is needed is a 10 oz. fuel tank and tubing, wheels, spinner, and a pilot bust, if one is desired. This give you an idea as to how complete the hardware and accessories pack is in this kit. After inspecting the contents of this kit, it became readily apparent that a lot of time and conscientious effort was put forth in the design, engineering, and fabrication of this kit. A complete inventory of all the parts (there are 174) in our test review kit revealed that the only missing item was the strip of CA type hinge material. Construction: Covering and finishing techniques are provided and over three pages are devoted to flying and trimming the Extra 300S. A few errors exist in the manual (and/or on the plan sheets) several of which Great Planes has already addressed, via an addendum sheet which accompanies the manual. In spite of the few other minor errors, the instruction manual is outstanding. Also included in the instruction manual are die-cut pattern outlines which simplify the parts' identification process. An additional plus is a replacement parts' list which allows the builder to reorder by number, any of the kit "subassembly packs" or loose parts, should the need ever arise. All balsa wing ribs and plywood fuselage parts (except for the balsa stringers and sheeting) are die-cut. All total, there are 18 sheets of die-cut parts and the quality of the die-cutting in our test kit was excellent. It was easy to remove every part without using a hobby knife. The tail surfaces are of built-up balsa stick construction and are assembled directly over the plan sheet. The wing panels, which are of a double tapering, symmetrical design, are partially assembled over the plan sheets. Each wing rib is die-cut with alignment tabs, or "feet," that allow it to be positioned above the plan sheet so that no shimming is required. The parts fit of the wing ribs to the main spars and leading and trailing edge caps is very good. Wing construction is all balsa except for the center section braces and wing dowel face plate, which are plywood. The fuselage is primarily of plywood construction and the assembly process is initiated by gluing the fuselage doublers to the fuselage sides and laminating the three fire wall pieces together. The fuselage consists of a variety of interlocking die-cut parts that are hand-assembled and held in place with rubber bands and masking tape, before any of the parts are glued together. The basic fuselage structure is then sequentially glued together. The fuselage parts fit is good, surprisingly so, for a structure that is fairly intricate and consisting of die-cut parts. The end result is a rugged basic fuselage structure that is in perfect alignment. After mounting the wing to the basic fuselage structure, the top fuselage formers, tail surfaces, stringers, sheeting, etc., are added to complete the fuselage. Final assembly includes fairing the wing belly pan into the fuselage, installing cockpit details and the canopy, mounting the engine and fitting the ABS plastic cowl, and finish sanding the entire model in preparation for covering. The overall wood quality in our test kit was very good. An adjustable, filled nylon engine mount is included in the kit, which will accept most engines that would be used to power the Extra 300S. As mentioned, the cowl and wheel pants are vacuumed-molded from ABS plastic. Modelers who prefer that these parts be of more durable fiberglass cloth and resin composition have the option of purchasing these aftermarket matching parts from Fiberglass Specialties. The cowl number is GP24 and the wheel pants are #100. Other than the radio system, engine, spinner, propellers, and a pilot bust, all additional items necessary to complete our test review kit were Great Planes products and consisted of the following: 6 and 30-minute Pro epoxies, thin and medium Pro CA adhesives, wing seating tape, fuel tubing, a 10-oz. fuel tank, 2-1/2" main wheels, a 1" tail wheel, switch and charge jack mount, three rolls of EconoKote covering material, and two cans of LustreKote spray paint. Any prospective builder of this kit might want to keep in mind that all of the aforementioned Great Planes accessory products are of the highest quality and perfectly matched for use with this aircraft. The Pro epoxies and CA adhesives were used for all assembly steps in the construction of our Extra 300S and worked very well. The instruction manual even suggests which adhesive should be used for various construction phases. Covering: As mentioned, the LustreKote paint produced a satiny gloss finish; however, this glossiness does not match the high gloss of film-type coverings. In order to better match the painted surfaces' gloss to the film covering, a final coat of clear gloss paint was applied. The end result was quite good. Top Flite EconoKote was then used to cover our test aircraft. A simple red and yellow color scheme was used, with no consideration being given to duplicating the appearance of any existing full-scale Extra 300S. Great Planes 1/8" striping tape was used to accent the basic color outlines and the pre-cut vinyl registration numbers and lettering were produced by Ward Graphics, who cater to the aeromodelers' graphic finishing needs. Several decals were also applied to enhance the appearance of our test model. Engine: Equally impressive, both from a manufacturing and performance standpoint, was the Slimline "Pitts" style muffler, which is perfectly suited for use with the Extra 300S, as it fits neatly and completely enclosed within the cowl, with no clearance alterations to the fuselage being required. The Slimline muffler is constructed from machined aluminum bar stock and tubing and has four sound supressing baffles. At a very modest 2.1 ounces, it is much lighter than the cast aluminum "Pitts" style mufflers and the stock manufacturer supplied mufflers. The suggested retail price of the Slimline No. 3214 muffler is $36.99; however, it is regularly offered at discounted prices. Radio: This resulted in the C.G. of our test aircraft being located 4" aft of the leading edge of the wing, which was exactly where the plans and instruction manual indicated that it should be for the first few test flights. Our ready-to-fly Extra 300S, less fuel, weighed in at 6 lbs. 2 oz., or 6 oz. more than the manufacturer's advertised weight of 5.75 lbs. Flying: Our Extra was then taxied into the slight breeze and full throttle was gently applied. A slight amount of right rudder was all that was necessary in order to keep the Extra tracking straight and true. The tail came up quickly, and after a take-off run of about 50 feet on the main landing gear, the Extra was airborne and climbing out with only a small amount of up elevator being required. After attaining a reasonable altitude, our Extra was trimmed for thumbs-off, straight and level flight. All that was required were a few clicks of right aileron and up elevator. Our Extra had been set up with the control surface travel limits set to the manufacturer's recommended amounts on both high and low rates. We had taken off with the controls set on high rate and a series of rolls, loops, and figure eights were then performed using both high and low rates. On high rates, the Extra is smooth yet nimble and highly responsive without being squirrely or twitchy. On low rates, the Extra is predictably more subdued and gentle. Snap rolls and spins are better performed at high rate. While Extra builders may elect to eventually adjust the high and low rates to suit their own flying preferences, the manufacturer's recommended control surface travel limits are an excellent starting point that will satisfy most RC'ers flying styles. Prospective Extra 300S builders who will be using a more basic radio system that does not have high and low rate switch, can simply use control surface travel limit amounts that are halfway between the suggested high and low rate amounts. With the engine throttled back, several stalls were performed. Upon stalling, the Extra breaks clean with no tendency to drop a wingtip. Our first landing was a full-flare, three-point type that was easy to perform. The landing approach was made using about 1/4 throttle and keeping the airspeed up, until on final when the throttle was closed to idle. With the Extra about a foot off the ground, the gradual application of full-up elevator as the airspeed diminished, produced a nice no bounce, full-flare landing. On the next flight, several touch-and-go landings were made and a wheel type final landing was made. This was accomplished by allowing the Extra to settle in on the main landing gear and then applying just a bit of down elevator until the rollout speed diminished and the aircraft settled in on the tail wheel. The Mecoa .46 engine proved to be a powerful, smooth-running engine with an easy-to-adjust carburetor, that is ideally suited for use in the Extra 300S. Summary: As a kit, it is very well engineered and fabricated, and it is very complete. The quality of materials and component parts is very good. While there are a few minor errors on the plan sheets and in the instruction manual, they are still outstanding. Any RC'er who has constructed a few wood type kits and possesses four function piloting skills, should not encounter any problems in constructing and successfully flying Great Planes Extra 300S. From a cost/value viewpoint, the Extra 300S is an excellent buy, especially at its frequently advertised discount prices. The Great Planes Extra 300S certainly merits serious consideration by any RC'er with an interest in aerobatic, sport-scale designs. List of suppliers: April, 1998 R/C Modeler Magazine Editor: Dick Kidd
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