DYNAFLITE SUPER DECATHLON 40
by Charlie Viosca
Aircraft Type Sportscale
Mfg. By Dynaflite
Distributed By Great Planes Model Dist. Co., P.O. Box 9021, Champaign, IL 61826-9021, (800) 682-8948. www.dynaflite.com
Mfg. Sug. Retail Price $279.99
Available From Retail Outlets
Wingspan 89 Inches
Wing Chord 14-1/4 Inches (Avg.)
Total Wing Area 1237 Sq. In.
Fuselage Length 69 Inches
Stabilizer Span 29 Inches
Total Stab Area 290 Sq. In.
Mfg. Rec. Engine Range 1.08-1.8 2-Stroke, 1.20-1.60 4-Stroke; 1.5-2.1 Cu. In. Gas
Rec. Fuel Tank Size 16 Oz.
Rec. No. of Channels 4
Rec. Control Functions Rud., Elev., Throt., Ail.,Parachute Drop Compartment
Basic Materials Used In Construction
Fuselage Ply, Lite Ply & Balsa
Wing Ply, Lite Ply, Balsa & Spruce
Tail Surfaces Balsa & Basswood
Building Instructions on Plan Sheets Yes
Instruction Manual Yes (35 pages)
Construction Photos Yes (121)
Radio Used Futaba Super 8 UAF, with 5 S9202 servos & 1 S3101
Engine Make & Disp. US Engines 1.5 gas with 16 x 8 prop
Tank Size Used Great Planes 16 Oz.
Weight, Ready to Fly 290 Oz. (18 Lbs., 2 Oz.)
Wing Loading 33.7 Oz./Sq. Ft.
The way everything went together, the clarity of the plans and instruction book. The finished product and how it flies.
WE DIDN'T LIKE:
The way the fittings were attached to the spruce strut ends.
The Dynaflite model of the Super Decathlon is an IMAA legal replica of the full scale Super Decathlon aerobatic trainer. With its high wing configuration andsemi-symmetrical airfoil, the Decathlon offers thesport scale modeler the best of both worlds, a sport scale aerobatic trainer. And like its full scale counterpart, it both looks and flies great!
The kit arrived in a 49-1/2" x 7-1/4" x 12-1/2" box, neatly packed with all the essentials necessary to build this model. The balsa is of high quality and all small parts neatly bagged. Die-cut parts fit very well. In the excellent instruction manual, you will find a list of accessories and additional items needed. Also, there is a list of building supplies and tools you will need. The instructions include good building tips and discuss different wood types and cyanoacrylate and epoxy adhesives. There are three plan sheets 55" x 36" with good instructions and tips. Instead of using pins, I use a Magic Magnet Builder available from Great Planes. I have been using this magnet system for years and it works great. When I saw the first advertisements of this model, I knew I had to build it. The full-size Super Decathlon aircraft is a basic aerobatic trainer, and the model performs very well in duplicating this role.
I always suggest that you start building with page one of the instructions and proceed without skipping, to the end of the instruction manual, which in this case is thirty five pages.
As you proceed, check off the items as you complete them. I followed the instructions and doing so will assure that you will not go wrong. The plans and instructions are excellent. When completed, you will be pleased with the results of this kit.
Let me tell you about four modifications I made. Since I like to fly float planes, I planned ahead and ordered a second landing gear strut so I could install floats. This strut was installed exactly like the main gear, only 12 inches rearward. Simply remove it when flying with wheels.
When building the fuselage, there is a large unused space behind the cabin section and ahead of the radio section.I made a servo (S3101) operated trap door here so I could drop parachutes.
During the wing construction phase, I added a 1/4" dowel (2" long) to the left wing hold-down block, 2" ahead of the trailing edge. The dowel is glued into the block in the left wing and inserts into a corresponding hole drilled into the right wing so that when you put both wing halves together, on the aluminum tube,the wing is easier to manage while installing it on the fuselage.
For the wing struts, after determining the correct length, I silver soldered a 1/16" steel welding rod to both (inner and outer) strut end mounting screws. I then cut a groove down the underside of the spruce strut and laid the wire in the groove and epoxied it in place and used filler to close the gap. This way, you have a much stronger strut as the two ends are connected and will not pull out of the spruce.
The instructions begin with the construction of the tail surfaces. Balsa is the wood used, and simple standard model construction is used throughout the model. There is a basswood spar used for strength in the stab. The stab, elevators, fin, and rudder are covered, not sheeted.
The wing construction is straightforward with no complicated items, and builds up very quickly. They use a unique method to set the wingtip twist by placing a 1/4" x 3/8" x 22" balsa strip on the plans (location drawn on the plans) and the wing ribs are glued in place on the spar. The way the balsa strip is curved forward gives the necessary twist. A very simple and effective method. The instructions are clear and no problems were encountered during the construction.
After constructing the ailerons, pre-fit them to the wing and mark the hinge locations. A "Slot Machine" was used to cut all hinge slots. Now, install the hinges for fit but do not glue them until the covering is completed. Install the aileron servos and make up the pushrods. Remove the servos and reinstall after covering the wing.
The fuselage is constructed of balsa and lite ply and builds up very quickly. After removing the parts from the balsa die-cut sheets, you are ready to proceed. First build up the firewall and sides from ply and lite ply parts and build the bulkheads from balsa as per the plans.
Following the instructions, assemble the fuselage by fitting the sides and bulkheads over the plans. The Great Planes Magic Magnet system is great to use here because it holds all the parts together before you start gluing anything. When satisfied with the fit, start using your CA and epoxy as called for in the instructions.
This model was entirely built with all necessary items including covering, engine, wheels, adhesives, motor mount, tank, control rods and linkages, and the Futaba radio from the same source, Great Planes. Ask you favorite hobby shop; if he doesn't have the items in stock, he can order everything for you.
The US Engines 1.5ci (25 cc) gas engine was chosen to power this model. This is a smooth running engine and well suited to the model, and no special mount is required. A small muffler is installed on the engine. The propeller used is a Top Flite 16 x 8. The kit instructions state the engine requirements are: "1.20-1.60 4-stroke and the O.S. 1.08-1.8 2-stroke or 1.5-2.1 gas engine." During the fuselage construction, I also fitted the O.S. 1.20 4-stroke engine and the O.S. 1.08 2-stroke engine. I used the ABS cowl and wheel pants included in the kit for these two engines. For the US Engines 1.5 cu. in. gas engine, I ordered a fiberglass cowl and wheel pants from Fiberglass Specialties in Macomb, MI. The fiberglass cowl and wheel pants are first class quality and only a small amount of fitting to the engine was necessary. This way I didn't have to cut up one cowl to fit all three engines. At the time of writing this article, I have flown the model with the US Engines 1.5 only, but I will eventually use all three engines. I expect that if you have a field where noise is a problem, you will use the O.S. 1.20 4-stroke engine. A 16 oz. gas fuel tank is used on the US Engines 1.5 and the same size glow tank is used for the 1.20 and 1.08 engines. A 3" Great Planes Aluminum Spinner completes the engine installation.
I chose the Futaba Super 8UAP radio for this model, as I wanted an 8 channel computer radio. Only four channels are required, five if you install the parachute compartment. When you install your radio and servos in the model, you do not have to worry about getting the servo direction correct nor the amount of throw. You can select all of this as well as do a lot of mixing, such as rudder with ailerons, flaperons, set trims, and many other functions too numerous to discuss in this review. You can use the radio in many models without having to re-program when you fly each different model. The instructions call for five high-torque servos so I used the Futaba S9202 servos, two elevator, two aileron, and one rudder. The throttle servo is a Futaba S3101 Micro Servo. The plans show where all the radio gear should be located and ample room is provided.
Coverite 21st Century pre-painted covering was used to cover the entire model. This material is easy to install and shrink. Be sure to follow installation instructions and pay attention to the heat range called for. For installation, I use the 21st Century covering iron and cover sock. I also use the trim iron to get into tight places. All the starburst patterns are taken from the plans and cut out of the covering material of the proper color. To save time, place the material back to back and cut out two at once. Using the proper iron temperature, iron on the trim. For my model, I used a mirror trim. The top of the wing, stabilizer, fin, and rudder, I covered in orange and used white starburst. The bottom of the wing and tail were covered white with an orange starburst. As you can see by the photos, it came out very pretty. Striping on the fuselage was Great Planes 1/4" Kwik Stripe, dark blue. The wing and tail starburst trim is 1/8" dark blue.
After covering, I installed the Dynaflite Super Decathlon interior kit and pilot. These are very lightweight and add a touch of realism to the model.
Flying by, wheel pants removed for test flight.
The second flight had the wheel pants installed. Photo by Clayton Eads.
Before flying the Super Decathlon, be sure to balance the model as well as the propeller. During construction (not in the instructions), I glued a 3/4" x 1" dowel into the center of the fuselage at the C.G. mark. This was cut off to fit against the bottom sheeting. A pilot hole is drilled into the dowel to screw a small eye bolt into to suspend the model on a string from a hanger on my shop ceiling. This is a great way to balance a model, as it checks the lateral as well as longitudinal axis. Set your radio with the high and low rates for the control throws. There were no surprises on the first flight. After take-off, about four clicks of right aileron, a couple of clicks of right rudder, and about four clicks of down trim were needed. After feeling the model out, I made some passes for photos. The low slow passes were very impressive and it really looks great in the air. The landing was easy, as the model just settled in tail low. On the second flight, the take-off tracked straight and the model lifted off smoothly. I did some loops and rolls and was very pleased in the way the model handles and responds. I want to thank my friend Clayton Eads for taking the flying photos. I know you will be as pleased as I was in building and flying this fine model. You'll be proud to show this model at your field.
Photos by Charlie Viosca. Reprinted with permission.
August, 2000 R/C Modeler Magazine
Editor: Dick Kidd
Dynaflite Home Page |
Product Reviews |