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Decathlon EP
I've been in the market for a high wing aerobatic speed 280 to 300 plane that I can throw in the back of the truck and fly at school hopefully in one of the soccer fields. I wanted an almost ready to fly plane that wouldn't take a lot of time to build and looked good in the air. The Wattage Decathlon fits those requirements quite nicely.
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Introduction:
I've been in the market for a high wing aerobatic speed 280 to 300 plane that I can throw in the back of the truck and fly at school hopefully in one of the soccer fields. I wanted an almost ready to fly plane that wouldn't take a lot of time to build and looked good in the air. The Wattage Decathlon fits those requirements quite nicely. It is fairly small, flies in an area a bit larger than a soccer field and looks great. The full scale Decathlon was designed as a fully aerobatics version of the highly successful Citabria planes. After World War 2 many people were looking for easy to fly reasonably priced planes and remembered the Champ that they had learned to fly in when they had entered the service. The Champ is another member of the Bellanca plane family and a cousin of the Decathlon. Here's a link to the club site for full scale Decathlons and other Bellanca planes: http://www.bellanca-championclub.com/
The box was in a well packed outer carton. Note the protected plastic covered parts. The plane is highly finished and almost ready to fly, it is pre-covered, the pushrod guides are already installed and WattAge has even installed the servo mounts for you. The balsa wood is of good quality, the covering was done well, and the plane's accessories were well packed. My overall first impression of the Decathlon was that this is one nice little plane.
View of the contents taken fresh out of the box. Everything needed to complete the kit.
Assembly
Wing
Since the plane is pre-covered building the wing is a snap, glue in the EZ-Hinges to connect the ailerons and put some washout into the wing. The washout really needs a bit of extra help to do but it is possible for you to do it alone. The wing only needs 1/8 of an inch and I did this by laying the wing flat, shimming the back of the wingtip up 1/8", applying pressure at the center of the wing, and then applying heat to get the wrinkles out. It really would have helped a lot if I had an extra pair of hands hold the wing down while I added the washout. The ailerons take only one servo that goes into a pre-built tray. Wattage has an unusual servo arm requirement where they have you cut the servo arms into a "V" instead of the standard "I". They call it a "Differential Servo Arm" and it allows the ailerons to move up more than move down. I really didn't see the need for this but figured "Why not? They must have a good reason to do this" and I wanted to build the plane exactly as the directions called for. Once the servo is installed and the pushrods hooked up, set the wing aside.
Prebuilt wing and servo box, Ailerons pre-installed. Aileron servo with V style control horn.
Stabilizer and Fin
The vertical fin is already attached to the kit, all you have to do is cut a slot for the elevator and cut back the elevator covering to glue it in. Wattage even has the slots cut out for the hinges and control horns. I used the provided hinges and leached thin CA between the stabilizer and elevator to secure the hinge. There is a tail wheel that installs into the rudder. I used a little bit of five-minute epoxy to secure it for a bit of added support. After the elevator was attached, I affixed the rudder to the vertical fin.
Stabilizer and elevator parts. Side shot showing tail wheel. Fuselage
As with the rest of the Decathlon, very little work was needed to assemble the fuselage. I used a small power tool to cut two slots in the firewall then a drill to open the slots up to the cooling air. The cowling needs to be screwed in and a battery support glued to the bottom of the fuselage. The directions are not clear where to mount this and my first attempt was too far aft. I ended up having to take the mount back out and try it again to obtain a proper Center of Gravity. There is a hook and loop strap included with the kit to hold the battery down while flying. I also put in some extra hook and loop material for the receiver and as a little extra insurance for holding the battery in during those harder than normal landings.
Battery area as seen from the bottom of the plane. Cabin area and windshield attached. 
A bit of black marker frames out the cockpit. Prop, spinner, and landing gear attached. Finishing Touches
Wattage provides aluminum landing gear with the Decathlon which is held to the fuselage with two screws. The servos drop into pre-built trays, pushrod tubes are also already installed in the plane. You do have to bend the provided metal pushrods to shape then install. In this case I used the micro pushrod holders from Dupro so I could have fast adjustment for the servos instead of "V" bends in the wire. Mounting the motor was also easy, just drill three holes in the firewall for the gearbox and screw it in. I marked the Center of Gravity on the underside of the wings 1 ¾" behind the leading edge. The plane balanced at this point but I had to redo the battery hold down inside the fuselage to get it right.The last major step in the assembly process is affixing decals to the Decathlon. They are sticky back decals, all on one sheet. You cut them out to put them on the plane
Decal placement on the wing Another decal down the side. 
Don't forget to cut a slot in the rudder decal. All the decals installed as seen from above. 
Wattage Decathlon ready to fly. Side shot of the Decathlon ready to go.
Flying
When I put the plane together, I took the easy way out and didn't use a servo extension for the aileron servo. That spur of the moment decision cost me during the first flight. I decided to hand launch the plane because of the location I was flying in, it was in the middle of a field with waist high grass that would help the plane survive a crash. I powered the plane up and gave it a toss, my first impression was that it is one fast little plane! Even with the stock geared 370 motor it was eating up a lot of airspace faster than I had anticipated. Since I was heading towards a tree line, I decided to turn it back in my direction. About halfway through the turn, I lost aileron control with the ailerons stuck in a right turn position. I then turned the Decathlon right into the ground from about 30 feet altitude. At least I turned off the motor on the way into the ground but the high grass didn't help too much. The Decathlon hit the ground very hard and fast, nose first; I damaged the spinner, broke the prop, and destroyed the cowling. The motor and gearbox survived the crash but the balsa firewall was snapped off, luckily the plane had no other damage. After I stopped crying and slapping myself for knowing better than taking a shortcut, I wrote an e-mail of shame to Mike Greenshields at Hobby People and ordered a new cowling, prop and spinner. In the meantime, a bit of CA glue here, a little bit there, installing a 6 inch servo wire extension, and the plane was ready to go when the parts came in the mail. Mike or someone in the parts department must have remembered prior orders that I've made and included a twin pack of props instead of one, just in case.
Slow fly-by of the Decathlon. Even on a cloudy day the plane is easy to see. Flight number two started just like the first. At full throttle the plane moves at a fast pace and eats up space fast. This time when I made the turn to avoid the tree line the plane stayed in control. As I came around for a fly-by another small detail slipped my mind. The field I was flying in is about 400 acres with one (yes, one) oak tree in the middle of it. It's an big old oak tree and I flew the plane right into it. (My excuse is that I wear trifocals and they affect my depth perception.) Luckily the plane literally bounced out from about twenty feet up and hit the ground on its wheels. I took the walk of shame thinking to myself things that we cannot write about on R/C Groups, picked the plane up and checked it out. No damage at all, not even ripped covering, I was one lucky guy and in shock but managed to toss the plane again. This time, the rest of the flight went without any more incidents.
The Decathlon has gone to school and work with me several times and has proven itself to be a nice flyer during lunch or after classes. It will loop well doing tight or medium sized loops. The roll rate on this one is slower than I thought it would be and the servo throws are set to the recommended specifications so it may be the high wing coming into play. I also like the 8 cell 5/4 AAA NIMH pack in this plane, it is providing plenty of power and four to five minutes of duration during flights.
Coming out of a loop. Overhead and looking good! 
Getting ready for a fly-by A man and his plane, life is good! 
Landing on a running track at the University of Tennessee in Martin..
Conclusion
I really like the ease of build of the Decathlon and the quality of materials of the kit. The plane exceeds my performance expectations and is a lot faster than I thought it would be. The only problem that I have with the plane is that I wanted a plane to fly in the area of a soccer field. You can do it but it is a bit of a challenge. It flies great in a traditional R/C field where you have room to correct mistakes.
I'm also not sold on the recommended "V" aileron servo connections (Differential Servo Arm) because my roll rates are not as fast as I would like them to be. I found out the hard way that Wattage has specific reasons for the wing to be built with 1/8" washout. I messed with the wing just to see what happened and found that it got unstable and developed a nasty, very quick tip stall, when you take the washout out. Wattage went out of their way in the directions to stress proper wing assembly so I wanted to see why. Now I know!
The wing is flat bottomed so you can only do basic aerobatics with the plane. One of my favorite tricks to do is to take the plane straight up into a stalling flat spin, point the nose down a bit, apply some rudder, then power out of the spin before the plane hits the ground.
Even though the build was fast and easy, this plane is not for beginners. It would make a great number three plane or number two for someone used to using four channels. The Decathlon is also very quick with the recommended 370 geared motor system so brushless would make it go ballistic. Built stock and using the recommended battery it is a joy to fly and gives this old boy plenty of excitement.
Discussion
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Jun 04, 2003, 05:11 AM
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Outside of Dyer, Tn. USA
Joined May 2000
7,135 Posts
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Since writing the article I've picked up a computer radio and having more control on the aeliron throws has made a huge difference in the roll rate. Now it's much better and I've kept the Differentual servo arm as it is. Even though the stock motor flies it quite well, I'm saving my pennies for a brushless setup and would appreciate any suggustions you might have for power systems.
Don |
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Jun 04, 2003, 05:31 AM
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USA, NC, Clayton
Joined Feb 2001
5,162 Posts
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Don,
Seems to me the perfect place for an astro 010 or Razor. Lighter setup and more power to boot!! Sure Tres or someone will suggest props and ratios...I would go look at pcalc, but I am sposed to be working!! Later, David |
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Jun 05, 2003, 12:44 PM
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Outside of Dyer, Tn. USA
Joined May 2000
7,135 Posts
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Thanks David,
DD or geared with the Razor? I don't have any brushless motors yet and have seen them fly in the past month. They are impressive!! Looks like I'll need to brush up on that techonolgy more, seeing the planes fly is a whole lot different than reading about how planes fly. I still find it hard to believe the performance difference and am glad to see the prices dropping to affordable levels. Don |
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Jun 08, 2003, 08:51 PM
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Chilliwack BC Canada
Joined Apr 2003
59 Posts
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Mine did'nt like to turn at low speeds with the recommened aileron control throw and crashed.
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Jun 09, 2003, 08:49 AM
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Outside of Dyer, Tn. USA
Joined May 2000
7,135 Posts
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Quote:
Thanks! Don |
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Jun 09, 2003, 04:48 PM
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San Diego,Ca, USA
Joined Aug 2000
2,756 Posts
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Quote:
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Jun 09, 2003, 06:30 PM
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Outside of Dyer, Tn. USA
Joined May 2000
7,135 Posts
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Quote:
 Glad you caught the little speck of R/C attempted humor.
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Jun 13, 2003, 06:45 PM
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Torrance, CA
Joined May 2003
1,678 Posts
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I also noticed the lack of control during power off and at lower speeds. I'm not using the differential servo arm for the ailerons, since I'm using the Cirrus 6.2 and I can't find a horn large enough. The plane does seem to glide forever when trying to land. I've managed to break off the landing gear 3 times during landing before giving up and leaving it off all together. I do much better with the belly landings.
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Jun 14, 2003, 09:17 PM
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Outside of Dyer, Tn. USA
Joined May 2000
7,135 Posts
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Thanks for your comments JDMstuff. I used some Goop to glue the gear back on the first time that they poped off. They haven't come off again. The Goop has a bit of give and seems to have done the trick.
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Jun 15, 2003, 12:08 AM
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Torrance, CA
Joined May 2003
1,678 Posts
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I fly in a grassy area, so it isn't completely smooth. The gear would catch and tear off the plywood plate that it was screwed into. At the same time, taking out the battery door cover. Larger wheels would have helped, but would take away from the scale look.
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Jun 16, 2003, 11:21 AM
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Chilliwack BC Canada
Joined Apr 2003
59 Posts
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mine did not turn at all during landing and crashed. I'm going to use more throw on the ailreons than what they recommend.Yes it has very poor turning at low speeds.
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Jun 16, 2003, 12:10 PM
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Huntington Beach, CA
Joined Apr 2001
1,281 Posts
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i think that the key is to build it as light as possible. my brushless Decathalon (geared RZ-300 w/3 etec1200's) AUW is 369 grams (13 oz). with this power system, it will go straight up in a hurry. i haven't had a problem with the landing gear at all ( i use a little larger wheels)& my ailerons work fine (even at fairly slow speeds), but the rolls are NOT axial at all.
IMO, i think that the ailerons could have been a little larger which would require less throw and would be more effective. btw, i have no washout in the wing and it flies very predictably. |
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Last edited by jk; Jun 16, 2003 at 12:42 PM.
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Jun 17, 2003, 12:13 AM
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Chilliwack BC Canada
Joined Apr 2003
59 Posts
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I used 3 55 servos futaba am receiver castle creations pixie 14 speed contro,motor and gearbox from my crazy max 3D 7 cell 600mah nicad battery packs. Two flights and two crashes on landing,ailerons not responding.I'm using the recommened aileron differential aileron servo control arm. Damage report landing gear broken off twice cowling cracked. Model looks very nice but is very fast.
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Jun 21, 2003, 04:46 PM
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Outside of Dyer, Tn. USA
Joined May 2000
7,135 Posts
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Paris,
Try a regular servo arm and let us know how it does. You've got plenty of room in the fuse for one. Don |
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