do335a

Step 10 on page 10 of the manual mentions what they call a wing jig to establish the wash out. That is the 1/4" x 3/8" x 42 inch strip that you have.

The location is shown on the plans. It does not run parallel to the trailing edge. That's how it creates the washout. It may not be easy to see on the plans, but the location of the strip is shown. It's drawn as dotted lines, not solid. If you look at the right wing panel drawing, you will see the reference to it, along with an arrow, pointing to it, just to the rib bay on the right of the sketch which shows the spar doublers.

It's also shown on the left wing panel drawing.

stevo revo

Look for a dashed diagonal line on the plan. Its there. Its toward trailing edge. If you still cant find it I will look at the plans and see if I can help more.

Rsad........... Im really thinking bout a 75cc waco.......

beepee

zippi,

Looking at the plan view of the wing, there is a slightly curved line (between the spars and the ailerons) showing where the 1/4 sq balsa gets pinned down. That forces in the twist to the wing, creating the washout.

Very straightforward. If that doesn't help come back and we will go at it again.

Bedford

rmadsen

Finally - my maiden flight. Perfect day with just a slight breeze. Same for the nerves. Hopefully the video link here will work.

[link=http://rcuvideos.com/video/Super-Decathalon-Saito-180-Maid]rcuvideos.com/video/Super-Decathalon-Saito-180-Maid[/link]

In case you can't see the video, takeoff and landing were a little sloppy, but I kept it one piece and can fly another day. Never flew a plane of this size before. Love the Saito singing up there. I think it's still running pretty rich with all the smoke.

Thanks to everyone posting to this thread. It made the build more enjoyable, a little easier, and I made some new cyber-friends.

zippidydoodah

Thanks for the replies guys.
Yeah I found the answer 2 minutes after I posted. I couldn't understand how 1 piece not tapered could do it... then I spotted it on the plans.
I sent out a new post explaining that, butI don't know where it went.
Anyway, I started the wing this morning and finished it tonight.. So I start on the left wing tomorrow.
I think it's a pretty hefty airplane, then I look over at my ST 3250 andthink,"yeh, lemme have some of that good old American heftyness."
I'm planning on putting the servos up front for balancing.No problemo making that adjustment.

I took aerobatics instruction in a Decathlon about 15 years ago, very differentfrom a Citabria. People have been asking about flaps, no need for them, it has asemi symetrical airfoil. Drop the power, raise the nose, down you come.

zippidydoodah

Congrats Ron, Smart maiden flight...conservative.
Grass looks like it could stand a trim.
Nice model, too.

zippidydoodah

Two wings done and now the aileroms, then the longeroms.

Hey I got a question, which plans cover do you use. Any type that cryo won't stick to?

skystar

hello,

what do you think of the new zenoah zg 26cc with a zimmerman pipe for this decathlon? Id like to fly all aerobatics that the plane can handle...
greetzz

stevo revo

Then put a DA 50 on it.

do335a

That's nuts.

This airframe is not sufficiently sturdy for that, especailly with that cheap lite ply firewall. You will also have insufficient prop clearance and landing gear problems since it already has difficulty handling the design weight of the plane.

It's aerobatic ability is a result of aerodynamic design, not brute power. If it is not aerodynamically capable of a particular manoeuvre, increasing overall weight (larger engine) and engine power will not change that.

If you doubt that, try making a 3 channel Sig Kadet Senior do sustained knife edge flight. Then try a flat, inverted spin with that Kadet. Put on as large a larger engine as you like and see if you do any better.

stevo revo

This plane is built like a brick sh_thouse. It could definitley handle it. I agree with the firewall re-do....and DEFINTLEY the landing gear would not cut it, but other than that, it could handle it.

Look at what they put da 50's on..... SUPER light laser cut airframes.......the decath is wayyyyy more than that.

Would it be fun???? Thats up to the builder what he's looking for..... and btw, there was a bit of sarcasm in my first reply........

rsad

The G38 is 67 ounces with out muffler. The DA 50 is 51 ounces with standoffs and no muffler. I think if it fits, and you beef it up like you would for the G38, you could easily use the DA50.

But, (and I know I will get ridiculed), if you build it light with the right mods to the parts and you fly it scale...............you can get away with a good 1.20 2 stroke or even less. But I remember flying 40 size planes with fp35s............

I will go comb what's left of my gray hair now.

skystar

i put a DL50 now on my 2m20 raven. not yet flown.
someone said the zenoah 26 is more then enough with a tuned pipe but i don't think so. a club member has an 3w 35cc he sells, but dont find anything of that engine if its a good one ore not.
50cc is a bit to overkill I think. oke it will fly and its weight is no more then an other one.but I think the resonatie and sound are not good for airframe and the ears I think
in belgium we not fly with pitts mufflers for the noise( a lot of clubs had to close about the noise)
the 3w 35 he sels for 180euro without muffler.

Chevalier

I didn't think this thread still lived! I was one of the people posting in the very first pages of this thread. Here's a few pictures of the decathlon that I built a few years ago. I built it to test out giant scale, and decided it wasn't really my thing. She weighs 14lbs 2 oz. ( that's with 12 oz of lead in the nose ) and is powered by an OS 120. It flies really nice: snaps, spins, knife edges and I think the lighter wing loading helps it fly better. Though with only a 1.20 I do have to decide what to do before pulling the nose up. Haven't flown it in a couple of years, but haven't sold or swapped it yet either.

dumorian

My Feedback: (6)

Nice! Congrats on the maiden and that is a very nice looking Decathlon! I really enjoyed the video.

isaacslaw

My Feedback: (4)

Hi guys! How are your decathlons doing? I have been doing a very slow build on mine and have just finished the right wing and am starting on the left.

One question for you guys that have built them how did you reattach your arms? Mine has come out of its socket from all the sanding. Seriously, though some of the shaping and planing and sanding is a bit much for a kit plans building ok you expect it. This one really makes you appreciate the laser cut kits.

Once I finished the wing half, though, it started to feel a bit more done and I am now plowing into the second wing half. Good thing I have another arm left.

stevo revo

It's funny you asked how the decaths were doing............as there's not been much activity here lately.

Glad your build is going well. I am enjoying mine. You will be happy with it once you are finished. Just remember to keep it light!!!!! The landing gear will thank you. TRUST ME!!!!

Actually I'm going to contact a guy here in the US about building some carbon fiber gear for it. I have seen how strong his gear can be first hand. I figured this would be a great plane to have some alternative gear for, because the kit gear really dont do the job. I'll update when I know more. I'm sure if he builds gear for me he'd like to sell more of the same.

Also, here area a few pics of the Decath from flying last weekend. And a quick vid too!!

http://www.youtube.com/watch?v=Sr9rn4ange0

http://www.youtube.com/watch?v=WL8yxq7DNvI

flygilmore

Nice....I may have missed but what smoke system are you using and smoke oil?

dumorian

My Feedback: (6)

My Decathlon is a fun plane to fly. It is a flyer and does best with input to all controls. I haven't set up aileron diff, which could likely correct this tendency, but I don't want to as I want full aileron throws for rolls... When doing an aileron only turn, the plane has a tendency to want to knife edge... tail drops. The rudder is your friend. Knife edge is very easy however with very little rudder or aileron input. It's actually amazing to me for a high wing plane. As a side note, I do have my CoG toward the rear of the range.

After building... I have only one "wish I had done". I used a 36cc Brillelli engine on mine and did not do the double firewall thing. First I didn't want the weight and second it interfered with the bolt pattern of the Brillelli. I instead used the laminated three sheets of light ply for the firewall. I really think this would have been an issue for either firewall mount. Basically, the light ply is just not rigid enough for a gasser and it compresses too much. I have had recurring issues with the engine loosening up. At this point the engine standoffs are compressed into the firewall by likely 1/8". I can only guess as to how much the T-nuts have been compressed on the backside. So, at the moment, for the last few weeks my Decathlon has been grounded.

As replacement of the firewall would be a very nasty task at this point, I plan to instead use some aluminum plate to spread the compression. I bought a few pieces of aluminum strapping, 1/16" thick by various widths and plans to place a strip both behind and in front of the firewall. Getting the one behind at the top is something I am NOT looking forward to. My idea, if I don't have interference is to run a strip like 3/4" x 1/16" side to side across the top and bottom mounting holes on the inside. Then run strips up and down on the outside of the firewall. This should provide a wide spread on the compression of mounting the engine.

Also, with my gassers when possible... I first use locktight on the mounting bolts but have started adding nylock nuts from the inside. I don't think I'll be able to accomplish this with the top bolts on the Decathlon. I do live on the east coast of the US... We have high humidity in the summers and often times very low humidity in the winters. Wood moves a lot. So, we do get more expansion and contraction of wood than many areas of the world. Metal of course is temperature related... so, during the summer the wood expands and gets compressed a bit by the metal bolts. Then when things dry out a bit, the wood shrinks. The compressed areas normally stay at least somewhat compressed. So, your engine bolts aren't as tight as they were.

On another model I was having this issue. I replaced the aluminum standoffs with a H-shaped cherry wood standoff. I ran the grain front to back as there is little expansion with the grain, lots across the grain. This has increased the area where the mount touches the firewall. So far it has performed much better than the aluminum standoffs although it is just a bit more weight. I used cherry because it is fairly stable but also machines extremely well. It's not as apt to split and such.

Anyway... I'll be back to my Decathlon very soon... but I'm still dreading the upper inside strap. I wish I had done like others on this thread who tossed the light ply firewall and used aircraft grade ply instead. Live and learn.

Nothrottle

Hey everyone, it's been awhile since posting here. I've moved out of the ARF world with the arrival of my Dynaflight Super Decathlon! I built several kits before the world of ARF's and I will soon dive into the building of this outstanding airplane! It will be powered by a well broke-in Magnum 180 4S which resided in a Goldberg Wildstik until it's timely demise. I say timely because the Wildstik literally fell apart at the seams! Rolls would rip out the wing mounts if not for constant applications of epoxy. Discontinued, surprise!
I'll appreciate advise from all of you Decathlon guru's during the construction of this aero-master ! It is obvious the Magnum 180 will be light. I plan to build the aft section as light as possible with the option of moving the elevator and rudder servos forward as possible. I know it isn't scale, but the Decathlon will be covered with Ultra-Cote and roll on bush type 6" inflatable tires! I hate wheel pants and I truly enjoy using Ultra-Cote, black, white and gold trim. My Katana X 200 is nearly repaired and once off the bench, construction begins.

Slime on, no emf's !

dumorian

My Feedback: (6)

This is a fun build and a fun flier.

A couple of things that might help along the way.

I used a gasser that weighs around 3.25 pounds. I did pretty much a standard build with locations and structure. The exceptions would be the addition of a bomb bay in the aft section of the cockpit, a tug release and I added flaps. This added four additional servos just behind the CoG. I was surprised that I was in the end struggling a bit to get the CoG off of the most rearward recommendation. I really thought the gasser would take care of that. I did not use the secondary firewall mount. I don't know how much your engine weighs, but I think you are wise to work toward lightening the tail and I think you will more than likely be looking at moving the rudder and elevator servos forward into the cockpit. Or adding lead to the nose (horrors!!!).

Some of what I did that added weight in front of the CoG. Much heavier phenolic LG. Batteries and such are all in the front of the cockpit area. I did make a tray for my gas tank. I did add some 1/4" aircraft grade ply to support the LG. It is now extremely robust.

The model really is just a bit tankish. A really tough bird. It can take some abuse and not complain. From that side of things, much could be done to remove weight in many areas of the tail and it would still be plenty sturdy.

Have fun with your build. 'Most' of mine was a delight. I have not done many kits, so there were challenges along the way for me... just a few frustrations... but all in all I'm really happy with where I am with the Decathlon.

rsad

Decathlon fans, what are your thoughts?

I have a love hate relationship with this model. I love it because its a Decathlon. I love Decathons, Citabrias, Cubs, and Champs. At the same time I hate this Decath because it doesn't really look like a Decathlon to me. I am a fanatic about these light civilian airplanes.

I have built many of them and have helped others build them. It is not a fast build when you compare it to a more scale airplane (this is fun scale and not close to scale BTW). It is very heavy for its size and doesn't have to be. Over the years the wood has gotten heavier in this kit (and many others). I replace most of it. If you have ever built a Sig 1/4 scale clipped wing cub or any of Sig's cubs and have flown them, you understand and have experienced how a plane like the Citabria and Decathlon should fly. When you cut the power, it should glide and loose altitude because of the "dragginess", not because of the weight and a high wing loading. That irks me about this model.

The Dynaflite Decathlon doesn't represent a lightly load plane like it should. For the size, this model should be able to fly very nicely on a 2 stroke 90 to 120. If the structure was built more like a Sig Cub , Citabria, or Nosen model, you could come in under 12 pounds EASY. I modded the heck out of a couple. I have done it.

The lines are just so wrong on this model. There is (my opinion again) no reason why the scaleness of this model had to suffer. Making the changes to get it scale does not effect its flying characteristics. Did the designer even look at scale views and drawings of the real aircraft. The fuselage looks more like a "that looks about right", that's a Decahlon. Put a Starburst pattern on it, it will look like a Decathlon.

Windows wrong, tail feathers wrong, longerons (stringers) wrong, windshield angle wrong, struts wrong......etc etc. I am beginning to think most kit designers don't know what a jury strut is. How much more effort is it to add this to a design?

Why do manufacturers produce large kits of "real" subjects but not make them scale models. I hope others agree with me that for an airplane this size, a light civilian aircraft that it is, and the effort everyone seems to put in to it, it would be nice if it was more SCALE. It certainly isn't a 4 evening build...that's fun scale. Look at some real pictures and three views, you will know what I am talking about.

I agree it flies fine. Make it lighter, it will fly better than fine. I have built and flown the Nosen and Sig 1/4 scale light planes (champ, citabria, cubs) and flew them on small engines. They flew great and are bigger than this model. Well I had some time on my hands and just happened to decide to write something. This is one of my favorite scale subjects. Everyone has built a beautiful model here on this thread. What are your thoughts regarding my comments? Anyone agree or disagree about the scale thing?

stevo revo

If you paid any attention to my build (a bit of sarcasam) I tried to scale this thing as best as I could. I am pretty happy with the results. I get WOW's every time I bring it out to the field.

But I had to put ALOT of effort into the scale factor. I studied view after view of a full scale decathlon, and did the best I could working with the contents of the box. A real decathlon fanatic could tear it apart though. You are 100% right about this kit. This kit is less than high quality. The wood is marginal at best. The scale factor is way off. Fun scale, like the box says.

When I want "fun scale" I will buy an arf. For a build, it better be at bare minimum 90% scale. And I am not reffering to finite details..... just the outline..... man it better match the full scale version....... Or what's the point????

As for the cg....I put a OS 1.60, 15 aa batteries, and a sub c in the nose to get balance. And I put all my tail servo's in the cockpit. Mine came in at an unofficial 19 lbs. WITH A GLOW ENGINE!!!

I did add a few extra's to make the scale factor.... so the weight penalty is partially my fault. But it sure does impress with a "smoke on" hammerhead....

I dont want to discourage anyone from building this kit. It is a fun build. But if scale is what you are looking for, then be prepared for some high effort. I have a SOLID four months into mine.

Nothrottle

Thx for the responses, I can see the future of this thread being an invaluable source of info in the near future. The Magnum 180 weighs 2lb. 3.4oz. w/ hub & muffler. Looking into the unknown future, I may be able to mount the engine on the foremost end of the mount. Plus add extensions on the firewall to push the engine mount to max forward.
A scale enthusiast probably will cringe when viewing my finished Decathlon. Sport/Scale/aerobatic would be an accurate description of this model when complete. My intentions are a build as light and as aerobatic as possible with the airframe while staying with in the limits of durability. I prefer aerobatics and pushing the models to their or my limits. The decathlon looks awesome in an inverted high speed pass 3 feet above the runway! The scale star bursts and a Ultra Cote skin are certain. The cockpit may end up crammed with servos, batteries and no lead!

Slime on, no emf's !

dumorian

My Feedback: (6)

Thought I'd take a quick trip to the Dynaflight website just to see what they actually advertise. They don't ever really say this is a 'scale' model... but do refer to scale enough to sort of lead you on. There is mention of several scale looking items. They also say IMAA legal and giant scale. For me, I really wasn't looking for a true scale model, but instead was more after function.

Another thing on their list about this model... "An easy access servo compartment has been thoughtfully placed near the tail for optimizing balance if heavy engines are used." So, apparently this rear compartment is only to be used 'if' a heavy engine is used.

I really don't care much for tubes and cables for control rods on larger aerobatic models. I suppose one could accomplish this with careful installation. Pull/pull for the rudder is really easy to do and is a neat installation. I built CF control rods for the elevators. The down side is they came out well in front of the elevators and show obviously. If I had not used the tray, I could have positioned the elevator servos closer together, allowing the exits to be more rearward. Also, if a person could work out crossing the elevator control rods, or perhaps a bell crank type system, the exit holes could be very near the tail. Just my after thoughts. I would do the pull/pull again for certain. I would have spent more time earlier in the build deciding on the elevator control system. And, I would have moved the tray forward by one bulkhead with my gasser... likely into the cockpit with a glow.

I had several reasons for building the Decathlon. It was to be a 'service' plane. Bomb drop, glider tug, something that looked decent and something fun to fly. The make or break part of this decision process was glider tug. For this reason, having a tough model is a good thing. Also, some extra weight isn't such a bad idea. It makes it a bit harder for the glider to affect the Decathlon as much. Also, when things do go wrong, the extra strength can make a bad landing just that, instead of a bad landing putting it in the shop for repairs.