I could be wrong, but methinks that Horizon is asleep regarding that manual. For whatever reason(s) it would appear it needs to be updated. In MinnFlyer's review (link posted above) you'll find this note as well as a couple of mentions regarding this problem:

Tech Notes from Seagull: The center of gravity noted in the manual is too far aft. The CG should be 2.75 - 3.5" (70 - 90mm) behind the leading edge of the wing.

These same dimensions are used in the manual supplied with my kit (70-90mm).

Interesting, as I didn't know what the original CG spec. was, will keep that in mind as I sort through this! Thanks, -Al

Al. when @ 3/4 power and you cut to throttle what is the plane doing ?</p>

It's a pretty draggy plane with the struts and flying wires on the tail so it slows pretty quickly, eventually heading for terra firma? There's no pitch up prior, and it doesn't just stop like a 3D plane might do. I guess there's nothing too unusual, not that I remember anyway. I haven't flown it for the 6 weeks as I was out of town.

Why?

-Al

Al, I was just wondering if something else was going with it.

Then thanks for asking! Should have some tests in later this week. Going to work the stuff that might affect the CG first, will post results as I get them. -Al

Testing a smoke pump
http://www.youtube.com/watch?v=FvPWr...ature=youtu.be

After flying this plane extensively (2 gallons+) I've decided not to pursue proper aerobatic handling further. Great looking fun plane, but it's not the simple flying "go to" plane I was looking for. My next step was going to be removing the dihedral, but I've decided to move on rather than go there...

Some stuff I learned that I'll pass along -

I found the recommended max rear CG still too conservative. I ended up about 1/2" in back of that. Rudder servo was moved to the rear, and about 3" of that lead strip was added to that. This was to suit MY flying style!!

The plane flies very differently with and without struts. Seemed more playful without for whatever reason (weight? drag?). I would suggest you fly it both ways to see which you like better. Structurally, I put it through some pretty extensive abuse without them with no sign of failure (while keeping a close eye on the wing tube for signs of failure!!) - but your mileage may vary!

Beefing up the landing gear (after tearing them out) required cutting out the flat area between the gear and firewall to get access. Very simple to do/undo. Doing that prior to ripping the gear out advised.... would have been much easier than the repair after the fact.

-Al

I cannot say that's simple; however, I have to do that – not because of the landing gear failure and crash, but f...ing Seagull tank stopper came out.
I noticed that there is no any fuel proof inside the tank compartment. Actually I did some Lastrikote spray, but couldn’t reach all the structures. Vietnamese plywood is the best to absorb oil from the fuel. It almost totally destroyed the bottom section of the fuselage. Tried everything – kitty litter, corn starch, K2r, heat and absorb -no way. It was seating there like for good. The frame needed some balsa and plywood to be changed.

I'm late to this thread but find it quite interesting and informative as I just aquired the 75-91 size I purchased at a swap meet. It came with a Saito FA 115, Futaba 3010 servos X 4 (2 for elevator and 2 for ailerons), a Hitec 605 BB for the rudder and a JR 537 for throttle. It has been completely recovered and appears to be well looked after. Are any of this threads previous contributers still flying their Decathlons? Hopefully they all haven't bit the dust ( planes, not pilots).

My was flying last summer and she is ready for 2014. If any questions ask

Thanks for the reply eclipse. Glad to hear your Decathlon is still flying. Are you pleased with the performance? I still have not had a chance to get the one I have in the air, colder than usual here and still have snow on the ground from a week ago. Nothing compared to what I'm sure you have in Toronto. I lived in Toronto for 2 years in the early 70's before I moved to B.C. Do you find the recommended control throws listed in the manual adequate for the style of aerobatics this plane should be capable of performing?

Hi Mustang,

My control throws as recommended, but CG moved a bit forward. It’s 25% now.
The plane is kinda difficult to fly; actually not to fly, but to land. It likes the speed. It stalls very fast if speed is not enough. However, if the speed is high, it starts bouncing on the ground. This summer I will try aileron washouts – bough ailerons 4-5 degrees up in neutral. I read it helps to decrees the critical speed, but I’m still skeptical.
My recommendations: control the speed and do not use asphalt strips for flying (bouncing).

Your plane is a bit smaller and behavior may be different.

It has been my experience that some of the aerobatic designs have a tendency to stall unexpectedly. Like warbirds, they need to be flown to the ground with just a tad of throttle maintained. As for asphalt runways, I avoid them whenever possible. I find them noisy and hot and they are tiring to stand on. I'm sure looking forward to getting a test flight in on the Decathlon I have. It has always been my practice to take a new plane up about 3-4 mistakes high and slowly reduce throttle while equally slowly applying up elevator to bring on a stall and that gives me an indication of what to expect when attempting to land. Some R/C pilots have the impression that the Decathlon, being a high wing design fly like the high wing trainers they see and I think this is where some folks go wrong, they are a more aerobatic style and need to be flown accordingly. About 15 years ago I had a scratch built, scale P-51 that I spent a number of years building and that plane caused many mixed emotions. It was a genuine pleasure to fly as it flew like it was on rails but takeoffs and landing really made my butt pucker. I ended up selling it to a fellow who was warbird crazy and wouldn't even consider owning any other type. He managed 3 flights on it before taking the pieces home in a garbage bag. Anyway, weather is supposed to warm up next week so maybe I'll get a chance to see what I have with the Decathlon. I'll post my impressions when that happens.

My D120 bit the dust...... had CRRC26 gas engine on it, mid flight the nose broke off... windshield forward just dangling there on the engine/servo connection. She got real tail heavy nosed up and came down hard in a field. contacted Horizon after finding almost No glue up front except the superglue I put on ...they went " O well your problem ". Plane done, engine head damage... live goes on.
Anyway reglue all joint as far you can reach

Wow CAT, sorry to hear that. How long did you have it? I hate to hear things like that. As I said in my original post, I looked the one I have over pretty thoroughly and it appears to be well built but you never know about the areas you cant see. I know from experiences of others that I have known who owned some brands of Chinese and Vietnamese ARF's that they can be pretty chincy with the adhesives and like to use hot glue instead of epoxy or CA. So did you bother with trying to repair it?

I took it apart, the wings got minor damage, tail cut off .is good all I really need is a fuse..... but I told my self I'm not going to buy from Horizon again....well lets see how long that will last....lol
I got 3 more RC projects and motorcycle .... wife and kids so time rare around here not to forget 50hr plus job so I can pay the bills. Also in progress changing radio manufactures

Is a fuse still available, either from Seagull or Horizon? Is this plane still in production and parts still available? I'm looking to change radios as well. Believe it or not, I'm still using a JR, PCM-10 that I purchased 21 years ago and the touch screen is getting a bit hard to read after so much use. I know people wonder why I'm still using what is I'm sure considered an antique transmitter but the truth is it has always done the job and has been a very dependable Tx. I guess I'm kinda old fashioned because I'm not looking to replace it with the newer types I see, I'm looking for a later version of the PCM-10, a 10S, 10SX, 10X or 10SXII. I have an XP-8103 as a backup but I prefer the feel of the heavier PCM-10 series but they're getting hard to find. Anyway, I hope you are able to find a fuse for the Decathlon and get it back in the air if that's what you decide to do but by all means, don't neglect the wife and kids and keep working to pay those bills.

My words are offered purely with a desire to be helpful. Almost every ARF I've owned needed additional support effort to both the firewall and gear support. After doing repairs on early ARF failures at these points, I now beef them as part of the commissioning. Much easier to do it that way, than rebuilding ripped out parts.

You're right AA5BY. I have had the same experience with the few ARF's that I have owned. The Decathlon I have that I bought at the swap meet has had the landing gear repaired as a result of a less than perfect landing. The fellow I bought it from was right up front about the fact that he had repaired it and what had happened to cause the repairs. He made more than a few improvements while he was doing the repairs and even went to the point of removing all the covering in order to inspect and re-glue all that he could and at the same time made improvements to the control rods etc. The plane has been completely recovered with Monokote ( I would have used Ultracote but that's no big deal) and hopefully things are as they should be now. I'll find out as soon as the weather warms up.

I've got the 120 size with a Valley View 20 gasser. Using a single 2500 LiFe pack and RcExl BEC igntion kill for a single battery setup. AUW 10# with no fuel. I find the plane to be a very enjoyable flier; I get very good, but not unlimited, vertical with a Xoar 17x6. The plane will do very nice upright flat spins, along with all the normal "scale" type maneuvers. Mine actually takes of and lands very nicely at pretty slow speeds. It will stall and drop a wing, much like the smaller .46size Phoenix Decathlon I had before, but this one is a little more forgiving than that plane.

I too ripped out the landing gear block on a not-very-ruff bouncer landing; it came out so clean, it didn't even rip the covering. Very little glue or support there. I didn't want to remove covering, so I put a layer of glass cloth all throughout the U-channel of the gear area--been holding so far!

ARF will be ARF cheap made for the masses....
Just sad that Horizon does not back there stuff.... at least for me...
When it was flying it looked good and was a good flyer.

I finally got a couple of opportunities to get the Decathlon in the air. I managed to log 4 flights over a couple of days. Everything worked well but this is not a plane that I would care to have long term, too many odd characteristics. It fly's "heavy" and although having lots of power and does nice, smooth aerobatics, it just feels funny to me. As stated before, it's not a plane I cared to keep so I have already sold it. At least I managed to get back the money I had invested in it and anytime you can do that with a model, you've done OK.

Ready to maiden my 91 size soon. I've been flying a great planes cub for the past few years so fancied something a bit quicker :-)

Suggest you wait for a nice breeze coming right down the runway for your maiden/early flights. Decathlon is much quicker than a Cub, demands you be right on top of it for take off. These things can make experienced fliers cry. A little wind can be a big help... and some patience. For Pete's sake, don't horse it up off the ground. You may get away with that a few times, but you won't for long. Needs to be flown off the ground. Nice and easy.

Yup, I've read they can be a handful. I'm good on the rudder when doing scale like take-offs with the cub ��